2  FM quick reads on ASHRAE 62.1

1. Using ASHRAE 62.1 to Maintain Good IAQ


Facility managers can use ASHRAE 62.1's recommended ventilation rates to get an idea of whether the rates in their buildings are too high (and therefore not energy efficient) or too low (and therefore not conducive to good indoor air quality).

Now, no one will likely check whether a building is in ongoing compliance with ASHRAE 62.1 on an outside airflow basis, but if there's ever a problem, it's going to look bad if you don't know whether you're in compliance or not. It's good risk management best practice to have the data available.

Another aspect of compliance with 62.1 is preventive maintenance, which also fosters good indoor air quality. If you're measuring the percentage of prescribed preventive maintenance being completed, based on the maintenance manual that ASHRAE 62.1 requires must be provided when the building is handed over, a high percentage of completed preventive maintenance points to likely good indoor air quality. It means you're regularly checking filters, regularly examining dampers to make sure they're opening and closing properly, and making sure drain pans aren't full of water.

ASHRAE 62.1 also provides a standard (maximum of 65 percent in the 2007 edition) for relative humidity, which also plays into indoor air quality. Air that is too wet promotes mold growth. But air that is too dry (especially in the winter) can be just as bad for indoor air quality, causing occupant's mucous membranes to dry out and making them uncomfortable.

Measuring the dew point temperature and humidity, and benchmarking that data, is one of the more important, yet overlooked, parts of maintaining good indoor air quality.

Measuring for IAQ

Ideally, ventilation rates in a facility are high enough to preserve indoor air quality. But some facility managers want to be sure, taking the extra step to measure particular contaminants they may be worried about — especially if there is a known source in the building of a particular contaminant.

But measuring just to measure is not cost- or time-effective. Unless there is a specific goal for the data, facility managers might be better off pursuing other strategies, like getting to the source.

Look for specific contaminant sources and head those off first. Some examples: A janitor's closet full of old paint cans. Harsh cleaning chemicals. Permanent markers. Off-gassing new carpet. Find the source and remove or mitigate the source rather than measure the air for the potentially hundreds of different contaminants.

Guidelines for Air Pollutant Management
Once you've pinpointed and eliminated the sources of air contamination, if there are still contaminants you're worried about, you can take measurements then. This can be done with pieces of equipment like a photo ionization detector or by hiring a consultant to come take air samples.

ASHRAE 62.1 Appendix B provides a list of acceptable levels of some of the more common contaminants, like carbon monoxide, radon, formaldehyde and sulfur dioxide. In fact, ASHRAE 62.1 provides two avenues of compliance. The first is the Ventilation Rate Procedure, which just involves totaling up all the CFMs for a space. The second is the IAQ Procedure, which involves taking measurements of a variety of contaminants in a space.

One other source to consult for contaminant levels is EPA's Building Assessment and Survey Evaluation (BASE) study. This involved a survey of 100 random office buildings for contaminant levels and then calculating normal levels for those contaminants.


ASHRAE 62.1 , IAQ , relative humidity , preventive maintenance

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