BS 1212-1:1953

Seven sizes, for attachment of floats to BS 1968, BS 2456. ⅜, ½, ¾, 1, 1¼, 1½, and 2 in. Provision for removable seats, different sized orifices for different pressure and flow. Materials, quality, workmanship, dimensions, performance test, mechanical strength test of levers. Computed flow through seat orifices at various heads of water appended.