BS 3799:1974

This British Standard specifies requirements for forged carbon and alloy steel screwed and socket-welding fittings for use in the petroleum and petrochemical industry.

Screwed fittings specified in this standard are intended for assembly with pipe threaded in accordance with API Std. 5B or ANSl B2.1. (N.P.T.)

Socket-welding fittings specified in this standard are primarily intended for assembly with plain end pipe dimensioned in accordance with BS 1600 and API Std. 5L. It should be noted, however, that with the exception of nominal size 24 in (65 mm) the socket dimensions are also suitable for use with plain end pipe dimensions in accordance with BS 3600 (ISO/R 64). See Notes to Purchaser (Appendix A) and Tables 13 and 16.

Ths standard provides for the following:

1. Screwed fittings:
   • Elbows, 90° and 45°
   • Crosses
   • Tees
   • Couplings and half-couplings
   • Caps
   • Square, hexagonal and round head plugs
   • Hexagonal head bushings
   • Hexagonal and round nipples
   • Unions
   • Welding bosses
   • Swage nipples*
2. Socket-welding fittings:
3. Elbows, 90° and 45°
4. Crosses
5. Tees
6. Couplings and half-couplings
7. Caps
8. Unions
9. Welding bosses
10. Swage nipples*

NOTE. The Standards referred to in this standard are listed on the inside back cover.

Forged carbon and alloy steel screwed and socket-welding fittings. Screw threads in accordance with API Std. 5B. Bore diameters of socket-welding fittings compatible with BS 3600 and BS 1600. Substantially agrees with ANSI B16.11, ASTM A 234 and ASTM A 403.