Pipe Fitting Specification, BSI

BS 3799 - Steel Pipe Fittings, Socket and Threaded Class designations correspond to the maximum cold working pressure of fittings in pounds force per square inch.
Pressure Class	2000	3000	6000	9000
Socket Fitting	-	80	160	-
Threaded Fitting	-	80	XXS	-

Class designations correspond to the maximum cold working pressure of fittings in pounds force per square inch.

Pressure Class

2000

3000

6000

9000

Socket Fitting

160

Threaded Fitting

XXS