Indoor Air Quality

Undertaking Construction & Remodeling Activities Things to Think About Before You Start

GUIDANCE DOCUMENT

Poor indoor air quality is more likely to be present during construction and renovation activities. Dust and odors migrating out of the work area and into occupied spaces can disrupt normal building operations, degrade the facility, and, under worst case scenarios, cause injury or illness to occupants. The mere presence of detectable dust or odors from a project, even at levels that are typically considered to be harmless, may trigger occupant concerns based on perceived hazards. When performing or coordinating construction or remodeling activities, be aware of what activities will impact occupant indoor air quality and follow these common sense guidelines to minimize indoor air quality complaints.

INITIAL PLANNING

Identify potential work-related airborne contaminants (i.e., dusts, fibers, odors, or hazardous volatile substances such as volatile organic compounds (VOCs), combustion products, and biological materials). These contaminants may be produced from disturbance of building materials or demolition (e.g., drywall, plaster, ceiling panels, flooring), from products used in the construction process (e.g., paints, adhesives, carpeting, cleaning agents), from equipment used in construction process (e.g., generators, compressors, welders, motor vehicles, heavy equipment), and when building systems are disrupted (e.g., natural gas, water, sewer, ventilation).

1. Identify how contaminants may spread through the building. Contaminants move from high pressure areas to low pressure areas via conduits, such as HVAC returns, HVAC system intakes, open doors, utility chases, wall penetrations, elevator shafts, etc.
2. Identify how building occupants may be affected by the spread of contaminants.
3. Identify available control options, such as containing the work area with sheets of polyethylene plastic, modifying HVAC operation, reducing emissions, intensifying housekeeping, rescheduling work hours, moving occupants, defining re-occupancy criteria, etc.
4. Design specific control measures into the project to keep dusts, odors and hazardous volatile substances out of occupied areas (consult SMACNA guidelines for details).

ISOLATE MAJOR CONSTRUCTION AREAS

1. Construction areas in occupied buildings must be isolated from adjacent non-construction areas using temporary walls, plastic sheeting, or other vapor retarding barriers.
2. Construction areas must be maintained at a negative air pressure to surrounding non-construction areas.
3. Recirculating air ducts must be temporarily capped and sealed (appropriate filters may be used if nuisance particulates are the only contaminant of concern).

PROTECT THE VENTILATION SYSTEM FROM DUST AND MOISTURE

1. Do not operate supply air systems without filters in place (minimum 60% efficiency for a 3Fm particle).
2. Building materials subject to degradation from ambient environmental exposure must be protected or replaced if damaged.
3. Duct-work and air handling equipment must be stored in a clean, dry location prior to installation and openings must be securely covered to prevent entry of dust, moisture, general construction debris/dirt and vermin.
4. Utilize the air handling units (AHUs) to "flush" the building to reduce off-gassing of interior furnishings and finishes at least 48 hours prior to occupancy. Fully open outside air intakes and fit AHUs with temporary filters during this period. Replace filters after system flushing.

NOTIFY OCCUPANTS

• Prior to the commencement of work, notify potentially affected building occupants (through the construction project manager and building monitor) with a brief description of the planned work, expected dates and times, and precautions taken to protect air quality. Advanced notice of construction or renovation should be given so employees may take necessary actions in anticipation of the work.

ONGOING MANAGEMENT

1. After work has begun, monitor and enforce plan specifications for keeping dusts, odors, and hazardous volatile substances out of occupied areas.
2. Provide periodic progressive updates to building occupants through the construction project manager and building monitor.

REFERENCES

• SMACNA IAQ Guidelines for Occupied Buildings Under Construction, Sheet Metal and Air Conditioning Contractors’ National Association, Inc., 1995.
• ANSI/ASHRAE Standard 62-1989/62-1999, Ventilation for Acceptable Indoor Air Quality, The American Society of Heating, Refrigeration and Air Conditioning Engineers, Inc.

APPLICABLE REGULATIONS

29 Code of Federal Regulations (CFR) § 1910.1000 Environmental Protections Agency (EPA) Building Air Quality Manual, 1991 American Society of Heating, Refrigeration, and Air Conditioning Engineering (ASHRAE) 62-1989