Site and General Building Design
Select site to minimize potential exposure to air and soil pollutants and electromagnetic fields (EMF). (Appendix 1)
Visit the site on several occasions to assess site criteria.
Note microclimate: wind direction, sun exposure.
Avoid sites near wetlands/stagnant water, low lying areas; sites should be well above 100 year flood plain.
To minimize moisture infiltration at the foundation, avoid earth berm construction and provide positive drainage from building.
Avoid below-grade occupied space.
Avoid tuck-under parking and indoor parking.
Roof gardens should be avoided because soil and water can foster mold growth. (Appendix 2)
Arrange drop-offs, loading docks, helicopter pads, and other vehicular access points to eliminate or minimize exhaust fumes from entering building directly or being drawn into the HVAC system.
Avoid the use of indoor plants because they can attract pests, stimulate pesticide use, trigger allergies, and foster mold growth. If smoking on site is permitted, dedicate a location that is remote from entries, main pedestrian paths and air intakes.
If smoking on site is permitted, dedicate an outdoor location that is remote from entries, main pedestrian paths and air intakes.
Group and isolate uses within a building that emit contaminants and could affect air quality.
High ceilings are preferred in order to dilute contaminants.
Avoid decorative indoor fountains.
Enclosure
Design for a tight building envelope to maximize the performance of the HVAC system. Meet or exceed Energy Star leakage area (less than 1.25 s.i./100 sf. (Reference 1)
- Building should be able to be sealed off from exterior events that would raise outdoor pollutant levels such as, toxic spills, pesticide spraying, fires, traffic accidents, and rush hour traffic.
- Operable windows are preferred. Being able to open windows is an important access issue for chemically sensitive individuals and can be beneficial for other occupants in certain situations. Operable windows should be detailed to minimize air infiltration.
Design to prevent pest problems. (Appendix 3)
- Use inert pest resistant materials. When treatment of wood is required, treating with disodium octaborate tetrahydrate may be among the safer options.
- Incorporate pest barriers such as termite shields, window screens, and bird screens in construction details. Bird and bat droppings pose great IAQ risks.
- Some pesticides such as boric acid are considered environmentally safe. If used, granular or gel forms are preferred. Care should be taken to ensure that particles do not infiltrate interior habitable space.
Shield occupants from external sources of EMF. Windows with low e glazing, metal roof, and siding components may reduce certain interior EMF. (Reference 2)
Roof Design
- Pitched roofs are preferred, because they shed water quickly, clean the roof of pollutants and potential toxins, and are less prone to leakage.
- Inert roofing materials, such as coated metal or clay tile, are ideal. Note that galvanized metal presents a rust hazard and should be avoided.
- Flat roofs are not preferred. If used, membrane and high albedo (highly reflective to heat) type are recommended. Asphalt or modified bitumen built-up roofs are less preferable. (Reference 3)
Wall Design
- Use best design practices to prevent moisture and condensation within walls. Calculate dew points for each exterior wall (and roof) type to verify performance at each condition. Provide detail for all flashing and counter-flashing locations.
Foundation Design
- Provide under-slab vapor barriers, insulation, and damp-proofing to prevent moisture infiltration and condensation.
Protect stored building materials from water damage and mold growth.
Avoid use of water-damaged or mold-affected materials.
Plumbing, Mechanical and Electrical Equipment
Properly insulate pipes to prevent condensation, especially within walls.
Use modeling software to determine airflow and to ensure isolation of pollutant sources and adequate ventilation.
Ventilate areas occupied by people with chemical sensitivities with goal of eliminating odors (ideally entire building). These ventilation rates meet or exceed all worldwide standards. (Reference 4)
Provide local control of temperature and airflow (ideally for every occupant). (Reference 5)
Utilize Displacement Air Distribution method to move pollutants away from occupants.
Dedicate building as Smoke-Free. (Reference 6)
Isolate mechanical equipment from occupied areas.
Provide direct exhaust from rooms and areas that have pollutant-generating sources or activities. These include but are not limited to: (see Appendix 5)
- Bathrooms (code requirement).
- Kitchens or office kitchenettes (this is in addition to code-required hoods or stove exhausts).
- Copy and print rooms.
- Computer rooms.
Ductwork
- Avoid insulation inside ductwork. Use external insulation wrap of non-friable (airborne particle creating) material.
- Oil coatings used in fabrication of sheet metal stock can affect air quality. Prior to installation, thoroughly clean ductwork with a low VOC product. Use methods that do not leave residue or cause oxidation. (Reference 7)
Prohibit the use of fragrances and disinfectants in air distribution systems.
Maintain relative humidity between 30%-50%.
Locate outside air louvers away from pollutant sources.
Filtration (Reference 8)
- Carbon and HEPA filters are preferred.
- Avoid ozone generating air-purification systems.
- Avoid electrostatic air cleaning due to ozone.
In renovation work, re-evaluate HVAC system performance to ensure that original design standards are met.
Shield occupants from internal EMF. Design electrical systems to minimize EMF. Maximum recommended magnetic field levels of 2.5 milligauss (preferably 1 milligauss in occupied areas) and as low as technically achievable in areas to be occupied by people with sensitivities.
Finishes and Furnishings
Refer to Products and Materials Group report for specific recommendations on materials.
Floor Coverings
- Use inert materials wherever possible, such as, but not limited to:
- Stone, tile, terra-cotta, brick, ceramic tiles,
- Terrazzo,
- Sealed concrete.
- Minimize the use of carpeting. Note that carpet that meets Carpet and Rug Institute Green Label Plus standards can still be problematic for chemically sensitive people. (Appendix 4)
- Use carpet systems that allow for small area replacement, such as certain of the self-adhesive backing carpet squares.
- Avoid glue-down carpet installations or use low-VOC adhesives. (see Products & Materials Committee recommendations)
- Cork and linoleum may contain linseed oil and should be avoided. Rubber flooring can also pose problems for chemically sensitive individuals and should be avoided.
- Use low-or no VOC materials for all flooring. (Appendix 4)
Construction Related Activites for Renovations
Provide advance notice to all occupants of any upcoming renovation work.
Post signs to alert occupants of renovation work.
Provide alternate accessible locations for affected individuals when occupied space will be rendered inaccessible due to the renovation.
Physically isolate renovation work areas from occupied portions of building.
Isolate the HVAC system from renovation work.
Implement a dust-control plan that identifies work methods and cleanup procedures.
Provide negative pressure in area of renovation work.
Occupancy
Establish policies for renovation and chemical usage in lease agreements.
Designate a Smoke-Free building.
Leases should include language to ensure that occupant activity does not degrade original design standards and building performance.
Provide a list of areas and uses requiring separate exhaust air systems.
Designate areas free from use of cell phones, two-way radios, and wireless equipment.
Commissioning
Develop a commissioning plan that includes the items listed above.
After construction or renovation provide a minimum flush-out period of two weeks prior to occupancy.
Re-commission buildings periodically. Building use shall be taken into account when determining the re-commissioning schedule.
Exterior Landscaping
- Gardens (see Appendix 6)
- Design gardens that can be maintained organically without pesticides.
- Avoid plants with fragrances that may provoke allergies.
- Exterior gardens and landscape should be free of all plantings that require pesticides, synthetic fertilizers, lime, or other chemical applications.
- Use indigenous plant materials that are hardy, naturally pest-resistant, require minimal maintenance, and low water use.
- Use xeriscaping principles.
