British standard pipe BS 1387 : 1967 medium

Nominal bore		Outside diameter				Thickness		Calculated weight of black tube
		max.	min	max.	min.			Plain End		Screwed and socketed
in	mm	in	in	mm	mm	in	mm	lb/ft	kg/m	lb/ft	kg/m
3/8	10	0.685	0.66	17.4	16.8	0.092	2.35	0.573	0.852	0.577	0.858
1/2	15	0.856	0.831	21.7	21.1	0.104	2.65	0.822	1.22	0.828	1.23
3/4	20	1.072	1.047	27.2	26.6	0.104	2.65	1.06	1.58	1.07	1.59
1	25	1.346	1.316	34.2	33.4	0.128	3.25	1.64	2.44	1.65	2.46
1 1/4	32	1.687	1.657	42.9	42.1	0.128	3.25	2.11	3.14	2.13	3.17
1 1/2	40	1.919	1.889	48.8	48	0.128	3.25	2.43	3.61	2.46	3.65
2	50	2.394	2.354	60.8	59.8	0.144	3.65	3.42	5.1	3.47	5.17
2 1/2	65	3.014	2.969	76.6	75.4	0.144	3.65	4.38	6.51	4.46	6.63
3	80	3.524	3.469	89.5	88.1	0.16	4.05	5.69	8.47	5.8	8.64
3 1/2	90	4.019	3.959	102.1	100.6	0.16	4.05	6.53	9.718	6.65	9.896
4	100	4.524	4.459	114.9	113.3	0.176	4.5	8.14	12.1	8.34	12.4
5	125	5.534	5.459	140.6	138.7	0.192	4.85	10.9	10.2	11.2	16.7
6	150	6.539	6.459	166.1	164.1	0.192	4.85	12.9	19.2	13.3	19.8