4" or 5" LDH - any advantages of one over the other?

[Captain Mike]

What advantages, if any, are there to using 4" vs. 5" Large Diameter Hose?
Any advantages to using one size over the other in terms of cost, friction loss, ease of use, amount of water that you can move, etc.
Although the Town of Lyons has hydrants we rely on tanker (tender) shuttles to supply the majority of our rural district.

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Captain Michael Guy
Lyons Fire Protection District
Lyons, Colorado

[neut]

There ar great advantages of 5" over 4" LDH. The greatest is alot less friction loss in 5" or 6". In 4" flowing 1000 gpm there is approx. 20 psi friction loss per 100' of hose and only 8 psi loss in 5" and 5 psi or less in 6" LDH. Flowing 1500 gpm there is 45 psi friction loss per 100' 4" hose and only 18 psi friction loss in 5" hose. With three or four hundred feet hose out you would need a plug with 80 to 100 psi pressure to flow just 1000 gpm using 4" hose compared to 50 or 60 psi with 5" hose unless you relay with another pumper at the plug. Remember use your largest gpm pumper at the plug. The biggest disadvantage is it does weigh more (I'm not sure of the weight difference) and cost more. Remember your plug has to be big enough to supply 1000 to 1500 gpm at that pressure and not just static (normal use) pressure.

[This message has been edited by neut (edited 06-14-2001).]