How to size a Water Meter

[jason7]

Hello Friends,

The calculated water usage for a new Carwash Facility that we are developing is about 3,350 GPD. I am currently showing a 2" water meter on my plan, but my client wants to use a 1" water meter.

Based on the projected flow of 3,350 GPD how can I determine what size water meter I need to use for this project.

A quick response to this query will be greatly appreciated.

Thank You

 

[Bjegovic]

many types are available on the market. some thoughts from the top of my head:

1) calculate peak flows. check that the foreseen flow meter can meet min/max flow demands. having smaller water meter can save you some money (not much on that diameter) and remember that you need pipe reductions.

2) make sure that pipe reduction does not harm accuracy of the meter (should not be an issue)

3) check the pressure drop if this is critical

 

[bimr]

Contact the manufacturer of the water meter. Badger or Sensus makes them. You probably need a turbo meter:

http://www.sensus.com/product_01c.asp

There is a headloss curve for the particular meter. The head loss at the peak flows should probably be 5 psig.

 

[hydrae]

AWWA has specifications on cold water meters, As I recall a 1" is good for 50 gpm peak, 1.5" is 100 gpm, and 2" is 160 gpm, manufactorers will rate them for slightly higher flows,
for continuous duty such as a car wash the rating is halved.

you client is probably concerned about the SDC's (system development charge) or 'buy in' fees on both potable water and sewer connection which is also sized to the water meter
The water purveyor and plumbing inspector will also require a minimum size based upon fixture unit counts or peak flow rates
Hydrae

 

[jason7]

Thank You all for the replies.

My Client is trying to save money on the water connection fees, the meter cost and the growth capacity fees levied by the City. The 2" meter would cost him $15,000 in fees (both water and sewer services) and the 1" meter would cost him $7000 in fees. So he wants to know if he can save some money by going with the smaller meter.

 

[Pump2005]

I work for a water company and there are minimum bills for each size meter. A smaller meter will mean they will pay less each billing period. Town codes usually dictate what size meter they should have.

 

[dicksewerrat]

The town will tell him what size he gets based on his estimated demand.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[LHA]

hydrae, pump and sewerrat are correct. Call the water provider, they will send you a service application. Then they, not the Applicant, will tell you the required meter size. It will probably not be relevant whether or not a 1" or 2" will work.

Remember, amateurs built the ark...professionals built the Titanic. -Steve

 

[bimr]

A 2 inch pipe will supply around 90-100 gpm continuously with minimum pressure loss. A 1 inch pipe will supply around 25-28 gpm continuously with minimum pressure loss.

A 1 inch disc meter has a pressure drop of 6.5 psig at 50 gpm with a maximum flow of 70 gpm.

A 1 - 1/2 inch disc meter has a pressure drop of 7.3 psig at 100 gpm with a maximum flow of 120 gpm.

I understand that automatic car washes use about 20 gallons per wash. If you are talking about only one bay, a two inch water supply and one inch meter will probably be adequate since it takes 5-10 minutes to wash each car.

If you are talking about only four bays, a two inch water supply and a 1- 1/2 inch meter will probably be adequate.