Equipment Services Department

Polyethylene is a very durable yet flexible material that is used in piping systems to transport liquids, gases, acids, or abrasives and is able to be joined by a fusion process eliminating joint failures and reducing system leakage.

MDPE is the common designation for “medium density polyethylene” and is commonly used for, but not limited to gas applications.  It has a lower pressure rating per inch of wall thickness than high density polyethylene.  HDPE is the common designation for “high density polyethylene” and is commonly used in water and select gas systems due to the difference in pressure ratings for higher pressure applications.

Water and sewer distribution, gas and oil collection-distribution, conduit piping systems, irrigation, reclaimed water and drainage systems, wind generation and other applications where durability is valued.

When pipe and fittings are fused together you eliminate the use of any mechanical fittings.  Fusion is actually a process of molding two pieces of polyethylene into one continuous piece, eliminating potential failure points.  The fusion process when performed properly will make the joint as strong or stronger than the pipe itself and will ensure longer life with limited repairs throughout the piping system.

There are three main types of fusion processes for joining pipe and fittings; socket, butt and electrofusion. While all three are a reliable source for fusion of pipe and fittings, butt fusion has the advantage of not using any additional fittings.  While socket and electrofusion require additional fittings they have the advantage of no internal bead generating less flow restrictions within the piping system.  There are different benefits to each of these fusion processes and selections should be based on the project or application.

Recommended sources include American Society for Testing Materials F2620 Standard Practice for Heat Fusion Joining of Polyethylene Pipe and Fittings, American Water Works Association M55 PE Pipe Design and Installation, Plastic Pipe Institute PE Handbooks TR-33 Generic Butt Fusion Joining Procedure and TR-41 Generic Saddle Fusion Joining Procedure, McElroy Catalogs and Training Videos, or you may contact an Industrial Sales Representative to assist you in locating the information of interest.