Condensate Generated in Cold Steam Pipes - Sizing of Steam Traps

When cold steam pipes are heated up they generate huge amounts of condensate that must be drained away from the pipe through steam traps - in Imperial Units.

When cold steam pipes are heated up they generate huge amounts of condensate that must be drained away from the pipe. It is important that the steam traps are designed to handle the start up load.

The diagram and table below can be used as a roughly estimate of the warm-up condensate load generated when the steam system is heated up.

Condensate load generated in cold steam pipes at start-up - dimensions of steam traps - diagram

Condensate generated in insulated steam pipes - SI units

Condensate Generated in Cold Steam Pipes vs. Steam Pressure
Steam Gauge Pressure (psi)	Warm-Up Condensate Load (lb/100 ft)
	Pipe Size (inch)
	2	2 1/2	3	4	5	6	8	10	12
0	6.2	9.7	12.8	18.2	24.6	31.9	48	68	90
5	6.9	11	14.4	20.4	27.7	35.9	53	77	101
10	7.5	11.8	15.5	22	29.9	38.8	58	83	109
20	8.4	13.4	17.5	24.9	33.8	44	66	93	124
40	9.9	15.8	20.6	29.3	39.7	52	78	110	145
60	11	17.5	22.9	32.6	44	57	86	122	162
80	12	19	24.9	35.3	48	62	93	132	175
100	12.8	20.3	26.9	37.8	51	67	100	142	188
125	13.7	21.7	28.4	40	55	71	107	152	200
150	14.5	23	30	43	58	75	113	160	212
175	15.3	24.2	31.7	45	61	79	119	169	224
200	16	25.3	33.1	47	64	83	125	177	234
250	17.2	27.3	35.8	51	69	89	134	191	252
300	25	38.3	51	75	104	143	217	322	443
400	27.8	43	57	83	116	159	241	358	493
500	30.2	46	62	91	126	173	262	389	535
600	32.7	50	67	98	136	187	284	421	579
800	38	58	77	113	203	274	455	670	943
1000	45	64	86	126	227	305	508	748	1052
1200	52	72	96	140	253	340	566	833	1172
1400	62	79	106	155	280	376	626	922	1297
1600	71	87	117	171	309	415	62	1018	1432
1750	78	94	126	184	333	448	746	1098	1544
1800	80	97	129	189	341	459	764	1125	1584

This table is based on an ambient temperature of 70^oF. For an ambient temperature of 0^oF, the values should be increased with 15% at 1800 psi and up to 50% at 0 psi.

1 ft (foot) = 0.3048 m
1 psi (lb/in²) = 6,894.8 Pa (N/m²) = 6.895×10^-2 bar
1 lb = 0.4536 kg