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Pressure drop in ducts

Alter The Velocity parameter to calculate pressure drop per meter in the duct sizes given. The maximum flow is the flow that will be achieved in the duct at the selected velocity. Only enter the velocity value in the yellow box.

The calculation assumes that the gas is air at 20 degC and that the duct has an roughness factor equivalent to plastic lined duct. The results are a rough guide to the pressure drop. It is advised that a rigorous pressure drop analysis is made of your specific duct runs before specifying fans or duct wall thickness etc.

Velocity

m/s

				Pressure drop in duct information at stated velocity
Dia (mm)	Area	Max Flow m3/hr	Reynolds No	Flow Regime	Friction Factor	Pa/m	Vel Pressure
100	0.007854	565	131257	Turbulent	0.01111	106.82	240 Pa
150	0.017671	1272	196886	Turbulent	0.00963	61.74	240 Pa
200	0.031416	2262	262514	Turbulent	0.00875	42.09	240 Pa
250	0.049087	3534	328143	Turbulent	0.00815	31.36	240 Pa
305	0.073062	5260	400334	Turbulent	0.00767	24.18	240 Pa
350	0.096211	6927	459400	Turbulent	0.00736	20.22	240 Pa
400	0.125664	9048	525028	Turbulent	0.00708	17.01	240 Pa
450	0.159043	11451	590657	Turbulent	0.00684	14.62	240 Pa
500	0.196350	14137	656285	Turbulent	0.00664	12.77	240 Pa
550	0.237583	17106	721914	Turbulent	0.00646	11.30	240 Pa
600	0.282743	20358	787543	Turbulent	0.00631	10.11	240 Pa
650	0.331831	23892	853171	Turbulent	0.00617	9.13	240 Pa
700	0.384845	27709	918800	Turbulent	0.00605	8.31	240 Pa
750	0.441786	31809	984428	Turbulent	0.00594	7.62	240 Pa
800	0.502655	36191	1050057	Turbulent	0.00584	7.02	240 Pa
900	0.636173	45804	1181314	Turbulent	0.00566	6.05	240 Pa
1000	0.785398	56549	1312571	Turbulent	0.00551	5.30	240 Pa
1100	0.950332	68424	1443828	Turbulent	0.00538	4.70	240 Pa
1200	1.130973	81430	1575085	Turbulent	0.00526	4.21	240 Pa