We're pumping potable water from a

[drain]

We're pumping potable water from a tank through 2 mains into a distribution system & have separate fire flow pumps. The distribution lines are as follows:
Main #4 Qmax=1160 gpm, Hmax=340 ft
Main #5 Qmax=160 gpm, Hmax=110 ft
We planning to use hydropneumatic tanks 10 time the size of Qmax, so we're probably going to have to reduce the Qmax in Main #4. But we've also got a huge range in Hmax in the two mains. The only solution we've considered is the use of residential pressure reducing valves at homes at the lower elevations. Any other cost effective strategies come to mind?

 

[drain]

I made an error. It should be:
Main #4 Qultimate=1160 gpm, Qinitial=150 gpm, Hmax=110 ft
Main #5 Qmax=160 gpm, Hmax=340 ft

 

[BobPE]

the two mains go to separate parts of the system and are not connected? what are the pressures at the homes you are concerned with? only one main has fire service? what type of tank are you pumping from? volume, elevation?

Give us as much info as you can and maybe we can help.

BobPE

 

[drain]

The mains will be connected in future when storage tank put at high point.

Hmax given accounts for the differential from tank through pump to discharge at high points. The client wants to pump for a few years before building the tank, and has to provide both domestic and fire flows. What standard do fire pumps usually have to be to--NFPA? Will it allow me to have both fire and domestic pumps in the same building, do I need a separation wall between them? To ensure the codes were met, I was considering a package system for the fire pumps and do the design ourselves for the domestic system.

Both mains have fire service, 1269usgpm and 20psi residual is the requirement.

Even at the low points, operating pressures will not exceed 150psi, so we need some residential prv's req'd to keep pressures below, I think, 100 psi. In the back of my mind I thought of having a second booster on Main #5, which has high head and low flow, but thought that a second station would not be cost-effective. Main #4 has low head and high flow, which could be the determinant for pump selection of the first booster if we used a two booster system. Any comments?

We have 1200m3 concrete ground level storage tank, lots available.