Brooklyn1 Gravesend1 wrote:
On Thu, 30 Jun 2011 18:05:26 -0400, "Stormin Mormon"
wrote:

When I was in the fire service, we learned that both length
and diameter matters. Smaller hose increases pressure drop,
usually measured in psi drop per 100 feet of length.
500 foot hose has 5 times the pressure drop of 100 foot
hose.

Prove it.

You obviously weren't paying attention in class... so long as pressure
and diameter remains constant volume remains constant... it's when
there is pressure loss and diameter decreases that volume decreases...
fire hose diameter reduces even when moved around corners... every
sailer learns this from shipboard fire control tutorials. And were
you truly in fire service you'd know that fire hose lays flat when
unpressurized and it's diameter changes with changes in pressure...
all you did at the firehouse is polish the firemen's poles.

The volume is not constant. The longer the hose, the greater the volume of
water is in the hose. More water in the hose the greater the weight of the
water and the pressure will decrease.

Water pressure that comes from the city municipals have Huge pumps that can
"increase" the amount of energy to keep the pressure constant. Fire trucks
and Ship pumps will "increase" the energy to keep that pressure constant
and the length of hose will not matter as long as the length is within the
pumps limitations. Auto variable pumps are very expensive.

My home well system pump has a "constant" power output and does not
increase power to the home water system and most urban homes have limits on
the max pressure, my well system is set at a max of 50 psi, therefore
pressure will decrease as the hose gets longer or every toilet get flushed
at the same time, because my home well pump does not have the power to
maintain that pressure for really long runs.

One can prove this by getting a hose of different lengths at find out for
yourself.

--
Enjoy Life... Nad R (Garden in zone 5a Michigan)