UL 405:2020 pdf download.Fire Department Connection Devices.
9.2 Clappers or other check devices, and accessories such as springs, shall be constructed of a materialhaving corrosion resistance equivalent to or exceeding that of brass or bronze or Series 300 stainlesssteel.
9.3lf used, clappers shall be mounted such that a 2-1/2 inch (63.5 mm) diameter sphere can be passedthrough any inlet. The hinge pins shall be of brass, bronze or other equivalent corrosion resistant material,not less than 1/4 inch (6.4 mm) in diameter, and supported at each end for a distance at least equal to thediameter of the pins. The hinge pins shall be securely fastened in position such as by riveting the ends orby other equivalent means which does not permit water leakage. Hinge pins secured with threads shall beprovided with a supplemental means of securement such as the use of a thread locking compound,permanent adhesive, or mechanical staking.
10Clearances
10.1 The clearance between the clapper rim and the body in all positions of travel shall be at least 1/4inch (6.4 mm) with gray,cast, or malleable iron bodies,and 1/8 inch (3.2 mm) with brass, bronze andSeries 300 stainless steel bodies. The clearance between the clapper hub or hinge and the body or seatring shall be at least 1/8 inch (3.2 mm).The length of the clapper hub or hinge shall be 1/32 inch (0.8 mm)less than the distance between the bearings. The hole through the clapper hub shall be at least 1/32 inch(0.8 mm) greater in diameter than the diameter of the hinge pin.
11Seat Rings
11.1 The seat or seat rings shall be constructed of a material having corrosion resistance equivalent to orexceeding that of brass or bronze and shall be smoothly machined. Raised seats shall be at least 1/4 inch(6.4 mm) wide and raised at least 1/8 inch (3.2 mm).Machined surfaces of seats which are not raised shallextend at least 1/8 inch (3.2 mm) beyond the clapper rim. If the seat rings are not a part of the bodycasting, they shall be screwed or pressed into place.
