Set Pressure Tolerance for Steam Safety Valves

[nasim123]

Dears
i need your advice for the steam service safety valve tolerance. If the PZV design is section 8 and the service is steam we need to follow Table 2 for the set pressure tolerance or Table 1.


Table 1 – Tolerances for Set Pressures of Pilot/Safety Relief Valves
(In English Units to Conform to ASME Code Requirements)
Set Pressure (CDTP) POP Pressure OK if
0 to 100 psi (0-690 kPa) ± 2 psig (14 kPa)
101 to 110 psi (696-758 kPa) ± 3 psig (21 kPa)
111 to 150 psi (765-1034 kPa) ± 4 psig (28 kPa)
151 to 199 psi (1041-1372 kPa) ± 5 psig (35 kPa)
over 200 psi (1379 kPa) ± 3 psig (21 kPa)
for every hundred psig

Table 2
Steam Safety Valves
Set Pressure (CDTP) POP Pressure OK if
0 to 70 psi (0-483 kPa) ± 2 psi (14 kPa)
71 to 300 psi (490-2068 kPa) ± 3%
301 to 1000 psi (2075-6895 kPa) ± 10 psi (70 kPa)
over 1000 psi (6902 kPa) ± 1%

 

[bljnv]

If the PSV (PZV ?) is designed according to Section VIII, Section VIII tolerances should be followed.

 

[nasim123]

bljnv.. thanks for your swift response.
In Saudi Aramco, PSVs are called PZVs.