ARLINGTON, Va. - The first in a four-part series of technical bulletins regarding direct-fired make-up air (MUA) equipment is available at the Air Conditioning Contractors of America's (ACCA) Web site.

ACCA Technical Bulletin 109 covers specifications for and operation of direct-fired MUA equipment in situations where one or more HVAC systems exhaust air from the space and require an equivalent amount of outdoor air (or make-up air) to maintain comfort, air quality, and equipment performance. Many commercial and industrial spaces have substantial make-up air or air-change requirements. These include manufacturing plants, garages, aircraft hangars, kitchens, shopping malls, and some warehouses.

Among the subjects addressed in the bulletin are:

  • Traditional use of direct-fired equipment.

  • Using direct-fired units for heating.

  • Using direct-fired units to purge contaminants.

  • Safety.

    Upcoming technical bulletins will address other issues associated with make-up air units: air balance, heat flow, humidity and condensation; duct systems, efficiency, controls (including indoor air quality), accessories, outdoor air intake; and sizing.

    The bulletin is available for ACCA members only, and can be downloaded at www.acca.org/tech/bulletins/.

    Publication date: 08/22/2005