A
Steam
B
Control valves
Safety valves
Local regulations may restrict the use of this product to below the conditions quoted.
In the interests of development and improvement of the product, we reserve the right to change the specification without notice.
© Copyright 2014
TI-S13-30
CH Issue 13
SV74
Carbon Steel
Safety Valve
Description
The SV74 steel series safety valves are built in conformance to Section I and VIII of the ASME Boiler and Pressure Vessel Code. They
are primarily intended for use on power boilers and unfired pressure vessels where ASME Section I and VIII stamped valves are required.
Applications
Protection of steam systems downstream of pressure regulating stations, on inlet to such equipment as air coils, heat exchangers and
process vessels. Also for use on flash recovery vessels on condensate return systems to protect vessels. Air systems to protect accumulation
vessels and air equipment from overpressurisation. Steam boilers and generators.
Available types
The SV74 is available with carbon steel body and stainless steel trim in orifice sizes from 'F' to 'R'. It has an open bonnet and easing
lever and flanged connections.
Certification
A manufacturers' Typical Test Report is provided as standard for each valve which will include valve set and hydraulic test pressure.
Also available on request is material certification in accordance with EN 10204 3.1.
Standards and approvals
Approved by National Board of Boiler and Pressure Vessel Inspectors to ASME Boiler and Pressure Vessel Cvode Sections I and VIII.
Seat tightness is in accordance with ASME/API STD 527-1992.
If National Board 'V' or 'UV' stamp is required, then this must be specified at the time of ordering.
The SV74 fully complies with the requirements of the European Pressure Equipment Directive 97/23/EC and carries the
Sizes and end connections
Inlet
Flanged ASME class 300 RF
Outlet
Flanged ASME class 150 RF
mark when so required.
11⁄2" x 2" to 6" x 8"
Pressure / temperature limits
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saturation
curve
Pressure psi g
The product must not be used in this region.
A - B To avoid spring damage, do not exceed an operating
temperature of 446°F.
Body design conditions
Set pressure range
Design temperature
Operating temperature
Overpressure
Performance
data
Blowdown limits
7%
0.955
0.955
Maximum permitted backpressure up to:
10% of set pressure
Tested at a maximum inlet cold hydraulic test pressure of 1 015 psi g
ASME 300
300 psi g
5 psi g
750°F
-20°F
Maximum
446°F
Maximum
Minimum
Maximum
Minimum
ASME I
ASME VIII
ASME I
ASME VIII
Steam
3%
Steam
10%
Air/gas
10%
Steam 2 - 6%
Steam
7%
Derated coefficient
of discharge values
Air / gas
Steam
Air / gas
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