UL 193:2016 pdf free download – STANDARD FOR SAFETY Alarm Valves for Fire-Protection Service.
10.6 A tapped opening in a valve body for a retarding chamber connection shall be not less than 1/2 inch pipe size, and an opening used exclusively for a pressure gauge shall be not less than 1/4 inch pipe size.
10.7 A tapped opening in a valve body for main drain connection shall be at least 3/4 inch pipe size for up to 2 inch valves, at least 1-1/4 inch pipe size for a 2-1/2 to 3 inch valve, and 2 inch pipe size for 4 inch and larger valves.
10.8 Tapped openings provided for main drain piping shall be so located as to assist in carrying away sediment or foreign material likely to collect at the valve seat and to drain water from the system piping when the valve is installed in any intended position.
10.9 A body handhole opening shall be provided and shall be sufficiently large:
a) To permit access to all working parts; and
b) To allow the removal of the clapper assembly.
It shall be so located that, when the valve is installed in the intended position, the opening is on the side or on the top.
Exception: A valve need not be provided with a body handhole opening, provided that:
a) The valve is constructed to permit the clapper and all other internal parts to be removed and replaced;
b) A means is provided to allow removal and reinstallation of the valve, or serviceable portion of the valve, without disassembly of the sprinkler system piping; and
c) The means for valve or part removal and reinstallation is integral with the valve.
10.10 If a body handhole opening is provided, a cover plate shall be attached to the body of a valve using bolts and nuts, or bolts alone, or studs and nuts, with the removable parts having external drive surfaces, such as a square or hexagonal head.
10.11 In a 6 inch size or larger valve, no stud or bolt smaller than 1/2 inch (12.7 mm) shall be used to assemble castings subject to full water pressure.
10.12 Bolts, nuts, and studs employed for the bolting of pressure-holding castings shall comply with the applicable requirements in the Standard Specification for Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength, ASTM A307, and in the Standard Specification for Carbon and Alloy Steel Nuts, ASTM A563. Bolts shall be Grade A or Grade B, as specified in ASTM A307.
10.13 The load on any bolt, exclusive of the force required to compress the gasket, shall not exceed the minimum tensile strength specified in Table 2 of the Standard Specification for Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength, ASTM A307, when the valve is pressurized to four times the rated working pressure. The area of the application of pressure is to be calculated as follows:
a) It a full-face gasket is used, the area of force application is that extending out to a line defined by the inner edge of the bolts.
b) It an “0” ring seal or ring gasket is used, the area of force application is that extending out of the center line of the “0” ring or gasket.
10.14 A handhole cover plate shall be constructed so that it cannot be installed in such a manner as to impair the operation of the valve.
11 Valve Mechanisms
11.1 General
11.1.1 A valve part that is constructed to be disassembled during field servicing shall be such that it cannot be reassembled in an unintended manner.
11.1.2 There shall be no waste of water when the valve is in a “ready” condition. See 5.2, 5.7, and 29.1.6.
11.1.3 A valve mechanism shall provide freedom of movement of operating parts.
11.1.4 The clapper assembly shall be hung in the interior of the valve body so that the clapper assembly will move toward the seat by gravity and seal as intended when no water is flowing. For valves intended for horizontal installation, the use of springs to effect intended seating is acceptable.
11.1.5 A spring used in an alarm valve shall be made of a material having corrosion resistance at least equivalent to phosphor bronze. See 20.2 and 20.3.