Pressure & Flame Protection
Safety Relief Valves
S a f e t y R e l i e f Va l v e s
‘ W B ’ S E R I E S S P R I N G L OA D E D
S A F E T Y R E L I E F VA LV E S
The WB is designed to safely relieve excess pressure in
pumps, pipework, tanks, calorifiers, gas and oil
separators and other process vessels. It is suitable for
gas, steam, vapour and liquid applications. The WB
conforms to API 526 pressure/temperature ranges,
orifice areas and dimensions.
‘SAFEFLO’ SAFETY AND
T H E R M A L R E L I E F VA LV E S
Safeflo valves are designed for similar duties to the WB
but for small capacity applications.They safely relieve
thermal expansion of process fluids in vessels and long
lengths of pipework, and are suitable for gas and liquid
applications.
‘ S A F E S E T ’ P I L O T O P E R AT E D
S A F E T Y R E L I E F VA LV E S
Safeset valves are self contained pilot operated safety
relief valves which use the system pressure to control
the valve opening and closing. No other source of
energy is required.
A choice of different types of Safeset pilot valves are
available, including pop and modulating action to suit a
variety of applications.
Safeset valves conform to API 526 pilot operated
pressure/temperature ranges and dimensions, with
multiple orifice areas contained within each valve
body size.
1
CONTENTS
Page
Birkett Range
Page
Sizing
3
4
Introduction
International approvals and authorisations
5
6
7 - 10
11 - 14
15 - 16
17
18
19 - 46
47 - 48
49 - 50
WB Series
Features and benefits
Valve types and action
Drawings
Accessories
Figure numbering system
Material temperature ranges
Valve selection charts, D to T
Valve adjustment
Seat tightness/seat leakage testing
81 - 82
83
84
85 - 90
91 - 96
97
Sizing formula
Nomenclature
Back pressure/blowdown limits and
orifice areas
Sizing factors
Capacity charts
Reaction forces
98
98
99
100
Definitions
Definitions of terms
Operational characteristics
Pressure term relationships
51
52
53 - 54
55
56
57 - 58
Safeflo
Features and benefits
Drawings
Accessories
Figure numbering system
Dimensions
59
60
61
62
63
65
69
69
71
76
77
79
Safeset
Features and benefits
Dual Outlet/Full Bore Pilot Valve
Pilot types and basic operation
Type 2 - Pop Action Pilot
Type 4 and 8 - Modulating Action Pilot
Technical specification
Drawings and materials of construction
Accessories
Figure numbering system
Dimensions
Operating pressure/temperature limits
- 64
- 68
- 70
- 75
- 78
- 80
2
S a f e t y R e l i e f Va l v e s
INTRODUCTION
The effects of exceeding safe pressure levels in an
unprotected pressure vessel or system can have
catastrophic effects on both plant and personnel.
Safety relief valves should be used to protect any
pressurised system from the effects of exceeding its
design pressure limit.
A safety relief valve is designed to automatically
discharge gas, steam, vapour or liquid from any
pressure containing system, preventing a
predetermined safe pressure being exceeded, and
protecting plant and personnel.
The Birkett range of safety relief valves
contains three distinct valve types:
WB Series – spring loaded safety relief valves.
Safeflo – safety and thermal relief valves.
Safeset – pilot operated safety relief valves.
All types are certified in accordance
with ASME Code Section VIII.
All Birkett valves are available through our global
agent distribution network supported by our own
regional sales offices around the world.
3
I N T E R N AT I O N A L A P P R O VA L S A N D A U T H O R I S AT I O N S
Our approvals and accreditations
include ISO 9001:2008, ASME,
Chinese Safety Quality Licence,
TUV, Bureau Veritas,
Stoomwezen, PED, ATEX and
GOST-R.
APPLICABLE STANDARDS
ISO 9001:2008
Quality Standard
ASME Code Section VIII
All valves are UV certified
API 520 : Part 1
Sizing and selection
API 526
Dimensions
API 527
Leakage Rates
ANSI B16.5
Flange Ratings
4
WB Series Spring loaded safety relief valve
1 Insitu testing
2 Accessories
3 High performance springs
4 Bellows back up piston
(not shown)
5 Guiding
6 Bellows
(not shown)
7 Trim
8 Seat integrity
9 Adjustable blow down
10 Nozzle design
11 API 526 face to face
dimensions
5
F E AT U R E S A N D B E N E F I T S
Design verification – all design options and the
various effects of system conditions, back pressure
etc. have been verified on Birkett’s
in-house, extensive mass flow test facility.
Lighter and more compact construction –
continuous design improvements have created
smaller and lighter valves to support current
industry design trends, especially space and weight
savings.
Interchangeable parts – valves can be modified
from type to type, gas, liquid, conventional and
bellows simply by changing only a few parts.
Simplified maintenance and service re-engineering has reduced the number of parts,
making maintenance easier and more cost
effective.
Material selection – a wide range of materials
are offered including non-ferrous for low
temperature and oxygen service, as well as exotic
alloys specifically for the chemical and process
industries.
Cryogenic and oxygen service – Birkett’s
state-of-the-art clean room and vapour degreasing
facilities ensure compliance with the stringent
demands of cryogenic and oxygen applications.
1
In-situ testing – valves can be supplied
suitable for application of “in-situ” set
pressure verification devices.
2
Wide range of accessories – available to
comply with international codes and to suit
system requirements.
3
High performance springs – safety relief
valve springs are specifically designed to
guarantee set point repeatability.
4
Bellows back-up piston – an optional
auxiliary back-up piston for balanced bellows
valves ensures fail-safe operation in the event
of bellows failure (see page 16).
5
Guiding surfaces – the material selection of
guiding components, together with a selfaligning disc and spindle pivot point, ensures
correct alignment and no galling of guiding
surfaces.
6
Bellows – ensures correct valve
performance under difficult back pressure
conditions (see page 12).
7
Trim – specific gas and liquid trim designs
give stable operation and eliminate the
damaging effect of chatter.
8
Seat leakage integrity – choice of nozzle
and disc materials (coupled with superior
lapping techniques) provides seat tightness to
API 527/ASME VIII.
9
Adjustable blow down – the valve
reseating pressure (blow down) can be simply
adjusted to suit special or specific
performance requirements.
10 Nozzle design – the method and location of
attachment to the body avoids transmission
of pipe stresses to the nozzle/disc mating
surfaces.
11 API 526 dimensions – standardised
dimensions allows pipework layouts to be
detailed confidently.
6
DIFFERENT TYPES
There are four basic types of WB Series safety
relief valve:
WB400 – conventional gas type.
WB300 – bellows gas type.
WB200 – conventional liquid type.
WB100 – bellows liquid type.
Conventional safety relief valves:
Can be used on systems where the discharge is
relatively simple. The pressure in the discharge
system can be atmospheric, at a constant level or
where the pressure may build up to a maximum of
10% of the set pressure. When a constant back
pressure exists, the valve should be set at the
differential pressure (refer to page 8).
Liquid service
Valves operating on liquid service require a
modified valve design to cope with the differing
dynamics of liquid flow.
A contoured plug disc is used to minimise initial
flow rate, eliminating any potential inlet pressure
drops due to excessive valve lift. The valve will
simmer until sufficient pressure is available to
generate lift. Once this has occurred, the lift will
stabilise to suit the flow and pressure conditions
required, thus avoiding the problem of chatter.
‘Chatter’ is the rapid opening and closing of the
valve which can have a damaging effect on the disc
and nozzle, causing it to leak.
Bellows safety relief valves:
The WB Bellows Valves are statically balanced and
can be used on more complex discharge systems
such as common discharge manifolds and flares
where several valves may discharge. This type of
system creates a variable superimposed back
pressure. The balanced bellows unit cancels out
the effects of variable back pressure, on the set
pressure of the safety relief valve.
Gas and vapour service:
The gas/vapour disc can be distinguished by the flat
underside, unlike the cone profile of the liquid disc.
Typical liquid relief valve disc
7
T H E E F F E C T O F B AC K P R E S S U R E
The configuration of a closed discharge pipework
system, typically for toxic or hazardous duty, can
generate back pressure. Back pressure applied to
the outlet of the valve will adversely affect its
performance, unless it is addressed.
Back pressure may take three forms:
1. Superimposed constant back pressure
This exists permanently and a conventional or
bellows valve can be used. A conventional valve
can be set at the differential pressure so that the
spring load is adjusted to take account of the back
pressure.
3. Superimposed variable back pressure
This is caused by other valves discharging into a
common disposal system, or other circumstances
that cause the back pressure to be variable.
Balanced bellows valves should be used for this
condition, adjusted to the predetermined set
pressure.
2. Built up back pressure
Built up back pressure is created by the
configuration of discharge pipework systems and
varies from zero when the valve is closed, to a
maximum, when fully open. Conventional spring
loaded valves can tolerate up to 10% of set
pressure as built up back pressure. For back
pressures in excess of 10%, a balanced bellows
design is required to maintain valve lift.
Constant back pressure - conventional valve
Variable back pressure - balanced bellows valve
8
VA LV E A C T I O N
Principles of operation – spring loaded
safety and thermal relief valves
SPRING FORCE
Safety relief valves use a spring force to hold a disc
against a nozzle. Under normal system operating
pressure, the valve will remain closed as the spring
force is greater than the inlet system pressure
force. The valve opens when the system pressure
force becomes greater than the closing force of
the spring.
Spring loaded safety and thermal relief valve
The WB and B/C series are designed to have a
short simmer, open rapidly to full lift position and
then re-seat at a controlled shut off pressure.
This is demonstrated in the graph below, which
shows the valve action and corresponding pressure
at the valve inlet.
SYSTEM PRESSURE FORCE
POPPING PRESSURE
SET PRESSURE
RE-SEAT PRESSURE
Popping and blowdown
The opening and closing characteristics of the valve
can be controlled by the adjustment of a
blowdown ring, as its position affects the shape
and volume of the huddling chamber. When the
blowdown ring is adjusted to its top position, the
exit area from the huddling chamber is restricted
to its minimum. The valve will pop distinctly with a
short simmer and long blowdown. Conversely,
9
when the blowdown ring is in its lowest position
there is a maximum exit area from the huddling
chamber and the valve will have a longer simmer
with a shorter blowdown. The blowdown ring can
be positioned between these two extremes to give
the required performance, but it is usually factory
set to achieve re-seating 7-10% below set pressure.
LIFT CYCLE
Stage 1 – Closed
Inlet pressure < set pressure
Inlet pressure is below the set pressure. The valve is
closed and there is no flow through the valve.
Stage 2 – Simmering
Inlet pressure is = > set pressure and < popping pressure
Inlet pressure increases to set pressure. At this point, the spring
force and system pressure force are equal; a further rise in inlet
pressure will then begin to lift the disc slightly. A small amount of
fluid is released into the huddling chamber (the valve simmers).
The system fluid is now acting on a larger area inside the
huddling chamber.
Stage 3 – Popping and opening
Inlet pressure = > popping pressure, valve fully open
The inlet pressure acting on a larger area produces a significant
force to accelerate the opening. A combination of this pressure
force, the kinetic energy from the fluid within the nozzle and the
deflection force of the fluid flow turning through the reaction
hood, is transformed into disc lifting force. The valve pops open
at < 5% overpressure and the valve reaches the full open
position at 110% of set pressure, in accordance with
international codes.
Stage 4 – Reseating
Inlet pressure falls to re-seating pressure
As system pressure starts to fall, the force from the spring
begins to close the valve. Typically, the system pressure falls
between 5-10% below the valve set pressure at which point
the spring force accelerates the valve disc to re-seat the valve.
The difference between the set pressure and the re-seating
pressure is known as blowdown.
10
WB 400 - CONVENTIONAL GAS TYPE
(up to and including class 600)
ITEM
PART
CARBON STEEL
STAINLESS STEEL
1
2
3
4*
5*
6*
8
9
10*
11
12
13
14
15
18
19
22*
27*
28*
29*
31*
32
33
34
35
42
80*
Body
Casing
Cap
Nozzle
Disc
Disc holder
Blowdown ring
Guide Assy
Spindle
Lower spring plate
Adjusting screw
Locking nut
Setting screw
Setting screw rod
Stud
Nut
Spring
Body gasket
Cap gasket
Set screw gasket
Ball
Upper spring plate
Data plate
Hammer drive screw
Grooved pin
Drain plug
Circlip
SA 216-WCB CARB ST
SA 216-WCB CARB ST
SA 216-WCB CARB ST
316 ST ST
316 ST ST
ASTM A479-316L
SA 351-CF8M ST ST
CARBON ST/17-4 ST ST
ASTM A479-431
ASTM A108-1021/Ni PLT
ASTM A479-410
ASTM A108-1021
ASTM A479-431
ASTM A479-316L
SA 193-B7 CR/MOL ST
SA 194-2H CARB ST
CARBON STEEL
ST-706
ST-706
ST-706
AISI 440C ST ST
ASTM A108-1021/Ni PLT
321 ST ST
ELECTRO BRASSED ST
ASTM A479-431
HTS HOLO-KROME
ASTM A313-316
SA 351-CF8M ST ST
SA 351-CF8M ST ST
SA 351-CF8M ST ST
316 ST ST
316 ST ST
ASTM A479-316L
SA 351-CF8M ST ST
316L/17-4 ST ST
ASTM A479-431
ASTM A479-431
ASTM A479-410
ASTM A479-316L
ASTM A479-431
ASTM A479-316L
SA 193-B8T ST ST
SA 194-8T ST ST
ASTM A313-316
ST-706
ST-706
ST-706
AISI 440C ST ST
ASTM A479-431
321 ST ST
ASTM A479-316L
ASTM A479-431
ASTM A479-316L
ASTM A313-316
* Recommended spares
11
W B 3 0 0 - B A L A N C E D B E L L OW S G A S T Y P E
(up to and including class 600)
ITEM
PART
CARBON STEEL
STAINLESS STEEL
1
2
3
4*
5*
6*
8
9
10*
11
12
13
14
15
18
19
22*
23*
27*
28*
29*
31*
32
33
34
35
42
80*
Body
Casing
Cap
Nozzle
Disc
Disc holder
Blowdown ring
Guide Assy
Spindle
Lower spring plate
Adjusting screw
Locking nut
Setting screw
Set screw rod
Stud
Nut
Spring
Bellows assembly
Body gasket
Cap gasket
Set screw gasket
Ball
Upper spring plate
Data plate
Hammer drive screw
Grooved pin
Drain plug
Circlip
SA 216-WCB CARB ST
SA 216-WCB CARB ST
SA 216-WCB CARB ST
316 ST ST
316 ST ST
INCLUDED IN ITEM 23
SA 351-CF8M ST ST
CARBON ST/17-4 ST ST
ASTM A479-431
ASTM A108-1021/Ni PLT
ASTM A479-410
ASTM A108-1021
ASTM A479-431
ASTM A479-316L
SA 193-B7 CR/MOL ST
SA 194-2H CARB ST
CARBON STEEL
ASTM A479-316L/SA240-316L
ST-706
ST-706
ST-706
AISI 440C ST ST
ASTM A108-1021/Ni PLT
321 ST ST
ELECTRO BRASSED ST
ASTM A479-431
HTS HOLO-KROME
ASTM A313-316
SA 351-CF8M ST ST
SA 351-CF8M ST ST
SA 351-CF8M ST ST
316 ST ST
316 ST ST
INCLUDED IN ITEM 23
SA 351-CF8M ST ST
316 L/17-4 ST ST
ASTM A479-431
ASTM A479-431
ASTM A479-410
ASTM A479-316L
ASTM A479-431
ASTM A479-316L
SA 193-B8T ST ST
SA 194-8T ST ST
ASTM A313-316
ASTM A479-316L/SA240-316L
ST-706
ST-706
ST-706
AISI 440C ST ST
ASTM A479 431
321 ST ST
ASTM A479-316L
ASTM A479-431
ASTM A479-316L
ASTM A313-316
* Recommended spares
12
WB 400 - CONVENTIONAL GAS TYPES
(class 900 and above)
ITEM
PART
CARBON STEEL
STAINLESS STEEL
1
2
3
4*
5*
6*
7
8
9
10*
11
12
13
14
15
16*
17*
18
19
20
21
22*
24*
27*
28*
29*
31*
32
33
34
35*
42
Body
Casing
Cap
Nozzle
Disc
Disc holder
Reaction hood
Blowdown ring
Guide plate
Spindle
Lower spring cap
Adjusting screw
Locking nut
Setting screw
Setting screw rod
Tabwasher
Pinning screw
Body stud
Body nut
Casing stud
Casing nut
Spring
Spindle head
Body gasket
Cap gasket
Setting screw gasket
Ball
Upper spring cap
Data plate
Hammer drive screw
Grooved pin
Drain plug
SA 216-WCB CARB ST
SA 216-WCB CARB ST
SA 216-WCB CARB ST
316 ST ST
316 ST ST
ASTM A479-316L
ASTM A479-431
SA 351-CF8M ST ST
17-4 ST ST
ASTM A479-431
ASTM A108-1021/Ni PLT
ASTM A479-410
ASTM A108-1021
ASTM A479-431
ASTM A479-316L
BS 1449-304S15 ST ST
ASTM A479-431
SA 193-B7 CR/MOL ST
SA 194-2H CARB ST
SA 193-B7 CR/MOL ST
SA 194-2H CARB ST
CARBON STEEL
ASTM A479-431
ST-706
ST-706
ST-706
AISI 440C ST ST
ASTM A108-1021/Ni PLT
321 ST ST
ELECTRO BRASSED ST
ASTM A479-431
HTS HOLO-KROME
SA 351-CF8M ST ST
SA 351-CF8M ST ST
SA 351-CF8M ST ST
316 ST ST
316 ST ST
ASTM A479-316L
ASTM A479-431
SA 351-CF8M ST ST
17-4 ST ST
ASTM A479-431
ASTM A479-431
ASTM A479-410
ASTM A479-316L
ASTM A479-431
ASTM A479-316L
BS 1449-304S15 ST ST
ASTM A479-431
SA 193-B8T ST ST
SA 194-8T ST ST
SA 193-B8T ST ST
SA 194-8T ST ST
ASTM A313-316
ASTM A479-431
ST-706
ST-706
ST-706
AISI 440C ST ST
ASTM A479 431
321 ST ST
ASTM A479-316L
ASTM A479-431
ASTM A479-316L
* Recommended spares
13
W B 3 0 0 - B A L A N C E D B E L L OW S G A S T Y P E
(class 900 and above)
ITEM
PART
CARBON STEEL
STAINLESS STEEL
1
2
3
4*
5*
6*
7
8
9
10*
11
12
13
14
15
16*
17*
18
19
20
21
22*
23*
24*
25
26
27*
28
29
31
32
33
34
35
42
50
Body
Casing
Cap
Nozzle
Disc
Disc holder base
Reaction hood
Blowdown ring
Guide plate
Spindle
Lower spring cap
Adjusting screw
Locking nut
Setting screw
Setting screw rod
Tabwasher
Pinning screw
Body stud
Body nut
Casing stud
Casing nut
Spring
Bellows
Spindle head
Piston
Guide spindle
Body gasket
Cap gasket
Setting screw gasket
Ball
Upper spring cap
Data plate
Hammer drive screw
Grooved pin
Drain plug
Grubscrew
SA 216-WCB CARB ST
SA 216-WCB CARB ST
SA 216-WCB CARB ST
316 ST ST
316 ST ST
ASTM A479-321
ASTM A479-431
SA 351-CF8M ST ST
17-4 ST ST
ASTM A479-431
ASTM A108-1021/Ni PLT
ASTM A479-410
ASTM A108-1021
ASTM A479-431
ASTM A479-316L
BS 1449-304S15 ST ST
ASTM A479-431
SA 193-B7 CR/MOL ST
SA 194-2H CARB ST
SA 193-B7 CR/MOL ST
SA 194-2H CARB ST
CARBON STEEL
SA240-316L
ASTM A479-431
ASTM A479-431
ASTM A479-321
ST-706
ST-706
ST-706
AISI 440C ST ST
ASTM A108-1021/Ni PLT
321 ST ST
ELECTRO BRASSED ST
ASTM A479-431
HTS HOLO-KROME
ASTM A479-321
SA 351-CF8M ST ST
SA 351-CF8M ST ST
SA 351-CF8M ST ST
316 ST ST
316 ST ST
ASTM A479-321
ASTM A479-431
SA 351-CF8M ST ST
17-4 ST ST
ASTM A479-431
ASTM A479-431
ASTM A479-410
ASTM A479-316L
ASTM A479-431
ASTM A479-316L
BS 1449-304S15 ST ST
ASTM A479-431
SA 193-B8T ST ST
SA 194-8T ST ST
SA 193-B8T ST ST
SA 194-8T ST ST
ASTM A313-316
SA240-316L
ASTM A479-431
ASTM A479-431
ASTM A479-3431
ST-706
ST-706
ST-706
AISI 440C ST ST
ASTM A479 431
321 ST ST
ASTM A479-316L
ASTM A479-431
ASTM A479-316L
ASTM A479-321
* Recommended spares
14
AC C E S S O R I E S
Screwed cap
This is the standard option on all valves.
Bolted cap
Option available on the WB Series when required
by the customer or for critical service where
fragile gaskets materials may be fitted.
Open lever*
The open lever assembly is not pressure tight and
is therefore only suitable where vapour can safely
be allowed to escape to atmosphere.
Packed lever*
The design of the packed lever assembly ensures
that leakage does not occur when the valve is open
or when back pressure is present.
*A lift lever can be used to test for correct valve operation where corrosion or deposits could prevent the valve from
opening. They can be used to release foreign particles trapped on the seat and must be fitted when codes dictate.
GAG SCREW
SEALING PLUG
Test gag
The test gag is used to prevent the safety valve
from lifting. This is mainly used when carrying out
a hydrostatic test on the system, during
commissioning.
After testing, the test gag must be removed and
replaced with the sealing plug.
15
FERRULE
Soft seat
Ferrule (government ring)
A ferrule, sometimes known as a government ring,
is a collar fitted beneath the head of the pressure
adjusting screw. Some authorities will require a
ferrule to be fitted to prevent unauthorised interference with the set pressure.
An O-ring seal offers maximum seat tightness,
over and above that of the standard metal-tometal seats. A wide range of seal materials are
available including Viton, Nitrile, Kalrez and PTFE.
For high integrity seat leakage, specify soft seat.
Steam jacket
Some process media can solidify or
form crystals if they cool within
the system. The medium within
the valve nozzle is not in the
flow path and thus cooling can
occur. Should the medium
solidify, crystallise, or if
sublimation of vapour
was to occur within
the nozzle, the valve
may not lift.
The steam jacket is
designed to keep the process
medium hot, helping to
maximise plant safety. The steam jacket has both
an inlet and outlet so that low pressure steam can
be passed through the jacket, keeping the valves
hot. This allows the valves to stay operational,
enabling the valve to successfully relieve pressure,
should an overpressure situation occur.
The steam jacket is manufactured out of material
that is compatible with the body of the valve and
the connections to the jacket can either be flanged
or screwed.
Auxiliary back-up piston
In the event of bellows failure, a potentially
dangerous situation can arise. The back pressure
causes an “out-of-balance” situation which may
cause:
1 Increase in set pressure.
2 Decrease in flow capacity.
3 Increase in re-seat pressure.
Specifying bellows valves with an auxiliary back-up
piston ensures that the above does not occur. The
piston itself has the same effective diameter as the
failed bellows, so any effect of the back pressure
increasing the set pressure is counteracted by an
upward thrust of the piston. This is an added
safety feature. The WB 300 valve has
incorporated the auxiliary back-up piston since its
inception. It is available as standard in all pressure
classes 900 and above and as an optional feature
for class 600 and below.
To ensure absolute safety, specify the auxiliary
back-up piston.
16
WB SERIES FIGURE NUMBERING SYSTEM
/
Inlet diameter
1” - 8”
Accessories
B Auxiliary
back-up piston
C Bolted cap
D Screwed cap
F Ferrule
(Government ring)
G Test gag
H* High Pressure
M Open lever
P Packed lever
R Soft seat
S Special feature
3 WB300 Bellows
API orifice letter
D-T
Outlet diameter
2” - 10”
Design
H ANSI 150, 300 and 600
/ ANSI 900, 1500 and 2500
Valve
1
2
3
4
type
Liquid bellows
Liquid conventional
Vapour bellows
Vapour conventional
ANSI
1
2
3
4
5
6
7
8
O
Trim
1
2
3
4
5
6
7
O
flange rating inlet x outlet
150 x 150
300 x 150
600 x 150
900 x 150
900 x 300
1500 x 150
1500 x 300
2500 x 300
Special
Flange face
1 ANSI RF x RF
2 ANSI RTJ inlet x RF
O Special
*In some instances when
both high pressures and
alloy springs are required,
the ‘H’ needs adding to
accessories. See individual
orifice pages.
17
Body
1
2
3
4
5
6
8
9
O
material nozzle and disc
Stainless steel PH 17/4
Stainless steel 316
Aluminium bronze / Monel
Hastelloy B
Stainless steel 316 stellited
Monel
Stainless steel 304
Special
Spring material
1 Carbon steel
2 Stainless steel 316
6 Tungsten alloy
9 Hastelloy B
A Aluminium Coated CS
N Stainless steel PH 17/4
Q Stainless steel PH 17/4 NACE
T Aluminium Coated Tungsten
Z Inconel X750
O Special
material
Carbon steel WCB
Carbon steel WCB NACE
Stainless steel CF8M NACE
Stainless steel CF8M
Carbon steel low temperature LCB
Bronze
Carbon steel WC6 - 0.5% Moly
Hastelloy B
Special
R E C O M M E N D E D M AT E R I A L T E M P E R AT U R E R A N G E S
Description
Minimum
deg F
deg C
Maximum
deg F
deg C
BODY
1 Carbon steel
SA 216-WCB
–20
–29
800
427
2 Carbon steel (NACE)
SA 216-WCB
–20
–29
800
427
3 Stainless steel (NACE)
SA 351-CF8M
–450
–267
1000
538
4 Stainless steel
SA 351-CF8M
–450
–267
1000
538
SA 352-LCB
–50
–46
800
427
6 Bronze (Oxygen spec.)
BS 1400 LG2
–450
–267
450
232
8 0.5% MOLY CS
SA 217-WC6
–20
–29
1000
538
SA 494-N12MV
–20
–29
1000
538
–75
–59
450
232
5 Low Temp. CS
9 Hastelloy B
SPRING
1 Carbon steel
A Aluminium coated CS
–75
–59
450
232
2 Stainless steel (316)
–450
–267
500
260
6 Tungsten alloy (BH12)
–4
–20
1000
427
T Aluminium coated tungsten
–4
–20
1000
427
9 Hastelloy B
–20
–29
800
427
N Stainless steel (PH17/4)
–130
–90
752
400
Q Stainless steel (PH17/4 NACE)
–130
–90
752
400
Z Inconel X750
–450
–267
1000
538
1 Stainless steel (PH 17/4 NACE 29-33 HRC)
–130
–90
752
400
2 Stainless steel (316)
–450
–267
1000
538
3 Al. Bronze/Monel
–76
–60
572
300
4 Hastelloy B
–20
–29
1000
538
5 Stainless steel (316 Stellited 39-43 HRC)
–321
–196
1000
538
6 Monel
–321
–196
800
427
7 Stainless steel 304
–238
–150
1000
538
NAF (ST-706)
–40
–40
800
427
Graphite (Supergraf)
–328
–200
932
500
Gylon 3504
–321
–196
500
260
Nitrile
–40
–40
212
100
Viton
–22
–30
392
200
Silicon
–85
–65
446
230
TRIM (Nozzle and disc)
GASKETS
SOFT SEAT
Ethylene Propylene
–58
–50
275
135
PTFE
–454
–270
428
220
Kalrez
–20
–29
500
260
BOLTING
B7 Alloy steel
–20
–29
800
427
B8T Stainless Steel
–454
–270
1000
538
Monel K500
–274
–170
482
250
Notes
1 All temperatures are at valve inlet.
2 Trim items 1 and 5 are recommended for maximum durability.
3 Alternative materials may be specified if agreed on enquiry.
18
427
800
BODY
D
– 0.110 in2
– 71 mm2
538
1000
1000
TUNGSTEN
538
CS - WC6
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
7
8
9 10
500
11
900
450
800
400
450
CARBON STEEL
232
CARBON STEEL - WCB
700
1
2
3
4
5
6
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
-50
-268
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
12
14
13
15
16
-200
17
-150
-300
-400
-450
1000 2000 3000 4000 5000 6000
-450
SET PRESSURE - PSIG
0
100 200
300
SET PRESSURE - BAR G.
0
10
20
400
-200
500
30 34.5
50
69 100
200
300
-250
-268
413.8
ORIFICE D (All dimensions in inches)
Size
(ins)
Rating
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
1x2
150 x 150
300 x 150
600 x 150
4.125
4.125
4.125
1.437
1.437
1.437
13.875
13.875
13.875
4.500
4.500
4.500
0.582
0.582
0.582
2
2
2
3/8
3/8
3/8
3/4
3/4
3/4
40 (18)
40 (18)
42 (19)
11/2 x 2
900 x 300
1500 x 300
4.125
4.125
1.750
1.750
25.000
25.000
5.500
5.500
0.625
0.625
5
5
3/8
3/8
3/4
3/4
90 (41)
97 (44)
11/2 x 3
2500 x 300
5.500
2.375
26.875
6.500
0.625
5
3/8
3/4
115 (52)
*–
–
–
–
If a gag is fitted, add 0.5 ins.
If a bellows is fitted in the 1 x 2 inch valve add 1.125 inch.
If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
19
VA LV E S E L E C T I O N TA B L E
D
– 0.110 in2
– 71 mm2
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
-21°F
to
-75°F
Conventional
Valve
-76°F
to
-450°F
1
1x2
150#RF
150#RF
-
-
285
185
80
-
285
230
2
1x2
300#RF
150#RF
-
-
740
615
410
-
285
230
Key
Valve size
No. inlet x outlet
(ins)
Inlet
Outlet
3
1x2
600#RF
150#RF
4
11/2 x 2
900#RF
300#RF
5
11/2 x 2
1500#RF
6
11/2 x 3
2500#RF
7
1x2
8
1x2
9
10
Body
Mat’l
-
-
1480
1235
825
-
285
230
-
-
2220
1845
1235
-
600
500
300#RF
-
-
3705
3080
2060
-
600
500
300#RF
-
-
6000
5135
3430
-
740
500
300#RF
150#RF
-
-
-
-
510
225
285
230
600#RF
150#RF
-
-
-
-
1015
445
285
230
11/2 x 2
900#RF
300#RF
-
-
-
-
1525
670
600
500
11/2 x 2
1500#RF
300#RF
-
-
-
-
2540
1115
600
500
11
11/2 x 3
2500#RF
300#RF
-
-
-
-
4230
1860
740
500
12
1x2
150#RF
150#RF
275
275
-
-
-
-
275
230
13
1x2
300#RF
150#RF
720
720
-
-
-
-
275
230
14
1x2
600#RF
150#RF
1440
1440
-
-
-
-
275
230
15
11/2 x 2
900#RF
300#RF
2160
2160
-
-
-
-
600
500
16
11/2 x 2
1500#RF
300#RF
3600
3600
-
-
-
-
600
500
17
11/2 x 3
2500#RF
300#RF
4000
6000
-
-
-
-
720
500
WCB
WC6
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
7 psig
22 psig
59 psig*
Conventional
(Inverted)
–
2 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version
There is no requirement to have an high pressure version for this orifice.
20
427
800
BODY
E
– 0.196 in2
– 127 mm2
538
1000
1000
TUNGSTEN
538
CS - WC6
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
7
8
9 10
500
11
900
450
800
400
450
CARBON STEEL
232
CARBON STEEL - WCB
700
1
2
3
4
5
6
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
-50
-268
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
12
14
13
15
16
-200
17
-150
-300
-400
-450
1000 2000 3000 4000 5000 6000
-450
SET PRESSURE - PSIG
0
100 200
300
SET PRESSURE - BAR G.
0
10
20
400
-200
500
30 34.5
50
69 100
200
300
-250
-268
413.8
ORIFICE E (All dimensions in inches)
Size
(ins)
Rating
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
1x2
150 x 150
300 x 150
600 x 150
4.125
4.125
4.125
1.437
1.437
1.437
13.875
13.875
13.875
4.500
4.500
4.500
0.582
0.582
0.582
2
2
2
3/8
3/8
3/8
3/4
3/4
3/4
40 (18)
40 (18)
42 (19)
11/2 x 2
900 x 300
1500 x 300
4.125
4.125
1.750
1.750
25.000
25.000
5.500
5.500
0.625
0.625
5
5
3/8
3/8
3/4
3/4
90 (41)
97 (44)
11/2 x 3
2500 x 300
5.500
2.375
26.875
6.500
0.625
5
3/8
3/4
115 (52)
*–
–
–
–
If a gag is fitted, add 0.5 ins.
If a bellows is fitted in the 1 x 2 inch valve add 1.125 inch.
If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
21
VA LV E S E L E C T I O N TA B L E
E
150#RF
Body
Mat’l
150#RF
-21°F
to
-75°F
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
-
-
285
185
80
-
Balanced
Bellows Valve
1x2
Outlet
-76°F
to
-450°F
Conventional
Valve
1
Inlet
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
Key
Valve size
No. inlet x outlet
(ins)
– 0.196 in2
– 127 mm2
285
230
2
1x2
300#RF
150#RF
-
-
740
615
410
-
285
230
3
1x2
600#RF
150#RF
-
-
1480
1235
825
-
285
230
4
11/2 x 2
900#RF
300#RF
-
-
2220
1845
1235
-
600
500
5
11/2 x 2
1500#RF
300#RF
-
-
3705
3080
2060
-
600
500
6
11/2
500
x3
WCB
2500#RF
300#RF
-
-
6000
5135
3430
-
740
7
1x2
300#RF
150#RF
-
-
-
-
510
225
285
230
8
1x2
600#RF
150#RF
-
-
-
-
1015
445
285
230
9
11/2 x 2
900#RF
300#RF
-
-
-
-
1525
670
600
500
10
11/2
x2
1500#RF
300#RF
-
-
-
-
2540
1115
600
500
11
11/2 x 3
2500#RF
300#RF
-
-
-
-
4230
1860
740
500
12
1x2
150#RF
150#RF
275
275
-
-
-
-
275
230
13
1x2
300#RF
150#RF
720
720
-
-
-
-
275
230
14
1x2
600#RF
150#RF
1440
1440
-
-
-
-
275
230
15
11/2 x 2
900#RF
300#RF
2160
2160
-
-
-
-
600
500
16
11/2 x 2
1500#RF
300#RF
3600
3600
-
-
-
-
600
500
17
11/2 x 3
2500#RF
300#RF
4000
6000
-
-
-
-
720
500
WC6
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
7 psig
22 psig
59 psig*
Conventional
(Inverted)
–
2 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version
There is no requirement to have an high pressure version for this orifice.
22
7
8
9 10
500
11
900
450
800
800
TUNGSTEN
427
400
700
CARBON STEEL - WCB
450
CARBON STEEL
232
538
1000
1000
CS - WC6
538
F
– 0.307 in2
– 198 mm2
BODY
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
1
2
3
4
5
6
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
16
-268
17
-50
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
13
12
-200
17
15
14
-150
-300
600
700
1000
3000
-400
-450
5000
40
48.3
69
200
344.8
-450
SET PRESSURE - PSIG
0
100 200
300
SET PRESSURE - BAR G.
0
10
20
400
500
30
-200
-250
-268
ORIFICE F (All dimensions in inches)
Size
(ins)
Rating
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
11/2 x 2
150 x 150
300 x 150
600 x 150
4.875
4.875
4.875
1.625
1.625
1.625
14.625
14.625
14.625
4.750
6.000
6.000
0.750
0.750
0.750
2
2
2
3/8
3/8
3/8
3/4
3/4
3/4
46 (21)
46 (21)
46 (21)
11/2 x 3
900 x 300
1500 x 300
2500 x 300
4.875
4.875
5.500
1.750
1.750
2.375
26.750
26.750
26.875
6.500
6.500
6.500
0.500
0.500
0.625
5
5
5
3/8
3/8
3/8
3/4
3/4
3/4
101 (46)
101 (46)
117 (53)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
23
F
VA LV E S E L E C T I O N TA B L E
Body
Mat’l
-21°F
to
-75°F
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
Outlet
-76°F
to
-450°F
Conventional
Valve
Inlet
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
Key
Valve size
No. inlet x outlet
(ins)
– 0.307 in2
– 198 mm2
285
185
80
-
285
230
230
1
11/2 x 2
150#RF
150#RF
-
-
2
11/2
x2
300#RF
150#RF
-
-
740
615
410
-
285
3
11/2 x 2
600#RF
150#RF
-
-
1480
1235
825
-
285
230
4
11/2 x 3
900#RF
300#RF
-
-
2220
1845
1235
-
740
500
5
11/2 x 3
1500#RF
300#RF
-
-
3705
3080
2060
-
740
500
6
11/2
x3
2500#RF
300#RF
-
-
5000
5000
3430
-
740
500
7
11/2 x 2
300#RF
150#RF
-
-
-
-
510
225
285
230
8
11/2 x 2
600#RF
150#RF
-
-
-
-
1015
445
285
230
9
11/2 x 3
900#RF
300#RF
-
-
-
-
1525
670
740
500
10
11/2 x 3
1500#RF
300#RF
-
-
-
-
2540
1115
740
500
11
11/2 x 3
2500#RF
300#RF
-
-
-
-
4230
1860
740
500
12
11/2 x 2
150#RF
150#RF
275
275
-
-
-
-
275
230
13
11/2 x 2
300#RF
150#RF
720
720
-
-
-
-
275
230
14
11/2 x 2
600#RF
150#RF
1440
1440
-
-
-
-
275
230
15
11/2
x3
900#RF
300#RF
2160
2160
-
-
-
-
720
500
16
11/2 x 3
1500#RF
300#RF
2200
3600
-
-
-
-
720
500
17
11/2 x 3
2500#RF
300#RF
3400
5000
-
-
-
-
720
500
WCB
WC6
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
7 psig
22 psig
59 psig*
Conventional
(Inverted)
–
2 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version
There is no requirement to have an high pressure version for this orifice.
24
427
BODY
CS - WC6
450
CARBON STEEL
232
– 0.503 in2
– 325 mm2
538
1000
1000
800
G
7
8
9
10
500
11
900
450
800
TUNGSTEN
538
400
700
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
350
600
300
500
250
400
200
300
150
6
1
2
3
4
5
100
200
50
100
0
0
-20
-75
-268
-50
16 + 17
15
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
12
13
16
14
-200
17
-150
-300
3000
-400
-450
4000
200
275.9
-450
SET PRESSURE - PSIG
0
100 200
300
SET PRESSURE - BAR G.
0
10
20
500
1000
50
2000
69 100
150
-200
-250
-268
ORIFICE G (All dimensions in inches)
Size
(ins)
11/2 x 3
2x3
Rating
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
150
150
150
300
4.875
4.875
4.875
4.875
1.312
1.312
1.437
1.750
18.750
18.750
18.750
27.500
4.750
6.000
6.000
6.500
0.500
0.500
0.500
0.500
2
2
2
5
3/8
3/8
3/8
3/8
3/4
3/4
3/4
3/4
60 (27)
64 (29)
66 (30)
119 (54)
1500 x 300
2500 x 300
6.125
6.125
2.125
2.812
32.000
32.000
6.750
6.750
0.500
0.687
5
2
1/2
1/2
3/4
3/4
126 (57)
139 (63)
150
300
600
900
x
x
x
x
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
25
VA LV E S E L E C T I O N TA B L E
G
Body
Mat’l
-21°F
to
-75°F
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
Outlet
-76°F
to
-450°F
Conventional
Valve
Inlet
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
Key
Valve size
No. inlet x outlet
(ins)
– 0.503 in2
– 325 mm2
285
185
80
-
285
230
230
1
11/2 x 3
150#RF
150#RF
-
-
2
11/2
x3
300#RF
150#RF
-
-
740
615
410
-
285
3
11/2 x 3
600#RF
150#RF
-
-
1480
1235
825
-
285
230
4
11/2 x 3
900#RF
300#RF
-
-
2220
1845
1235
-
740
470
5
2x3
1500#RF
300#RF
-
-
3705
3080
2060
-
740
470
6
2x3
2500#RF
300#RF
-
-
3705
3705
3430
-
740
470
7
11/2 x 3
300#RF
150#RF
-
-
-
-
510
225
285
230
8
11/2 x 3
600#RF
150#RF
-
-
-
-
1015
445
285
230
9
11/2 x 3
900#RF
300#RF
-
-
-
-
1525
670
740
470
10
2x3
1500#RF
300#RF
-
-
-
-
2540
1115
740
470
11
2x3
2500#RF
300#RF
-
-
-
-
3705
1860
740
470
12
11/2 x 3
150#RF
150#RF
275
275
-
-
-
-
275
230
13
11/2 x 3
300#RF
150#RF
720
720
-
-
-
-
275
230
14
11/2 x 3
600#RF
150#RF
1440
1440
-
-
-
-
275
230
15
11/2
x3
WCB
WC6
CF8M
900#RF
300#RF
1600
2160
-
-
-
-
720
470
16
2x3
1500#RF
300#RF
2450
3600
-
-
-
-
720
470
17
2x3
2500#RF
300#RF
2600
3600
-
-
-
-
720
470
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
13 psig
13 psig
40 psig*
Conventional
(Inverted)
–
2 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version
There is no requirement to have an high pressure version for this orifice.
26
427
BODY
CS - WC6
450
CARBON STEEL
232
– 0.785 in2
– 506 mm2
538
1000
1000
800
H
7
8
9
500
10
900
450
800
TUNGSTEN
538
400
700
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
2
1
3
4
6
5
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
-50
-268
-100
SS - CF8M
STAINLESS STEEL
-29
-59
-100
15
11 + 12
-200
14
13
-150
16
-300
-400
-450
3000
-450
SET PRESSURE - PSIG
0
100 200
300
SET PRESSURE - BAR G.
0
10
20
400
500
1000
30 34.5
50
69
2000
100
-200
150
-250
-268
206.9
ORIFICE H (All dimensions in inches)
Size
(ins)
Rating
11/2 x 3
150 x 150
300 x 150
2x3
300
600
900
1500
x
x
x
x
150
150
150
300
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
5.125
5.125
1.375
1.375
18.750
18.750
4.875
4.875
0.500
0.500
2
2
3/8
3/8
3/4
3/4
60 (27)
60 (27)
5.125
6.062
6.062
6.062
1.375
1.687
2.312
2.375
19.000
20.000
31.750
32.000
4.875
6.375
6.375
6.375
0.500
0.687
0.687
0.750
2
2
5
5
3/8
3/8
1/2
1/2
3/4
3/4
3/4
3/4
64 (29)
86 (39)
176 (80)
187 (85)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
27
VA LV E S E L E C T I O N TA B L E
H
Body
Mat’l
-21°F
to
-75°F
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
Outlet
-76°F
to
-450°F
Conventional
Valve
Inlet
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
Key
Valve size
No. inlet x outlet
(ins)
– 0.785 in2
– 506 mm2
1
11/2 x 3
150#RF
150#RF
-
-
285
185
80
-
285
230
2
11/2 x 3
300#RF
150#RF
-
-
285
285
285
-
285
230
3
2x3
300#RF
150#RF
-
-
740
615
410
-
285
230
4
2x3
600#RF
150#RF
-
-
1480
1235
825
-
285
230
5
2x3
900#RF
150#RF
-
-
2220
1845
1235
-
285
230
6
2x3
1500#RF
300#RF
-
-
2750
2750
2060
-
740
415
7
2x3
300#RF
150#RF
-
-
-
-
510
225
285
230
8
2x3
600#RF
150#RF
-
-
-
-
815
445
285
230
WCB
WC6
9
2x3
900#RF
150#RF
-
-
-
-
1225
670
285
230
10
2x3
1500#RF
300#RF
-
-
-
-
2040
1115
740
415
11
11/2 x 3
150#RF
150#RF
275
275
-
-
-
-
275
230
12
11/2 x 3
300#RF
150#RF
275
275
-
-
-
-
275
230
13
2x3
300#RF
150#RF
720
720
-
-
-
-
275
230
14
2x3
600#RF
150#RF
CF8M 1440
1440
-
-
-
-
275
230
15
2x3
900#RF
150#RF
1485
2160
-
-
-
-
275
230
16
2x3
1500#RF
300#RF
1600
2750
-
-
-
-
720
415
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
7 psig
13 psig
28 psig*
Conventional
(Inverted)
–
2 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials cannot be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Orifice
rating
1.5H
150#
285
1.5H
300#
285
2H
300#
2H
600#
Spring Material (pressures in Psig)
Pressure Psig Carbon st.
316 SS
Tungsten
17/4PH
17/4PH NACE Inconel X750
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
740
n/a
n/a
n/a
n/a
n/a
n/a
1480
n/a
1000
n/a
n/a
1000
n/a
28
J
427
BODY
CS - WC6
450
CARBON STEEL
232
800
– 1.287 in2
– 830 mm2
538
1000
1000
500
10
9
8
7
900
450
800
TUNGSTEN
538
400
700
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
2
3
1
4
6
5
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
14
-268
15
-50
16
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
-200
13
11 + 12
14
15 +16
-300
0
100 200
300
SET PRESSURE - BAR G.
0
10
20
400
500
1000
30 34.5
50
69
2000
100
-200
-400
-450
3000
-450
SET PRESSURE - PSIG
-150
150
-250
-268
206.9
ORIFICE J (All dimensions in inches)
Size
(ins)
Rating
2x3
150 x 150
300 x 150
3x4
300
600
900
1500
x
x
x
x
150
150
150
300
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
5.375
5.375
1.625
1.625
19.250
19.250
4.875
4.875
0.750
0.750
2
2
3/8
3/8
3/4
3/4
64 (29)
64 (29)
7.250
7.250
7.250
7.250
2.125
2.125
2.375
2.750
21.750
23.000
33.875
33.875
7.125
7.125
7.125
7.125
0.750
0.750
0.750
0.750
2
2
5
5
3/8
3/8
1/2
1/2
3/4 82 (37)
3/4 99 (45)
3/4 231 (105)
3/4 253 (115)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
29
J
VA LV E S E L E C T I O N TA B L E
– 1.287 in2
– 830 mm2
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
-21°F
to
-75°F
Conventional
Valve
-76°F
to
-450°F
1
2x3
150#RF
150#RF
-
-
285
185
80
-
285
230
2
2x3
300#RF
150#RF
-
-
285
285
285
-
285
230
3
3x4
300#RF
150#RF
-
-
740
615
410
-
285
230
4
3x4
600#RF
150#RF
-
-
1480
1235
825
-
285
230
5
3x4
900#RF
150#RF
-
-
2220
1845
1235
-
285
230
6
3x4
1500#RF
300#RF
-
-
2700
2700
2060
-
600
230
7
3x4
300#RF
150#RF
-
-
-
-
510
225
285
230
8
3x4
600#RF
150#RF
-
-
-
-
815
445
285
230
Key
Valve size
No. inlet x outlet
(ins)
Inlet
Outlet
Body
Mat’l
WCB
WC6
9
3x4
900#RF
150#RF
-
-
-
-
1225
670
285
230
10
3x4
1500#RF
300#RF
-
-
-
-
2040
1115
600
230
11
2x3
150#RF
150#RF
275
275
-
-
-
-
275
230
12
2x3
300#RF
150#RF
275
275
-
-
-
-
275
230
13
3x4
300#RF
150#RF
14
3x4
600#RF
150#RF
15
3x4
900#RF
16
3x4
1500#RF
500
720
-
-
-
-
275
230
625
1440
-
-
-
-
275
230
150#RF
800
2160
-
-
-
-
275
230
300#RF
800
2700
-
-
-
-
600
230
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
5 psig
13 psig
34 psig*
Conventional
(Inverted)
–
1.5 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials cannot be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Orifice
rating
2J
150#
285
2J
300#
285
3J
300#
3J
600#
Spring Material (pressures in Psig)
Pressure Psig Carbon st.
316 SS
Tungsten
17/4PH
17/4PH NACE Inconel X750
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
740
n/a
500
n/a
n/a
430
n/a
1480
n/a
900
n/a
900
870
900
30
427
800
BODY
– 1.838 in2
– 1185 mm2
538
INCONEL
CS - WC6
1000
450
CARBON STEEL
232
1000
K
6
7
500
9
8
900
450
800
TUNGSTEN
538
400
700
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
5
1
2
3
4
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
12
-268
13
14
-50
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
10
11
12
+
13
-200
14
-300
0
100 200
300
SET PRESSURE - BAR G.
0
10
20
400
30
500
600
700
1000
40
48.3
69
2000
100
150
-200
-400
-450
3000
-450
SET PRESSURE - PSIG
-150
-250
-268
206.9
ORIFICE K (All dimensions in inches)
Size
(ins)
Rating
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
3x4
150 x 150
300 x 150
600 x 150
6.125
6.125
7.250
2.000
2.000
2.125
21.750
21.750
23.500
6.375
6.375
7.125
0.875
0.875
0.875
3
3
3
3/8
3/8
3/8
3/4
3/4
3/4
108 (49)
108 (49)
141 (64)
3x6
900 x 150
1500 x 300
7.812
7.750
2.562
2.875
40.000
40.000
8.500
8.500
0.937
0.875
5
5
3/4
3/4
3/4 339 (154)
3/4 353 (160)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
31
VA LV E S E L E C T I O N TA B L E
K
– 1.838 in2
– 1185 mm2
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
-21°F
to
-75°F
Conventional
Valve
-76°F
to
-450°F
1
3x4
150#RF
150#RF
-
-
285
185
80
-
285
150
2
3x4
300#RF
150#RF
-
-
740
615
410
-
285
150
3
3x4
600#RF
150#RF
-
-
1480
1235
825
-
285
200
4
3x6
900#RF
150#RF
-
-
2220
1845
1235
-
285
200
5
3x6
1500#RF
300#RF
-
-
2220
2220
2060
-
600
200
6
3x4
300#RF
150#RF
-
-
-
-
510
215
285
150
7
3x4
600#RF
150#RF
-
-
-
-
815
445
285
200
8
3x6
900#RF
150#RF
-
-
-
-
1225
670
285
200
9
3x6
1500#RF
300#RF
-
-
-
-
2040
1115
600
200
10
3x4
150#RF
150#RF
275
275
-
-
-
-
275
150
11
3x4
300#RF
150#RF
525
720
-
-
-
-
275
150
12
3x4
600#RF
150#RF
600
1440
-
-
-
-
275
200
13
3x6
900#RF
150#RF
600
2160
-
-
-
-
275
200
14
3x6
1500#RF
300#RF
750
2220
-
-
-
-
600
200
Key
Valve size
No. inlet x outlet
(ins)
Inlet
Outlet
Body
Mat’l
WCB
WC6
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
5 psig
13 psig
26 psig*
Conventional
(Inverted)
–
1.5 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials can not be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Orifice
rating
K
150#
285
K
300#
740
K
600#
1480
Spring Material (pressures in Psig)
Pressure Psig Carbon st.
316 SS
Tungsten
17/4PH
17/4PH NACE Inconel X750
n/a
n/a
n/a
n/a
n/a
n/a
n/a
450
n/a
n/a
600
n/a
n/a
750
n/a
n/a
570
1070
32
427
BODY
CS - WC6
450
CARBON STEEL
232
– 2.853 in2
– 1840 mm2
538
1000
1000
800
L
7
8
10
9
500
900
450
800
TUNGSTEN
538
400
6
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
700
2
1
3
4
5
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
13
-268
-50
15
14
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
-200
11 + 12
13 + 14
15
-300
0
SET PRESSURE - BAR G.
0
200
10
400
20
30
600
40
1000
800
50
60
-200
-400
-450
1500
-450
SET PRESSURE - PSIG
-150
69
-250
-268
103.5
ORIFICE L (All dimensions in inches)
Size
(ins)
Rating
3x4
150 x 150
300 x 150
4x6
300
600
900
1500
x
x
x
x
150
150
150
150
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
6.125
6.125
2.000
2.000
21.750
21.750
6.500
6.500
0.875
0.875
4
4
3/8
3/8
3/4
3/4
108 (49)
108 (49)
7.062
7.062
7.750
7.750
2.062
2.312
2.687
2.937
27.000
28.250
41.875
44.000
7.125
8.000
8.750
8.750
0.812
0.812
0.750
0.812
5
5
5
5
1/2
1/2
1/2
1/2
1
1
1
1
234
249
353
361
(106)
(113)
(160)
(164)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
33
L
VA LV E S E L E C T I O N TA B L E
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
– 2.853 in2
– 1840 mm2
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
-21°F
to
-75°F
Conventional
Valve
-76°F
to
-450°F
1
3x4
150#RF
150#RF
-
-
285
185
80
-
285
100
2
3x4
300#RF
150#RF
-
-
285
285
285
-
285
100
3
4x6
300#RF
150#RF
-
-
740
615
410
-
285
170
4
4x6
600#RF
150#RF
-
-
1000
1000
825
-
285
170
5
4x6
900#RF
150#RF
-
-
1500
1500
1235
-
285
170
6
4x6
1500#RF
150#RF
-
-
1500
1500
1500
-
285
170
7
4x6
300#RF
150#RF
-
-
-
-
510
225
285
170
8
4x6
600#RF
150#RF
-
-
-
-
1000
445
285
170
9
4x6
900#RF
150#RF
-
-
-
-
1500
670
285
170
10
4x6
1500#RF
150#RF
-
-
-
-
1500
1115
285
170
11
3x4
150#RF
150#RF
275
275
-
-
-
-
275
100
12
3x4
300#RF
150#RF
275
275
-
-
-
-
275
100
13
4x6
300#RF
150#RF
535
720
-
-
-
-
275
170
14
4x6
600#RF
150#RF
535
1000
-
-
-
-
275
170
15
4x6
900#RF
150#RF
700
1500
-
-
-
-
275
170
Key
Valve size
No. inlet x outlet
(ins)
Inlet
Outlet
Body
Mat’l
WCB
WC6
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
5 psig
13 psig
23 psig*
Conventional
(Inverted)
–
1.5 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials cannot be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Orifice
rating
3L
150#
285
3L
300#
285
4L
300#
4L
600#
Spring Material (pressures in Psig)
Pressure Psig Carbon st.
316 SS
Tungsten
17/4PH
17/4PH NACE Inconel X750
n/a
n/a
n/a
n/a
255
n/a
n/a
n/a
n/a
n/a
255
n/a
740
n/a
n/a
n/a
n/a
n/a
n/a
1000
n/a
850
n/a
n/a
825
n/a
34
427
800
BODY
– 3.60 in2
– 2320 mm2
538
INCONEL
CS - WC6
1000
450
CARBON STEEL
232
1000
M
6
5
500
7
900
450
TUNGSTEN
538
800
4
400
700
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
1
2
3
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
-268
-50
10
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
-200
8
9
10
-300
0
SET PRESSURE - BAR G.
0
200
10
400
20
30
600
40
1000
800
50
60
-200
-400
-450
1500
-450
SET PRESSURE - PSIG
-150
69
-250
-268
103.5
ORIFICE M (All dimensions in inches)
Size
(ins)
4x6
Rating
150
300
600
900
x
x
x
x
150
150
150
150
A
B
C*
D
E
F
G
H†
7.000
7.000
7.000
7.750
2.000
2.000
2.250
2.500
26.500
26.500
28.250
41.875
7.250
7.250
8.000
8.750
0.750
0.750
0.750
0.750
5
5
5
5
1/2
1/2
1/2
1/2
1
1
1
1
Wt
lbs (kg)
234
234
249
377
(106)
(106)
(113)
(171)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
35
M
4x6
Outlet
150#RF
Body
Mat’l
150#RF
-76°F
to
-450°F
-21°F
to
-75°F
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
-
-
285
185
80
-
Balanced
Bellows Valve
1
Inlet
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
Key
Valve size
No. inlet x outlet
(ins)
– 3.60 in2
– 2320 mm2
Conventional
Valve
VA LV E S E L E C T I O N TA B L E
285
80
2
4x6
300#RF
150#RF
-
-
740
615
410
-
285
160
3
4x6
600#RF
150#RF
-
-
1100
1100
825
-
285
160
4
4x6
900#RF
150#RF
-
-
1100
1100
1100
-
285
160
5
4x6
300#RF
150#RF
-
-
-
-
510
225
285
160
WCB
WC6
6
4x6
600#RF
150#RF
-
-
-
-
1015
445
285
160
7
4x6
900#RF
150#RF
-
-
-
-
1100
670
285
160
8
4x6
150#RF
150#RF
275
275
-
-
-
-
275
80
9
4x6
300#RF
150#RF
525
720
-
-
-
-
275
160
10
4x6
600#RF
150#RF
600
1000
-
-
-
-
275
160
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
4 psig
13 psig
27 psig*
Conventional
(Inverted)
–
1.5 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials can not be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Orifice
rating
M
150#
285
M
300#
740
M
600#
1100
Spring Material (pressures in Psig)
Pressure Psig Carbon st.
316 SS
Tungsten
17/4PH
17/4PH NACE Inconel X750
n/a
n/a
n/a
n/a
n/a
n/a
n/a
500
n/a
n/a
590
n/a
n/a
825
n/a
1000
900
1000
36
427
BODY
CS - WC6
450
CARBON STEEL
232
– 4.34 ins2
– 2800 mm2
538
1000
1000
800
N
5
6
500
7
900
450
800
TUNGSTEN
538
400
700
4
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
1
2
3
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
10
-268
-50
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
-200
8
9
10
-300
0
SET PRESSURE - BAR G.
0
200
10
400
20
600
30
800
40
50
-200
-400
-450
1000
-450
SET PRESSURE - PSIG
-150
60
-250
-268
69
ORIFICE N (All dimensions in inches)
Size
(ins)
4x6
Rating
150
300
600
900
x
x
x
x
150
150
150
150
A
B
C*
D
E
F
G
H†
7.750
7.750
7.750
7.750
2.000
2.000
2.250
2.500
29.250
29.250
34.250
41.500
8.250
8.250
8.750
8.750
0.750
0.750
0.750
0.750
5
5
5
5
1/2
1/2
1/2
1/2
1
1
1
1
Wt
lbs (kg)
242
242
258
395
(110)
(110)
(117)
(179)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
37
VA LV E S E L E C T I O N TA B L E
N
Body
Mat’l
-21°F
to
-75°F
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
Outlet
-76°F
to
-450°F
Conventional
Valve
Inlet
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
Key
Valve size
No. inlet x outlet
(ins)
– 4.34 ins2
– 2800 mm2
1
4x6
150#RF
150#RF
-
-
285
185
80
-
285
80
2
4x6
300#RF
150#RF
-
-
740
615
410
-
285
160
3
4x6
600#RF
150#RF
-
-
1000
1000
825
-
285
160
4
4x6
900#RF
150#RF
-
-
1000
1000
1000
-
285
160
5
4x6
300#RF
150#RF
-
-
-
-
510
225
285
160
6
4x6
600#RF
150#RF
-
-
-
-
1000
445
285
160
7
4x6
900#RF
150#RF
-
-
-
-
1000
670
285
160
8
4x6
150#RF
150#RF
275
275
-
-
-
-
275
80
9
4x6
300#RF
150#RF
450
720
-
-
-
-
275
160
10
4x6
600#RF
150#RF
500
1000
-
-
-
-
275
160
WCB
WC6
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
5 psig
13 psig
29 psig*
Conventional
(Inverted)
–
1.5 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials can not be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Orifice
rating
N
150#
285
N
300#
N
600#
Spring Material (pressures in Psig)
Pressure Psig Carbon st.
316 SS
Tungsten
17/4PH
n/a
n/a
n/a
n/a
17/4PH NACE Inconel X750
n/a
n/a
740
n/a
680
n/a
n/a
700
n/a
1000
n/a
n/a
n/a
n/a
n/a
n/a
38
450
CARBON STEEL
232
800
BODY
– 6.38 ins2
– 4120 mm2
538
CS - WC6
1000
5
6
500
7
900
450
800
400
700
4
CARBON STEEL - WCB
427
1000
INCONEL
538
P
TUNGSTEN
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
1
2
3
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
-268
-50
10
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
-200
8
9
10
-300
0
SET PRESSURE - BAR G.
0
200
10
400
20
600
30
800
40
50
-200
-400
-450
1000
-450
SET PRESSURE - PSIG
-150
60
-250
-268
69
ORIFICE P (All dimensions in inches)
Size
(ins)
4x6
Rating
150
300
600
900
x
x
x
x
150
150
150
150
A
B
C*
D
E
F
G
H†
7.125
8.875
8.875
8.875
2.000
2.000
2.250
2.500
27.750
29.250
35.250
45.000
9.000
10.000
10.000
10.000
0.750
0.750
0.750
0.750
5
5
5
5
1/2
1/2
1/2
1/2
1
1
1
1
Wt
lbs (kg)
254
254
269
412
(115)
(115)
(122)
(187)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
39
VA LV E S E L E C T I O N TA B L E
P
Body
Mat’l
-21°F
to
-75°F
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
Outlet
-76°F
to
-450°F
Conventional
Valve
Inlet
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
Key
Valve size
No. inlet x outlet
(ins)
– 6.38 ins2
– 4120 mm2
1
4x6
150#RF
150#RF
-
-
285
185
80
-
285
80
2
4x6
300#RF
150#RF
-
-
525
525
410
-
285
150
3
4x6
600#RF
150#RF
-
-
1000
1000
825
-
285
150
4
4x6
900#RF
150#RF
-
-
1000
1000
1000
-
285
150
5
4x6
300#RF
150#RF
-
-
-
-
510
225
285
150
6
4x6
600#RF
150#RF
-
-
-
-
1000
445
285
150
7
4x6
900#RF
150#RF
-
-
-
-
1000
670
285
150
8
4x6
150#RF
150#RF
175
275
-
-
-
-
275
80
9
4x6
300#RF
150#RF
300
525
-
-
-
-
275
150
10
4x6
600#RF
150#RF
480
1000
-
-
-
-
275
150
WCB
WC6
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
4 psig
13 psig
24 psig*
Conventional
(Inverted)
–
1.5 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials can not be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Orifice
rating
P
150#
285
P
300#
P
600#
Spring Material (pressures in Psig)
Pressure Psig Carbon st.
316 SS
Tungsten
17/4PH
n/a
n/a
n/a
n/a
17/4PH NACE Inconel X750
n/a
n/a
525
n/a
350
n/a
n/a
390
460
1000
n/a
640
n/a
n/a
336
n/a
40
Q
427
BODY
CS - WC6
450
CARBON STEEL
232
800
– 11.05 in2
– 7130 mm2
538
1000
1000
4
500
5
900
450
800
TUNGSTEN
538
400
700
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
1
2
3
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
8
-268
-50
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
-200
6
7
8
-300
0
10
SET PRESSURE - BAR G.
0
0.69
50
2
100
4
6 6.9
200
10
300
15
400
20
-200
-400
-450
600
-450
SET PRESSURE - PSIG
-150
500
30
-250
-268
41.4
ORIFICE Q (All dimensions in inches)
Size
(ins)
Rating
6x8
150 x 150
300 x 150
600 x 150
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
9.437
9.437
9.437
2.312
2.312
2.750
31.750
31.750
36.750
9.500
9.500
9.500
0.812
0.812
0.812
3
3
6
1/2
1/2
1/2
1
1
1
364 (165)
364 (165)
399 (181)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
41
Q
VA LV E S E L E C T I O N TA B L E
1
6x8
150#RF
150#RF
2
6x8
300#RF
150#RF
Body
Mat’l
WCB
-21°F
to
-75°F
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
-
-
165
165
80
-
115
70
-
-
300
300
300
-
115
115
Balanced
Bellows Valve
Outlet
-76°F
to
-450°F
Conventional
Valve
Inlet
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
Key
Valve size
No. inlet x outlet
(ins)
– 11.05 in2
– 7130 mm2
3
6x8
600#RF
150#RF
-
-
600
600
600
-
115
115
4
6x8
300#RF
150#RF
-
-
-
-
165
165
115
115
5
6x8
600#RF
150#RF
-
-
-
-
600
445
115
115
6
6x8
150#RF
150#RF
165
165
-
-
-
-
115
70
7
6x8
300#RF
150#RF
250
300
-
-
-
-
115
115
8
6x8
600#RF
150#RF
300
600
-
-
-
-
115
115
WC6
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
4 psig
13 psig
23 psig*
Conventional
(Inverted)
–
1.5 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials can not be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Spring Material (pressures in Psig)
Orifice
rating
316 SS
Tungsten
17/4PH
Q
150#
Pressure Psig Carbon st.
165
n/a
109
n/a
n/a
17/4PH NACE Inconel X750
117
n/a
Q
300#
300
n/a
109
n/a
165
117
165
Q
600#
600
n/a
109
n/a
400
117
390
42
427
BODY
CS - WC6
450
CARBON STEEL
232
– 16.00 in2
– 10300 mm2
538
1000
1000
800
R
5
500
6
900
450
TUNGSTEN
538
800
2
400
700
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
1
3
4
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
10
-268
-50
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
-200
7+8
9
10
-300
0
SET PRESSURE - BAR G.
0
10
20
1
30
2
40
50
100
3 3.45
5
6.9
200
10
-200
-400
-450
300
-450
SET PRESSURE - PSIG
-150
15
-250
-268
20.7
ORIFICE R (All dimensions in inches)
Size
(ins)
Rating
A
B
C*
D
E
F
G
H†
Wt
lbs (kg)
6x8
150 x 150
300 x 150
9.437
9.437
2.312
2.312
34.750
34.750
9.500
9.500
0.812
0.812
3
3
1/2
1/2
1
1
370 (168)
370 (168)
6 x 10
300 x 150
600 x 150
9.437
9.437
2.312
2.750
34.750
40.750
10.500
10.500
0.812
0.812
3
6
1/2
1/2
1
1
465 (211)
489 (222)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
43
VA LV E S E L E C T I O N TA B L E
R
– 16.00 in2
– 10300 mm2
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
538°C
Balanced
Bellows Valve
-21°F
to
-75°F
Conventional
Valve
-76°F
to
-450°F
1
6x8
150#RF
150#RF
-
-
100
100
80
-
60
60
2
6x8
300#RF
150#RF
-
-
100
100
100
-
60
60
3
6 x 10
300#RF
150#RF
-
-
230
230
230
-
100
100
4
6 x 10
600#RF
150#RF
-
-
300
300
300
-
100
100
5
6x8
300#RF
150#RF
-
-
-
-
100
100
60
60
6
6 x 10
600#RF
150#RF
-
-
-
-
300
300
100
100
7
6x8
150#RF
150#RF
55
100
-
-
-
-
60
60
8
6x8
300#RF
150#RF
55
100
-
-
-
-
60
60
9
6 x 10
300#RF
150#RF
150
230
-
-
-
-
100
100
10
6 x 10
600#RF
150#RF
200
300
-
-
-
-
100
100
Key
Valve size
No. inlet x outlet
(ins)
Inlet
Outlet
Body
Mat’l
WCB
WC6
CF8M
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
4 psig
13 psig
25 psig*
Conventional
(Inverted)
–
1.5 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials can not be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Orifice
rating
6R8
150#
100
6R8
300#
100
6R10
300#
6R10
600#
Spring Material (pressures in Psig)
Pressure Psig Carbon st.
316 SS
Tungsten
17/4PH
17/4PH NACE Inconel X750
n/a
73
n/a
n/a
90
n/a
n/a
73
n/a
n/a
90
n/a
230
n/a
73
n/a
224
90
147
300
n/a
190
n/a
n/a
180
n/a
44
427
BODY
CS - WC6
450
CARBON STEEL
232
– 26.00 in2
– 16770 mm2
538
1000
1000
800
T
500
3
900
450
800
TUNGSTEN
538
400
700
CARBON STEEL - WCB
TEMPERATURE
LIMITS API 526
SPRING
VA LV E S E L E C T I O N G U I D E
1
2
350
600
300
500
250
400
200
300
150
100
200
50
100
0
0
-20
-75
5
-268
-50
-100
-100
SS - CF8M
STAINLESS STEEL
-29
-59
-200
4
5
0
SET PRESSURE - BAR G.
0
10
20
1
30
2
40
50
3
60
4
70
80
90
5
6
100
-200
-400
-450
300
-450
SET PRESSURE - PSIG
-150
-300
200
6.9
-250
-268
20.7
ORIFICE T (All dimensions in inches)
Size
(ins)
8 x 10
Rating
A
150 x 150 10.875
300 x 150 10.875
B
C*
D
E
F
G
H†
Wt
lbs (kg)
2.625
2.625
42.250
42.250
11.000
11.000
1.000
1.000
6
6
1/2
1/2
1
1
661 (300)
683 (310)
* – If a gag is fitted, add 0.5 ins.
– If a lever is fitted, add a maximum of 3.5 inch. (Only if flange rating is 600# or less.)
– For certified height (c), consult factory.
† Vent hole ‘H’ on bellows valves only.
45
T
Outlet
1
8 x 10
150#RF
150#RF
2
8 x 10
300#RF
150#RF
3
8 x 10
300#RF
150#RF
4
8 x 10
150#RF
150#RF
5
8 x 10
300#RF
150#RF
Body
Mat’l
-76°F
to
-450°F
-21°F
to
-75°F
100°F
to
-20°F
450°F
800°F 1000°F
-60°C
to
-268°C
-30°C
to
-59°C
38°C
to
-29°C
232°C
427°C
WCB
-
-
65
65
65
-
30
30
-
-
300
300
300
-
100
100
-
-
-
-
300
225
100
100
50
65
-
-
-
-
30
30
65
120
-
-
-
-
60
60
WC6
CF8M
538°C
Balanced
Bellows Valve
Inlet
Max. Back
Pressure
(psig)
Max. Set Pressure (psig)
and Temperature Limits
Flanges ANSI
Key
Valve size
No. inlet x outlet
(ins)
– 26.00 in2
– 16770 mm2
Conventional
Valve
VA LV E S E L E C T I O N TA B L E
RF=Raised Face
Minimum set pressure limits for metal seat trim
Conventional
Bellows - Gas
Bellows - Liquid
–
–
–
4 psig
13 psig
18 psig*
Conventional
(Inverted)
–
1.5 psig
*For liquid bellows valves below this pressure refer to factory
Note: Soft seated valves require a minimum set pressure of 15 psig.
High Pressure Version.
Certain spring materials can not be used in the low pressure version of the valve, up to the maximum
pressure. If the required set pressure with your choice of spring material is in excess of the figure shown in
the table either choose another material or add “H” to the valve accessories to select an high pressure valve.
Inlet
Max. Set
Orifice
rating
T
150#
65
T
300#
300
Spring Material (pressures in Psig)
Pressure Psig Carbon st.
316 SS
Tungsten
17/4PH
n/a
n/a
n/a
n/a
17/4PH NACE Inconel X750
n/a
n/a
200
79
200
138
96
83
46
PRESSURE ADJUSTMENT
Each valve is factory set and normally would not
need any pressure adjustment; however, if the
occasion arises, the following procedures apply:
3
13
ASME
If the valve is ASME stamped (UV)(NB), repairs
must be carried out by an ASME authorised repair
company, i.e. one holding either the (UV) or (VR)
stamp.
12
Test rig
It is normally desirable to remove the valve from
the plant and use a suitable test rig, specifically
designed for safety relief valves.
Range
Each spring has a definite range, the limits of which
should not be exceeded. These should be checked
with the factory, since if a set pressure change is
required, it may be necessary to obtain a new
spring. Should the set pressure be changed it is
important to ensure that the valve will still have
sufficient capacity under the new service
conditions.
Procedure
1) Remove the cap (3). This exposes the
compression screw (12).
2) Slacken the locknut (13).
3) Introduce pressure to the valve inlet. The spring
pressure and consequently the valve set
pressure may be increased or decreased by
turning the compression screw.
Clockwise - increases set pressure
Anti-clockwise - decreases set pressure
Check against a calibrated pressure gauge.
4) Re-tighten the locknut and refit the cap.
Replace cap gasket if damaged.
5) Check seat leakage (see page 49/50).
COLD DIFFERENTIAL TEST PRESSURE
When setting a valve intended for use at high
temperature on a test rig using a test fluid at
ambient temperatures, it is necessary to set
the valve at a slightly higher pressure, so that
it will open at the correct set pressure under
relieving conditions. The necessary allowance
is shown in the following table.
Relieving
temperature –
Centigrade
WB, B + C Series
Up to 121°C
% Increase in set
pressure at ambient
temperature
Up to 250°F
None
>121°C to 316°C
>250°F to 600°F
1
>316°C to 427°C
>600°F to 800°F
2
>427°C to 538°C
>800°F to 1000°F
3
D Series
Up to 100°C
47
Relieving
temperature –
Fahrenheit
Up to 212°F
None
>100°C to 150°C
>212°F to 302°F
2
>150°C to 260°C
>302°F to 500°F
3
B L OW D OW N R I N G S E T T I N G
The blowdown adjustment is achieved by means of
a single blowdown ring.
By reducing the blowdown gap,
blowdown is increased.
By increasing the blowdown gap,
blowdown is decreased.
Blowdown is defined as the difference between the
set pressure of the valve and the reseating
pressure.
Important
It is important to reset the blowdown ring to
the correct position after maintenance has
been carried out on the valve.
Note: It is dangerous to adjust the blowdown ring
when the valve is under pressure, unless a suitable
‘test gag’ is fitted to prevent inadvertent valve
opening
Method
1) Removing the setting screw in the body permits
access to the blowdown ring.
2) Close the blowdown gap until the ring is
touching the face of the disc (turn the ring from
left to right).
3) Consult the chart in the maintenance manual to
determine the correct blowdown ring setting,
or consult the factory.
4) Wind back the blowdown ring the right number
of notches to establish the correct position
(count the number of notches or serrations on
the outside of the blowdown ring).
5) Relocate the locking pin into the notches
provided on the outside diameter of the
blowdown ring.
6) Tighten up the setting screw, ensuring that an
undamaged gasket is in place.
48
S E AT T I G H T N E S S / S E AT L E A K A G E T E S T I N G
(in accordance with API 527)
Described here are methods of determining the
seat tightness of metal and soft-seated pressure
relief valves, including those of conventional,
bellows and pilot-operated designs.
The maximum acceptable leakage rates are defined
for pressure relief valves with set pressures from
15 Psig to 6,000 Psig. If greater seat tightness is
required, the purchaser shall specify it in the
purchase order.
The test medium for determining the seat tightness
- air, steam or water - shall be the same as that
used for determining the set pressure of the valve.
For dual-service valves, the test medium - air,
steam or water - shall be the same as the primary
relieving medium.
To ensure safety, the procedures outlined shall be
performed by persons experienced in the use and
functions of pressure relief valves.
Test apparatus for
air seat tightness
Tube 5⁄16" o.d. x 0.035" wall
1
⁄2"
Cover plate
Air receiver
API 527 Air Leakage Rates
TESTING WITH AIR
A1 Test apparatus
A test arrangement for determining seat tightness
with air is shown opposite. Leakage shall be
measured using a tube with an outside diameter of
5/16 inch and a wall thickness of 0.035 inch. The
tube end shall be cut square and smooth. The tube
opening shall be 1⁄2 inch below the surface of the
water. The tube shall be perpendicular to the
surface of the water.
A2 Test medium
The test medium shall be air (or nitrogen) near
ambient temperature.
A3 Test configuration
The valve shall be vertically mounted on the test
stand and the test apparatus shall be attached to
the valve outlet, as shown opposite. All openings including but not limited to caps, drain holes, vents,
and outlets – shall be closed.
A4 Test pressure
For a valve whose set pressure is greater than
50 Psig, the leakage rate (in bubbles per minute)
shall be determined with the test pressure at the
valve inlet held at 90% of the set pressure. For a
valve set at 50 Psig or less, the test pressure shall
be held at 5 Psig less than the set pressure.
A5 Leakage test
Before the leakage test, the set pressure shall be
demonstrated and all valve body joints and fittings
should be checked with a suitable solution to
ensure that all joints are tight.
Before the bubble count, the test pressure shall be
applied for the following times:
Valve size
Up to 2ins
3ins to 4ins
6ins and above
Time
1 min
2 min
5 min
The valve shall then be observed for leakage for at
least 1 minute.
A6 Acceptance criteria
For a valve with a metal seat, the leakage rate in
bubbles per minute shall not exceed the
appropriate value in chart opposite. For a softseated valve, there shall be no leakage for 1 minute
(0 bubbles per minute).
49
S E AT T I G H T N E S S / S E AT L E A K A G E T E S T I N G
(in accordance with API 527)
TESTING WITH STEAM
TESTING WITH WATER
S1 Test medium
The test medium shall be saturated steam.
IMPORTANT– ALL LIQUID TRIM VALVES
MUST BE TESTED ON WATER.
OTHERWISE SET PRESSURES AND
LEAKAGE RATE RESULTS WILL BE FALSE.
S2 Test configuration
The valve shall be vertically mounted on the steam
test stand.
S3 Test pressure
For a valve whose set pressure is greater than
50 Psig, the seat tightness shall be determined
with the test pressure at the valve inlet held at
90% of the set pressure. For a valve set at 50 Psig
or less, the test pressure shall be held at
5 Psig less than the set pressure.
S4 Leakage test
Before starting the seat tightness test, the set
pressure shall be demonstrated and the test
pressure shall be held for at least 3 minutes. Any
condensate in the body bowl shall be removed
before the seat tightness test. Air (or nitrogen)
may be used to dissipate condensate.
After any condensate has been removed, the inlet
pressure shall be increased to the test pressure.
Tightness shall then be checked visually using a
black background.
The valve shall then be observed for leakage for at
least 1 minute.
S5 Acceptance criteria
For both metal and soft-seated valves, there shall
be no audible or visible leakage for 1 minute.
W1 Test medium
The test medium shall be water near ambient
temperature.
W2 Test configuration
The valve shall be vertically mounted on the water
test stand.
W3 Test pressure
For a valve whose set pressure is greater than
50 Psig, the seat tightness shall be determined
with the test pressure at the valve inlet held at
90% of the set pressure. For a valve set at 50 Psig
or less, the test pressure shall be held at
5 Psig less than the set pressure.
W4 Leakage test
Before starting the seat tightness, the set pressure
shall be demonstrated and the outlet body bowl
shall be filled with water. The pressure gauge shall
be allowed to stabilise with no visible flow from
the valve outlet. The inlet pressure shall then be
increased to the test pressure. The valve shall then
be observed for 1 minute at the test pressure.
W5 Acceptance criteria
For a metal-seated valve whose inlet has a nominal
pipe-size of 1 inch or larger, the leakage rate shall
not exceed 10 cubic centimetres per hour per inch
of nominal inlet size. For a metal-seated valve
whose inlet has a nominal pipe size of less than
1 inch, the leakage rate shall not exceed 10 cubic
centimetres per hour. For soft-seated valves, there
shall be no leakage for 1 minute.
IMPORTANT: Test rig cleanlines is vital to avoid contamination and damage to the safety relief
valve seat surfaces.
50
Safeflo Safety and thermal relief valves
1 Accessories
2 High
performance
springs
3 Guiding
surfaces
4 Trim
51
F E AT U R E S A N D B E N E F I T S
Design verification – The:
B Series (gas/vapour)
C Series (liquid)
D Series (gas, liquid and steam)
have been developed on Birkett’s in-house,
extensive mass flow test facility.
Simplified maintenance – For the flanged
version, a slip on inlet flange makes it easier to
realign into existing pipework after servicing.
Interchangeable parts – Valves can easily be
modified from gas to liquid or liquid to gas with
the minimum number of parts. The
D Series is certified for all media without
modification.
Safe and reliable – Proven dependability
ensures safe and reliable performance.
Cryogenic and oxygen service – Birkett’s
state-of-the-art clean room and vapour
degreasing facilities ensure compliance with the
stringent demands of cryogenic and oxygen
applications. (The D Series is not available for
cryogenic service.)
1. Wide range of accessories – Available to
comply with international codes and to suit
system requirements.
2. High performance springs – Safety relief
valve springs are specially designed to guarantee
set point repeatability.
3. Guiding surfaces – The material selection of
guiding components, together with self aligning
disc pivot points, ensures correct alignment and
no galling of guiding surfaces.
4. Trim – B/C Series valves have been designed
with metal trim to give optimum performance
at higher pressures. The 7D is available with a
soft seat or metal seat, while the 6D is metal
seated only.
Balanced piston – Available on the 7D Series to
counter the effects of variable back pressure.
Material selection – A wide range of
materials are offered, including non-ferrous for
low temperature and oxygen service, and
exotic alloys specified for the chemical and
process industries.
52
B / C S E R I E S T H E R M A L R E L I E F VA LV E S
Cryogenic versions of the B and C Series are available
ITEM
PART
CARBON STEEL
STAINLESS STEEL
1
3
4*
5*
6*
9
11
12
13
22*
28*
31*
32
33
34
76
85
Body
Cap
Nozzle
Disc
Disc holder
Guide
Lower spring plate
Adjusting screw
Locking nut
Spring
Cap gasket
Ball
Upper spring plate
Data plate
Hammer drive screw
Capscrew
Flange
SA 216-WCB CARB ST
ASTM A108-1021
316 ST ST
316 ST ST
SA564 17/4 (33HRC)
SA351-CF8M ST ST
ASTM A479-431
ASTM A479-410
ASTM A479-316L
C.S. ALUMINIUM COATED
ST-706
AISI 440C ST ST
ASTM A479 431
321 ST ST
ELECTRO BRASSED CS
ST ST BS6105 A2-70
SA 105 CARB ST
SA 351-CF8M ST ST
ASTM A479-316L
316 ST ST
316 ST ST
SA564 17/4 (33HRC)
SA351-CF8M ST ST
ASTM A479-431
ASTM A479-410
ASTM A479-316L
ASTM A313-316
ST-706
AISI 440C ST ST
ASTM A479 431
321 ST ST
ASTM A479-316L
ST ST BS6105 A2-70
SA 182-F316 ST ST
* Recommended spares.
53
D S E R I E S T H E R M A L R E L I E F VA LV E S
ITEM
PART
CARBON STEEL
STAINLESS STEEL
1
3
4*
5*
9
10
12
13
22*
28*
30
33
34
75
85
147
188
235
Body
Cap
Nozzle
Disc
Guide
Spindle
Adjusting screw
Locking nut
Spring
Cap gasket
Body gasket
Data plate
Hammer drive screw
Grub screw
Inlet flange
Flange nut
Adjusting screw bush
Spring end plate
SA 216-WCB CARB ST
SA 216-WCB CARB ST
316 ST ST
316 ST ST
17/4 PH ST ST
316 ST ST
ASTM A479-410
ASTM A479-316L
C.S. ALUMINIUM COATED
ST-706
ST-706
321 ST ST
ELECTRO BRASSED CS.
ASTM A479-316L
SA 105 CARB ST
SA564 17/4 (33HRC)
VIRGIN PTFE
ASTM A479-431
SA 351-CF8M ST ST
SA 351-CF8M ST ST
316 ST ST
316 ST ST
17/4 PH ST ST
316 ST ST
ASTM A479-410
ASTM A479-316L
ASTM A313-316
ST-706
ST-706
321 ST ST
ASTM A479-316L
ASTM A479-316L
SA 182-F316 ST ST
SA564 17/4 (33HRC)
VIRGIN PTFE
ASTM A479-431
* Recommended spares.
54
AC C E S S O R I E S
Packed lever
Balanced piston
The design of the packed lever assembly ensures that
leakage does not occur when the valve is open or
when back pressure is present.
This option is only available on the 7D Series
valves. It is designed to overcome the effects of
variable back pressure.
Open lever design is not available on Safeflo valves.
Test gag
Gag Screw
Sealing Plug
The test gag is used to prevent the
safety valve from lifting. This is
mainly used when carrying out a
hydrostatic test on the system,
during commissioning.
The test gag must never be left in
the valve. The sealing plug should
be fitted at all other times, allowing
the valve to operate freely.
Pressure adjustment: refer to page 47.
Cold differential test pressure: refer to page 47.
Seat tightness/Seat leakage testing: refer to page 49/50.
Minimum pressure setting: B Series, normal attitude 10 Psig.
C Series, normal attitude 15 Psig.
7D Series, normal attitude 5 Psig.
6D Series, normal attitude 740 Psig.
Lower pressures are NOT available by inverting the valve.
55
S A F E F L O - S A F E T Y A N D T H E R M A L R E L I E F VA LV E
Different types: There are two different types, both are conventional designs.
B Series - Safety and thermal relief valve, gas duty.
C Series - Safety and thermal relief valve, liquid duty.
D Series - Safety and thermal relief valve, gas, steam and liquid duty.
All are certified in accordance with ASME Code Section VIII.
SAFEFLO FIGURE NUMBERING SYSTEM
/
Orifice
Area in2
1 0.062**
2 0.110**
3 0.196**
4 0.442**
6 0.070*
7 0.169*
Valve series
B Gas vapour
C Liquid
D Gas, steam and liquid
Connection size
1 1⁄2" x 1" orifice 1, 2, 6 or 7
2 3⁄4" x 1" orifice 1, 2, 6 or 7
3 1" x 11⁄2" orifice 3
4 11⁄2" x 2" orifice 4 – screwed only
5 1" x 1" orifice 1, 2, 6 or 7
Inlet
A
B
C
D
1
2
3
7
O
connection type
BSP Tr male screwed
BSP female screwed
API male screwed
API female screwed
ANSI 300/600 RF flange
ANSI 900/1500 RF flange**
ANSI 2500 RF flange**
ANSI 150 RF flange
Special**
Outlet connection type
E BSP female screwed
F API female screwed
1 ANSI 150 RF flange
2 ANSI 300 RF flange**
O Special**
/
Accessories
C Screwed cap
P Packed lever
G Test gag
F Ferrule (Government ring)
S Special feature
B Balanced piston†
R Soft seat†
Trim - nozzle and disc material
1 Stainless steel PH 17/4
2 Stainless steel 316
4 Hastelloy B**
5 Stainless steel 316 stellited**
6 Monel 400**
7 Stainless steel 304**
O Special**
Spring material
A Aluminium Coated CS
2 Stainless steel 316
6 Tungsten alloy
9 Hastelloy B**
T Aluminium Coated Tungsten
Z Inconel X750
O Special**
Body material
1 Carbon steel WCB
2 Carbon steel WCB NACE
3 Stainless steel CF8M NACE
4 Stainless steel CF8M
O Special**
*Available on D Series only.
**Not available on D Series.
†Available on 7D only.
56
B/C SERIES DIMENSIONS
Female screwed
Male screwed
Flanged
Note: A packed
lever version and
gagging facility are
also available.
Sizes (ins)
inlet & outlet
1/2
3/4
x1
x1
Inlet & Outlet
connection
Orifice
No.
Screwed
Female
x
Female
1
2
1
2
1
2
1x1
1 x 11/2
3
11/2 x 2
1/2
x1
3/4
x1
4
Screwed
Male
x
Female
1x1
1
2
1
2
1
2
1 x 11/2
3
11/2 x 2
4
3/4
1/2
1/2
x 1,
1x1
x 1, 3/4 x 1,
1x1
x 1, 3/4 x 1,
1x1
3/4
150# x 150#
1+2
300/600# x 150#
1+2
900/1500# x 300#
1+2
x 1, 1 x 1
2500# x 300#
1
2
1 x 11/2
150# x 150#
3
1 x 11/2
300/600# x 150#
3
1 x 11/2
900/1500# x 300#
3
1 x 11/2
2500# x 300#
3
Dimensions ins (mm)
A
B
C*
D
2.500
(64)
2.500
(64)
2.500
(64)
3.250
(83)
3.250
(83)
2.562
(65)
2.562
(65)
2.312
(59)
3.250
(83)
3.250
(83)
4.625
(117)
4.625
(117)
4.625
(117)
4.750
(121)
5.625
(143)
5.625
(143)
5.625
(143)
5.625
(143)
-
8.625
(219)
8.625
(219)
8.625
(219)
13.750
(349)
13.750
(349)
9.375
(238)
9.375
(238)
9.375
(238)
14.750
(375)
14.875
(378)
10.250
(260)
10.250
(260)
10.375
(264)
10.500
(267)
16.750
(425)
16.750
(425)
16.750
(425)
16.750
(425)
1.687
(43)
1.687
(43)
1.687
(43)
2.375
(60)
2.375
(60)
1.687
(43)
1.687
(43)
1.687
(43)
2.375
(60)
2.375
(60)
3.750
(95)
3.750
(95)
3.750
(95)
3.750
(95)
5.500
(140)
5.500
(140)
5.500
(140)
5.500
(140)
0.750
(19)
0.750
(19)
1.000
(25)
1.000
(25)
1.125
(29)
1.000
(25)
1.375
(35)
1.187
(46)
2.000
(51)
1.000
(25)
1.375
(35)
1.812
(46)
2.000
(51)
*If a gag screw is fitted, add 2 ins (51mm) to dimension C for orifice nos. 1 & 2 only.
*If a packed lever is fitted, add 13⁄4 ins (44mm) to dimension C for orifice nos. 1 & 2 only.
Orifice sizes: refer to sizing section, page 84.
Minimum set pressure
B Series (Gas) = 10 Psig (0.7 Barg)
C Series (Liquid) = 15 Psig (1.035 Barg)
Orifice No.1 = 1480 Psig (102 Barg)
Temperature range (with suitable material selection)
-320°F to 1,000°F (-196°C to 538°C)
57
Max pressure upto
100°F (Psig)
Inlet
Outlet
5000
3600
5000
3600
5000
3600
Weight
lbs (kg)
425
9 (4)
425
9 (4)
425
9 (4)
5000
425
26 (12)
2500
375
26 (12)
425
9 (4)
425
9 (4)
425
9 (4)
3000
425
26 (12)
2500
375
26 (12)
285
285
17 (7.25)
1480
285††
17 (7.25)
3000
1480
5000
3600
5000
3600
3600
425
20 (9)
5000
3600
425
20 (9)
285
285
40 (18)
1480
285††
40 (18)
3600
425
40 (18)
5000
425
40 (18)
†425 Psig with 300# outlet
D SERIES DIMENSIONS
Female screwed
Male screwed
Flanged
Note: A packed
lever version and
gagging facility are
also available.
Sizes (ins)
inlet & outlet
Inlet & Outlet
connection
x1
x1
1x1
Screwed
Female x Female
Screwed
Male x Female
x1
1x1
ANSI 600# x 150#
x1
x1
1x1
Screwed
Female x Female
Screwed
Male x Female
x1
1x1
ANSI 150# x 150#
ANSI 300# x 150#
1/2
3/4
3/4
1/2
3/4
3/4
†If
†If
†If
†If
a
a
a
a
Orifice
No.
6
6
6
7
7
7
Dimensions ins (mm)
A
1.732
(44)
1.687
(43)
4.610
(117)
1.732
(44)
1.687
(43)
4.610
(117)
B
C†
-
7.440
(189)
8.230
(209)
10.315
(262)
7.440
(189)
8.230
(209)
10.315
(262)
0.750
(19)
1.625
(41)
0.750
(19)
1.625
(41)
D
2.165
(55)
2.165
(55)
3.750
(95)
2.165
(55)
2.165
(55)
3.750
(95)
Max pressure upto
100°F (Psig)
Inlet
Outlet
Weight
lbs (kg)
1480
285
9 (4)
1480
285
9 (4)
1480
285
14 (6.5)
740
285
9 (4)
740
285
9 (4)
285
740
285
14 (6.5)
packed lever is fitted, add 1.062 ins (27mm) to dimension C for orifice 7 only.
gag screw is fitted, add 0.395 ins (10mm) to dimension C for orifice 7 only.
balanced piston is fitted, add 2.125 ins (54mm) to dimension C for orifice 7 only.
gagged balanced piston is fitted, add 2.520 ins (64mm) to dimension C for orifice 7 only.
Orifice sizes: refer to sizing section, page 84.
Minimum set pressure
7D (Gas, Steam or Liquid) = 5 Psig (0.35 Barg)
6D (Gas, Steam or Liquid) = 740 Psig (51 Barg)
Temperature range (with suitable material selection)
6D and 7D -51°F to 500°F (-46°C to 260°C)
58
Safeset Pilot operated safety relief valve
1 Close differential
pressure setting
15 State-of-the-art
piston seals
14 Two part piston
assembly
2 Close blowdown
and overpressure
tolerance
3 Non-flowing
pilots
4 Integral
pilot filter
5 All stainless
steel pilots,
dome, tubes
and fittings
6 Adjustable
orifice areas
7 Full lift
capability
8 Soft seat
9 Enhanced
seat
tightness
10 Unique full
nozzle design
11 API 526
compliant
13 Dual outlet option
59
12 Integral sensing
of pilot
F E AT U R E S A N D B E N E F I T S
Close system operating pressure
The system operating pressure can be much closer
to the set pressure on a pilot operated valve than
with a standard spring loaded safety relief valve.
System pressures in the region of 95% to 98% of
set pressure are often accommodated.
Tolerates high inlet pressure loss
High inlet pressure losses due to difficult inlet
piping systems can be accommodated by remote
sensing the pilots, hence trouble free operation can
be assured.
1. Close differential pressure setting – Pop
acting pilot valves are quick acting and hence
there is no delay between the pilot and the main
valve opening pressures. Modulating valves
inherently have a delay, which is nominally 2%.
This ensures the pilot is not leaking when the
system pressure is close to the set pressure.
2. Close blowdown and overpressure
tolerance – Pop action pilots can be adjusted
to give zero overpressure and a blowdown
typically equal to 3% of set pressure.
3. Non flowing pilot – Safeset pilots are of the
non flowing design. The risk of freezing due to
pressure drops in the flowing medium is
removed. Additionally, dirt particles are not
transported to the pilot as the medium is static.
This improves life in service and ensures trouble
free operation.
7. Full lift capability – Pilot valves will maintain full
lift against high levels of back pressure. Unlike
spring loaded valves, which would need either
differential setting or the addition of balanced
bellows.
8. Soft seat – Safeset pilots and main valves are soft
seated to give optimum leak tightness. Materials are
available for a wide range of duties. Maintenance is
simplified as seat lapping is reduced.
9. Enhanced seat tightness – The main valve is
piston operated. The piston area is in excess of
30% larger than the seat bore area. This ensures
the seat closing force is always at least 30% greater
than the seat opening force for all pressures, right
up to the set point. This produces more effective
seat tightness, reducing the possibility of seat
leakage.
A spring loaded valve will have maximum seat
clamping force when there is no system pressure.
As the system pressure approaches the set point,
the upward acting valve opening force approaches
the closing force generated by the spring, hence the
clamping force approaches zero and seat leakage
may occur. A pilot valve with a 30% differential
piston design will maintain a 30% seat clamping
force right up to the set point, ensuring maximum
seat tightness.
4. Integral pilot filter – Safeset pilots are fitted
with integral filters.
5. Stainless steel – Safeset pilots, domes, tubes
and fittings, pistons and nozzles are made from
stainless steel as a minimum, i.e. all process
wetted parts. This reduces the risk of oxides
contaminating seals and hence prolongs their life
in service.
6. Adjustable orifice areas – The standard
range of single outlet main valves consists of 8
body sizes, which by simple adjustment
accommodates all 21 standard orifice sizes. This
allows for easy adjustment should service
conditions dictate a change in required orifice
area.
Seat clamping =
Valve closing force
force
– Valve opening force
60
10. Unique full nozzle design – The nozzle is
a patented push-in design, held in position
with a locking ring. Being of the full nozzle
design, it reduces mechanical and thermal
stresses at the seat, reduces inlet pressure
losses, increases the discharge co-efficient
and allows for lower specification body
materials on corrosive duties.
11. API 526 compliant – Fully conforms to the
latest edition of API 526 for pressure/
temperature ratings and over flange
dimensions for pilot valves.
14. Two part piston-disc assembly – This gives a
reduced guiding geometry, keeping the size of the
components within the body bowl to a minimum,
thus increasing the effective discharge area
through the valve outlet.
15. State of the art piston seals and bearing
rings – Reduce friction and galling of materials at
the guide and pistons surfaces – essential for
modulating pilots.
12. Integral sensing – Safeset pilots are sensed
from the nozzle, giving a compact design and
accurate pressure sense from within the flow
stream. Remote sensing for difficult inlet
piping systems is recommended.
13. Dual outlet option – The 8 inch valve is
also available with a dual outlet (see below).
D U A L O U T L E T / F U L L B O R E P I L O T VA LV E
This valve is suitable for extremely high
capacity duties. It achieves maximum discharge
capacities by having a full bore 8 inch inlet with
an available discharge area of 44.178 sq.in. and
two opposing 10 inch outlets, which can assist
with reaction force problems.
Available with all Pilot Types 2, 4, and 8.
61
M O D E O F O P E R AT I O N
Safeset consists of a separate pilot valve
connected to a main valve via a sensing pipe.
This pipe senses the inlet pressure within the main
valve nozzle and provides the pressure signal to
the pilot.
Pilot valve
Main valve
The main valve conforms to the latest version of
API 526 Pressure/Temperature ratings and face to
face dimensions. It has 21 orifice variants in just 8
inlet x outlet body sizes. Safeset is a differential
piston operated design, the opening is controlled
by the pilot valve.
The pilot valve controls the
discharge of fluid through the
main valve by responding
accurately to the system
pressure. All Birkett pilots
are of a non flowing design,
which means there is an absence
of system flow through the pilot
during the relief cycle.
The benefits of non flowing
designs are that freezing of
moisture-containing fluid and
the carrying of particulate
matter into the pilot are
minimised, ensuring correct
valve performance.
P I L OT VA LV E T Y P E S
Pop (Type 2) – Controls the main valve in a
rapid manner, it is either open or closed.
Specifically for gas applications.
Modulating (Types 4 and 8) – The main valve is
opened in a controlled manner, the over pressure is
constantly monitored and the opening of the main
valve is proportionate to the overpressure.
B A S I C O P E R AT I O N O F S A F E S E T
Simply, the pilot valve is a very accurate springloaded safety valve, with two seats. At low system
pressures, pressure from the system is fed from
the inlet nozzle, through the sense line, past the
lower pilot seat and into the main valve dome. The
dome area is in excess of 30% larger than the seat
bore area. This differential of areas ensures that
the main valve remains closed. When the system
pressure reaches the set point of the pilot, the
lower pilot seat closes and the upper pilot seat
opens, releasing the dome pressure to the
atmosphere. With no pressure above the piston, the
main valve opens. The reverse of this sequence of
events occurs when system pressure falls and once
again the main valve dome will be fed with system
pressure, which in turn closes the main valve.
62
P O P A C T I O N - T Y P E 2 P I L OT
Pilot construction
SETTING
SPRING
The pilot is essentially a spring loaded
safety valve with blowdown adjustment
which, during its operation, positions
itself on one of two seats. The upper
drain seat is used to determine pilot set
pressure, the lower feeding seat
determines pilot blowdown.
The valve disc is held on the soft upper
drain seat by the setting spring, which
also determines the pilot set pressure.
This valve disc is connected via a spindle
to the lower feeding seat, which controls
the system flow into the dome and
which also controls the pilot blowdown.
DISC
UPPER
DRAIN
SEAT
TO AND
FROM MAIN
VALVE DOME
EXHAUST
SPINDLE
FEEDING
The valve disc and lower feeding seat
move together; this action opens and
closes each respective seat, thereby
allowing the pilot to control the
operation of the main valve during the
relieving cycle.
LOWER
FEEDING
SEAT
FILTER
Pilot operation
With pop action pilot operation, the main valve is
either in the fully open or shut position. The
operation is characterised by a distinct rapid “pop”
action, which is evident at the opening of the main
valve, followed by a positive re-seat action when
the main valve closes.
This graph demonstrates pop action. When set
pressure is reached, the pilot valve opens rapidly;
this action de-pressurises the dome volume very
quickly and the main valve opens. This is shown by
the vertical (rising) line on the graph, illustrating
that the main valve achieves its design lift at set
pressure.
The re-seating characteristic is equally positive:
when the system pressure has fallen to the pre-set
pilot re-seat pressure, the pilot drain seat closes
rapidly. This action allows the dome to be repressurised very quickly, thereby closing the main
valve completely. This is shown on the graph by
the vertical (falling) line.
63
The re-seat pressure of the Type 2 pilot valve is
adjustable externally, independently of the set
pressure adjustment.
S TA G E S O F O P E R AT I O N - T Y P E 2 P I L OT
Stage 1
System pressure below the pilot
set pressure, dome pressurised,
main valve closed.
Stage 2
System pressure equal to set
pressure, drain seat opens,
dome de-pressurises, main valve
fully lifts with no overpressure.
Stage 3
System pressure equal to or
greater than set pressure, dome
pressure is atmospheric, main
valve is fully open.
Stage 4
System pressure falls to equal the
re-seat pressure, drain seat closes,
feeding seat opens, dome is
pressurised, main valve closes.
Stage 5
System pressure below the pilot
set pressure, dome pressurised,
main valve closed and ready for
next upset condition.
Key Points – Pilot Type 2
• Pilot set pressure = Main valve set pressure.
• Main valve fully open at 0% overpressure.
• The pilot is non flowing.
• Adjustable blow-down feature.
• Integral filter fitted.
• Gas duty only.
64
M O D U L AT I N G A C T I O N - T Y P E 4
Pilot construction
Modulating pilots are essentially
diaphragm or piston operated safety
valves with a feedback piston for fine
control of the pressure in the dome.
SETTING
SPRING
DETECTOR
DIAPHRAGM
The Type 4 Pilot is used for pressures up
to 1480Psig
When the set pressure is reached the
main valve opens in proportion to the
system pressure rise. This is achieved by
the pilot controlling the dome pressure.
The main valve will maintain a lift
necessary to discharge the system flow.
As the system pressure increases, the
main valve lift will change to
accommodate the new flow condition.
As the system pressure falls, the main
valve will begin to close, finally closing at
a pressure just below the set pressure.
RETURN
SPRING
FEEDBACK
PISTON
FEEDING
DOME
FILTER
FEEDING
SEAT
DRAIN
DRAIN
SEAT
Type 4/1 Pilot
(29 to 100 Psig)
The diaphragm senses the system
pressure and the feedback piston senses
the dome pressure. The combination of
these pressures accurately provide a
force balanced with the adjusting spring
to open/close the feeding/drain seats.
This maintains dome pressure for
accurate positioning of the main valve.
DETECTOR
PISTON
Type 4/2 Pilot
(100 to 1480 Psig)
Note: The Pilot Type 4 always drains to the main valve outlet, and a back flow preventer should be fitted (see page 72).
65
M O D U L AT I N G A C T I O N - T Y P E 8
The Type 8 Pilot is similar to the Type 4
Pilot except that instead of using a
diaphragm to lift the valve, the Type 8
Pilot uses a piston.
SETTING
SPRING
The pressure range for the Type 8 Pilot
is 1480 Psig to 6170 Psig.
Note: The Type 8 Pilot always drains to
the main valve outlet, and a back flow
preventer should be fitted (see page 72).
DETECTER
PISTON
RETURN
SPRING
FEEDBACK
PISTON
DOME
FEEDING
SEAT
DRAIN
FILTER
FEEDING
DRAIN
SEAT
Type 8 Pilot
P I L O T O P E R AT I O N
The action of the main valve may be characterised
as “modulating”. In order to achieve this the pilot
accurately controls the pressure in the main valve
dome which positions the main valve disc to
match the system upset flow condition; this will
then control the system pressure.
Effective pilot operation requires a small
overpressure above the set pressure, to achieve
full design lift of the main valve and a small
pressure drop to re-seat the main valve.
A typical modulating performance is shown in the
graph opposite. The overpressure as a
percentage of set pressure will vary with the
system flow requirement; this means that an
infinite number of relieving cycles can occur
within the limits shown. The valve lift will,
however, always be in proportion to the rise in
system pressure, ensuring a safe stable relief cycle.
66
S TA G E S O F O P E R AT I O N - T Y P E S 4 A N D 8
Type 4 & 8 Pilots are fully modulating. They are
intended for use with gas, liquid and mixed phase
fluids. Both types are non flowing designs.
STAGE 1
System pressure below set pressure
The feeding seat remains open with the drain seat
closed. This maintains equal pressures in the
dome and the system. The main valve is closed,
held tightly against the nozzle.
Pilot Valve Drain
STAGE 2
System pressure approaches set pressure
When the system pressure approaches the set
pressure the feeding seat closes. The drain seat
remains closed and the main valve is closed.
The pressure in the dome is now controlled by
the inlet system pressure acting against the pilot
diaphragm/piston and the dome pressure acting on
the feed back piston. The combination of these
two forces controls the opening of the drain seat,
thereby controlling the dome pressure and hence
the main valve lift.
P
When the drain seat opens it discharges a small
volume of fluid from the dome. At no time is the
drain seat continually flowing. It drains in short
bursts.
STAGE 3
System pressure reaches set pressure
As the system pressure gradually rises to the set
pressure, the dome pressure gradually falls
approximately 30%. Due to the differential size,
top and bottom of the piston, the main valve
opening and closing forces are now in equilibrium.
67
STAGE 4
System pressure above set pressure
As the system pressure increases above the set
pressure, modulation occurs with the main valve
opening an amount sufficient to maintain system
flow rate. This is brought about by the increased
system pressure acting against the pilot
diaphragm/piston to re-open the drain seat. The
dome pressure is reduced further, allowing the
main valve to open. The reduced dome pressure
now acting on the feedback piston produces a
lower upward force and the adjusting spring closes
the drain seat.
The above actions cycle in very small increments
and hence give the modulating effect.
STAGE 5
Main valve fully open
The main valve will be fully open before the system
pressure reaches 110% of the set pressure.
STAGE 6
Main valve closes
When the system upset condition has ended, the
system pressure will begin to fall. The reduced
system pressure acting on the pilot
diaphragm/piston will cause the feeding seat to reopen. This will increase the dome pressure and
the main valve will begin to close. The feeding seat
will close as the dome pressure increases due to
the feedback piston effect. This cycle will repeat as
the system pressure is further reduced. The main
valve will close with a progressive action. When
the system pressure reaches approximately 97% of
set pressure the main valve will be closed.
Key points – Pilot Types 4 and 8
• Pilot set pressure is when the drain seat first
opens.
• Main valve discharge maintains the system
pressure at its respective flow condition,
thereby achieving fully modulating action.
• The pilot valve is firmly closed when the main
valve closes.
• Integral filter fitted.
68
T E C H N I C A L S P E C I F I C AT I O N - P I L O T VA LV E
Valve type
2
4
8
Pilot action
Pop
Modulating
Modulating
Fluid
Gas
Gas, Liquid
Dual Phase
Gas, Liquid
Dual Phase
Overpressure
0%
<10%
<10%
Blowdown
3-10%*
<3%
<3%
Adjustable
Fixed
Fixed
5%
2%
Pilot/main valve set pressure differential
0%
Max back pressure Built up and Superimposed
70%
70%
70%
Back pressures in excess of these limits can be accommodated - consult factory
Pressure (Psig)
range
(Barg)
29-6170
2.0-425.5
29-1480
2.0-102
1480-6170
102-425.5
-65 to 500
-54 to 260
-65 to 500
-54 to 260
High pressure pilots are available - consult factory
Temp. range (deg F) -65 to 500
(deg C) -54 to 260
Accessories are available for cryogenic and high temperature applications - consult factory
*Unless otherwise required or specified, the type 2 Pilot will be factory set for 5% blowdown.
Type 2 Pilot must have the exhaust vent open to atmosphere or piped to a safe area.
Types 4 and 8 Pilots always have their exhaust vents connected into the main valve outlet.
MAIN VALVE - SOFT GOODS
Material
Temperature
degF (degC)
Pressure range
Psig (Barg)
Main valve seat
St St filled PTFE
PEEK
Viton
Buna-N
Polyurethane
-50/500 (-46/+260)
-85/500 (-65/+260)
-4/400 (-20/+205)
-50/248 (-46/+120)
-65/300 (-54/+150)
Upto 1480 (102)
Over 1480 (102)
Upto 1480 (102)
Upto 1480 (102)
400/1480 (27.6/102)
Main valve seat (NACE)
PEEK
-85/500 (-65/+260)
Viton
-4/400 (-20/+205)
Polyurethane
-65/300 (-54/+150)
Over 1480 (102)
Upto 1480 (102)
400/1480 (27.6/102)
Pilot seat and seals
Buna-N
-50/248 (-46/+120)
Viton
-4/400 (-20/+205)
EPR
-65/300 (-54/+150)
EPDM
-50/400 (-46/+205)
Aflas
-20/400 (-29/+205)
Gaskets
Carbon Fibre
Laminated graphite
All pressures
All pressures
Heating or cooling coils required
above 400degF (205degC) and below
-50degF (-46degC)
-50/500 (-46/+260)
-50/500 (-46/+260)
Static seals
Viton
-4/400 (-20/+205)
AED Viton
-4/400 (-20/+205)
Options: Buna-N, Aflas, Chemras, Kalrez
69
Upto 1480 (102)
Over 1480 (102)
PILOT VALVE - MATERIALS
Material
Temperature
degF (degC)
Body
Bonnet
Spring
Trim
St
St
St
St
St
St
St
St
316
316
316
316
All
All
All
All
M AT E R I A L S O F C O N S T R U C T I O N - M A I N VA LV E
BODY MATERIAL
Item
Description
1
2
3
4
5
6
7
8
9
10
11
12
13&25
14
15
16
19
20
21
22
23
24
27
32
Body
Nozzle
Guide
Disc holder
Disc insert
Piston
Locknut
Lift stop
Cover
Retaining plate
Disc holder seal
Piston seal
Guide rings
Body stud
Body nut
Lock ring
Spring
Body gasket
Guide seal
Nozzle seal
Retaining plate screw
Counter sunk screw
Fittings
Tubes
42
Drain plug
CARBON STEEL
† -29 to +260 ºC
STAINLESS STEEL
-46 to +260 ºC
-46 to +260 ºC
SA 216 WCB
St. St. 316
St. St. 17/4
St. St. 316
Viton *
St. St. 316
St. St. 316
St. St. 316
St. St. 316
St. St. 316
Viton *
Viton *
Carbon/PTFE
A193/B7
A194/2H
St. St. 316
St. St. 316
Carbon fibre
Viton *
Viton *
Viton *
St. St. 316
St. St. 316
St. St. 316
SA 352 LCB
St. St. 316
St. St. 17/4
St. St. 316
Viton *
St. St. 316
St. St. 316
St. St. 316
St. St.316
St. St. 316
Viton *
Viton *
Carbon/PTFE
A193/B8T
A194/8T
St. St. 316
St. St. 316
Carbon fibre
Viton *
Viton *
Viton *
St. St. 316
St. St. 316
St. St. 316
SA 351 CF8M
St. St. 316
St. St. 17/4
St. St. 316
Viton *
St. St. 316
St. St. 316
St. St. 316
St. St. 316
St. St. 316
Viton *
Viton *
Carbon/PTFE
A193/B8T
A194/8T
St. St. 316
St. St. 316
Carbon fibre *
Viton *
Viton *
Viton*
St. St. 316
St. St. 316
St. St. 316
HTS HOLO-KROME
HTS HOLO-KROME
ASTM A479-316L
Note:
*Soft goods materials listed above are standard. For a full listing to cover the temperature ranges of the body materials listed
above, it is necessary to refer to the seals, gaskets, selection table on the previous page.
†Maximum temperature is limited by the seal material.
Alternative materials and accessories are available, for NACE, high temperatures and cryogenic
applications.
70
AC C E S S O R I E S
Back Flow
Preventer
Exterior
Supply Filter
71
AC C E S S O R I E S
Back flow preventer
High back pressures may exist in the outlet for
various reasons such as common disposal systems. If
this back pressure can be more than the inlet system
operating pressure, the main valve could lift allowing
reverse flow from the outlet to inlet system.
A back flow preventer is a two-way check valve,
which is fitted into the dome line. It allows the highest
pressure from either the inlet system or outlet system
to enter the dome, ensuring the main valve remains
closed and prevents the possibility of reverse flow.
All modulating pilots (Types 4 + 8) should be fitted
with a back flow preventer.
A back flow preventer should always be fitted if
a vacuum can exist in the inlet pipework.
When using back flow preventers with back pressure
above 50% of the set pressure, the actual service
conditions must be reviewed by the factory.
Sense Line
(Max 100ft/30m including
one 90° bend. Min inside
diameter 0.254"/6mm)
External supply filter
This unit protects the pilot valve when working under
“dirty” flow stream conditions. All Safeset pilots are
fitted with integral filters as standard; however, under
conditions where there is likely to be large amounts
of particulate matter in the flow stream, a supply filter
should be used. This unit is fitted into the pilot sensing
pipe, upstream of the pilot, and is suitable for gas and
liquid duty. It is removed easily for maintenance.
Remote Pressure Sensing
Remote pressure sensing
Many codes and standards restrict the inlet
pipework pressure loss to 3% of the safety valve
set pressure. There are occasions however,
when the pipework loss is greater than this. In
these instances the safety valve should always be
connected for remote sensing. The valve is
normally supplied with integral sensing; this
means that the pilot senses pressure at the main
valve nozzle entry. Under conditions of excessive
system pressure loss, the valve, under flowing
conditions, may cycle open and closed. This is
due to the pilot sensing a reduced (artificial)
pressure.
In order to overcome this problem the valve
should be sensed remotely. The pilot in this case
should have its inlet connected directly to the
pressure source where the system pressure is
stable and not flowing. The main valve nozzle will
not contain a sensing tapping in this case.
Excessive system pressure losses will also reduce
the flow rate through the valve. This will be in
proportion to the absolute system pressure and
must be taken into account when sizing the valve.
Remote sensing will ensure that the pilot operated
safety valve operates without cycling or chatter
when high inlet pressure losses are encountered.
72
AC C E S S O R I E S
Heating or
Cooling Coils
Field Test
Connector
Remote Pressure Sensing
Heating or cooling coils
High or low temperature duties may require the
addition of coils to act as heat exchangers to either
warm or cool the medium before it enters the pilot
valve or main valve dome. This ensures that
extremeties of temperature do not affect the
operation of the safety valve.
The use of such coils allows us to use standard pilots
on valves with inlet temperatures in the range of 196°C (-320°F) to 260°C (500°F).
Field test connector
This provides verification of set pressure setting
during normal system operation. The field test
connector is a two way check valve which is fitted
into the sensing pipe and is an integral part of the pilot
operated valve system. If this facility is required, it
must be specified on the valve order.
73
An external pressure supply needs to be connected
to the check valve via an isolating valve and pressure
gauge. The external pressure should be admitted
slowly through the supply isolating valve. When the
supply pressure is greater than the system pressure
the check valve delivery seat will open and the
system seat will close.
Pressure can now be applied to the pilot and dome.
When set pressure is reached the pilot will open.
N.B. Pop action pilots will ‘pop’ open; this is the
main valve set pressure. Modulating pilots will start
to vent from their drain seat; this will occur at
approximately 2% below the main valve set pressure.
The nameplate should be referred to in order to
obtain the main valve set pressure.
The main valve may open briefly with pop action
pilots.
AC C E S S O R I E S
Others
Similar to the spring loaded safety relief valves
(see page 15), pilot valves can be fitted with:
• Packed lift levers.
• Ferrules (government rings).
• Test gags (max pressure 1480 Psig).
Available options
•
•
•
•
•
Dual pilot assemblies.
Dual pilot interlock system.
Heated or unheated control cabinets.
Dual outlet/full bore design.
Differential pressure switch.
Dual pilots
If a process plant is running, it is earning a
profit for its operator. Traditionally, when a
valve required maintenance the plant had to be
shut down, resulting in reduced earning time.
A solution to this is to install a second pilot on
to the main valve and install a simple system of
ball valves or an interlocked changeover valve
system, thus allowing one pilot to be removed
while the plant is still operating. We can offer
either solution.
74
AC C E S S O R I E S
Remote unloader
This device enables the main valve to be opened
remotely. It is a three way spool valve which can
be operated electronically or pneumatically.
The valve is mounted into the dome line and
allows a free flow from the pilot into the dome.
When remote operation is required, a signal
(pneumatic or electrical) opens the exhaust vent of
the spool valve and vents the dome, allowing the
main valve to open.
The valve will normally be supplied mounted onto
the main valve with the dome connected directly
to the pilot.
When the spool valve is energised the dome will
vent directly to atmosphere.
75
Remote Unloader
S A F E S E T P I L OT F I G U R E N U M B E R I N G S Y S T E M
P
/
Accessories
A Remote pressure sensing
B Back flow preventer
C Cooling/heating coils
D Screwed cap
E External filter
**G Test gag
*L Liquid duty
P Packed lever
T Field test connector
U Remote unloader
S Special
Inlet diameter
1 - 8"
Orifice designation D-T
X = 8" x 10" x 10" full bore
Outlet diameter 2" - 10"
Pilot
2
4
8
description
Pop action, gas
Modulating, LP
Modulating, HP
Pressure range Psig (Barg)
Range Type 2
Type 4
1
ANSI flange rating
1 150 x 150
2 300 x 150
3 600 x 150
5 900 x 300
7 1500 x 300
8 2500 x 300
A 600 x 300
B 1500 x 600
C 2500 x 600
O Special
Flange type
1 ANSI RF x RF
2 ANSI RTJ x RF
O Special
Main valve body code
1 Carbon steel SA 216-WCB
2 Carbon Steel SA 216-WCB (NACE)
3 St steel SA 351-CF8M (NACE)
4 St steel SA 351-CF8M
O Special
29 - 6170
(2.0 - 425.5)
2
29 - 100
(2.0 - 6.8)
Type 8
1480 - 6170
(102 - 425.5)
>100 - 1480
(>6.8 - 102)
These are min/max pressures of the pilot.
Several springs are required to cover these ranges
Main valve trim
1 St St 316 and
2 St St 316 and
4 St St 316 and
8 St St 316 and
9 St St 316 and
O Special
PEEK
Viton
Buna N
Polyurethane
PTFE
Main valve spring material
2 St steel 316
Z Inconel X750 (NACE)
O Special
*Dual phase duties should use the liquid trim versions of the modulating pilot Types 4 and 8
**Test gag available to a max pressure of 1480 Psig
76
DIMENSIONS
Size
(ins)
Orifice
Rating
A (ins)
D (ins)
B (ins)
C (ins)
Type 2
1x2
D, E, F
1.5 x 2
D, E, F
1.5 x 3
G, H
150x150
300x150
600x150
900x300
1500x300
2500x300
150x150
300x150
600x150
900x300
1500x300
2500x300
150x150
300x150
600x150
900x300
1500x300
2500x300
150x150
300x150
600x150
900x300
1500x300
1500x600
2500x300
2500x600
4.13
4.38
4.38
4.94
4.94
4.94
4.88
4.88
4.88
5.88
5.88
5.88
5.13
5.13
5.13
6.38
6.38
6.38
5.38
5.38
5.38
6.56
6.56
6.56
7.00
7.00
4.50
4.50
4.50
4.75
4.75
4.75
4.75
4.75
4.75
5.50
5.50
5.50
4.88
4.88
4.88
6.75
6.75
6.75
4.88
4.88
4.88
6.75
6.75
6.75
6.75
6.75
1.69
1.69
1.69
2.25
2.25
2.25
1.69
1.69
1.69
2.63
2.63
2.63
1.69
1.69
1.69
2.62
2.62
2.62
1.81
1.81
1.81
2.44
2.44
2.44
2.88
2.88
14.00
14.00
14.00
16.00
16.00
16.00
14.50
14.50
14.50
17.00
17.00
17.00
15.00
15.00
15.00
18.25
18.25
18.25
15.25
15.25
15.25
19.25
19.25
19.25
19.25
19.25
2x3
G, H, J
C (ins) C (ins)
Type Remote
4 and 8
pilot
19.00
19.00
19.00
21.00
21.00
21.00
19.50
19.50
19.50
22.00
22.00
22.00
20.00
20.00
20.00
23.25
23.25
23.25
20.25
20.25
20.25
24.25
24.25
24.25
24.25
24.25
9.00
9.00
9.00
11.50
11.50
11.50
9.50
9.50
9.50
12.50
12.50
12.50
10.25
10.25
10.25
13.50
13.50
13.50
10.50
10.50
10.50
14.50
14.50
14.50
15.00
15.00
Weight
lbs (kg)
42 (19)
45 (20.5)
45 (20.5)
53 (24)
53 (24)
53 (24)
46 (21)
49 (22)
49 (22)
57 (26)
57 (26)
57 (26)
55 (25)
62 (28)
62 (28)
79 (36)
79 (36)
79 (36)
55 (25)
60 (27)
64 (29)
93 (42)
93 (42)
93 (42)
104 (47)
104 (47)
Notes:
• Certified dimensions available on request.
SINGLE OUTLET
77
•
Dimensions A and B are for RF inlet, sensed
integrally and remotely.
•
Dimensions A and B are for RTJ inlet, sensed
remotely.
•
Add 1/2" to dimensions A and B for RTJ inlets
1" to 3" when sensed integrally.
•
Add 3/4" to dimensions A and B for RTJ inlets
4" to 6" when sensed integrally.
•
Add 1" to dimensions A and B for RTJ inlet 8"
when sensed integrally.
•
Height may vary.
•
Weight is approximate for Type 2 Pilot. For
Types 4 and 8 Pilots add approx. 5kg.
•
Cap withdrawal 40mm (1.6").
•
Additional filter 3.5kg.
Size
(ins)
Orifice
Rating
A (ins)
D (ins)
B (ins)
C (ins)
Type 2
3x4
J, K, L
4x6
L, M,
N, P
6x8
Q, R
8 x 10
S, T
150x150
300x150
600x150
600x300
900x300
1500x300
1500x600
150x150
300x150
600x150
600x300
900x300
1500x300
1500x600
150x150
300x150
600x150
600x300
150x150
300x150
600x150
600x300
150x150
300x150
6.13
6.13
6.33
7.50
7.50
7.50
7.50
7.75
7.75
7.75
9.81
9.81
9.81
9.81
9.44
9.44
9.69
9.69
10.88
10.88
11.69
11.69
10.88
10.88
6.38
6.38
6.38
7.13
7.13
7.13
7.63
8.25
8.25
8.25
9.19
9.19
9.19
10.38
9.50
9.50
9.50
10.44
11.00
11.00
11.00
12.00
11.00
11.00
2.00
2.00
2.25
3.00
3.00
3.00
3.00
2.31
2.31
2.31
3.38
3.38
3.38
3.57
2.31
2.31
2.75
2.75
2.69
2.69
3.25
3.25
1.75
1.75
17.00
17.00
17.25
20.25
20.25
20.25
20.25
20.75
20.75
20.75
25.00
25.00
25.00
25.25
25.50
25.50
25.50
26.00
29.00
29.00
29.75
30.25
31.75
31.75
8x10x10
X
C (ins) C (ins)
Type Remote
4 and 8
pilot
22.00
22.00
22.25
25.25
25.25
25.25
25.25
25.75
25.75
25.75
30.00
30.00
30.00
30.25
30.50
30.50
30.50
31.00
34.00
34.00
34.00
35.25
36.75
36.75
12.00
12.00
12.25
15.50
15.50
15.50
15.50
15.50
15.50
15.50
19.75
19.75
19.75
20.25
20.50
20.50
20.75
21.00
24.50
24.50
24.25
25.75
31.00
31.00
Weight
lbs (kg)
137 (62)
137 (62)
154 (70)
183 (83)
205 (93)
214 (97)
227 (103)
225 (102)
225 (102)
225 (102)
370 (168)
390 (177)
401 (182)
456 (207)
403 (183)
408 (185)
419 (190)
556 (252)
595 (270)
661 (300)
728 (330)
948 (430)
959 (435)
959 (435)
DUAL OUTLET
78
O P E R AT I N G P R E S S U R E S
Maximum Operating Pressures to API 526
Size
(ins)
Orifice
1x2
D, E, F
11/2x2
D, E, F
11/2x3
G, H
2x3
G, H
2x3
3x4
J
J, K
ANSI
Flange
Inlet
Outlet
Maximum
Pressure
(Psig)
Inlet
Outlet
150
300
600
900
1500
2500
150
300
600
900
1500
2500
150
300
600
900
1500
2500
150
300
600
900
1500
2500
150
300
600
900
1500
2500
150
300
600
900
1500
150
150
150
300
300
300
150
150
150
300
300
300
150
150
150
300
300
300
150
150
150
300
300
300
150
150
150
300
300
300
150
150
150
300
300
285
740
1480
2220
3705
6170
285
740
1480
2220
3705
6170
285
740
1480
2220
3705
6170
285
740
1480
2220
3705
6170
285
740
1480
2220
3650
3650
285
740
1480
2220
3705
285
285
285
740
740
740
285
285
285
740
740
740
285
285
285
740
740
740
285
285
285
740
740
740
285
285
285
740
740
740
285
285
285
740
740
Maximum Operating Pressures to API 526
Size
(ins)
Orifice
3x4
L
4x6
L, M, N
4x6
P
6x8
Q
6x8
R
8x10
T
8x10x10 X
ANSI
Flange
Inlet
Outlet
Maximum
Pressure
(Psig)
Inlet
Outlet
150
300
600
600
900
1500
150
300
600
900
1500
150
300
600
600
900
1500
1500
150
300
600
600
150
300
600
600
150
300
600
600
150
300
150
150
150
300
300
300
150
150
150
300
300
150
150
150
300
300
300
600
150
150
150
300
150
150
150
300
150
150
150
300
150
150
285
740
1240
1480
2220
2900
285
740
1480
2220
3705
285
740
1305
1480
2220
3080
3705
285
740
1330
1480
285
740
915
1480
285
740
900
1480
285
740
285
285
285
740
740
740
285
285
285
740
740
285
285
285
740
740
740
1480
285
285
285
740
285
285
285
740
285
285
285
740
285
285
Notes:
• Outlet pressure limits for temperature above 100°F to conform to ANSI/ASME B16.34.
• Pressure ratings given are for carbon steel bodies at -20°F to 100°F. Austenitic stainless steel and other
materials suitable for the service may be used within the code limits for pressure and temperature.
• API Standard 526 specifies lower allowable pressures for service temperatures above and below the
ranges given in these charts, for both carbon and stainless steel bodies.
79
F L A N G E P R E S S U R E / T E M P E R AT U R E L I M I T S
Graph 1.0
ANSI Class 150,300,600 Inlet Flange Valves
Set Pressure (Barg)
Graph 2.0
ANSI Class 900,1500,2500 Inlet Flange Valves
Set Pressure (Barg)
Valves can be operated down to -196°C (-320°F) when fitted with appropriate heating coils.
80
VA LV E S I Z I N G
Overview
Gas and Vapour Flow
A safety valve is fitted to restrict system
overpressure to a predetermined level; this is
normally 110% of the safety valve set pressure.
(1) Mass Flow (imperial units)
In order to ensure that the overpressure is not
exceeded, the flow rate through the safety valve
has to be calculated. This calculation uses
formulae which are derived from ASME VIII and
API 520 Codes which are recognised throughout
the world.
Sizing
The sizing of the safety valve uses data from the
physical properties of the fluid, the valve set
pressure, overpressure limits and effective
discharge area.
Formulae are presented for sizing valves on steam,
gas and liquid. The constants used in the sizing
formulae may have a different value dependent
upon the valve type; where this is the case, it is
clearly illustrated on the graph or table. All
discharge coefficients are relative to the valve type
and have been approved to the ASME VIII Code.
Capacity tables are also shown for sizing on dry
saturated steam, air and water. When calculating
the flow rate through the safety valve, it is
important that the flow rate through the valve is
greater than the required flow rate generated by
the system.
Selection
The safety valve selected must be suitable for the
pressure and temperature required in the system;
the appropriate section of the safety valve
catalogue should be referred to.
The selected total discharge area of the safety
valve must always be greater than the calculated
discharge area required to relieve the system flow
rate under all working conditions.
81
VA LV E S I Z I N G F O R M U L A E
A= W
TZ
C P Kd Fb Ff Fp M Kc
(2) Volumetric Flow (imperial units)
A= Q
GTZ
1.175 C P Kd Ff Fb Fp Kc
(3) Constant (C) (imperial units)
C = 520 k
k+1
2 k-1
k+1
Table 1
Nozzle Gas Constant
K
C
Imperial
C
Metric
K
C
Imperial
C
Metric
1.00
1.02
1.04
1.06
1.08
1.10
1.12
1.14
1.16
1.18
1.20
1.22
1.24
1.26
1.28
1.30
1.32
1.34
1.36
315
318
320
322
324
326
329
331
333
335
337
339
341
343
345
347
349
350
353
2.40
2.41
2.43
2.45
2.46
2.48
2.50
2.51
2.53
2.55
2.56
2.58
2.59
2.61
2.62
2.63
2.65
2.66
2.68
1.38
1.40
1.42
1.44
1.46
1.48
1.50
1.52
1.54
1.56
1.58
1.60
1.62
1.64
1.66
1.68
1.70
2.00
2.20
354
356
358
359
361
363
364
366
368
369
371
372
374
376
377
378
380
400
412
2.69
2.70
2.72
2.73
2.74
2.76
2.77
2.78
2.79
2.80
2.82
2.83
2.84
2.85
2.86
2.87
2.89
3.04
3.13
(4) Constant, Fb
Fb =
2k
k-1
Pb
P
k
2/k
(k+1)/k
- Pb
P
(k+1)/(k-1)
2
k+1
Liquid viscosity correction (Fv):
When a relief valve is sized for viscous liquid
service, it should first be sized as it was for nonviscous type application so that a preliminary
required discharge area, A, can be obtained. The
next larger orifice size should be used in
determining the Reynold’s number, R, from either
of the following relationships:
Steam Flow (Sonic and Subsonic flow)
(5) Mass Flow (imperial units)
R = VL(2800G)
e A
(8)
R = 12,700VL
u A
(9)
or
A=
W
51.5 P Kd Fsh Fb Ff Fn Fp Kc
High pressure steam correction factor Fn:Fn = 1.0 when P≤1515 Psia
Use the following formulae when P>1515 Psia
(104.5 Bara) and P<3215 Psia (221.7 Bara)
(6) Fn (imperial units)
Fn =
0.1906 P - 1000
0.2292 P - 1061
Liquid Flow
(7) Liquid Flow (imperial units)
A=
VL G
38 Kd F1 Fv Kc
(Pg - Pbg)
Viscosity Correction Factor Fv
Graph 1.0
Factor FV - capacity correction due to viscosity.
where:
VL = flow rate at the flowing temperature, in U.S.
gallons per minute.
G = specific gravity of the liquid at the flowing
temperature referred to water (1.00 at
70ºF).
e = absolute viscosity at the flowing
temperature, in centipoise.
A = effective discharge area, in square inches
(from manufacturer’s standard orifice
areas).
U = viscosity at the flowing temperature, in
Saybolt Universal seconds.
Note:
Equation 9 is not recommended for
viscosities less than 100 Saybolt Universal
seconds. Hence use Fv = 1
After the value of R is determined, the
factor Fv is obtained from graph 1.0.
Fv is applied to correct the preliminary
required discharge area. If the corrected
area exceeds the chosen standard orifice
area, the above calculations should be
repeated using the next larger standard
orifice size.
R = Reynold’s Number
82
N O M E N C L AT U R E
Symbol
Description
Imperial Units
A
Orifice discharge area
sq. ins
C
Gas constant, from the specific heat ratio (k);
if unknown use 315 (see page 81 equation (3) or Table 1)
......dimensionless......
e
Ff
Liquid absolute viscosity
Back pressure correction factor for gas - takes account
of subsonic flow Balanced Bellows Valves (Page 87, Graph 2.0)
Fb
Back pressure correction factor for gas - takes account
of subsonic flow Conventional Spring Loaded; WB 400;
B Series; Pilot Operated Valves; Type 2, 4 and 8 Pilots:
(use Graph 3.0, page 87 or equation (4) page 82)
......dimensionless......
Fl
Back pressure correction factor for balanced bellows
spring loaded valves (WB 100) liquid duty only,
(use Graph 4.0, page 88)
......dimensionless......
Fn
High temperature steam correction factor.
Fp
Subsonic flow factor for low set
pressure on gas duty only, (use Graph 5.0, page 88)
......dimensionless......
Fsh
Correction factor for superheated steam (Table 4, page 89)
.....dimensionless......
Fv
Liquid viscosity correction factor (Page 82, Graph 1.0)
......dimensionless......
G
Specific gravity
......dimensionless......
Kc
Derating factor = 0.9 for use with
bursting discs; if no bursting disc use 1.0
......dimensionless......
Kd
83
........Centipoise........
Certified ASME Code Section VIII discharge coefficient:
WB100 / 200
= 0.653 (actual)
WB 300 / 400
= 0.975 (actual)
WB 300B
= 0.925 (actual)
B Series
= 0.857 (derated)
C Series
= 0.509 (derated)
6D Series (gas/steam)
= 0.811 (derated)
6D Series (liquid)
= 0.670 (derated)
7D Series (gas/steam)
= 0.824 (derated)
7D Series (liquid)
= 0.506 (derated)
Pilots: Types 2, 4, 8
= 0.849 gases (derated)
Pilots: Types 4, 8
= 0.696 liquids (derated)
For full bore 8" x 10" x 10" pilot valves refer to page 96
......dimensionless......
k
Isentropic exponent (ratio of specific heats)
......dimensionless......
M
Molecular weight
..........kg/kmole..........
P
Set pressure + overpressure + atmospheric pressure
where:– Overpressure = 10% or 3 Psi whichever is the greater
– Atmospheric pressure = 14.7 Psia
(actuals are used on
WB valves, as the
derating factor has
been applied to the
the orifice area).
Psia
Pg
Set pressure + Overpressure
Psig
Pb
Back pressure at safety valve outlet
Psia
Pbg
Back pressure at safety valve outlet
Psig
Q
Volumetric flow rate @ 14.7 Psia and 60 ºF
SCFM
R
Reynolds number
......dimensionless......
T
Temperature at valve inlet deg.R = 460 + ºF
deg.Rankine
VL
Liquid flow rate
us gpm
W
Mass flow rate
lb/h
w
Liquid density
lb/cu ft
Z
Compressibility factor (if unknown use 1.0)
......dimensionless......
B AC K P R E S S U R E A N D B L OW D OW N L I M I T S
Figures shown are expressed as a percentage of set pressure.
Valve type
Built up Superimposed
Constant
Blowdown
back
variable back
superimposed
%
pressure %
pressure %
back pressure %
Safeset Pilot operated safety valves
Refer to page 69
Conventional spring loaded safety valves
WB 200
10
3
80
WB 400
10
3
80
10 – 15
7
B
10
3
80
10
C
D
10
10
3
3
80
80
10 – 15
15 – 20
Balanced bellows spring loaded safety valves
WB 100
50
50
50
10 – 15
WB 300
20
20
20
7
WB 300B
70
70
70
7
7D (piston) Gas 70
70
70
15 - 20
7D (piston) Liq. 50
50
50
15 - 20
ORIFICE AREAS
Orifice
letter
WB Series
in2 mm2
Safeset Pilot
in2
mm2
WB Series – Spring Loaded SRV
WB100 / 200/ 300 / 300B & 400
The actual orifice area is 11% larger than those
shown in this table. This ensures that after
derating the discharge coefficient in accordance
with industry standards, the full benefits of the
API 526 orifice area can still be obtained. It is
important to use the actual coefficient of
discharge as the areas are already derated.
D
0.110
71
0.164
106
E
0.196
127
0.256
165
F
0.307
198
0.338
218
G
0.503
325
0.616
397
H
0.785
506
0.871
562
J
1.287
830
1.427
921
K
1.838
1185
2.139
1380
L
2.853
1840
3.167
2043
M
3.600
2320
4.307
2779
Safeset – Pilot Operated SRV
N
4.340
2800
5.162
3330
P
6.380
4120
7.068
4560
Q
11.050
7130
12.864
8299
R
16.000
10300
17.758
11456
The areas shown in the table are actual orifice
areas of the main valves and are larger than the
standard API 526 dimensions. This ensures that
after derating the discharge coefficient in
accordance with industry standards, the full
benefits of the API 526 orifice area can still be
obtained. It is important to use the derated
coefficient of discharge as the areas are actuals.
S
–
–
22.118
14270
T
26.000
16770
28.860
18619
X
–
–
44.178
28302
Orifice no.
1
2
3
4
6
7
Safeflo – Spring Loaded Types
Safeflo
in2
mm2
0.062
0.110
0.196
0.442
0.070
0.169
40
71
127
285
45
109
The orifice areas shown in the table are in
accordance with industry standards. API 526
does not specify requirements for thermal
relief valves. It is important to use the derated
coefficient of discharge as the areas are actuals.
84
Table 2
Representative data on some vapours and gases useful in sizing
safety relief valves
Gas or Vapour
Acetaldehyde
Acetic Acid
Acetylene
Air
Ammonia
Argon
Benzene
Butadiene 1.3
n-Butane
Iso-Butane
i-Butane
Iso-Butylene
Carbon Dioxide
Carbon Disulphate
Carbon Monoxide
Chloride
Cyclohexane
Decane
Dowthern A
Dowthern E
Ethane
Ethene (Ethylene)
Ethyl Alcohol
Ethyl Benzine
Ethyl Chloride
Freon 11
Freon 12
Freon 22
Freon 114
Helium
n-Heptane
n-Hexane
Hydrogen Chloride
Hydrogen
Hydrogen Sulphide
Methane
Menthyl Alcochol
Menthyl Butane
Methyl Chloride
Natural Gas
Nitric Oxide
Nitrogen
Nitrous Oxide
Nonane
n-Octane
Oxygen
n-Pentane
Phenol
Propane
Propylene
Sulphur Dioxide
Steam
Styrene
Toluene
k
C
imperial
C
metric
M
√M
G*
√G
1.14
1.15
1.26
1.40
1.31
1.67
1.12
1.12
1.09
1.1
1.11
1.12
1.29
1.21
1.40
1.36
1.09
1.03
1.043
—
1.19
1.24
1.13
1.07
1.19
1.14
1.14
1.18
1.09
1.66
1.05
1.06
1.41
1.41
1.32
1.31
1.20
1.08
1.20
1.27
1.40
1.40
1.30
1.04
1.05
1.40
1.07
1.30
1.13
1.15
1.29
1.33
1.07
1.09
331
332
343
356
348
377.5
329
329
325
327
327
329
346
338
356
353
325
319
320
—
336
341
330
323
336
331
331
335
325
377
321
322
357
357
349
348
337
324
337
344
356
356
347
320
321
356
323
347
330
332
346
349
323
325
2.51
2.52
2.61
2.70
2.64
2.87
2.50
2.50
2.47
2.49
2.49
2.49
2.68
2.57
2.70
2.68
2.47
2.42
2.43
—
2.55
2.59
2.50
2.46
2.55
2.51
2.51
2.55
2.47
2.86
2.44
2.45
2.71
2.71
2.65
2.64
2.56
2.46
2.56
2.61
2.70
2.70
2.63
2.43
2.44
2.70
2.46
2.63
2.50
2.52
2.63
2.66
2.46
2.47
44
60
26.04
28.97
17.03
40
78.11
54.09
58.12
58.12
56.10
56.10
44.01
76.13
28.00
70.91
84.16
142
165
147
30.07
28.05
46.07
106.16
64.50
137.37
120.92
86.48
170.93
4
100
86.17
36.47
2.02
34.08
16.04
32
72.15
50.48
19
30
28.02
44
128
114.22
32
72.15
94
44.09
42.08
64.06
18
104.14
92
6.633
7.746
5.103
5.382
4.127
6.325
8.838
7.355
7.63
7.63
7.49
7.49
6.634
8.726
5.292
8.421
9.174
11.92
12.85
12.12
5.483
5.297
6.787
10.31
8.031
11.72
10.995
9.299
13.073
2
10
9.283
6.039
1.421
5.838
4.005
5.657
8.494
7.105
4.359
5.477
5.294
6.633
11.31
10.687
5.657
8.494
9.695
6.64
6.487
8.004
4.243
10.21
9.592
1.519
2.071
0.899
1
0.587
1.381
2.70
1.922
2.07
2.07
1.937
1.998
1.53
2.628
0.967
2.45
2.905
4.91
5.696
5.074
1.05
0.977
1.59
3.67
2.226
4.742
4.174
2.985
5.90
0.138
3.49
2.97
1.27
0.070
1.19
0.555
1.11
2.49
1.742
0.656
1.036
0.967
1.519
4.43
3.94
1.10
2.49
3.27
1.55
1.476
2.26
0.622
3.60
3.18
1.232
1.439
0.948
1
0.766
1.175
1.643
1.386
1.439
1.439
1.392
1.413
1.237
1.621
0.983
1.565
1.705
2.216
2.386
2.253
1.025
0.988
1.261
1.916
1.492
2.177
2.043
1.727
2.429
0.3716
1.868
1.723
1.127
0.265
1.091
0.745
1.054
1.578
1.320
0.8099
1.018
0.9834
1.233
2.105
1.985
1.0490
1.578
1.808
1.245
1.214
1.503
0.7887
1.897
1.783
*Air = 1.0 at 14.7 Psia and 60ºF.
85
Table 3
Representative data on liquids useful in sizing safety valves
Liquid
G**
G
Liquid
G**
G
Acetic Acid
1.05
1.025
n-Heptane
0.688
0.830
Acetone
0.792
0.890
n-Hexane
0.664
0.815
Ammonia
0.617
0.786
Hydrochloric Acid (40%)
1.20
1.095
Benzene
0.885
0.941
Kerosene
0.82
0.906
1, 2 Butadiene
0.658
0.811
Methane
0.248
0.498
1, 3 Butadiene
0.627
0.792
Methyl Alcohol (100%)
0.796
0.892
Iso-Butane
0.563
0.750
Methyl Butane
0.625
0.791
n-Butane
0.584
0.764
Naphtha
0.88
0.938
j-Butane
0.601
0.775
Nitric Acid (91%)
1.50
1.225
Carbon Dioxide
0.816
0.903
Nitrogen
0.804
0.897
Carbon Disulphide
1.26
1.122
Iso-Octane
0.696
0.834
Chlorine
1.423
1.93
n-Octane
0.707
0.841
Oils, Minerals and
Lubricants
0.910
0.954
Iso-Pentane
0.625
0.791
n-Pentane
0.631
0.794
Dowtherm A at 212ºF
0.997
0.999
Dowtherm E at 212ºF
1.181
1.086
Ethane
0.377
0.614
Ethyl Alcohol
0.794
0.891
Ethyl Benene
0.872
0.934
Fuel Oil, Bunker C
1.014 (max.) 1.007
Fuel Oil, No. 3 (60ºF)
0.898 (max.) 0.948
Fuel Oil, No. 5 (60ºF)
0.993 (max.) 0.997
Fuel Oil, No. 6 (60ºF)
0.993 (min.)
Petrol (Gasoline)
0.75
0.997
0.886
Phosphoric Acid
1.88
1.371
Propane
0.508
0.713
Polythene
0.522
0.723
Styrene
0.911
0.955
Sulphuric Acid (87%)
1.80
1.342
Water
1.00
1.00
**Water = 1.0 at 70ºF.
86
Graph 2.0
Factor Ff – For application sizing and capacity determination of balanced bellows safety
relief valves against variable and constant back pressure – vapours and gases only.
Graph 3.0
Use the curve to evaluate back pressure correction factor Fb, for pilot valves and for
conventional valves with constant back pressure use.
87
Graph 4.0
Factor Fl – For application sizing and capacity determination of balanced bellows safety
relief valves against variable or constant back pressure – liquids only (10% overpressure).
Graph 5.0
Factor Fp – For low set pressure – vapours and gases only.
88
Table 4
Superheated Steam Correction Factors – FSH
For capacity on superheated steam, multiply saturated steam capacity by correction factor below
89
Set
Pressure
p.s.i.—
gauge
Saturated
steam
Temp.°F
300
400
500
600
700
800
900
1000
1100
1200
15
250
1.00
0.98
0.93
0.88
0.84
0.80
0.77
0.74
0.72
0.70
20
259
1.00
0.98
0.93
0.88
0.84
0.80
0.77
0.74
0.72
0.70
40
287
1.00
0.99
0.93
0.88
0.84
0.81
0.77
0.74
0.72
0.70
60
308
1.00
0.99
0.93
0.88
0.84
0.81
0.77
0.75
0.72
0.70
80
324
1.00
0.99
0.93
0.88
0.84
0.81
0.77
0.75
0.72
0.70
100
338
1.00
0.99
0.94
0.89
0.84
0.81
0.77
0.75
0.72
0.70
120
350
1.00
0.99
0.94
0.89
0.84
0.81
0.78
0.75
0.72
0.70
140
361
1.00
0.99
0.94
0.89
0.85
0.81
0.78
0.75
0.72
0.70
160
371
1.00
0.99
0.94
0.89
0.85
0.81
0.78
0.75
0.72
0.70
180
380
1.00
0.99
0.94
0.89
0.85
0.81
0.78
0.75
0.72
0.70
200
388
1.00
0.99
0.95
0.89
0.85
0.81
0.78
0.75
0.72
0.70
220
395
1.00
0.99
0.95
0.89
0.85
0.81
0.78
0.75
0.72
0.70
240
403
-
1.00
0.95
0.90
0.85
0.81
0.78
0.75
0.72
0.70
260
409
-
1.00
0.95
0.90
0.85
0.81
0.78
0.75
0.72
0.70
280
416
-
1.00
0.96
0.90
0.85
0.81
0.78
0.75
0.72
0.70
300
422
-
1.00
0.96
0.90
0.85
0.81
0.78
0.75
0.72
0.70
350
436
-
1.00
0.96
0.90
0.86
0.82
0.78
0.75
0.72
0.70
400
448
-
1.00
0.96
0.91
0.86
0.82
0.78
0.75
0.72
0.70
500
470
-
1.00
0.96
0.92
0.86
0.82
0.78
0.75
0.73
0.70
600
489
-
1.00
0.97
0.92
0.87
0.82
0.79
0.75
0.73
0.70
800
520
-
-
1.00
0.95
0.88
0.83
0.79
0.76
0.73
0.70
1000
546
-
-
1.00
0.96
0.89
0.84
0.78
0.76
0.73
0.71
1250
574
-
-
1.00
0.97
0.91
0.85
0.80
0.77
0.74
0.71
1500
597
-
-
-
1.00
0.93
0.86
0.81
0.77
0.74
0.71
1750
618
-
-
-
1.00
0.94
0.86
0.81
0.77
0.73
0.70
2000
636
-
-
-
1.00
0.95
0.86
0.80
0.76
0.72
0.69
2500
670
-
-
-
1.00
0.95
0.85
0.78
0.73
0.69
0.66
3000
690
-
-
-
-
1.00
0.82
0.74
0.69
0.65
0.62
Total Steam Temperature in Degrees Fahrenheit
Pressure Protection
90
WAT E R C A PA C I T Y C H A R T
Water Capacity U.S.G.P.M.
WB 100/200
10% over pressure or 3 Psig minimum
ORIFICE SIZE LETTER DESIGNATION
Set
Psig
Gauge
10
20
30
40
50
60
70
80
90
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
420
440
460
480
500
520
540
560
580
600
620
640
660
680
700
720
740
760
780
800
850
900
950
1000
1100
1300
1500
1750
2000
2250
2500
2750
3000
3250
3500
3750
4000
4250
4500
4750
5000
5250
5500
5750
6000
D
E
F
G
H
10
13
16
18
20
22
24
26
27
29
31
34
36
38
40
42
44
46
48
50
51
53
54
56
57
59
60
61
63
64
65
67
68
69
70
71
72
74
75
76
77
78
79
80
81
83
86
88
91
95
103
111
120
128
136
143
150
157
163
169
175
181
187
192
197
202
207
212
217
222
18
23
28
32
36
40
43
46
48
51
56
60
65
68
72
76
79
82
85
88
91
94
97
99
102
105
107
109
112
114
116
119
121
123
125
127
129
131
133
135
137
139
141
142
144
149
153
157
161
169
184
198
213
228
242
255
267
279
291
302
312
323
333
342
352
361
370
378
387
395
28
37
44
51
56
62
67
71
76
80
88
95
101
107
113
119
124
129
134
138
143
147
152
156
160
164
168
171
175
179
182
186
189
192
196
199
202
205
208
211
214
217
220
223
226
233
240
246
253
265
288
309
334
357
379
399
419
438
455
473
489
505
521
536
551
565
45
60
72
83
93
101
110
117
124
131
143
155
166
176
185
194
203
211
219
227
234
241
248
255
262
268
275
281
287
293
299
304
310
315
321
326
331
336
341
346
351
356
361
366
370
382
393
403
414
434
472
507
548
585
621
655
686
717
746
774
70
93
112
129
144
158
171
183
194
204
224
242
258
274
289
303
316
329
342
354
365
377
388
398
409
419
429
438
448
457
466
475
483
492
500
509
517
525
533
541
548
556
563
571
578
596
613
630
646
678
737
791
855
914
969
1021
1071
J
115
153
183
212
237
259
280
300
318
335
367
396
424
449
474
497
519
540
560
580
599
618
636
653
670
686
703
718
734
749
764
778
793
807
820
834
847
860
873
886
899
911
923
935
947
977
1005
1032
1059
1111
1208
1297
1401
1498
1589
1675
Note: This chart should be used as a guideline only.
91
K
L
M
N
P
Q
R
T
164
219
262
303
338
371
400
428
454
478
524
566
605
642
676
709
741
771
800
829
856
882
908
932
957
980
1003
1026
1048
1070
1091
1112
1132
1152
1172
1191
1210
1229
1247
1266
1284
1301
1319
1336
1353
1395
1435
1474
1513
1586
1725
1853
2001
2139
255
340
407
470
525
575
621
664
704
742
813
879
939
996
1050
1101
1150
1197
1242
1286
1328
1369
1409
1447
1485
1522
1557
1592
1627
1660
1693
1725
1757
1788
1819
1849
1878
1908
1936
1964
1992
2020
2047
2074
2100
2165
2227
2289
2348
2463
2677
2876
322
428
513
593
662
726
784
838
889
937
1026
1109
1185
1257
1325
1390
1451
1511
1568
1623
1676
1728
1778
1826
1874
1920
1965
2009
2053
2095
2136
2177
2217
2256
2295
2333
2370
2407
2443
2479
2514
2549
2583
2617
2650
2732
2811
2888
2963
3107
388
516
619
714
799
875
945
1010
1072
1129
1237
1336
1429
1515
1597
1675
1750
1821
1890
1956
2020
2083
2143
2202
2259
2315
2369
2422
2475
2526
2576
2625
2673
2720
2767
2812
2857
2902
2945
2988
3031
3073
3114
3154
3195
3293
3388
3481
3572
571
759
909
1050
1174
1286
1389
1485
1575
1660
1819
1965
2100
2228
2348
2463
2572
2677
2778
2876
2970
3062
3150
3237
3321
3403
3483
3561
3638
3713
3786
3858
3929
3999
4067
4134
4201
4266
4330
4393
4455
4517
4577
4637
4696
4841
4981
5118
5251
989
1315
1575
1819
2033
2228
2406
2572
2728
2876
3150
3403
3638
3858
4067
4265
4455
4637
4812
4981
5144
5303
5456
5606
5752
5894
6032
6168
6301
6430
6558
6683
6805
6926
7044
1431
1904
2281
2634
2944
3225
3484
3724
3850
4164
4561
4927
5267
5587
5889
6176
6451
6714
6968
7212
2326
3094
3706
4280
4785
5241
5661
6052
6419
6767
7412
8006
8559
9078
9569
10036
10483
10911
11323
11720
S AT U R AT E D S T E A M C A PA C I T Y C H A R T
WB 400
Saturated Steam Capacities lb/hr
10% over pressure or 3 Psig minimum
ORIFICE SIZE LETTER DESIGNATION
Set
Psig
Gauge
10
20
30
40
50
60
70
80
90
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
420
440
460
480
500
520
540
560
580
600
620
640
660
680
700
720
740
760
780
800
850
900
950
1000
1100
1300
1500
1750
2000
2250
2500
2750
2900
D
E
F
G
142
208
263
324
385
446
506
567
628
689
810
932
1053
1175
1296
1418
1539
1661
1782
1940
2025
2147
2268
2390
2511
2633
2755
2876
2998
3119
3241
3362
3484
3605
3727
3848
3970
4091
4213
4334
4456
4577
4699
4820
4942
5246
5549
5853
6157
6764
7980
9155
10820
12561
14403
16381
18549
19976
252
371
469
578
686
794
902
1011
1119
1227
1444
1660
1877
2093
2310
2526
2743
2959
3176
3392
3609
3825
4042
4258
4475
4692
4908
5125
5341
5558
5774
5991
6207
6424
6640
6857
7073
7290
7506
7723
7939
8156
8372
8589
8805
9347
9888
10429
10970
12053
14218
16313
19279
22382
25664
29189
33052
35593
395
581
735
905
1074
1244
1414
1583
1753
1922
2261
2601
2940
3279
3618
3957
4296
4635
4974
5314
5653
5992
6331
6670
7009
7348
7688
8027
8366
8705
9044
9383
9722
10062
10401
10740
11079
11418
11757
12096
12435
12775
13114
13453
13792
14640
15488
16336
17183
18879
22270
25551
30198
35058
40199
45719
51770
55751
648
952
1205
1483
1760
2038
2316
2594
2872
3150
3705
4261
4816
5372
5928
6483
7039
7595
8150
8706
9262
9817
10373
10929
11484
12040
12596
13151
13707
14263
14818
15374
15930
16485
17041
17596
18152
18708
19263
19819
20375
20930
21486
22042
22597
23986
25376
26765
28154
30932
36489
41863
49477
57440
65863
74907
84821
91344
H
1011
1486
1880
2314
2747
3181
3615
4048
4482
4915
5782
6650
7517
8384
9251
10118
10985
11853
12720
13587
14454
15321
16188
17056
17923
18790
19657
20524
21392
22259
23126
23993
24860
25727
26595
27462
28329
29196
30063
30930
31798
32665
33532
34399
35266
37434
39602
41770
43938
48274
56945
65334
77216
89643
102788
116903
132375
J
1658
2436
3083
3793
4504
5215
5926
6637
7348
8059
9480
10902
12324
13745
15167
16589
18011
19432
20854
22276
23697
25119
26541
27963
29384
30806
32228
33649
35071
36493
37915
39336
40758
42180
43601
45023
46445
47867
49288
50710
52132
53553
54975
56397
57819
61373
64927
68482
72036
79144
93362
107114
126594
146969
168520
191662
217028
K
2367
3479
4402
5417
6433
7448
8463
9478
10493
11509
13539
15569
17600
19630
21661
23691
25721
27752
29782
31813
33843
35873
37904
39934
41965
43995
46025
48056
50086
52116
54147
56177
58208
60238
62268
64299
66329
68360
70390
72420
74451
76481
78512
80542
82572
87648
92724
97800
102876
113028
133332
152972
180793
209891
240668
L
3675
5401
6833
8409
9985
11561
13137
14712
16288
17864
21016
24167
27319
30471
33622
36774
39926
43077
46229
49380
52532
55684
58835
61987
65139
68290
71442
74594
77745
80897
84048
87200
90352
93503
96655
99807
102958
106110
109262
112413
115565
118716
121868
125020
128171
136050
143930
151809
159688
175446
206962
237448
M
4637
6815
8622
10611
12599
14588
16576
18565
20553
22541
26518
30495
34472
38449
42426
46402
50379
54356
58333
62310
66287
70263
74240
78217
82194
86171
90148
94124
98101
102078
106055
110032
114008
117985
121962
125939
129916
133893
137869
141846
145823
149800
153777
157754
161730
171673
181615
191557
201499
221383
N
5590
8216
10395
12792
15189
17586
19983
22381
24778
27175
31969
36763
41558
46352
51146
55941
60735
65529
70324
75118
79912
84706
89501
94295
99089
103884
108678
113472
118266
123061
127855
132649
137444
142238
147032
151826
156621
161415
166209
171004
175798
180592
185386
190181
194975
206961
218946
230932
242918
P
8217
12077
15281
18805
22329
25853
29377
32901
36242
39948
46996
54044
61092
68140
75185
82235
89283
96331
103379
110427
117474
124522
131570
138618
145666
152714
159761
166809
173857
180905
187953
195001
202048
209096
216144
223192
230240
237288
244335
251383
258431
265479
272527
279574
286622
304242
321861
339481
357101
Q
14232
20918
26466
32570
38673
44776
50880
56983
63086
69190
81396
93603
105810
118016
130223
142430
154636
166843
179049
191256
203463
215669
227876
240083
252289
264496
276703
288909
301116
313323
325529
337736
349943
362149
374356
R
20607
30288
38322
47160
55997
64834
73672
82509
91347
100184
117859
135534
153208
170883
188558
206233
223908
241582
259257
276932
T
33487
49218
62274
76634
90995
105356
119717
134077
148438
162799
191521
220242
248964
277685
306407
335128
363850
392571
421193
450014
Note: This chart should be used as a guideline only.
92
A I R C A PA C I T Y C H A R T
Air Capacity s.c.f.m.
WB 400
10% over pressure or 3 Psig minimum
ORIFICE SIZE LETTER DESIGNATION
Set
Psig
Gauge
10
20
30
40
50
60
70
80
90
100
120
140
160
180
200
220
240
260
280
300
320
340
360
380
400
420
440
460
480
500
520
540
560
580
600
620
640
660
680
700
720
740
760
780
800
850
900
950
1000
1100
1300
1500
1750
2000
2250
2500
2750
3000
3250
3500
3750
4000
4250
4500
4750
5000
5250
5500
5750
6000
D
E
F
G
50
74
94
115
137
159
180
202
224
245
289
332
375
418
462
505
548
592
635
678
721
765
808
851
895
938
981
1024
1068
1111
1154
1198
1241
1284
1327
1371
1414
1457
1501
1544
1587
1630
1674
1717
1760
1868
1977
2085
2193
2409
2842
3275
3816
4357
4898
5439
5980
6521
7062
7603
8144
8685
9226
9767
10308
10849
11390
11931
12472
13013
89
131
167
206
244
283
321
360
399
437
514
591
668
746
823
900
977
1054
1131
1208
1285
1363
1440
1517
1594
1671
1748
1825
1902
1980
2057
2134
2211
2288
2365
2442
2519
2597
2674
2751
2828
2905
2982
3059
3136
3329
3522
3715
3908
4293
5064
5836
6800
7764
8728
9692
10656
11620
12584
13548
14512
15476
16440
17404
18368
19332
20296
21260
22224
23188
140
205
262
322
383
443
503
564
624
685
805
926
1047
1168
1289
1409
1530
1651
1772
1893
2013
2134
2255
2376
2497
2617
2738
2859
2980
3101
3221
3342
3463
3584
3705
3825
3946
4067
4188
4309
4429
4550
4671
4792
4913
5215
5517
5819
6121
6724
7932
9140
10650
12160
13670
15180
16690
18200
19710
21220
22730
24240
25750
27260
28770
30280
229
336
429
528
627
726
825
924
1023
1122
1320
1518
1716
1913
2111
2309
2507
2705
2903
3101
3299
3497
3695
3893
4091
4288
4486
4684
4882
5080
5278
5476
5674
5872
6070
6268
6466
6663
6861
7059
7257
7455
7653
7851
8049
8544
9038
9533
10028
11018
12997
14976
17450
19924
22398
24872
27346
29820
32294
34768
H
357
525
670
824
979
1133
1287
1442
1596
1751
2060
2369
2677
2986
3295
3604
3913
4222
4531
4840
5148
5457
5766
6075
6384
6693
7002
7311
7619
7928
8237
8546
8855
9164
9473
9782
10090
10399
10708
11017
11326
11635
11944
12253
12561
13334
14106
14878
15650
17195
20283
23372
27233
31094
34955
38816
42677
J
586
861
1098
1351
1604
1858
2111
2364
2617
2870
3377
3883
4390
4896
5402
5909
6415
6922
7428
7934
8441
8947
9454
9960
10466
10973
11479
11986
12492
12998
13505
14011
14518
15024
15530
16037
16543
17050
17556
18062
18569
19075
19581
20088
20594
21860
23126
24392
25658
28190
33254
38318
44648
50978
57308
63638
69968
Note: This chart should be used as a guideline only.
93
K
836
1229
1568
1930
2291
2653
3014
3376
3738
4099
4822
5546
6269
6992
7715
8438
9162
9885
10608
11331
12054
12778
13501
14224
14947
15670
16394
17117
17840
18563
19286
20010
20733
21456
22179
22902
23626
24349
25072
25795
26518
27242
27965
28688
29411
31219
33027
34835
36643
40259
47491
54723
63763
72803
81843
L
1298
1908
2434
2995
3557
4118
4679
5240
5802
6363
7486
8608
9731
10853
11976
13098
14221
15344
16466
17589
18711
19834
20956
22079
23202
24324
25447
26569
27692
28814
29937
31060
32182
33305
34427
35550
36672
37795
38918
40040
41163
42285
43408
44530
45653
48460
51266
54072
56879
62492
73717
84943
M
1638
2408
3071
3779
4488
5196
5904
6612
7321
8029
9445
10862
12278
13695
15111
16528
17944
19361
20777
22194
23610
25027
26443
27860
29276
30693
32109
33526
34942
36359
37775
39192
40608
42025
43441
44858
46274
47691
49107
50524
51940
53357
54773
56190
57606
61148
64689
68230
71771
78854
N
1975
2902
3703
4556
5410
6264
7118
7972
8826
9679
11387
13095
14802
16510
18218
19925
21633
23341
25048
26756
28464
30171
31879
33587
35294
37002
38710
40417
42125
43833
45540
47248
48956
50663
52371
54079
55786
57494
59202
60909
62617
64325
66032
67740
69448
73717
77986
82255
86524
P
2903
4267
5443
6698
7953
9208
10464
11719
12974
14229
16739
19250
21760
24271
26781
29291
31802
34312
36822
39333
41843
44353
46664
49374
51884
54395
56905
59415
61926
64436
66946
69457
71967
74478
76988
79498
82009
84519
97029
89540
92050
94560
97071
99581
102091
108367
114643
120919
127195
Q
5028
7390
9427
11601
13775
15949
18123
20297
22471
24644
28992
33340
37688
42036
46384
50732
55080
59427
63775
68123
72471
76819
81167
85515
89862
94210
98558
102906
107254
111602
115950
120297
124645
128993
133341
R
7280
10700
13650
16798
19945
23093
26241
29389
32537
35684
41980
48275
54571
60866
67162
73458
79753
86049
92344
98640
T
11830
17388
22181
27296
32411
37526
42642
47757
52872
57987
68217
78448
88678
98908
109138
119369
129599
139829
150059
160290
A I R C A PA C I T Y C H A R T
Main Valve Discharge Capacities s.c.f.m.
Pilot:Types 2, 4 & 8
10% over pressure or 3 Psig whichever is the greater. Kd = 0.849
ORIFICE SIZE LETTER DESIGNATION (DISCHARGE AREA sq in)
*
Set
Psig
Gauge
D
E
(0.164) (0.256)
F
(0.338)
G
(0.616)
H
(0.871)
29
40
60
80
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
1200
1400
1480
1600
1800
2000
2200
2400
2600
2800
3000
3500
3705
4000
4350
4500
5000
5500
6000
6170
119
150
206
262
319
459
600
740
881
1021
1162
1302
1442
1583
1723
1864
2004
2145
2285
2426
2566
2707
2847
3409
3971
4196
4533
5095
5657
6219
6781
7343
7905
8467
9872
10448
11277
12261
12682
14087
15492
16897
17375
246
309
425
541
657
946
1236
1525
1815
2104
2394
2683
2973
3263
3552
3842
4131
4421
4710
5000
5289
5579
5869
7027
8185
8648
9343
10501
11660
12818
13976
15134
16293
17451
20346
21533
23242
25269
26137
29033
31929
34824
35809
448
563
774
985
1196
1724
2252
2780
3307
3835
4363
4890
5418
5946
6474
7001
7529
8057
8584
9112
9640
10168
10695
12806
14917
15761
17028
19139
21249
23360
25471
27582
29693
31804
37081
39244
42358
46052
47635
52912
58189
63466
65261
634
796
1095
1393
1692
2438
3184
3930
4676
5423
6169
6915
7661
8407
9153
9900
10646
11392
12138
12884
13630
14377
15123
18107
21092
22286
24077
27061
30046
33031
36015
39000
41985
44969
52431
55490
59892
65116
67354
74816
82277
89739
92276
186
234
322
410
497
717
936
1155
1374
1594
1813
2032
2252
2471
2690
2910
3129
3348
3568
3787
4006
4225
4445
5322
6199
6550
7076
7954
8831
9708
10585
11463
12340
13217
15410
16309
17603
19138
19796
21989
24183
26376
27121
J
(1.429)
1039
1307
1796
2286
2776
4000
5224
6448
7672
8896
10121
11345
12569
13793
15017
16242
17466
18690
19914
21138
22363
23587
24811
29708
34604
36563
39501
44398
49295
54191
59088
63985
68882
73778
86020
91039
98262
106831
110504
122746
134988
147230
151392
K
(2.139)
1556
1956
2689
3422
4155
5987
7819
9652
11484
13317
15149
16982
18814
20646
22479
24311
26144
27976
29809
31641
33473
35306
37138
44468
51798
54730
59127
66457
73787
81116
88446
95776
103106
110435
128759
136272
L
(3.166)
2303
2895
3980
5064
6149
8862
11574
14286
16998
19710
22423
25135
27847
30559
33272
35984
38696
41408
44121
46833
49545
52257
54969
65818
76667
81007
87516
98365
109214
120063
130912
141761
152610
163459
190581
201701
M
(4.307)
3133
3938
5414
6890
8366
12055
15745
19435
23124
26814
30504
34193
37883
41573
45262
48952
52642
56332
60021
63711
67401
71090
74780
89539
104298
110201
119056
133815
148574
163333
178091
192850
207609
222368
259265
274392
N
(5.162)
3755
4720
6488
8257
10026
14448
18871
23293
27715
32137
36559
40981
45403
49826
54248
58670
63092
67514
71936
76358
80781
85203
89625
107313
125002
132077
142691
160379
178068
195756
213445
231134
248822
266511
310732
328863
P
Q
R
S
T
(7.068) (12.864) (17.758) (22.118) (28.862)
5141
6462
8884
11306
13728
19783
25838
31893
37948
44003
50058
56113
62168
68223
74278
80333
86388
92443
98498
104553
110608
116663
122718
146938
171157
180845
195377
219597
243817
268037
292257
316477
340696
364916
425466
450291
9357
12917
11762
16236
16170
22321
20578
28406
24986
34492
36006
49704
47026
64917
58047
80130
69067
95343
80087 110556
91107 125768
102128 140981
113148 156194
124168 171407
135188 186620
146209 201832
157229 217045
168249 232258
179269 247471
190290 262684
201310 277896
212330 293109
223350 308322
267431 369173
311512 430024
329145 454365
355593 490876
399674 551727
443755 612578
487836 673429
531917 734281
575998 795132
620079 855983
664160 916834
774363 1068962
819546 1131335
16088
20223
27802
35381
42960
61908
80856
99804
118752
137700
156647
175595
194543
213491
232439
251387
270335
289283
308231
327179
346126
365074
384022
459814
535605
565922
20994
26387
36276
46166
56055
80779
105502
130226
154949
179673
204397
229120
253844
278567
303291
328015
352738
377462
402185
426909
451633
476356
501080
599974
698868
738426
*Note: Type 4 Pilot is available to 1480 Psig.
Type 8 Pilot is available from 1480 Psig.
For 8" x 10" x 10" full bore capacity chart see page 96.
94
WAT E R C A PA C I T Y C H A R T - U . S . G . P. M .
Pilot: Types 4 and 8
Main Valve Discharge Capacities Water u.s.g.p.m.
10% over pressure or 3 Psig whichever is the greater. Kd = 0.696
ORIFICE SIZE LETTER DESIGNATION (DISCHARGE AREA sq in)
Set
Psig
Gauge
*
29
40
60
80
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
1200
1400
1480
1600
1800
2000
2200
2400
2600
2800
3000
3500
3705
4000
4350
6170
D
E
(0.164) (0.256)
25
29
35
41
45
56
64
72
79
85
91
97
102
107
111
116
120
125
129
133
136
140
144
158
170
175
182
193
203
213
223
232
241
249
269
277
288
300
357
38
45
55
64
71
87
100
112
123
133
142
151
159
167
174
181
188
194
201
207
213
219
225
246
266
273
284
301
318
333
348
362
376
389
420
432
449
468
558
F
(0.338)
G
(0.616)
H
(0.871)
J
(1.429)
K
(2.139)
L
(3.166)
M
(4.307)
N
(5.162)
51
59
73
84
94
115
133
148
162
175
188
199
210
220
230
239
248
257
265
273
281
289
269
325
351
361
375
398
419
440
459
478
496
514
555
571
593
618
736
92
108
132
153
171
209
242
270
296
320
342
362
382
401
419
436
452
468
483
498
513
527
540
592
639
657
683
725
764
801
837
871
904
936
1011
1040
1081
1127
1342
130
153
187
216
242
296
342
382
418
452
483
513
540
567
592
616
639
662
683
704
725
745
764
837
904
929
966
1025
1080
1133
1184
1232
1278
1323
1429
1471
1528
1593
1898
214
251
307
355
396
485
561
627
687
742
793
841
886
930
971
1011
1049
1086
1121
1156
1189
1222
1253
1373
1483
1525
1586
1682
1773
1859
1942
2021
2097
2171
2345
2413
2507
2614
3114
320
375
460
531
593
727
839
938
1028
1110
1187
1259
1327
1391
1453
1513
1570
1625
1678
1730
1780
1829
1876
2055
2220
2283
2373
2517
2653
2783
2907
3025
3140
3250
3510
3612
473
555
680
785
878
1076
1242
1389
1521
1643
1756
1863
1964
2060
2151
2239
2324
2405
2484
2560
2635
2707
2777
3042
3286
3379
3513
3726
3927
4119
4302
4478
4647
4810
5196
5346
644
756
925
1069
1195
1463
1690
1889
2069
2235
2389
2534
2671
2802
2926
3046
3161
3272
3379
3483
3584
3682
3778
4139
4470
4596
4779
5069
5343
5604
5853
6092
6322
6544
7068
7272
771
906
1109
1281
1432
1754
2025
2264
2480
2679
2864
3037
3202
3358
3507
3651
3788
3921
4050
4175
4296
4413
4528
4960
5358
5509
5728
6075
6404
6716
7015
7301
7577
7843
8471
8716
*Note: Type 4 Pilot is available to 1480 Psig.
Type 8 Pilot is available from 1480 Psig.
For 8" x 10" x 10" full bore capacity chart see page 96.
95
P
Q
R
S
T
(7.068) (12.864) (17.758) (22.118) (28.862)
1056
1240
1519
1754
1961
2401
2773
3100
3396
3668
3921
4159
4384
4598
4802
4999
5187
5369
5545
5716
5882
6043
6200
6792
7336
7543
7842
8318
8768
9196
9605
9997
10374
10739
11599
11934
1922
2257
2764
3192
3568
4370
5046
5642
6181
6676
7137
7570
7979
8368
8741
9097
9441
9772
10093
10403
10705
10998
11284
12361
13351
13728
14273
15139
15958
16737
17481
18195
18882
19545
21111
21720
2654
3115
3816
4406
4926
6033
6966
7788
8532
9215
9852
10449
11015
11552
12066
12559
13033
13490
13932
14361
14778
15183
15577
17064
18431
18950
19703
20899
22029
23104
24132
25117
26065
26980
29142
29983
3305
3880
4752
5488
6135
7514
8677
9701
10627
11478
12271
13015
13719
14389
15028
15642
16232
16802
17353
17887
18406
18910
19401
21253
22956
23603
4313
5063
6201
7161
8006
9805
11322
12659
13867
14978
16012
16983
17902
18776
19611
20411
21182
21925
22644
23341
24018
24676
25317
27734
29956
30800
D U A L O U T L E T / F U L L B O R E P I L O T VA LV E
This valve is suitable for extremely high
capacity duties. It achieves maximum discharge
capacities by having a full bore 8 inch inlet with
an available discharge area of 44.178 sq.in. and
two opposing 10 inch outlets, which can assist
with reaction force problems.
Available with Pilot Types 2 and 4.
Capacity chart (full bore 8" x 10" x 10" pilot valve)
Actual orifice area
Air S.C.F.M.
Water U.S.G.P.M.
44.178sq.in.
@ 60ºF and 10% over pressure
@ 10% over pressure
Set pressure
Psig
Pilot types 2 and 4
Derated kd 0.802
Pilot type 4
Derated kd 0.658
29
30270
6239
50
45275
8192
100
81002
11585
150
116729
14189
200
152455
16384
250
188182
18318
300
223909
20067
350
259635
21674
400
295362
23171
450
331089
24576
500
366815
25906
550
402542
27170
600
438269
28378
650
473995
29537
700
509722
30652
740
538303
31516
*Note: Pilot type 2 is available from 29 Psig. Overpressure at 29 Psig is 3 Psig minimum.
96
R E A C T I O N F O R C E - VA P O U R A N D G A S E S
The discharge from a safety relief valve exerts a
reaction force on the valve or outlet piping. If the
discharge piping is unsupported, this force is
transmitted to the valve inlet and associated piping.
The following formula can be used to determine
the reaction force, assuming that critical flow of
the gas or vapour occurs at the valve outlet.
kT
F =W
(k+1) M
366
+(Po x Ao)
F = Reaction force (lbs).
W = Flow rate of gas or vapour (lb/hr).
K = Ratio of specific heat (imperial).
M = Molecular weight of gas or vapour.
T = Temperature at valve inlet, degrees
Rankine
(equal to degrees F plus 460).
Po = Outlet pressure (Psig).
Ao = Discharge connection area (in2).
97
Discharge piping should be adequately supported. If
pipework is not supported, it must be
remembered that the reaction force will act on the
end of the discharge pipe, and that the discharge
pipe will act as a lever. The force applied to the
valve will therefore be determined by the reaction
force and the geometry of the discharge pipework.
DEFINITION OF TERMS
Pressure Relief Devices
A pressure relief device is actuated by inlet static
pressure and designed to open during an emergency
or abnormal conditions to prevent a rise of internal
fluid pressure in excess of a specified value. The
device also may be designed to prevent excessive
internal vacuum. The device may be a pressure relief
valve, a nonreclosing pressure relief device, or a
vacuum relief valve.
A spring-loaded pressure relief valve is a
pressure relief device designed to automatically
reclose and prevent the further flow of fluid.
A relief valve is a spring-loaded pressure relief valve,
actuated by the static pressure upstream of the valve.
The valve opens normally in proportion to the
pressure increase over the opening pressure. A relief
valve is used primarily with incompressible fluids.
A safety valve is a spring-loaded pressure relief
valve, actuated by the static pressure upstream of the
valve and characterised by rapid opening or pop
action. A safety valve is normally used with
compressible fluids.
A safety relief valve is a spring-loaded pressure
relief valve that may be used as either a safety or
relief valve, depending on the application.
A conventional pressure relief valve is a springloaded pressure relief valve whose performance
characteristics are directly affected by changes in the
back pressure on the valve.
Dimensional Characteristics of Pressure
Relief Devices
The actual discharge area is the measured
minimum net area that determines the flow
through a valve.
The curtain area is the area of the cylindrical or
conical discharge opening between the seating
surfaces above the nozzle seat created by the lift
of the disc.
The required discharge area is a nominal or
computed area of a pressure relief valve used in
recognised flow formulae to determine the size of
the valve. It will be less than the actual discharge
area.
The nozzle area is the cross-sectional flow area
of a nozzle at the minimum nozzle diameter.
A huddling chamber is an annular pressure
chamber in a pressure relief valve located beyond
the seat for the purpose of generating a rapid
opening.
The inlet size is the nominal pipe size (NPS) of
the valve at the inlet connection, unless otherwise
designated.
The outlet size is the nominal pipe size (NPS) of
the valve at the discharge connection, unless
otherwise designated.
Lift is the actual travel of the disc away form the
closed position when a valve is relieving.
A balanced pressure relief valve is a springloaded pressure relief valve that incorporates a
means for minimising the effect of back pressure on
the performance characteristics.
A pilot-operated pressure relief valve is a
pressure relief valve in which the main valve is
combined with and controlled by an auxiliary
pressure relief valve.
A rupture disc device is a nonreclosing differential
pressure relief device, actuated by inlet static
pressure and designed to function by bursting the
pressure-containing rupture disc. A rupture disc
device includes a rupture disc and a rupture disc
holder.
98
O P E R AT I O N A L C H A R A C T E R I S T I C S
The maximum operating pressure is the
maximum pressure expected during system operation.
The maximum allowable working pressure
(MAWP) is the maximum gauge pressure permissible
in a vessel at its designated temperature. The
maximum allowable working pressure is the basis for
the pressure setting of the pressure relief devices that
protect the vessel.
The design gauge pressure refers to at least the
most severe conditions of coincident temperature and
pressure expected during operation. This pressure
may be used in place of the maximum allowable
working pressure in all cases where the MAWP has
not been established. The design pressure is equal to
or less than the MAWP.
Accumulation is the pressure increase over the
maximum allowable working pressure of the vessel
during discharge through the pressure relief device,
expressed in pressure units or as a percentage.
Maximum allowable accumulations are established by
applicable codes for operating and fire contingencies.
Overpressure is the pressure increase over the set
pressure of the relieving device, expressed in pressure
units or as a percentage. It is the same as
accumulation when the relieving device is set at the
maximum allowable working pressure of the vessel.
Rated relieving capacity is that portion of the
measured relieving capacity permitted by the
applicable code or regulation to be used as a basis for
the application of a pressure relief device.
Stamped capacity is the rated relieving capacity that
appears on the device nameplate. The stamped
capacity is based on the set pressure or burst pressure,
plus the allowable overpressure for compressible fluids
and the differential pressure for incompressible fluids.
The set pressure is the inlet gauge pressure at which
the pressure relief valve is set to open under service
conditions.
The cold differential test pressure is the pressure
at which the pressure relief valve is adjusted to open
on the test stand. The cold differential test pressure
includes corrections for the service conditions of back
pressure or temperature or both.
Back Pressure is the pressure that exists at the
outlet of a pressure relief device as a result of the
pressure in the discharge system. It is the sum of the
superimposed and built-up back pressure.
99
Built up back pressure is the increase in
pressure in the discharge header that develops as a
result of flow after the pressure relief device opens.
Superimposed back pressure is the static
pressure that exists at the outlet of a pressure relief
device at the time the device is required to operate.
It is the result of pressure in the discharge system
coming from other sources and may be constant or
variable.
Blowdown is the difference between the set
pressure and the closing pressure of a pressure
relief valve, expressed as a percent of the set
pressure or in pressure units.
Opening pressure is the value of increasing inlet
static pressure at which there is a measurable lift of
the disc or at which discharge of the fluid becomes
continuous.
Closing pressure is the value of decreasing inlet
static pressure at which the valve disc re-establishes
contact with the seat or at which lift becomes zero.
Simmer is the audible or visible escape of
compressible fluid between the seat and disc at an
inlet static pressure above the set pressure and at
no measurable capacity.
Leak-test pressure is the specified inlet static
pressure at which a seat leak test is performed
(normally 90% of set pressure according to
AP1 527).
The term relieving conditions is used to indicate
the inlet pressure and temperature on a pressure
relief device at a specific overpressure. The
relieving pressure is equal to the valve set pressure
(or rupture disc burst pressure) plus the
overpressure. (The temperature of the flowing fluid
at relieving conditions may be higher or lower than
the operating temperature.)
Popping pressure is the pressure at which the
valve disc rapidly moves from a slightly open
(simmer) position to a practically full open position.
Discharge capacity is the actual mass flow rate of
discharge which can also be expressed in volumetric
terms.
Equivalent capacity is the mass volumetric flow
rate of a fluid calculated from the capacity of the
valve for a test fluid. The fluids commonly used for
the test purposes are steam, air and water.
P R E S S U R E T E R M R E L AT I O N S H I P
Pressure Vessel
Requirements
Maximum permited
accumulated pressure
Vessel Pressure
% Design Pressure
110
Accumulation
Design pressure
Safety Valve
Characteristic
Maximum relieving
pressure
Overpressure (Typical)
Set pressure
100
Blowdown (Typical)
Reseat pressure
Operating margin
Maximum operating
pressure
90
Notes: The system operating pressure must not exceed the reseat pressure of the safety valve.
Blowdown control is designed to conform to ASME Code Section V111, however liquid
applications may demand up to 15% blowdown.
Overpressure and blowdowns shown are typical for spring loaded SRVs and can be
reduced when using Safeset Pilot Operated SRVs. Refer to the appropriate catalogue
section for details.
100
N OT E S
Birkett
Pressure
Protection
101
B/C Series
S A F E T Y R E L I E F VA LV E S
D Series
WB Series
Safeset
C O M P L E M E N TA RY P R O D U C T L I N E S
Bursting Discs
Pressure Vacuum Valves
Flame Arresters
102
Safety Systems UK Ltd.
Sharp Street,Worsley, Manchester, UK, M28 3NA.
Tel +44 (0)161 703 1977
Fax +44 (0)161 703 8451
Email support@safetysystemsuk.com
Web site www.safetysystemsuk.com
BIPR0410
Registered Office:
Victoria Road, Leeds,
LS11 5UG, UK