Why are there no Class 300 Malleable Iron Plugs or Bushings?

Why are there no Class 300 Malleable Iron Plugs or Bushings?

Malleable Iron Plugs and Bushing are not manufactured in Class 300! So, the question becomes what do you use for plugs and bushings in a system requiring Class 300 pipe fittings?

The answer is found in standard ASME B16.14-1991 PAGE #1 (FERROUS PIPE PLUGS, BUSHINGS AND LOCKNUTS WITH PIPE THREADS)

Accordance with ANSI / ASME B16.4 if made of cast iron, or ANSI / ASME

B16.3 if made of malleable iron, ductile iron or steel. Use of cored plugs

and hexagon head bushings should be limited to Class 125 cast iron and

Class 150 malleable iron threaded fittings.

SOLUTION:

SOLID PLUGS and FACE BUSHINGS are recommended for use with Class 250 cast iron fittings and Class 300 malleable iron fittings.

NOTE: Locknuts are not pressure-temperature rated.