10 States Standards Minimum Slopes
10 States Standards Minimum Slopes
(OP)
Hi all,
I was thinking about how the minimum slopes came to be in the 10 states standards manual for storm and sanitary design criteria. Does anyone know how the slopes that are used came to be? How do we know an 8-inch sanitary line needs a minimum slope of 0.4% and not 0.35%. Just a thought I had that maybe someone with a little more knowledge on the criteria could shed some light on. I'm kind of hoping someone will point me in the direction of published lab results, but if not that's alright too.
Thanks!
I was thinking about how the minimum slopes came to be in the 10 states standards manual for storm and sanitary design criteria. Does anyone know how the slopes that are used came to be? How do we know an 8-inch sanitary line needs a minimum slope of 0.4% and not 0.35%. Just a thought I had that maybe someone with a little more knowledge on the criteria could shed some light on. I'm kind of hoping someone will point me in the direction of published lab results, but if not that's alright too.
Thanks!





RE: 10 States Standards Minimum Slopes
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RE: 10 States Standards Minimum Slopes
You may be interested that quite similar requirements and provisions have also been included in ASCE's "Gravity Sanitary Sewer Design and Construction" (WPCF FD-5) Manuals and reports on Engineering Practice, used in much larger areas and jurisdictions also for many years. The latter reference I know explained, "Generally, Manning's "n" for a given sewer, after some time in service, will approach a constant which is not a function of the pipe material but represents the grit accumulation and slime build-up on the walls. This n will be on the order of 0.013. A coefficient which will yield higher friction losses should be selected for sewers where disturbing influences are known or aniticpated. Because of the empirical nature of each formula, conservative design is prudent." [I suspect there is some testing revealing the basic flow, so to speak, of this passage]
About the only other thing I will say is that I have attended a few Engineering presentations (since first reading these manuals many years ago) indicating that as sewers get much larger, even much higher flow velocities in the realm e.g. of at least 3-4 fps or more etc., may be helpful for large sewers it appears to develop sufficient shear to adequately move most sediment including larger grit and even some rocks etc. that somehow seems to make its way into these larger lines.
RE: 10 States Standards Minimum Slopes
The problem occurs with new installations where the flow is less than full flow and the sewers are at minimum slope. In this scenario, additional sewer cleaning will be necessary because the sewer velocities are low.
RE: 10 States Standards Minimum Slopes
Now, CA is not the rest of the country, but the national specifications for toilets, water, gasoline, electric safety, cancer chemicals, and food labelling and seemingly everything else seems to creep east from the CA land.
RE: 10 States Standards Minimum Slopes
RE: 10 States Standards Minimum Slopes
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: 10 States Standards Minimum Slopes
RE: 10 States Standards Minimum Slopes
“With regard to municipal sewer lines, the transport of waste has not proven to be an issue of
concern in those areas with a concentration of high‐efficiency toilets. Supplementary
wastewater flows from other end‐uses are always sufficient to move solids through the system.
Furthermore, some wastewater utilities are co‐funding and sponsoring the toilet replacement
programs and other water efficiency initiatives of the water utilities for the very purpose of
reducing sewer flows to their treatment plants.”
http://www.allianceforwaterefficiency.org/uploaded...
RE: 10 States Standards Minimum Slopes
Are they actually reliable, or only reliable inside Sacramento and Washington DC's beltway when asking about more money and rules benefiting their clients? 8<)
RE: 10 States Standards Minimum Slopes
he Alliance for Water Efficiency is a stakeholder-based 501(c)(3) non-profit organization dedicated to the efficient and sustainable use of water. Headquartered in Chicago, the Alliance serves as a North American advocate for water efficient products and programs, and provides information and assistance on water conservation efforts.
This work is being led by the Plumbing Efficiency Research Coalition (PERC), a group of U.S.‐based organizations that support water efficiency and sustainable plumbing, in collaboration with the Australia‐based Australasian Scientific Review of Reduction of Flows on Plumbing and Drainage Systems (ASFlow) Committee. PERC members include the Alliance for Water Efficiency (AWE), International Association of Plumbing & Mechanical Officials (IAPMO), International Code Council (ICC), Plumbing‐Heating‐Cooling Contractors National Association (PHCC), Plumbing Manufacturers International (PMI), and the American Society of Plumbing Engineers (ASPE).
Many advocates there.
RE: 10 States Standards Minimum Slopes
RE: 10 States Standards Minimum Slopes
RE: 10 States Standards Minimum Slopes
RE: 10 States Standards Minimum Slopes
If it is mainline, reconnect 1-2 Catch basins to the line. If it is in an easement look for a water source. Last resort, shrink the pipe size. Clean on an accelerated schedule. Inspect about once a month to see the buildup. That means "don't jet" the line before you send the camera in.
Richard A. Cornelius, P.E.
WWW.amlinereast.com