Pipework - Heat Loss from Uninsulated Copper Pipes

Heat loss in Watts per metre by temperature differential between the pipe contents and and ambient air.

Nominal bore		Heat loss for the fluid inside pipe (W/m)
		Temperature difference (oC)
(mm)	(inches)	22	38	55
15	1/2	21	32	45
22	3/4	28	43	60
28	1	34	53	76
35	1 1/4	41	64	89
42	1 1/2	47	74	104
54	2	59	93	131
67	2 1/2	71	111	156
76	3	83	129	181
108	4	107	165	232