Converting WSFU to GPM

Converting Water Supply Fixture Units - WSFU - to GPM

The Water Supply Fixture Units - WFSU - are used to determine the water demand in water supply systems. One WFSU for a singel unit corresponds to one GPM.

  • 1 WSFU = 1 GPM

This conversion can only be used for one or a few fixtures. When the total amount for many fixtures are added up, the number must be compensated due to the intermittent use of the fixtures. This is normal taken care of in the tables available for sizing supply pipe lines.

When special equipment or manifolds are sized the table below can be used to indicate the flowrate. Note that the minimum flow rate can never be less than the fixture with the largest demand.

The tables below can be used to estimate the demand in the water supply system when the load in WSFU is known. There are tables for systems with and without flush valves.

Water Supply System without Flush Valves

WSFU GPM ft3/min liter/sec
1 3 0.41 0.19
2 5 0.68 0.32
4 8 1.07 0.51
8 12.8 1.71 0.81
15 17.5 2.3 1.1
30 23.3 3.1 1.5
50 29.1 3.9 1.8

Water Supply System with Flush Valves

flush valve

WSFU GPM ft3/min liter/sec
5 15 2 1
7 19.8 2.7 1.3
10 27 3.6 1.7
15 31 4.1 2
20 35 4.7 2.2
30 42 4 1.9
50 50 6.7 3.2

Building Water Supply Diagram in gal/min

Fixtures - WFSU - and building water demand supply diagram - gallons per minute

Building Water Supply Diagram in l/s

Fixtures - WFSU - and building water demand supply diagram - litre per second

Related Topics

  • Water Systems - Hot and cold water systems - design properties, capacities, sizing and more

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