Peaking Factors as a function of design capacity

[jartgo]

Hello All,
The Maryland Department of Environment (MDE) specifies peaking factors as a function of design capacities:
Specifically,
Hourly PF = (3.2 * Design Capacity ^ (5/6))/Design Capacity

I can't seem to locate a source or explanation for this (beyond the MDE manual). That is, typically I see state design manuals reference the population equation in the 10-states. Is anyone more familiar with the peaking described above or perhaps you know where it originates from? The equation above is described on page three of the MDE manual, provided at the link below.

http://www.mde.maryland.gov/program...cuments/Wastewater_Design_Guidelines_2012.pdf

 

[bimr]

The Maryland Department of Health developed the peak flow ratios.

Don't have the old textbook from Fair and Guyer, Water Supply and Waste-water Disposal from 1954, but it is referenced in that textbook.

https://books.google.com/books?id=kxRSAAAAMAAJ&focus=searchwithinvolume&q=136

The linked graph may show the same ratios.

[link ftp://www.ilga.gov/JCAR/AdminCode/035/03500370ZZ9996dR.html]Graph[/url]