Calculation of pressure drop in pipework

• Calculating nominal length

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Calculation of pressure drop

Flow rate			m³/min
Nominal length			m
Absolute working pressure			bar
Pipework inner diameter			mm
Pressure drop			bar

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	The nominal length of the pipeline is calculated by adding together the length of the straight pipeline and the equivalent lengths of the fittings installed.
	An estimate of the equivalent lengths of the fittings can be provided using the adjacent program or accepted on an approximate basis by adding 60% onto the length of the straight pipeline, e.g. nominal length = length of straight pipeline x 1.6.
	The calculation is valid for smooth pipes.

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Calculate the equivalent pipe length

Piping diameter		DN	25 40 50 80 100 125 150 200 250 300 400
		Equivalent length [m]	Number
Knee bend		1.5
Bend R = 2d		0.3
Bend R = d		0.4
Outlet direction of T-piece		0.5
Branching direction of T-piece		1.5
Seat valve		5
Butterfly valve/ball valve		0.3
Check valve		2
Reduction to DN:   20		0.5
Equivalent pipe length of all fittings installed			m

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