A335 P91 Pipe MAWP Calculator

ASTM A335 -P91 Alloy Steel Pipe SMLS <=3" thk, 9Cr-1Mo-V

Pressure Ratings > Pipe MAWP > A335 P91

Material Properties

Specification

A335 P91

Description

ASTM A335 -P91 Alloy Steel Pipe SMLS <=3" thk, 9Cr-1Mo-V

Tensile Strength

85 ksi

Yield Strength

60 ksi

B16.5 Flange Group

Group 1.15 — Alloy Steel 9Cr-1Mo-V

Min Design Temperature

-20 °F

Y Coefficient

Ref 3 — Ferritic steels

Calculator Settings

Corrosion Allowance (in)

Mill Tolerance (%)

Units

Schedule Selection

STDXSXXS10S40S80S2030406080120140160

Temperature Selection

100 °F150 °F200 °F250 °F300 °F350 °F400 °F450 °F500 °F550 °F600 °F650 °F700 °F750 °F800 °F850 °F900 °F950 °F1000 °F1050 °F1100 °F1150 °F1200 °F

Maximum Allowable Working Pressure (psig)

NPS	OD (in)	100 °F	200 °F	300 °F	400 °F	500 °F	600 °F	700 °F	800 °F
1/8	0.405	9,423	9,423	9,423	9,389	9,356	9,223	8,890	8,291
1/4	0.54	9,110	9,110	9,110	9,078	9,046	8,917	8,595	8,015
3/8	0.675	7,372	7,372	7,372	7,346	7,320	7,216	6,956	6,487
1/2	0.84	7,069	7,069	7,069	7,044	7,019	6,919	6,669	6,219
3/4	1.05	5,764	5,764	5,764	5,744	5,723	5,642	5,438	5,072
1	1.315	5,391	5,391	5,391	5,372	5,353	5,276	5,086	4,743
1 1/4	1.66	4,439	4,439	4,439	4,423	4,407	4,345	4,188	3,906
1 1/2	1.9	3,993	3,993	3,993	3,979	3,965	3,908	3,767	3,513
2	2.375	3,364	3,364	3,364	3,352	3,340	3,293	3,174	2,960
2 1/2	2.875	3,679	3,679	3,679	3,666	3,653	3,601	3,471	3,237
3	3.5	3,194	3,194	3,194	3,183	3,172	3,127	3,014	2,811
3.5	4	2,913	2,913	2,913	2,903	2,893	2,852	2,749	2,563
4	4.5	2,708	2,708	2,708	2,699	2,689	2,651	2,555	2,383
5	5.563	2,374	2,374	2,374	2,366	2,357	2,324	2,240	2,089
6	6.625	2,157	2,157	2,157	2,149	2,142	2,111	2,035	1,898
7	7.625	2,011	2,011	2,011	2,003	1,996	1,968	1,897	1,769
8	8.625	1,899	1,899	1,899	1,892	1,885	1,858	1,791	1,670
9	9.625	1,805	1,805	1,805	1,798	1,792	1,766	1,703	1,588
10	10.75	1,722	1,722	1,722	1,716	1,710	1,686	1,625	1,516
12	12.75	1,487	1,487	1,487	1,482	1,477	1,456	1,403	1,309
14	14	1,352	1,352	1,352	1,347	1,342	1,323	1,275	1,189
16	16	1,180	1,180	1,180	1,176	1,172	1,155	1,113	1,038
18	18	1,047	1,047	1,047	1,043	1,040	1,025	988	921
20	20	941	941	941	938	934	921	888	828
22	22	854	854	854	851	848	836	806	752
24	24	782	782	782	780	777	766	738	688
26	26	722	722	722	719	716	706	681	635
28	28	670	670	670	667	665	655	632	589
30	30	625	625	625	622	620	611	589	549
36	36	520	520	520	518	516	509	490	457
42	42	445	445	445	443	442	436	420	392
44	44	425	425	425	423	422	416	401	374
46	46	406	406	406	405	403	397	383	357
48	48	389	389	389	388	386	381	367	342

Custom Wall Thickness

NPS

Wall Thickness (in)

Allowable Stress vs Temperature

Matching Flange Group

Group 1.15 — Alloy Steel 9Cr-1Mo-V(A182 F91, A217 C12A, A387-91)

Disclaimer: This calculator is for guidance only. Results are based on ASME B31.3-2024 allowable stresses for seamless pipe (Ej=1.0, W=1.0). Always verify against the current edition of the standard. The engineer of record is responsible for all design decisions.