High losses through 1ö meter setting for fire flows

[scotulla]

We spec Mueller Thermal-Coil meter box 330CS2136FFBN for our 1” meters for combined domestic and fire service. We recently heard some concerns from one fire suppression system designer about the head losses through this type of meter setting. I have not seen the flow curve, and was wondering if this has come up with anyone else?

 

[Artisi]

What has come up ?
Might be a good idea to source the headloss data.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Pinwards]

Typically fire flow is provided via a separate fire line of a larger diameter where needed. A 1" meter would typically be used for a domestic water service line, and is not meant for larger fire flows. Is this a single family home or a larger structure?

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[bimr]

The additional head loss through this meter arrangement is negligible compared to the head loss across the meter itself. The meter arrangement just adds some additional piping. Most of the head loss will still be generated by the meter itself not the piping.

 

[scotulla]

Thanks for the comments (I have been out for a bit). The situation is that on new residential construciton over a certain square footage, fire protection in required. We (the water company) require 1" meter pits for these new proterties. So, yes we have 1" meter settings with residential fire flows. It does not appear that this has come up for others.

I will get the flow cures from the Mueller and see what developes.
Thanks,

 

[cvg]

I agree with BIMR, the extra length of poly pipe in the thermo coil box will add very little headloss. The headloss is primarily in the meter and the 1" line to the building. However, it is entirely possible that your supply pressure is on the low side and that the headloss through a 1-inch meter delivering enough flow for sprinklers will exceed the available pressure. Since you have not given any information on the required fire flow or on your system pressures, or on pipe length nor on the type of meter used in your thermo coil box, hard to come up with anything to help you.