Lost Water Revenue 1" vs. 5/8" Meter
Lost Water Revenue 1" vs. 5/8" Meter
(OP)
I am drafting a rule to cover Single Family Residential Fire Sprinkler installations. The underlying intent is to make it as easy and cost-free as possible for the residential owner, while minimizing the water utility's added expense. In this system, the standard meter size installed for single family residences is 5/8-inch, with a 3/4-inch service line. The water utility wants there to be one metered service line that Ts after the meter, providing water for both domestic and fire protection systems. In order to achieve the required flow for the sprinkler installation, it will sometimes be necessary to install a 1-inch meter and service line when a 5/8 meter would otherwise be sufficient.
I am trying to put an approximate cost figure on the additional volume of low flow rate water that would pass uncounted through the 1" vs. the 5/8" meter. This would be a cost shouldered by the water utility unless it were--somehow--included in the customer charges.
Performance curves for the meters in question demonstrate the lower sensitivity of the 1", which has 99% accuracy at about 1.25 gpm, and the 5/8", which has 99% at 0.5 gpm. However, the overall average uncounted water impact for a single family residence is not easy to arrive at.
I am trying to put an approximate cost figure on the additional volume of low flow rate water that would pass uncounted through the 1" vs. the 5/8" meter. This would be a cost shouldered by the water utility unless it were--somehow--included in the customer charges.
Performance curves for the meters in question demonstrate the lower sensitivity of the 1", which has 99% accuracy at about 1.25 gpm, and the 5/8", which has 99% at 0.5 gpm. However, the overall average uncounted water impact for a single family residence is not easy to arrive at.





RE: Lost Water Revenue 1" vs. 5/8" Meter
RE: Lost Water Revenue 1" vs. 5/8" Meter
ACCURACY 100% ± 1.5% of actual thruput
http://www.sensus.com/Module/Catalog/File?id=22
RE: Lost Water Revenue 1" vs. 5/8" Meter
RE: Lost Water Revenue 1" vs. 5/8" Meter
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Lost Water Revenue 1" vs. 5/8" Meter
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Lost Water Revenue 1" vs. 5/8" Meter
So the overall accuracy is guaranteed no matter what the size of the meter.
That makes sense because .5 gpm * 12 hours * 5% error is only 18 gallons.
At the other end of the scale, 30 gpm * 12 hours * .5% accuracy is 108 gallons.
It makes more sense to have higher accuracy at the higher flows, because the lost water at the low flows will tend to be inconsequential.
I agree with CVG in that the loss of revenue is insignificant. However, you may want to consider specifying the meter with the best guaranteed accuracy.
RE: Lost Water Revenue 1" vs. 5/8" Meter
The utility has visions of cumulative loses due to tiny leaks out of customer taps and toilets--0.25 gpm leaking for a billing quarter means the utility paid to treat and pump out almost 33,000 gallons and got nothing in return.
But, I agree, the loss will most often be inconsequential; meters can be sized to reduce the problem, and the minimum charge is a convenient vehicle for balancing losses.
RE: Lost Water Revenue 1" vs. 5/8" Meter
RE: Lost Water Revenue 1" vs. 5/8" Meter
RE: Lost Water Revenue 1" vs. 5/8" Meter
They charge the same for all taps--the actual cost of labor and materials, if utility personnel actually perform the tap. A larger diameter tap may take longer, of course.
RE: Lost Water Revenue 1" vs. 5/8" Meter
I understand the post is about meter accuracy but I'm questioning why such a larger meter is being sought? If it appears I am robbing or derailing your post I apologize.
RE: Lost Water Revenue 1" vs. 5/8" Meter
RE: Lost Water Revenue 1" vs. 5/8" Meter