UL 193-2021 pdf free download

UL 193-2021 pdf free download.Alarm Valves for Fire-Protection Service. 10.11 In a 6 inch size or larger valve, no stud or bolt smaller than 112 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 appflcable requirements in the Standard Specification for Carbon Steel Bofts 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) If 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) If an “0” ring seal or ring gasket is used, the area of force application is that extending out of the center line of the “O 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 202 and 20.3. 11.1.6 A part that bears against, rotates within, or slides...