What is the recommended Manning s n value for PVC pipe?
The appropriate conservative “n” value for minimum slope design of PVC sewer pipe is 0.009, as correctly justified by actual test data. The justification of this value is briefly described below. For many years it has been popular and convenient to use a single “n” value for all pipe materials. However, there is no data that technically supports the single “n” value approach, and the most cost-effective sewer designs are precluded by such an over-simplified design criterion. The recognition of “n” value variations among the commonly used sewer pipe materials is long overdue. To properly justify the use of product specific “n” values, an extensive literature research program was undertaken. This included review of a comprehensive listing of technical studies involving sanitary sewer pipe hydraulics that have been published within the past 30 years. A number of important conclusions have been derived from this literature review.
The appropriate conservative “n” value for minimum slope design of PVC sewer pipe is 0.009, as correctly justified by actual test data. The justification of this value is briefly described below. For many years it has been popular and convenient to use a single “n” value for all pipe materials. See similar questions…
