Investigation identifies likely causes of complaints about poor IAQ.

Details a NIOSH (US National Institute of Occupational Safety and Health) investigation of a school whose occupants suffered from allergic symptoms. The investigation found that occupants' symptoms were consistent with sick building syndrome. Many complaints were apparently related to insufficient outdoor air, temperature extremes in some cases, and temperature controls that were inadequately responsive to classroom conditions. Two potential causes of poor IAQ were the boiler exhaust stack located in close proximity to the fresh-air intake and janitorial supplies stored in an HVAC return-air access area. In both cases it would be possible for contaminants to be drawn through the HVAC system and circulated throughout the building. Recommendations included raising the boiler-exhaust stack to reduce or eliminate the possibility that combustion gases enter the outdoor-air intake during the heating season; remove janitorial supplies from the return-air access area so that spilled or leaked chemical odours are not distributed throughout the building; rebalance and adjust the HVAC system; relocate thermostats that do not gauge actual room conditions; replace stained ceiling tiles so that new leaks are easy to spot; provide local exhausts for the pottery kiln and woodworking machinery - these special areas should be under negative pressure; assign a full time person to be responsible for adequate maintenance of building mechanical systems; set up and maintain a file for the HVAC system and log complaints; replace worn out carpeting and clean carpeting with organic-based solvents.