Model GP21 positive-pressure ventilator reduces or eliminates hazardous dusts, fumes, and temperature extremes found at construction sites. Consists of a heavy-gauge, tubular structure that directs air stream (11,000 c.f.m.) through an opening and into a job site. In turn, onboard propellers channel airstream through an available exit and into the atmosphere. Open screen design allows ventilator placement close to inlet openings, including congested spaces found in office complexes, warehouses, and other sites. Equipped with pneumatic wheels that ease transport and positioning on both rugged and flat terrain. Runs on 5.5-hp. gasoline engine. Complies with OSHA regulations for atmospheric contamination. Electric-powered model also available. General Equipment Co., Owatonna, MN