Flow Rates of Different Hose

[RockyTRJ]

Looking for more information on flow rates of different hose.

In my brigade the general fireground figures for flow rates spoken about by nearly everyone are - 

• 19mm hose reel - 100 LPM 
• 45mm - 300 LPM
• 70mm - 600 LPM

After a crude test of emptying the 1800L tank with said hoses with and without branches (7 bar) these figures were way off. The flow rates marked on some of the branches was also wrong which doesn't fill me with confidence as a pump operator. 

Any more info/calculations anyone has would be appreciated. 

[Becile]

Ah that old chestnut, ask your workshops if they have a flow rate meter, to get an accurate reading.

Also an old perennial is crews thinking setting 23 bar at the pump gives them the correct pressure and flow for gas cooling-  sadly not !

[SB6089]

You’ve lots of variables to consider that directly impact flow such as pump efficiency, frictional loss, hose lay and branch chosen. For example, a smooth bore will flow a considerable amount more than that of a combination branch at the same pressure, and a HRJ will be more efficient when completely off the drum when compared to being on etc etc. 

A single length of open 70mm can be expected to deliver 700lmp at 7 bar, without accounting for frictional loss

55m 22mm HJR without a branch can be expected to deliver circa 280lmp (again, no frictional loss accounted for) at 25 bar in optimum conditions. Add a branch such as a TFT F07 and we’re down at 150lmp in real terms.
 

As mentioned above, a flow rate meter is needed to see the real numbers.