Professional Supply Inc. (PSI) is a 20-year old technology company specialising in innovative industrial HVAC systems and non-pressured hot water systems. The Bigfoot technology, utilising large scale direct gas fired air make up units, had been implemented in several US automotive plants with Ford Oakville being the first Canadian installation. The entire project was implemented on a turnkey, performance contract basis with the Canadian subsidiary of PSI providing all services from final design through construction, commissioning, training, and maintenance. The Bigfoot project allowed for the complete shutdown of the steam boiler system.
Ausenco was selected to provide mechanical and electrical engineering in May 2000 for system installation and contract administration. Engineering was carried out on a fast track basis with the installation of grillage, gas piping, electrical distribution, etc., in preparation for lifting the Bigfoot units in place. The retrofitting of existing equipment was minimised in the design process.
The design philosophy of the Bigfoot was to create a positive pressurisation of 0.02” wc and eliminate the negative pressure in the plant. A total of 13 “Bigfoot” roof-top units were installed creating a new ductless heating and ventilation system for Oakville Assembly and Ontario Truck plants. Each Bigfoot consists of a large air housing containing two 100 hp fans. Fresh outside air is heated by a direct fired natural gas burner and mixed with return air to provide building air balance. Supply air is kept between 50° and 90°F at the discharge head. This tempered air forces the hot air down keeping the space temperature at the floor level virtually constant at 70°F + 2°F (winter). In the summer, the space temperature will not exceed the outside air by more than 5°F. Space temperature is monitored at three levels: ceiling, mid height, and 5 feet above the floor.