Preventive Thinking Goes a Long Way
Over the past decade, GLE has helped alleviate thousands of indoor air quality problems. Many have been in newly renovated buildings, and most could have been avoided if IAQ issues had been considered from the beginning of the design stage.

One thing has become very clear. The earlier you include HVAC system, building envelope and off-gassing issues into your planning, the better your chances of avoiding problems. Early consideration equals dramatically reduced liabilities.

Renovation Contaminants
The most common renovation-related IAQ contaminants are mold, dust and fibers, odors and fumes, and emissions from new furnishings. Contamination can be pre-existing or it can be caused by renovation activities or new furnishings. It can appear in any phase of a project, including design, construction and post-construction. All should be addressed and considered in the architectural design portion of the project.

Existing Contamination
The first step in minimizing your IAQ risks is to look for any existing indoor air quality problems. Existing problems which can, and should, be corrected during renovation generally fall into two categories:

• Moisture intrusion
• HVAC concerns

Moisture intrusion creates opportunities for microbiological contamination such as mold. Moisture intrusion can occur in many parts of the building envelope and can originate from obvious sources such as leaking roofs, soffits and windows or from less obvious sources such as clogged weep holes and aging brick veneer.

Microbiological contamination may be masked by interior finishes and surfaces. Checking behind wall coverings, above acoustical ceiling tiles, under and on carpet and behind drywall is recommended. If mold is present, the indoor air quality problems it creates will continue to grow. It is important to take care of microbiological contamination immediately.

Most renovation projects involve modification or change-out of the HVAC system. A properly designed and fully functioning HVAC system will provide thermal comfort, offer adequate amounts of ventilation, and filter the air. The HVAC system also must provide proper dehumidification, particularly in our humid climate, or it will create an environment conducive to mold growth.

There is great potential for microbiological contamination in HVAC systems. If you plan to leave any portion of the system in place, be sure to have these components analyzed early in the design phase.

Construction-Related IAQ Problems
Renovation activities provide a host of opportunities to generate indoor air quality problems. In general, new IAQ problems can be created by the following:

• Dust and fibers from demolition and reconstruction
• Gases and fumes
• Water and the resulting humidity

Whenever large quantities of water will be used during renovation activities, such as high-pressure water cleaning or asbestos abatement, make sure that there is adequate ventilation and dehumidification; otherwise, a mold-conducive environment is created.

If the HVAC system is to be shut down during any part of the reno-vation, you will need to plan for some other method of dehumidification. If possible, schedule major shut downs for seasons of lower humidity.

Dust and gas migration becomes a problem in buildings that remain partially occupied during the renovation. Construction activities such as metal cutting, welding, drywall sanding, painting, staining, and roof replacement can generate dust, gases, and fumes well above acceptable levels. Cleaning solvents and mastics also produce gases. Proper design gives you options to reduce dust and gas migration. These options include:

• Scheduling potential dust and gas producing activities for times when the building is unoccupied
• Providing engineering controls to isolate construction areas from occupants
• Selecting proper products to minimize gassing or dust and fumes

Post-Construction IAQ Issues
After construction, IAQ problems can be caused by:

• Improper testing and balancing of the HVAC system
• Off-gassing of new building materials
• Moisture intrusion due to construction defects

It is essential to ensure that your HVAC system is functioning properly and will be able to dehumidify in hot humid envi-ronments. This eliminates conditions that allow for microbiological growth.

Partitions, carpets and modular furniture are all potential sources of off-gassing. Careful selection of these products can help avoid problems. Many suppliers now offer environmentally-friendly “green” products at competitive prices.

Any moisture intrusion should be immediately identified and corrected.

Plan to Avoid IAQ problems
Renovation projects are full of prime opportunities for the creation or exacerbation of indoor air quality problems. IAQ problems are typified by a high frequency of minor issues which, left alone, can become major liabilities. You can minimize or avoid these problems altogether by simply addressing the issues during the preliminary design of the project. Every design for a renovation project should include the following:

• Identification of existing IAQ problems and plans to eliminate them
• Identification of potential IAQ problems and plans to avoid them

Questions to Ask
Questions to consider during the design process include:

• Have there been any visible signs of moisture intrusion, such as surface stains or condensation?
• Have any surface coverings, such as wallpaper or carpet, begun to pull loose from the surface?
• Have there been instances of standing water on any part of the roof?
• Are there any deteriorated or damaged areas of the building envelope that would allow moisture to penetrate?
• Have there been any reports of musty odors?
• Does your HVAC system provide enough outdoor air to furnish proper ventilation?
• Is the ductwork interior lined?
• Are the interior surfaces of air handling units and ductwork contaminated?
• Does the HVAC system adequately dehumidify the air?

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