INDOOR AIR QUALITY EFFECTS BASIC INFORMATION AND TUTORIAL


The concept of indoor air quality (IAQ) is not new. Publications as far back as the early 1800s discuss the subject and suggest ventilation as the solution.

These early writers mostly recommended a minimum of 5 ft3 /min of outdoor air per person, but later writers increased that number. The present ASHRAE Standard 62 value is 20 ft3 /min for
normal situations.

Most of this early work was done in England, where a number of public buildings were provided with heating and ventilating systems, including the House of Commons. Centrifugal fans were developed, using small steam engines for motive power.

Schools were a prime target for ventilation, and by the early part of the twentieth century the schoolroom unit ventilator was developed and advertised. Electric motors were available by then. A three-story elementary school, built in 1916, included an outdoor air-ventilation system with a direct current motor-driven supply fan (rheostat control provided manual variable volume!) and cast iron steam-heating coils in the ventilation air for winter use.

When the new science of air cooling came along, the value of introducing outdoor air through the cooling/heating system was obvious. And, as the material in the previous parts of this book shows, present technology allows us to control outdoor air ventilation very accurately.

Negative Effects of Poor Air Quality
Two terms are important: building related illness (BRI) and sick building syndrome (SDS). BRI relates to individual illness due to poor IAQ. Much of this relates to allergens, to which some people are more sensitive than others.

SBS means that many people become sick in the building environment, and this, of course, causes loss of production and, perhaps, lawsuits. In addition, there are problems with odors (including those caused by smoking) and problems with high or low humidity.

High humidity may allow mold growth and deterioration of the building or furnishings. Excessive air movement (drafts) is a common complaint. When people are sick or complaining, they are not producing.

Positive Effects of Air Quality
Many studies have shown an increase in productivity of 10 percent or more, when the air quality and other environmental factors are optimized, and there is less time off for sickness and fewer complaints.

Housekeeping and cleaning are made easier and less expensive. Thus, good IAQ is economically advantageous, and it improves the morale of the people who work and live in the building.

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