Indoor Supply & Drainage Design Second Flow

Design second flow qg / qp for indoor water supply and drainage from fixture units N and building-type coefficients.

Water-supply design second flow

Building type

qg = α·0.2·√Ng

α = 2.5

Washbowl	Toilet	Bath	Sink	Washer	Shower	Total N
						—

With self-closing valve (+1.10 L/s)

Design second flow qg

—

L/s

With self-close valve

—

L/s

Drainage design second flow

Drainage type

Washbowl	Toilet	Bath	Squat toilet	Urinal	Total Np
					—

Total fixture units Np

—

Design drainage flow qp

—

L/s

qp = k·√Np + qmax, where qmax is the largest single-fixture discharge (2 L/s here).