Pipe Schedules

What is a Pipe Schedule?

Pipes are designed to carry fluid, therefore their internal diameter is their critical dimension. This critical dimension is referred to as the nominal bore, appreviated as NB. Obviously, for pipes containing pressurised fluids the wall thickness, and by implication the pipe's strength, is important. Wall thickness is expressed in "schedules", refered to as pipe schedules.
 
The wall thickness associated with a particular schedule depends on the pipe size as can be seen from the charts below for some of the more common sized carbon steel pipes encountered.
 
Abbreviations used: NB - nominal bore, STD - Standard, EH - Extra Heavy, DBL EH - Double Extra Heavy.
 

2"NB		OD = 2.375 inch (60.32 mm)
Schedule	5	10	20	30	40 STD	60	80 EH	100	120	140	160	DBL EH
ID (ins)	2.245	2.157	---	---	2.067	---	1.939	---	---	---	1.689	1.503
ID (mm)	57.02	54.79	---	---	52.5	---	49.25	---	---	---	42.9	38.18

 

3" NB		OD = 3.5 inch (88.9 mm)
Schedule	5	10	20	30	40 STD	60	80 EH	100	120	140	160	DBL EH
ID (ins)	3.334	3.260	---	---	3.068	---	2.900	---	---	---	2.624	2.300
ID (mm)	84.68	82.8	---	---	77.93	---	73.66	---	---	---	66.65	58.42

 

4" NB		OD = 4.5 inch (114.3 mm)
Schedule	5	10	20	30	40 STD	60	80 EH	100	120	140	160	DBL EH
ID (ins)	4.334	4.260	---	---	4.026	---	3.826	---	3.624	---	3.438	3.152
ID (mm)	110.08	108.2	---	---	102.26	---	97.18	---	92.05	---	87.33	80.06

 

6" NB		OD = 6.625 inch (168.275 mm)
Schedule	5	10	20	30	40 STD	60	80 EH	100	120	140	160	DBL EH
ID (ins)	6.407	6.357	--	--	6.065	--	5.761	--	5.501	--	5.189	4.897
ID (mm)	162.74	161.47	--	--	154.05	--	146.33	--	139.73	--	131.8	124.38

 

8" NB		OD = 8.625 inch (219.1 mm)
Schedule	5	10	20	30	40 STD	60	80 EH	100	120	140	160	DBL EH
ID (ins)	8.407	8.329	8.125	8.071	7.981	7.813	7.625	7.439	7.189	7.001	6.813	6.375
ID (mm)	213.54	211.56	206.38	205	202.72	198.45	193.67	188.95	182.6	177.83	173.05	161.93

 

10" NB		OD = 10.750 inch (273 mm)
Schedule	5	10	20	30	40 STD	60	80 EH	100	120	140	160	DBL EH
ID (ins)	10.482	10.42	10.25	10.136	10.02	9.750	9.564	9.314	9.064	8.750	8.500	---
ID (mm)	266.24	264.67	260.35	257.45	254.5	247.65	242.93	236.58	230.23	222.25	215.9	---

 

12" NB		OD = 12.750 inch (323.85 mm)
Schedule	5	10	20	30	40 STD	60	80 EH	100	120	140	160	DBL EH
ID (ins)	12.42	12.39	12.25	12.09	11.938 12.000	11.626	11.376 11.750	11.064	10.75	10.50	10.126	---
ID (mm)	315.47	314.7	311.15	307.1	303.22 304.8	295.3	288.95 298.45	281.03	273.05	266.7	257.2	---