scope:

This standard covers the various types and classes of cold-water fire-service-type meters in sizes 3 in. (75 mm) through 10 in. (250 mm) and the materials and workmanship used in their fabrication. A fire-service meter shall consist of a combination of (1) a main-line meter of the proportional type, having an unobstructed passageway of essentially the full pipe size, for measuring high flow rates and (2) a bypass meter of appropriate size for measuring low flow rates. The meter shall have an automatic valve mechanism for diverting low flow rates through the bypass meter.

Alternative fire-service meter. A turbine-type (high-velocity) meter can be used to measure fire flows if it meets the flow-rate, head-loss, accuracy, and dimensional criteria as presented in this standard. Local authorities having jurisdiction will probably require that meters used for fire service be approved by the National Fire Protection Association (NFPA) or be listed with the Underwriters' Laboratories (UL) in their fire-protection equipment list. This approval requires the use of a main-line strainer having NFPA or UL approval and a minimum straining area of four times the pipe cross-sectional area of the turbine meter. Where the need for reverse-flow protection is considered to be