Sizing Water Main
Sizing Water Main
(OP)
I know the demands required for an area that is far away, 12 km and requires water servicing. I want to apprpriately size a water main and am not sure I am doing this correctly (first try). I have used Hazen Williams to calculate the headloss. Now I am not sure how to proceed. I don't think I need a detailed explanation but if someone could help with what equation to use or what parameters to check to make sure size is suitable that would be great. Thanks.





RE: Sizing Water Main
RE: Sizing Water Main
If you know the peak flow in gpm take the square root of it. The answer will be the required pipe size in inches. Use the next higher pipe size, again in inches. This is crude but will give you a good first approximation.
By the way, EPANET will not size pipes for you.
good luck
RE: Sizing Water Main
RE: Sizing Water Main
Yes, pick a pipe size and then check pressures and velocities at design flow and at other possible flows; average day demand, maximum day demand, peak hour demand and maybe max. day plus fire flow. Because pipe costs are rising slowly and energy costs everywhere I know are rising steeply, I would think choosing a larger pipe is the wisest choice over the life of the system.
The 5 ft/sec guideline is a good indicator for most water systems. Velocities less than 2 ft/sec are probably too low and those over 10 ft/sec are probably too high under most conditions. During emergency conditions, such as a fire, they can be tolerated but should be avoided if possible for the reasons mentioned in my earlier post.
All this is based on the experiences of many water system operators and can be verified by looking at other nearby systems and by a review of the many AWWA publications available.
good luck
RE: Sizing Water Main
RE: Sizing Water Main
RE: Sizing Water Main
RE: Sizing Water Main
RE: Sizing Water Main