Early identification of existing building hazards is the first step toward eliminating the development of an IAQ problem. Inspect the area to be renovated during the project planning stage. Look for possible asbestos and lead containing materials which may be disturbed. Attempt to identify sources of dust and microbial contamination. Consult EH&S documentation and arrange for surveys and analyses when appropriate. Implement a strategy of source management by choosing one or more of the following:
Identify a source of contamination and relocate it so that it will not impact the IAQ. For example, do not locate a diesel generator or a roofing kettle near a building air intake.
Identify a material likely to impact the IAQ and select a similar but less toxic substitute. Review MSDS’s, manufacturer specifications, and consult with EH&S. For example, choose latex over oil based paint, hardwood over pressed wood, water based over solvent based adhesives, low formaldehyde emitting fabrics, and continuous filament carpet. Consult Boston College Standards for materials which have been reviewed and determined to be acceptable.
Create a barrier around the source and isolate it from other areas of the building so that there is no recirculation of air from the work area into occupied spaces. This may include physically isolating a section of the building with polyethylene sheeting or other barriers, as well as isolating the space from the general ventilation system by blocking return air grilles. Keep doors closed and seal stairwells so that they do not act as conduits for contaminants.
Utilize either dilution ventilation or local exhaust ventilation in conjunction with isolation techniques to reduce contaminant levels. Dilution ventilation increases the amount of outside air passing through an area to dilute and flush out low levels of contaminants. If the building ventilation system will be in contact with the work area, consider installing additional filters to keep particulates out of the ductwork. Change all filters at the conclusion of the project. When strong odors and higher contaminant levels are expected, the area should be encapsulated and placed under negative pressure. This technique isolates the work area from the building ventilation system and uses exhaust fans to directly remove contaminants to the outside. Explosion proof fans must be used while there are flammable chemicals being used in the work area. Positively pressurizing non-work areas and running ventilation systems overnight will minimize contaminant migration into occupied spaces.