BS 1212-1:1990

Foreword
Committees responsible
Specification
Section one. General
1 Scope
2 Definition
3 Designation for ordering
4 Marking
Section two. Materials
5 Quality and finish
6 Plastics
7 Castings
8 Hot stampings
9 Mouldings
10 Machining
Section three. Design, construction and dimensions
11 General
12 Screw threads
13 Inlet connections
14 Backnuts
15 Bodies
16 Body coupling nuts
17 Body end caps
18 Pistons and piston washers
19 Seats
20 Levers
21 Locknuts for levers
22 Float adjusters and thumb screws
23 Split cotter pins
Section four. Performance
24 Hydraulic pressure and shut-off
25 Backnut distortion
26 Locknut distortion
27 Mechanical strength of levers
Appendices
A Method of test for shut-off when assembled with
    appropriate float
B Method of test for distortion of size 1/2 plastics
    backnuts
C Method of test for distortion of plastics locknuts
D Method of test for mechanical strength of levers
E Discharge of water through piston type float
    operated valves
Tables
1 Materials
2 Body, seat and float combination
3 Side entry inlet shank and inlet for connection to
    12 mm and 15 mm copper tube
4 Type (a) backnuts (integral flange)
5 Type (b) backnuts (spigoted)
6 Type (c) backnuts (fixed flange)
7 Bodies
8 Body coupling nuts
9 Body end cap
10 Pistons and piston washers
11 Seats and joint ring for seats
12 Seat numbers
13 Levers
14 Test loads for levers
15 Computed flow through seat orifices
Figures
1 Section of typical size 1/2 piston type float
    operated valve with detail of inlet and alternative
    lever arm
2 Inlet shank
3 Inlet elbows
4 Backnuts
5 Bodies
6 Body coupling nuts
7 Body end cap
8 Pistons and piston washers
9 Seats and joint ring for seats
10 Levers and socket for soldered joint for two piece
    levers
11 Float adjuster, thumb screw and split cotter pin

Specifies materials, workmanship, dimensions and performance requirements for piston type valves of nominal size 3/8, 1/2, 3/4, 1, 11/4, 11/2 and 2, intended for use with floats complying with the requirements of BS 1968 and BS 2456.

This Part of BS 1212 specifies materials, dimensions, tolerances and performance requirements for piston type float operated valves (copper alloy body) of nominal sizes ⅜, ½, ¾, 1, 1¼, 1½ and 2 with six patterns of body, designated 1, II, III, IV, V and VI, intended for use with floats complying with BS 1968 and BS2456.

NOTE 1. The nominal sizes correspond with the pipe size of the thread on the inlet shank as specified in BS 2779. The nominal sizes ⅜ and 1 ¾ are formed by making special inlets on the Sizes ½ and 1 ½ respectively. Nominal sizes ⅜ and ½ are made in body form pattern I or II.

NOTE 2. The titles of the publications referred to in this standard are listed on the inside back cover.