GO Galvanised Malleable Iron Square Head Plug Range Scr BSP BS EN 10242



GO Galvanised Malleable Iron Square Head Plug Range Scr BSP BS EN 10242


Plugs are fittings that provide flow control by plugging branches and outlets – the name is quite self-explanatory.

Plugs come in several design: bull plugs (either round or hex), round head plugs, and hex head plugs.  Most plugs are threaded; however some are provided without threads and are referred to as socket-weld plugs.

Bull plugs have long heads and a smaller lower area where the piece enters the system.  This lower area has a thread for threaded plugs, or is smooth (plain) for socket weld plugs.  The size of a bull plug corresponds to the thread size and the outer diameter, which is equal to the nominal pipe size.

Round head, hex head, and square head plugs are plugs with a round threaded or round smooth end connection and a round, hex, or square head (respectively).  The diameter of the round head plug is the same on the top and the bottom, therefore, however the diameters differ between the top and bottom for hex and square head plugs.


  • Blackheart Malleable Iron casting.


  • generally to ASME B16.3 or JIS B2301, depending on manufacturing source.
  • JIS B2301 dimensions are generally considered to be corresponding values to BS143 and BS1256, although some sizes are not exact equivalents.


  • BSP pipe thread, to BS.21 (AS 1722, Part 1).
  • The specification for BS 143 fittings is:
    • Taper External (Series R) Taper Internal (Series RC)
    • The specification for BS 1256 fittings is:
    • Taper External (Series R) Parallel Internal (Series RP)


  • Hot Dip Galvanised is the standard finish for stock.


  • Fittings shall be subject to an internal hydraulic pressure of 2068 kPa without showing any sign of leakage or abnormality.

WORKING PRESSURES (except flanges)

  • Recommended maximum working pressures are 1379 kPa for water and 1034 kPa for steam, air, gas and oil. NOTE: Working pressures may also be limited by relevant Pressure Piping Codes or Industry regulations.


  • When ordering Reducing Sockets, Nipples, Bushes and Elbows, always state largest size first — e.g. 80 x 40 bush.  When ordering 3- or 4- way fittings, the sizing sequence illustrated below should be adopted.


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