Sewer line air testing, Mandrel testing and Manhole vacuum testing provide the customer and or the city/ State with proof that all lines and structures are installed correctly and will serve the community for many years to come
How vacuum testing works
The whole idea behind vacuum testing is to suck air from within an enclosed space (manhole structure) and create a pressure differential between the interior and the atmospheric pressure on the outside of the manhole. Air pressure will seek an equilibrium state and therefore a vacuum is created. Atmospheric pressure is about 15 psi absolute
(103 kPa). When we pull a vacuum of 10 in. (25 cm) Hg, an internal pressure of roughly -5 psi gauge (-35 kPa), or 10 psi absolute (69 kPa), is created. The atmospheric pressure on the exterior of the manhole, 15 psi absolute, will thus exert 5 psi (35 kPa) of differential pressure on all surfaces, joints and connectors.
We uses deflection gauges (mandrels) to test sewer pipe for out-of-roundness or deflection per ASTM specifications D3034 and F679. This testing ensures that flexible sewer pipe has been properly bedded and backfilled (ASTM D2321) as it's critical to optimal and long-term performance for newly installed sewer lines.