Pressure-Temperature Ratings for Cast Iron Gate Valves

Metal seated cast iron gate valves (American standard) may be made of gray iron or ductile iron in accordance with MSS SP 70 and MSS SP 128, respectively. The gray iron shall be in accordance with ASTM A126, while the ductile iron shall be in accordance with ASTM A395 or ASTM A536. They are generally used for various non-shock applications and the pressure-temperature ratings are presented in the tables below.

Temp. °F	Class 125 2"~12" psi	Class 125 14"~24" psi
-20~150	200	150
200	190	135
225	180	130
250	175	125
275	170	120
300	165	110
325	155	105
350	150	100
375	145	-
400	140	-
425	130	-
450	125	-

*Pressure-temperature ratings for Class 125, gray iron gate valves made of ASTM A126 Gr.B, abstracted from MSS SP 70.

Temp. °F	NPS 2"~12" psi	NPS 14"~24" psi
-20~150	500	300
200	460	280
225	440	270
250	415	260
275	395	250
300	375	240
325	355	230
350	335	220
375	315	210
400	290	200
425	270	-
450	250	-

*Pressure-temperature ratings for Class 250, gray iron gate valves made of ASTM A126 Gr.B, abstracted from MSS SP 70.

Temp. °F	Class 150 2"~24" psi	Class 300 2"~24" psi
-20~100	250	640
200	235	600
300	215	565
400	200	525
500	170	495
600	140	465
650	125	450

*Pressure-temperature ratings for Class 150 & Class 300, ductile iron gate valves made of ASTM A395, abstracted from MSS SP 128.

Temp. °F	Class 125 2"~12" psi	Class 125 14"~24" psi
-20~150	200	150
200	190	135
225	180	130
250	175	125
275	170	120
300	165	110
325	155	105
350	150	100
375	145	-
400	140	-
425	130	-
450	125	-

*Pressure-temperature ratings for Class 125, ductile iron gate valves made of ASTM A536, abstracted from MSS SP 128.

Temp. °F	Class 250 2"~12" psi	Class 250 14"~24" psi
-20~150	500	300
200	460	280
225	440	270
250	415	260
275	395	250
300	375	240
325	355	230
350	335	220
375	315	210
400	290	200
425	270	-
450	250	-

*Pressure-temperature ratings for Class 250, ductile iron gate valves made of ASTM A536, abstracted from MSS SP 128.