Lowara NSCF 300-450/3150/W45 VDC4 [197/204] Flow resistance table of flow resistance in bends valves and gates

197

FLOW RESISTANCE

TABLE OF FLOW RESISTANCE IN BENDS, VALVES AND

GATES

The flow resistance is calculated using the equivalent pipeline length method according to the table below:

The table is valid for the Hazen Williams coefficient C=100 (cast iron pipework);

for steel pipework, multiply the values by 1,41;

for stainless steel, copper and coated cast iron pipework, multiply the values by 1,85;

When the equivalent pipeline length has been determined, the flow resistance is obtained from the table of

flow resistance.

The values given are guideline values which are bound to vary slightly according to the model, especially for gate

valves and non-return valves, for which it is a good idea to check the values supplied by manufacturers.

TABELLA LUNGHEZZA DI TUBAZIONE EQUIVALENTE

ACCESSORY

TYPE

25 32 40 50 65 80 100 125 150 200 250 300

45° bend 0,2 0,2 0,4 0,4 0,6 0,6 0,9 1,1 1,5 1,9 2,4 2,8

90° bend 0,4 0,6 0,9 1,1 1,3 1,5 2,1 2,6 3,0 3,9 4,7 5,8

90° smooth bend 0,4 0,4 0,4 0,6 0,9 1,1 1,3 1,7 1,9 2,8 3,4 3,9

Union tee or cross 1,1 1,3 1,7 2,1 2,6 3,2 4,3 5,3 6,4 7,5 10,7 12,8

Gate - - - 0,2 0,2 0,2 0,4 0,4 0,6 0,9 1,1 1,3

Non return valve 1,1 1,5 1,9 2,4 3,0 3,4 4,7 5,9 7,4 9,6 11,8 13,9

G-a-pcv-en_a_th

Equivalent pipeline length (m)

TECHNICAL APPENDIX