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Six steps for improving indoor air quality.

Today environmental concerns are shared by everyone, particularly among property managers. Our medical vocabulary now features such ominous terms as "sick building syndrome" and "Legionnaire's Disease.' It is a consumer issue which captures media headlines. It is a financial issue, as well, for those who worry about the prospect of litigation and loathe to spend tens of thousands of dollars on yet another "possible" health risk.

What is a sick building?

A sick building is one in which at least 20 percent of the occupants exhibit several of the following symptoms: headache, dizziness, drowsiness, fatigue, nausea, and irritation of the eyes and respiratory system. If these manifestations persist for more than two weeks and disappear or abate when the tenants leave the building, the symptoms are probably caused by a build-up of contaminants within the building.

Honeywell's Indoor Air Quality Diagnostic Center estimates that 20 percent of the buildings in the United States have air-quality problems.

Years of energy-conscious building management has made building envelopes tighter and ventilation schedules more stringent. In a sense we have created a new problem in solving an older one. As we enter an era of renewed energy awareness, it is necessary to reorder our priorities and strive for bottom-line economies that maximize both energy conservation and clean indoor air.

Exposing tenants to contaminated air can be a costly affair. Even if only a few individuals become ill, the cost of litigation can be enormous. A recent article in the Wall Street Journal stated that "Sick-building suits could rival those that have proliferated over asbestos." And unless the offending conditions are diagnosed and corrected immediately, they can be expected to worsen, portending still more lawsuits, unfavorable publicity, tenant cancellations, and government intervention.

Yet, in many cases, indoor air quality can be achieved with a six-step, practical approach to cleaning up the air and maintaining a healthy indoor environment. This simple system is aimed at preventing problems in buildings before they occur and at assuring building owners and property management that they are providing a healthy and productive environment for their tenants, without significant financial outlays.

Become familiar with indoor

air quality standards

The most powerful of the air quality standards is ASHRAE 62-1989, enacted recently by the American Society of Heating, Refrigeration and Air Conditioning Engineers. This respected organization has considerable power in the construction industry and its new air quality standard affects the design of every new building. While not directly enforceable in existing buildings, it can serve as a valuable guideline for assuring acceptable air quality and defining the limits of liability.

Because most buildings were designed before ASHRAE 62-1989 was written, they are probably not in compliance. The requirement is a minimum airflow of 15 cubic feet per minute (cfm) per person, and in most situations the standard is 20 cfm or more. Specific requirements depend on occupant density and the activity for which the space is used.

Further, the standard specifies that these quantities be verified by measurement in the occupant's breathing zone, not by inspection of the operations manual or measurements in the duct-work. This recognizes the fact that duct leakage, obstructions in work space, and poor air distribution may reduce air flow, even though adequate ventilation is available.

Many buildings may be able to comply with these new provisions without retrofit expense merely by altering damper positions. If a system is undersized, modifications will be necessary.

Another provision of ASHRAE 62-1989 requires that outside air used for ventilation meets federal ambient air quality standards. This suggests that the outside air supply may have to be curtailed during critical periods of pollution, e.g., traffic rush hours. During such periods, properly filtered recirculated air may be substituted.

A copy of Standard 62-1989 is available from ASHRAE in Atlanta, Georgia. Inquire also about applicable state and/or local indoor air quality standards.

Check for building flaws

In addition to design deficiencies attribute to subsequent code changes such as ASHRAE 62-1989, many buildings are hampered by mistakes in the structure that increase the likelihood of indoor air contamination. The manager should look especially at the air intake vents on a building and search for nearby sources of contamination.

One of our clients, a hospital, had the exhaust stack from the cafeteria kitchen immediately adjacent to the intake vent for the surgery wing. At certain times of the day, operating room personnel could smell the odor of frying hamburgers.

Many low-rise buildings have fresh air grilles located above or close to loading docks. Air drawn into the building for ventilation purposes comes from an area containing idling truck engine fumes and, often, trash dumpster odors. The logical explanation for this error is that both grilles and docks are unsightly features, leading the building designers to hide them on the back side of the building.

Like the frying hamburgers, this design flaw would be laughable if its consequences were not so dangerous. The solution? Usually it involves little more than the installation of physical barriers to separate the two airstreams and has no effect on energy consumption.

Though hardly a design flaw, the variable-air-volume HVAC systems so prevalent today can sometimes interfere with adequate ventilation. As the name implies, the system controls air temperature by varying the volume of air delivered to the occupied spaces. When the temperature control setpoint can be satisfied by delivery of a very low air volume, the work space can become stuffy and stagnant. If this appears to be a problem in a building, consult an HVAC specialist. There are remedies.

Bring ventilation

schemes up to grade

Building usage changes frequently as tenants come and go. Personnel density changes, usually on the plus side. Walls move and cubicles are relocated. Copying machines add particulate matter to the air. Personal computers increase the thermal load. These are the facts of life in a leased building, or even in an owner-occupied one. The missing ingredient in many buildings, however, is a ventilation scheme dynamic enough to keep pace with the changes. As people and equipment are added to a space, ventilation air must be added. When walls are moved, air distribution must be modified to assure proper air circulation. Local sources of indoor air pollutants such as copying machines should have their own exhaust systems. A building might have had an excellent ventilation system when the first tenants moved in. Does it still, or is the ventilation system still adjusted for that long-gone first tenant?

The solution here is simple and non-controversial. It is a matter of establishing flexible ventilation procedures and conducting periodic audits. As spaces are occupied more intensively, fan energy consumption may rise slightly to keep pace. But this will not be a major factor in overall energy cost.

Re-examine control strategies

As suggested previously, past energy conservation measures may be a major contributor to declining indoor air quality. Most building ventilation schemes, for example, probably keep fresh air intake to a minimum. Without a doubt, changes implemented to improve indoor air quality, increasing outdoor air damper positions and prolonging fan operation, could impact utility costs.

If we are to achieve our goal of minimizing bottom line operating expenses, this energy increase needs to be offset. In building after building, we have found that incentive in improving the efficiency of the ventilation delivery system itself.

Most systems are very inefficient, having been designed to hold down installation costs rather than to deliver clean air to "the occupant's breathing zone." Return air from fan systems steals air from the make-up air fan systems - sometimes as much as one-third. The same thing can happen at the zone and diffuser level. The ventilation air actually reaching the occupant is but a small portion of that specified, even though fans are operating (and consuming power) at full volume.

One of our clients, who was experiencing a net loss of two-thirds of the outdoor air because of an inefficient ventilation delivery system, was able to erect a few sheet metal barriers in the system and double the local ventilation rate without increasing fan energy consumption. An isolated case? We find the existence of such opportunities to be the rule rather than the exception.

Re-examine preventive

maintenance programs

We find that poor maintenance procedures contribute to indoor air quality problems in 75 percent of the buildings we inspect. Maintenance deficiencies also rob the HVAC system of efficiency, driving up energy costs. A properly designed program of preventive maintenance, administered by a trained staff, will do wonders for air quality, utility costs, and the bottom line.

Some of the things often found in a poorly maintained building include:

* Air filters that are either so clogged that air movement is obstructed or that have been removed altogether.

* Untreated cooling water that has fouled surfaces with moss and fungi.

* Moisture and dirt that combine in ductwork and promote the growth of microorganisms.

* Unrepaired damper linkages, causing too much or too little air to circulate.

* Control settings that have been accidentally upset by marginally trained maintenance workers. (This is especially damaging in an automation system.)

The solution is obvious. Train your people, improve planning, and inspect thoroughly. Air quality will go up and net operating cost will go down.

Get professional help

If in spite of these precautionary measures, the tenant complaint level indicates that there may be air quality problems present, do not wait - get help. An air quality consultant will survey a building's occupied spaces, equipment rooms, and operating procedures. An initial assessment can be completed in one day. Then he or she will report the findings and suggest actions - a series of specific corrective measures or, in severe cases, in-depth diagnostic testing of the problem areas in the building.

In every sick building we have surveyed, the cost of the cure was less than the probable cost of ignoring the problem in terms of tenant good will, exposure to litigation, and publicity.

Tim Kennedy is the manager of the Indoor Air Quality Diagnostic Center at Honeywell, Inc. in Minneapolis.
COPYRIGHT 1991 National Association of Realtors
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Copyright 1991 Gale, Cengage Learning. All rights reserved.

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Author:Kennedy, Tim
Publication:Journal of Property Management
Date:Mar 1, 1991
Words:1664
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