Extra High Molecular Weight High Density as originally noted in ASTMAmerican Society of Testing and Materials; technical organization formed for the development of standards on characteristics and performance of materials, products, systems and services, and the promotion of related knowledge. D1248, GradeThe elevations shown on plans and/or survey grade stakes for the installation of the carrier pipe. It is occasionally to give elevations for casing. In most cases, it is given to the flow line but can also be given to the top of the pipe or casing. P34 materials were specifically EHMW high-density polyethylene materials.
