Estimating Main Breaks
Estimating Main Breaks
(OP)
What is the best or most realistic method to estimate water main breaks? I have situations where our field guys find a leak and report back something like "it was a 10 inch broke straight around" and then ask me to determine the flowrate. I'm not sure of the best method to attempt to estimate such a leak.
Thanks
Thanks





RE: Estimating Main Breaks
RE: Estimating Main Breaks
The best way is to monitor meters feeding the area if they exist and comparing flows during the leak and after the leak is fixed.
It can also be estimated during the repair, but keep in mind that as the leak is excavated the flow increases since the soil around the pipe was also holding back some of the pressure. Another method is to measure how much water was needing to be pumped during the excavation, such as we had two 2 inch pumps going full out to get the water below the level of the break. The pump says it flows 173 gpm, subtract some losses and figure 125 gpm each so that would be 250 gpm for that leak when exposed.
Hydrae
RE: Estimating Main Breaks
RE: Estimating Main Breaks
I have met this question, and also asked clients to come up with an answer for it in connection with emergency shutdown valves.
As indicated by the three good answers above, you have to approach this by a 'guesstimate', taking all variables into considerartion.
The first question is calculation for what purpose, and consequences if the estimation is too high or two low.
Next, very often, a double consideration/calculation will do: probably not higher than contra most possibly not lower than, and an avarage.
Your considerations should contain the data (as figueres) of your calculations and modifications (example : buried pipeline reducing leak in estimated area (xxx square) at mean water pressure ( yy bar) with ( zz backpressure) and (aa percentage reduced area) - or whatever depending on method, enabling later control or repetition of the estimate.
RE: Estimating Main Breaks