Uniform Soil Groups for Pipe Installation

The language in pipe installation standards and specifications should be as clear, concise, and consistent as possible. Accordingly, there should be uniformity in all the soil groupings for buried pipe installation. In the ASTM and AWWA standards for different pipe types, the exact same soil is variously described as "Class II", "SC2", "Category I", "Type 4 laying condition", "Coarse-grained soils with little or no fines", and "Suitable bedding material," etc. Why should a pipe designer wade through all the different soil descriptions to select the best soil type for the different types of pipes that could be included in the specifications? Confusion can lead to either over-designed or under-designed pipe. Uniform soil groups will help contractors better understand the type of soil they have to provide and make more accurate bids (are five different soils needed or does one soil fit all requirements?). Pipeline inspectors should not have to refer to many different installation standards to determine whether or not the right soil is being used. Unnecessary complexity and confusion leads to poor installation and future pipe failures and leaks. The specifications and project manuals can be simplified by using consistent language in the installation standards. A uniform soil grouping is proposed that can apply to all types of pipe. These soil groups have already been incorporated into some standards. The committees responsible for the other pipe standards and manuals are encouraged to adopt these soil groups.