Heat Loss of Steel Pipes

For various water temperatures and steam pressures

**Heat loss W/m for fluid inside pipe**
Nominal bore	mm	Water				Steam
		50°C	60°C	75°C	100°C	1 bar	4 bar
½	15	30	40	60	90	130	190
¾	20	35	50	70	110	160	220
1	25	40	60	90	130	190	270
1¼	32	50	70	110	160	230	330
1½	40	55	80	120	180	250	370
2	50	65	95	150	220	310	440
2½	65	80	120	170	260	360	530
3	80	100	140	210	300	440	630
4	100	120	170	260	380	550	800
6	150	170	250	370	540	770	1100

**Correction factors for use with above table**
Condition	Factor
Single pipe along skirting or riser	1.0
More than one pipe along skirting or riser	0.90
Single pipe along ceiling	0.75
More than one pipe along ceiling	0.65
Single pipe freely exposed	1.1
More than one pipe freely exposed	1.0