Butt Fusion — The “Leak Free” Answer

The natural gas industry adopted polyethylene pipe over 30 years ago and it is still the material of choice for distribution systems across the US and Canada . It has proven to be the long-term answer to the decaying infrastructure problem because of its 50-100 year life, non-corrosion characteristics, ease of installation, low life cycle cost and economical leak-free butt fusion joints.

Now the potable water industry, with it’s failing infrastructure, is growing in its acceptance of AWWA C-906 polyethylene pipe (HDPE) for the same reasons. The concept of a “Leak Free” system is new to this industry that has grown to accept a 10% to 30% loss of treated water because of leaky joints and corrosion failures in conventional piping materials. In addition, these leaky joints allow contamination into the water lines that we use for drinking water.

An HDPE piping system is “Leak Free” mainly because the pipe joints are butt fused together creating one homogeneous pipeline with no opportunity for leakage at the connection.

Most of the HDPE manufacturers have adopted the Generic Butt Fusion Procedure (Technical Report TR-33) developed by the members of the Plastics Pipe Institute ( www.plasticpipe.org ). This document, is being drafted to be included in the ASTM standard D2657 (Practice for Heat Fusion Joining of Polyolefin Pipe and Fittings), including the step-by-step procedures for butt fusing polyethylene pipe and it also provides a wide range of parameters that can be used to accomplish this.

Generally, two important details should be considered for fusing polyethylene pipe:

  1. Recognize the importance of good fusion equipment and keeping that equipment in good working condition. Well-designed and maintained equipment not only saves the contractor time on the job but also insures that the proper fusion parameters are achievable.
  2. Recognize the importance of having trained operators for the fusion equipment. Properly trained operators are more productive and pay attention to the step-by-step procedures recommended to make quality butt fusion joints.

Well designed / maintained fusion equipment and trained operators make the joining of HDPE a simple and economical task. This is an estimate on the amount of HDPE that can be installed above ground in an (8) hour day using 40′ straight lengths of pipe:

  • 4″ pipe — 2,000 – 3000 feet
  • 12″ pipe — 700 – 1,000 feet
  • 24″ pipe — 520 – 700 feet

With many states now experiencing a water shortage and buying water from adjacent states, it makes sense to use a ” Leak-Free ” polyethylene system with butt-fused joints as a conservation effort.