Peak daily sewage flow from a building, how to calculate

[GRANITE80]

Hi -

I'm looking for some guidance on how to calculate the peak daily sewage flow leaving my building for purposes of comparing that to our permitted DEQ capacity (septic system). This seems like such a simple procedure, yet I can't find a metholology in any of my references! I'm looking in the Uniform Plumbing Code, CERM, ... ideas?!?

(yes, I just posted this in the waste water area but realized this might be more "general civil"...)

Thanks!

 

[CarlB]

Peak flow as calculated in the plumbing code (based on Drainage Fixture Units) is to ensure pipes have plenty of capacity. Doubtful if a building will ever experience that peak, especially with attenuation within the lines. Septic ssytem design is typically based on a daily average flow.

Is your water useage metered? That would be a good check.

 

[bimr]

Look it up in a book. Piping Handbook Published by McGraw Hill has the procedure to calculate fixture units from a building. Get the book at your local library.

 

[CarlB]

For estimating PEAK flow, this site hsa some good info;

http://www.hawsedc.com/peakfact.htm

 

[jeffcivil2]

generally speaking from multifamily experience in my city:
for residential peak , use 240 gpd/unit x 4 (peak factor)
for general retail, use 0.01 gpd/s.f. x 4 (peak factor)


I don't have the # right now for restaurant kitchens, so you'll have to look that up if your building has one.

Jeff

http://www.civiltips.com

 

[GRANITE80]

Thanks for all the input. I contacted our local DEQ and found that we have a simple table that gives minimum gallons per day for septic system based on different uses. MUCH simpler than I was making it!