Installation of PVC Pipe into a Mechanical Joint (MJ)

A “mechanical joint” (MJ) is defined in ASTM Standard D3139 as: “a joint in which a positive seal is achieved when a gasket is compressed by means of a mechanical device.” The MJ connection is very commonly used in North American pressure pipelines and usually is installed without any problems.

Occasionally, however, I hear of projects where there are issues with MJs.

Correct Installation Methods Minimize Problems

As with most construction projects, successful installations occur when tried-and-true methods are used. For any pipeline installation where bolts and nuts are used, it is important to tighten the bolts in the correct order (a “star pattern”) and to tighten the bolts to the correct torque value. In the case of an MJ, failure to follow these simple guidelines can result in leaks or other problems.

For my Tech Brief on PVC pipe and mechanical joints, click here.

Regards,
	John F. Houle, P.E. Senior Technical Consultant, PVC Pipe Industry 201 E. John Carpenter Freeway, Suite 750 | Irving, TX 75062 T. 972.243.3902 | F. 972.243.3907 www.uni-bell.org