UL 1472-2020 pdf free download.Centrifugal Stationary Pumps for FireProtection Service.
7.8 The impellers shall be dynamically balanced to the G6.3 balance quality grade in accordance with the requirements for pump impellers in the Mechanical Vibration — Rotor Balancing — Part 11 Procedures and Tolerances for Rotors with Rigid Behaviour. ISO 21940.11.
Exception: The impellers may be statically (single plane) balanced in accordance with ISO 21940-11 if the ratio of the maximum outside diameter to the width at the periphery (including the shroud but not including the back vane) is equal to or greater than 6.
7.9 Flange dimensions and bolt layouts used in pipe connections shall comply with the requirements of one of the following standards:
a) Standard for Cast Iron Pipe Flanges and Flanged Fittings, ANSI/ASME B 16.1
b) Standard for Ductile Iron Pipe Flanges and Flanged Fittings: Classes 150 and 300, ANSI/ASME B1642; or
c) Standard for Pipe Flanges and Flanged Fittings: NPS 1/2 through 24, ANSI/ASME B16.5, when steel is used
Exception: A pump intended for use 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.
7.10 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 intended for use in installations where the connected piping has national pipe threads that are different from ANSI/ASME B 1.20.1 shall be permitted to be constructed with threads complying wiTh the national pipe thread standard compatible with the connected piping.
7.11 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.
7.12 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 (1892 Limin) or less; or
b) 1/2 inch (12.7 mm) for a pump rated more than 500 gallons per minute (1892 L/min).
7.13 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.UL 1472 pdf download.