Stainless steel pipe: ANSI standards & chart

Stainless steel pipe is one of the more standardized materials in the building and engineering industries. The thickness of the pipe walls, diameter of the pipe and even the chemical composition are all written as part of the American National Standards Institute standards, which is just one of multiple standards available.

Wall Thickness
Stainless steel pipe categorized by the American National Standards Institute uses the term schedule in reference to the pipe’s wall thickness. Despite this standardization, the wall thickness is not the same for every diameter of pipe. Instead, the schedule refers to the general strength of the pipe. Therefore, a schedule 40S stainless pipe has a wall thickness of approximately 1.73mm for a pipe with outside diameter of 10.3mm but increases to 9.53mm for a pipe of the same schedule but 323.9mm in diameter. There are four general schedules for stainless pipe; 5S, 10S, 40S and 80S.

Diameter
Within each schedule of pipe there are multiple diameters of stainless steel pipe standardized by ANSI. These diameters range from 10.3mm (or .405 inches) to 323.9mm (or 12.75 inches). It is important to note that some diameters are not available in every schedule. For instance, the smallest diameters are not available in schedule 5S and many diameters are very difficult to find in some schedules, or very expensive if they are available.

Materials
Though ANSI standardizes stainless steel pipe, there are multiple formulas of stainless steel available. The two primary steels used in the manufacture of stainless steel pipe are ANSI 304 stainless steel and ANSI 316. Both steels have similar chemistry and differ only slightly in the amount of chromium in the steel.

Stainless Steel Pipe Chart

American National Standards Institute – ANSI

NPS	OD	Schedule Designations	Wall Thickness	Inside Diameter	Weight
	(Inches)	(ANSI/ASME)	(Inches)	(Inches)	(lbs./ft.)
1/8	0.405	10/10S	0.049	0.307	0.1863
		Std./40/40S	0.068	0.269	0.2447
		XS/80/80S	0.095	0.215	0.3145
1/4	0.54	10/10S	0.065	0.41	0.3297
		Std./40/40S	0.088	0.364	0.4248
		XS/80/80S	0.119	0.302	0.5351
3/8	0.675	10/10S	0.065	0.545	0.4235
		Std./40/40S	0.091	0.493	0.5676
		XS/80/80S	0.126	0.423	0.7388
1/2	0.84	5/5S	0.065	0.71	0.5383
		10/10S	0.083	0.674	0.671
		Std./40/40S	0.119	0.622	0.851
		XS/80/80S	0.147	0.546	1.088
		160	0.188	0.466	1.309
		XX	0.294	0.252	1.714
3/4	1.05	5/5S	0.065	0.92	0.6838
		10/10S	0.083	0.884	0.8572
		Std./40/40S	0.113	0.824	1.131
		XS/80/80S	0.154	0.742	1.474
		160	0.219	0.618	1.944
		XX	0.308	0.434	2.441
1	1.315	5/5S	0.065	1.185	0.8678
		10/10S	0.109	1.097	1.404
		Std./40/40S	0.133	1.049	1.679
		XS/80/80S	0.179	0.957	2.172
		160	0.25	0.815	2.844
		XX	0.358	0.599	3.659
1 1/4	1.66	5/5S	0.065	1.53	1.107
		10/10S	0.109	1.442	1.806
		Std./40/40S	0.14	1.38	2.273
		XS/80/80S	0.191	1.278	2.997
		160	0.25	1.16	3.765
		XX	0.382	0.896	5.214
1 1/2	1.9	5/5S	0.065	1.77	1.274
		10/10S	0.109	1.682	2.085
		Std./40/40S	0.145	1.61	2.718
		XS/80/80S	0.2	1.5	3.631
		160	0.281	1.338	4.859
		XX	0.4	1.1	6.408
2	2.375	5/5S	0.065	2.245	1.604
		10/10S	0.109	2.157	2.638
		Std./40/40S	0.154	2.067	3.653
		XS/80/80S	0.218	1.939	5.022
		160	0.344	1.689	7.462
		XX	0.436	1.503	9.029
2 1/2	2.875	5/5S	0.083	2.709	2.475
		10/10S	0.12	2.635	3.531
		Std./40/40S	0.203	2.469	5.793
		XS/80/80S	0.276	2.323	7.661
		160	0.375	2.125	10.01
		XX	0.552	1.771	13.69
3	3.5	5/5S	0.083	3.334	3.029
		10/10S	0.12	3.26	4.332
		Std./40/40S	0.216	3.068	7.576
		XS/80/80S	0.3	2.9	10.25
		160	0.438	2.624	14.32
		XX	0.6	2.3	18.58
3 1/2	4	5/5S	0.083	3.834	3.472
		10/10S	0.12	3.76	4.973
		Std./40/40S	0.226	3.548	9.109
		XS/80/80S	0.318	3.364	12.5
		XX	0.636	2.728	22.85
4	4.5	5/5S	0.083	4.334	3.915
		10/10S	0.12	4.26	5.613
		Std./40/40S	0.237	4.026	10.79
		XS/80/80S	0.337	3.826	14.98
		120	0.438	3.624	19
		160	0.531	3.438	22.51
		XX	0.674	3.152	27.54
4 1/2	5	Std./40/40S	0.247	4.506	12.53
		XS/80/80S	0.355	4.29	17.61
		XX	0.71	3.58	32.43
5	5.563	5/5S	0.109	5.345	6.349
		10/10S	0.134	5.295	7.77
		Std./40/40S	0.258	5.047	14.62
		XS/80/80S	0.375	4.813	20.78
		120	0.5	4.563	27.04
		160	0.625	4.313	32.96
		XX	0.75	4.063	38.55
6	6.625	5/5S	0.109	6.407	7.585
		10/10S	0.134	6.357	9.289
		Std./40/40S	0.28	6.065	18.97
		XS/80/80S	0.432	5.761	28.57
		120	0.562	5.491	36.39
		160	0.719	5.189	45.35
		XX	0.864	4.897	53.16
7	7.625	Std./40/40S	0.301	7.023	23.57
		XS/80/80S	0.5	6.625	38.05
		XX	0.875	5.875	63.08
8	8.625	5S	0.109	8.407	9.914
		10/10S	0.148	8.329	13.4
		20	0.25	8.125	22.36
		30	0.277	8.071	24.7
		Std./40/40S	0.322	7.981	28.55
		60	0.406	7.813	35.64
		XS/80/80S	0.5	7.625	43.39
		100	0.594	7.439	50.95
		120	0.719	7.189	60.71
		140	0.812	7.001	67.76
		XX	0.875	6.875	72.42
		160	0.906	6.813	74.69

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