Managing indoor air quality

April 30, 2001
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Indoor air is a matter of quality. Working or living in a “sick building” with inadequate ventilation poses risks for everyone involved. Common questions and concerns include the possibility of contracting Legionnaires Disease due to poorly maintained ventilation systems, and developing a respiratory illness or allergies due to exposure to indoor molds.

Indoor air quality (IAQ) issues often center around the mechanical operation and effectiveness of the heating, ventilation, and air conditioning (HVAC) system. And research indicates that HVAC systems might be responsible for up to 60 percent of IAQ-related problems. At the same time, HVAC systems can be used to resolve up to 80 percent of the common IAQ issues. So, HVAC design, maintenance, and operation are all critical elements for maintaining quality indoor air. In addition to taking care of your HVAC system, here are five things you can do to head off indoor air complaints:

1. Address ventilation systems during the building-design phase and prior to renovations.

Building design doesn’t always consider what the occupancy of a building will be several years after construction, so many buildings end up being occupied beyond HVAC system capabilities. In addition, renovations often occur without readjusting the HVAC system to account for the changes. Often, this leads to insufficient supply ventilation and air mixing, potentially creating a poor quality of indoor air.

To reduce this risk, be sure HVAC system design and operating parameters are addressed during construction and renovation projects.

2. Establish a building IAQ management program.

An IAQ management program can help ensure that building air quality is not overlooked. Typical program elements that address the factors that lead to IAQ issues are included in the accompanying sidebar.

3. Conduct baseline and annual building assessments.

Every building owner or facility manager should have an understanding of how the HVAC system is operating, as well as whether employee comfort parameters are being maintained, in order to promote early detection and remediation of indoor air problems. Several comfort parameters to evaluate include:

Carbon dioxide — CO2, a product of nature and a by-product of human respiration, is an indicator of ventilation effectiveness within a building. CO2 is present in the ambient environment at concentrations of 300 to 400 parts of contaminant per million parts of air (ppm), on average. Some studies recommend CO2 levels be maintained below 700 ppm for occupant comfort, and ASHRAE recommends that indoor CO2 levels be maintained below 1,000 ppm. Indoor levels approaching or exceeding this point indicate ineffective mixing of air and result in an increase of general air contaminants.

Temperature. ASHRAE recommends that indoor temperatures during the winter months be maintained between 68°F and 75°F, and indoor temperatures during the summer should be between 73°F and 79°F. However, an increase in complaints may occur if the indoor temperature is not maintained at approximately 72°F.

Relative humidity — Relative humidity (RH) is the amount of moisture maintained in the air. ASHRAE recommends that RH be maintained between 30 and 60 percent for indoor environments. RH below 30 percent may cause drying of the mucous membranes and discomfort. RH above 60 percent may increase the potential for indoor microbial growth.

Dilution of contaminants with outdoor air and air movement — Your HVAC system must be designed to supply fresh air into the building, allowing the contaminants that build up to be diluted and removed. Per ASHRAE, the minimum concentration of outside air to be supplied to office buildings while the building is occupied is 20 cubic feet per minute (CFM) per person in each occupied zone. In buildings with variable occupancies, the amount of supplied outdoor air may be different.

If the HVAC is shut down overnight, the system must be started at least one hour before occupants arrive in order to properly ventilate the building.

If these precautions aren’t taken, air will become stale. Other contributors to stale and poorly mixed air include poor location of supply and exhaust air diffusers, improper building or system design, or indoor structures that prevent free movement of air. Smoke tubes or other devices may be used to evaluate air patterns in a particular area to determine if the air is mixing properly.

Carbon monoxide — CO, a common contaminant in some buildings, is produced as a by-product of combustion, so it can be present in areas where fuel-operated systems are utilized. Concentrations should remain as close to non-detectable as possible.

4. Remediate water-damaged building materials.

Wet or water-damaged building materials harbor the potential for mold growth. Coupled with increased humidity, water damage within a building creates the perfect condition for mold to colonize and cultivate. All porous building materials — drywall, wood, and particleboard — exposed to water should be replaced quickly to decrease the potential for mold growth. In addition, products such as wall insulation, carpet, and carpet padding should be removed, discarded, and replaced as they become wet.

Routinely inspect buildings for potential water damage so water losses can be minimized and damaged areas can be repaired before mold starts growing. Care should also be taken to ensure that inclement weather does not affect building materials during new construction or renovation.

5. Quickly address complaints.

Increasingly busy schedules and demands for our time often cause us to overlook seemingly minor complaints regarding the quality of indoor air. But it’s essential that IAQ concerns be investigated swiftly to ensure that they do not snowball into a larger issue.

People often become disgruntled when it appears their concerns are being ignored or disregarded, especially when they think their health is at risk. Prompt investigation will prove that you are committed to addressing your occupant’s concerns and will fix indoor air issues before they explode into a building-wide panic.

Sidebar: IAQ & litigation

Since most people spend the majority of their time indoors, the possibility of exposure to chemical or biological contaminants in problem buildings is widespread. Indoor air pollution typically falls into one of the following categories: Sick Building Syndrome (SBS), Building-Related Illness (BRI), and Multiple Chemical Sensitivity (MCS).

Poor ventilation, moisture intrusions, improper chemical storage and/or use are all conditions allowing for indoor air quality problems, even though some of these conditions have been around since the beginning of time. Increased awareness of IAQ issues has been largely driven by media coverage.

This coverage has ranged from articles in BusinessWeek, The New York Times, and USA Today to television coverage on “48 Hours” and “Prime Time Live”. Increased public awareness from this coverage has had the inevitable effect of making its way into the courtroom.

Types of suits

Legal aspects of IAQ include both personal injury claims and property damage. Depending on the state in which an IAQ legal action is filed, there are a number of actions that a plaintiff can pursue, including: Personal Injury Negligence, Workers’ Compensation, Failure to Disclose, Strict Liability, Professional Malpractice, Breach of Warranties, and Constructive Eviction.

The legal community has taken notice of this potential windfall of cases; some people are even calling microbiological contamination the “Asbestos of the ‘80s and ‘90s”. Court cases such as Dean H.M. Chenensky, et al v. Glenwood Management Corp., et al, (seeking $180 million for mold exposure), and Robert E. Coiro, et al v. Dormitory Authority of the State of New York (seeking $65 million for mold exposure) are enough to put the fear of litigation into any potential defendant and open the eyes of many lawyers to the potential windfall of court cases and monetary verdicts.

An excellent source of mold contamination toxic torts and property claims is compiled in Mealey's Mold Litigation Report. A paid monthly report is available from Mealey's publications and a synopsis of the reports can be viewed at no charge by visiting Mealey's Web site.

This information appeared in Aerotech Laboratories' “IAQ Tech Tip Program”, a free program distributed by Aerotech Laboratories, Inc. To subscribe, go to http://www.aerotechlabs.com/techtips.cfm or send a message to info@aerotechlabs.com with “Add IAQ Tech Tips” as the subject line.”

Sidebar: So you want quality indoor air…

Here are the components of an IAQ management program:

  • Document in writing your IAQ program.

  • Conduct a baseline IAQ profile of all facilities.

  • Implement effective design specifications.

  • Proactively plan and manage construction projects and contractors.

  • Ban smoking completely in your facilities, or segregate smokers in separately ventilated smoking areas.

  • Implement controls for specific contaminants and their sources.

  • Effectively maintain and operate HVAC systems.

  • Have a system for documenting and handling all employee complaints.

  • Investigate all complaints in a timely manner.

  • Effectively communicate building conditions and investigation findings resulting in improvement actions.

  • Conduct cross-functional training between contractors, building maintenance technicians, and others.

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