UL 448-2017 pdf download – Centrifugal Stationary Pumps for Fire-Protection Service
Exception: A pump intendedforuse in installations where the connection piping has national pipe flange dimensions that are different from these standards shall be permitted to be constructed with flanges complying with the national pipe flange standard compatible with connection piping. 6.10 A threaded opening used for pipe connection shall comply with the requirements in the Standard for Pipe Threads, General Purpose, Inch, ANSI/ASME B1.20.1. Exception: A pump intendedforuse in installations where the connectedpiping has nationalpipe threads that are different from ANSI/ASME B1.20.1 shall be permitted to be constructed with threads complying with the national pipe thread standard compatible with the connected piping. 6.11 A pump shall be provided with the following: a) Automatic air-release valve (self-venting pumps excluded); b) Circulation relief valve (except for engine driven pumps for which engine cooling water is taken from the pump discharge) and; c) Pressure gauges. 6.12 The minimum internal dimensions of the passages at any point in the impeller shall not be less than: a) 5/16 inch (7.9 mm) for a pump rated 500 gallons per minute (1893 L/min) or less; or b) 1/2 inch (12.7 mm) for a pump rated more than 500 gallons per minute. 6.13 Impeller, impeller wearing rings, case wearing rings, shaft sleeves, guide or diffusion vane rings, lantern rings, interior nuts, glands, gland nuts, and drain plugs shall be of corrosion-resistant material. SPLIT-CASE, END-SUCTION, IN-LINE, AND MULTISTAGE MULTIPORT PUMPS 7 Pump Casings 7.1 Except for multistage multiport pumps, a pump casing shall be constructed to permit examination of impellers and other interior parts without disturbing suction or discharge piping. The casing shall include means to facilitate disassembly of the casing, and the stuffing box cover (if provided), without requiring the use of wedges or prying elements, such as by provision of tapped holes for jackscrews.