Longmont CSMS HVAC Upgrade

This renovation project involved upgrading the Mechanical HVAC systems for a 60,000 SF military maintenance facility with mixed occupancies. The facility comprised approximately 30,000 SF for vehicle maintenance, 4,000 SF for woodworking and canvas repair, 12,000 SF for electronics repair, 2,000 SF for welding and metal fabrication, and 12,000 SF for office space and miscellaneous functions. Schendt Engineering Corp. was the prime consultant and coordinated with electrical and structural sub-consultants. As-built mechanical system drawings were prepared and existing equipment condition evaluated. A comprehensive code compliance plan was developed to define each occupancy classification, associated ventilation requirements, and fire separation requirements between occupancies.

The vehicle maintenance facility was designed for repair of light commercial and heavy military vehicles. Vehicle maintenance areas normally required 6 air changes per hour ventilation. However, the bays were 30 feet high, requiring ventilation exceeding Group H occupancy standards. Justification was prepared for a code waiver to lower the ventilation rate to 1.5 CFM/SF, which was approved by the code consultant. Ventilation for vehicle maintenance areas was provided by direct-fired make-up air units on the roof. Up-blast roof exhaust fans ducted within 18 inches of the floor were utilized to remove potentially flammable vapors and discharge fumes upward, minimizing re-circulation into the building.

The welding booth required a ventilation rate of 1 CFM/SF, provided by a direct-fired make-up air unit and an up-blast exhaust fan mounted on the roof. Local exhaust for welding operations was provided by 14-foot long articulated arm exhaust systems. A gas-fired DX rooftop unit with economizer was utilized for office areas. The project included replacement of four make-up air handling units, one rooftop unit, three exhaust fans, and installation of three welding exhaust booms.

During the design phase, drawings of the existing roof structure were unavailable. The roof was double tee construction, and the double tees were X-rayed to determine their design for structural engineer evaluation. This thorough investigation ensured all mechanical systems could be properly supported and integrated with the existing structure while meeting all updated ventilation and safety requirements.