www.safetyandhealthmagazine.com/articles/manhole-ventilation-system-2

Manhole ventilation system

September 1, 2012

The Manhole Ventilation Passthru is designed to maintain and redirect air flow with minimal restrictions into manholes, sewers and tanks. The unit is lightweight at 11 pounds and made of bright yellow, recyclable high-impact polyethylene to withstand heavy use and temperature extremes. The complete unit is easy to store and transport and ships in one small carton.

Allegro Industries