Hosereels

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What length of hosereel do you carry on an appliance these days?

What is the maximum length of hosereel you would be happy to take into a building?

[fireftrm]

Carry 2 x 60m in 3 x 20m lengths. Would be happy to take any length in, the length not being an issue, the ability to haul it is.

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Isn't water flow a limiting factor on the functional length of hose?

[fireftrm]

Yes, but hosereel hose is very low friction and the high pressures used mean the pressure loss due to friction is unimportant over ther sort of distanes likely to be adopted.

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Would 200m be a suitable distance?

[kurnal]

200m would be impossible for hosereel tubing in my opinion. As the pumps carry a drum of three per side, you would need to unwind one full drum, disconnect the hose from the drum, disconnect the branch, recouple up, then find another appliance to rob a further length from. The flow would be affected by frictional losses over this distance and the whole thing would be impossible to drag due to weight. And at the end of the day its still hosereel with limited firefighting capabilites.
Dont also forget that to reach 200m you need at least 250m of hose unless you can take an absolute direct route.

No for 200m you really need 8 lengths of standard delivery hose. In my day and brigade  appliances carried 6  25m lengths 45mm hose and 14  25m lengths of  70mm hose.

Do you have an access for firefighters problem somewhere?

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Agree entirely Kurnal, same in my day.  Just thinking over a recent large fire...

[fireftrm]

Yep 200m of hosereel is not really practical, as I said pulling it would be the proble, though two pumps would give you 240m for one line. It is far easier to run out layflat hose, b ut if charged then hosereel is still easier to drag than layflat.

[Paul Grimwood]

ALL fire service hose-reels have very high frictional losses. This leads to low nozzle pressures and limited flow capability. 60m of high-pressure 19mm reel will rarely provide you more than 100 litres/min which is not enough water to deal with a room fire verging on, or surpassing the point of flashover.

A 25mm high-pressure reel will provide 200 litres/min or more and this is a more effective flow-rate to take into a serious room fire. However, where the fire is spreading rapidly to involve other rooms; structural elements; or a high fire load, hose-reels of any size are not capable of effective suppression.

The advantages of hose-reels are in their speed of deployment and their ability to gain rapid knock-down of static (hanging) gaseous layers through the application of finely divided droplets in suspension. Where the gaseous layer is gaining in momentum and moving quickly, then the knock-down may not be so easy with such a low flow-rate. A fast moving flaming gas layer may occur where air is rushing in to feed rapid fire growth or where an exterior wind is creating a forced draft.

www.euro-firefighter.com

[Andy Cole]

We only carry 3 lengths of 20 metre high pressure hosereel on one drum, on the other side we carry a CAFS (Compressed Air Foam) hose.

[Julie Andrews]

Yes, but hosereel hose is very low friction and the high pressures used mean the pressure loss due to friction is unimportant over ther sort of distanes likely to be adopted.

Um, no.

 Hosereel has a very high friction factor and pressure loss by friction is a very important consideration in its use.

A 200m run is going to be unworkable for firefighting, but it would probably be ok to water your flower beds.

[Midland Retty]

Spot on Julie and may I say that I thought you were great in Mary Poppins

The frictional loss in HP hoses can be significant. Consider also the issues of hose lines running vertically as well as horizontally - I forget the exact calculation but you loose a certain ammount of pressure per meter in height in both low and high pressure hose.

[kurnal]

The pressure loss  (or gain) due to head is 0.1 Bar per metre.
Least it was when I was at school but of course it may been changed as a result of modernisation of the fire service!!

I dont know the pressure loss due to friction per length of hose reel tubing- it is of course approx  0.2Bar per 25m length of delivery hose. Anybody help on this?
But if you dont need a lot of water - for example in rural firefighting where water is at a premium- even though the pressure loss due to friction will be higher you are starting from a higher pressure. A common compromise up on the  high remote moors is to run a single line water relay using 70mm  delivery hose terminating in a male instantaneous to hosereel adaptor and to use a hosereel and branch to apply the water in a economic manner.

[eddie burns]

if i remember rightly the pressure lost in hosereel attack can be severe.
depending on how much tubing is actually left on the drum at the time of attack , it can be anywhere between 10-15bar.

i am sure there has been countless debates over the years to the efficiency of hosereels for a house fire attack due to critical flow rates and such forth.
I still see h/r as being ideal for a first tactical approach but always backed up with a support jet of 38/45mm.   reason behind this is most of our house fires are confined to a one room job and a hosereel is usually enough to cope as long as the pump operator gives adaquate pressure but general rule of thumb to me is big fire then big water.

experts still say 51mm is the way forward

[Rich]

My knowledge of hydraulics is limited but I can recall being told that a huge amount of pressure is lost through couplings on high pressure hosereel.  To that effect my brigade went down the road of single lengths of 60m tubing.  However that went out the window soon after they got fed up replacing 60m of hose each time it was damaged so we are now back to to 3 x 20m the same as everyone else (ooh ours is now a nice yellow colour - really easy to keep clean as you can imagine!!).