Steel Tubes - Working Pressures

Normal maximum working pressures for steel tubes- in psi (lb/in²) and kPa (kN/m²)

The working pressures below are conservative estimates. Be aware that domestic rules may give lower limits.

Nominal bore		Water						Steam / Air, screwed connections				Steam / Air, welded connections
Nominal bore		Light		Medium		Heavy		Medium		Heavy		Medium		Heavy
inches	mm	psi	kPa	psi	kPa	psi	kPa	psi	kPa	psi	kPa	psi	kPa	psi	kPa
1/4	8	150	1000	300	2000	350	2400	150	1000	175	1200	250	1750	300	2000
3/8	10	150	1000	300	2000	350	2400	150	1000	175	1200	250	1750	300	2000
1/2	15	150	1000	300	2000	350	2400	150	1000	175	1200	250	1750	300	2000
3/4	20	150	1000	300	2000	350	2400	150	1000	175	1200	250	1750	300	2000
1	25	150	1000	300	2000	350	2400	150	1000	175	1200	250	1750	300	2000
1 1/4	32	125	850	250	1750	300	2000	125	850	150	1000	200	1400	300	2000
1 1/2	40	125	850	250	1750	300	2000	125	850	150	1000	200	1400	300	2000
2	50	100	700	200	1400	250	1750	100	700	125	850	200	1400	300	2000
2 1/2	65	100	700	200	1400	250	1750	100	700	125	850	200	1400	300	2000
3	80	100	700	200	1400	250	1750	100	700	125	850	150	1000	200	1400
4	100	80	550	150	1000	200	1400	80	550	100	700	150	1000	200	1400
5	125			150	1000	200	1400	80	550	100	700	150	1000	200	1400
6	150			125	850	150	1400	60	400	80	550	125	850	75	1200

Note!