When sewer pipes are installed it is critical to confirm that the proper installation and field construction techniques were used. Flexible pipes such as HDPE, PVC and polyethylene will deflect when placed under a load, but there is a limit to how much deflection is allowable. One of the ways to test if deflection is within allowable limits is to use a mandrel or deflection gauge. The mandrel is dragged through the pipeline to verify that the inner diameter has not been deflected beyond acceptable limits. A nine-point mandrel is typically specified for deflection testing. These mandrels can be collapsed to fit down into a manhole, and they are available in many diameters.

Deflection Gauges

Deflection Gauge Specifications:

• Manufactured with exact precision
• Field-certifiable with proving rings
• Sized to fit through 400mm manhole openings