AKF - Bulletins - Indoor Air Quality Regulations

Indoor Air Quality Regulations

On April 5, 1994, OSHA published proposed rules for regulating indoor air quality (IAQ) in the workplace. The rules cover all non-industrial work places including public and private buildings, schools, health care facilities, and offices. The proposed rules include a complete ban on smoking or restriction of smoking to specially exhausted lounges, the development and implementation of IAQ compliance plans for all buildings and verification that building ventilation systems are functioning properly.

The OSHA rules have yet to be adopted and there is sure to be a long drawn out review and comment period. But the proposed OSHA rules are one more indication of the increasing public concern over IAQ.

The prudent building owner, operator or facilities manager should not wait for the adoption of OSHA rules to ensure that proper IAQ exists in their facilities. A two step approach is required; careful control of materials and products installed and used inside buildings and verification that building HVAC systems are operating properly to provide adequate quantities of good quality ventilation air. Many HVAC systems designed and built prior to the present concern over IAQ do not provide quantities of outside air consistent with current recommendations. Even those systems that meet the outdoor air standards and code requirements in place when they were designed, may not do so during all occupied hours and for all load conditions.

IAQ deficiencies common to many existing HVAC systems include:

VAV boxes with non-existent or inadequate minimum set points.
VAV systems with fixed minimum outside air dampers. These systems may not provide adequate outside air quantities at less than full flow.
Excessive carryover or inadequate condensate drainage from cooling and dehumidifying coils.
Inadequate filtration efficiencies and/or poorly maintained filters.
Improper application of humidifiers resulting in excessive carryover and potential microbial and fungal growth.
Poorly installed or improperly applied acoustic duct liner which can provide a breeding ground for bacteria and fungi.
Outdoor air intakes that are subjected to contamination or re-intrainment of exhaust air.
Improperly balanced systems which result in lower than expected outdoor air quantities.
Controls that do not maintain proper air flow relations between supply, return, outside air, relief and exhaust air.

All of the above common deficiencies can lead to a degradation of indoor air quality. More importantly, if there is a real or perceived IAQ problem, even if not caused by the HVAC system, the above deficiencies provide ammunition to those trying to prove a case. The prudent building operator will take measures now to ensure that building HVAC systems are operating properly.