"Rick Blaine" wrote in message
...
dpb wrote:

"...given that there is a single boost[er] pump supplying both lines
and
the fitting on the pump is smaller than the larger line."

If I interpret this correctly, the system still has a single-point
choke
point. Downstream of that increasing the line size or number of
lines
can't help w/ what is an upstream restriction. Am I wrong?


Right... That's what I was trying to say. The fitting on the booster
pump looks
to be around 1 inch, maybe 1.5". It goes through an adapter to a
pipe that acts
like a manifold with the 1.5" and 2" lines tapped off. So my
assumption is that
as long as the pump can provide the pressure over the rise and
distance and
supply the demand, it doesn't make any difference if they are tied
together and
then split at the midpoint or run as separate lines.

Bigger pipes lessen the pressure loss in the pipe, no matter what size
of pipe the source is. If the pipes are big enough, their length makes
less difference to the pressure and volume available at the end. There
is just less pressure drop.

Having both pipes available to both houses just lessens the
opportunities for line pressure drop to make a difference between what
pressure is available in any house.


The tank at the service end resolves the problem in that manner as
long
as the total demand isn't greater than the tank capacity. Only
place
that should be a problem would be perhaps in the event of the
sprinklers
being in play, I would think.

Yep. I need to check the rating on the boost pump...

Fire Sprinklers are probably the defining parameter here, and the
codes concerning this will probably assure that other problem won't
occur. Just make sure the sprinkler demands are met.

Bob