FM 1021 : 1973

I. INTRODUCTION
II. GENERAL DESCRIPTION
     2.1 Description
     2.2 Markings
     2.3 Sizes
     2.4 Rated working Pressure
     2.5 End Connections
III. DESIGN
     3.1 General
     3.2 Operation
     3.3 Orientation and Parts Removal
     3.4 Serviceability
     3.5 Materials
     3.6 Friction Loss
     3.7 Performance
     3.8 Clearances
     3.9 Trim Equipment
     3.10 Intermediate Chamber
     3.11 Auxiliary Equipment
IV. TESTS - DRY PIPE VALVES
     4.1 Operational Tests
     4.2 Friction Loss
     4.3 Strength of Clapper Latch
     4.4 Strength of Clapper
     4.5 Hydrostatic Tests
V. TESTS - RUBBER FACINGS
     5.1 General
     5.2 Water Absorption
     5.3 Hardness
     5.4 Ageing
     5.5 Adhesion
APPENDIX - APPROVAL MARKS