Always block plugs when conducting air tests!


How to calculate pipeline forces and pressures.

1) Determine the inside diameter of the pipeline in inches.
2) Determine the maximum backpressure.
3) Calculate the pipe area in square inches.
4) Calculate the force the plug must withstand.

Example with 36 pipe: 18 x 18 x 3.14 x 5 psi = 5087 POUNDS OF FORCE!

Calculating pounds of force aid in building plug blocking systems. It also illustrates the tremendous force generated by a sewer air test.


Pressures being exerted on a plug, regardless of the medium (liquid, water or air) are the same. Ten (10) PSI water is the same as ten (10) PSI air. However, AIR IS A COMPRESSIBLE MEDIA. Therefore extreme caution should be observed when air testing.

Air back-pressure ratings reflect absolute back-pressure capabilities. Common engineering standards have been used to convert head pressure to PSI. It is imperative to block pipe plugs when performing air-pressure tests and to ensure no one is in the zone of danger when a plug is in use. (Please see our Safety and Instruction Manual for complete details.)