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TITLE 25HEALTH SERVICES
PART 1DEPARTMENT OF STATE HEALTH SERVICES
CHAPTER 297INDOOR AIR QUALITY
SUBCHAPTER AGOVERNMENT BUILDINGS
RULE §297.4Design/Construction/Renovation

(a) Building design (new construction). The following factors should be considered during the planning and design stages.

  (1) New buildings. Design and construction standards that facilitate the maintenance of acceptable IAQ should be established.

  (2) Site selection. During the selection of building sites, consideration should be given to minimizing or designing to avoid potential contaminant sources. Some of these considerations include the following.

    (A) Environmental assessment. A Phase I (visual inspection and condition measurements) environmental assessment of property to identify on-site contamination that could affect indoor air quality should be conducted.

    (B) External contaminants. Potential external contaminant sources such as combustion sources (freeways or power plants), dust generators (agricultural or cement plants), and industrial plants that may emit pollutants into the air should be identified.

    (C) Climate. Climate assessment data that include factors affecting building layout and other architectural design considerations such as temperature, relative humidity, dewpoint, rain quantity and prevailing direction, elevation and prevailing winds should be developed and evaluated.

    (D) Radon. A radon assessment of the site should be conducted, if applicable.

    (E) Drainage. Conduct a drainage survey to assure water can be diverted from the building site and away from the building.

  (3) Documentation. Facility design should include the development of owner's project requirement (the listing of facility uses, requirements and intent for the building), and basis of design (the design professional's description of the building elements and systems to accomplish the owner's project requirements) documents to guide the design and construction team in the selection of the least polluting materials and the production of a healthy building environment for the occupants. Some of the documentation and methods include:

    (A) The design team should be assembled from qualified and licensed professionals that are knowledgeable in air quality issues.

    (B) A building use and occupancy plan, schedule, and requirements should be assembled.

    (C) An indoor pollutant source control plan should be developed to guide the materials usage, equipment selection and activities in the building.

    (D) Comply with appropriate codes and standards.

    (E) Assess the budget and schedule impacts of all materials and systems.

    (F) A testing and commissioning plan should be developed to quantify the facility performance results required.

    (G) Building operational and training documentation plans should be provided including the requirements for equipment systems manuals.

  (4) Site and Facility Planning. The building design should consider the following.

    (A) Building structure factors. Factors that can affect IAQ, such as the shape and size, orientation, layout, proximity to pollution-generating activities, building materials, types of windows and doors, ventilation system design, location of air intakes and exhausts, and susceptibility to pest intrusion should be considered.

    (B) Internal contaminant sources. Proper venting to the outside atmosphere of pollution source areas, such as laboratories and preparation rooms, housekeeping and material storage, restrooms, workshops, cooking areas, art and hobby rooms, computer rooms, copy rooms, and other emission-producing spaces should be provided.

    (C) Loading Docks. Loading docks should be designed such that vehicle exhaust shall be prevented from entering enclosed work spaces (including air intakes and building openings) by installing barriers to airflow from loading dock areas (i.e. doors, curtains, etc.) and using pressurization. Outside air intakes should not be near or above truck or other vehicle access areas.

    (D) Moisture prevention. Water intrusion, condensation, water vapor intrusion, and other moisture problems in the building should be avoided through the proper design and installation of the building components. The use of vapor barriers (membrane inserted in a wall assembly to reduce moisture flow) should be based on best practices design for the local area. Care should be taken not to have two vapor barriers in one wall such as an exterior barrier with vinyl wall covering on the inside. In hot and humid climates, vinyl wall covering should not be used on exterior walls to avoid condensation and mold growth behind the covering.

    (E) Space allocation.

      (i) Adequate space for maintenance access and proper operation of building equipment, such as HVAC system equipment and boilers, should be provided.

      (ii) Separate designated rooms used for materials and chemical storage only and that are kept under negative pressure and vented to the outside atmosphere should be provided.

    (F) Building materials, interior finishes, and furnishings.

      (i) The lowest chemical-emitting building materials, interior finishes, and furnishings that are practical should be used. Contaminant-emitting and retention potential of furnishings, floor and wall coverings and casework, and other interior finishes should be evaluated. Emissions data from manufacturers should be evaluated before specifying or approving construction products and building furnishings.

      (ii) Materials that prevent (or at least inhibit) microbial growth without occupant exposure to potentially harmful chemicals should be used.

      (iii) The use of porous or fleecy materials is discouraged where unmanaged excessive moisture or improper maintenance could occur.

      (iv) Projected life cycles of materials and equipment should be considered to provide the most sustainable construction.

      (v) Recycling of construction waste and materials from remodeled facilities should be provided where possible.

      (vi) Maintenance requirements should be considered. Materials that can be easily cleaned with the least toxic cleaning supplies should be utilized when possible.

      (vii) Building materials and products susceptible to water damage should be properly stored and protected to prevent damage before or during construction phase.

  (5) HVAC system design. HVAC systems should be designed to include the following.

    (A) Air intakes. Sufficient acceptable outside air to maintain a healthy environment in all occupied areas should be provided. (Reference ASHRAE Standard 62-2001). Preconditioning of outside air supplies, particularly dehumidification, is recommended where possible.

    (B) Air distribution. Proper air distribution should be provided to all occupied areas.

    (C) Filters. Medium to high efficiency (MERV 9 - 11) filtering systems should be used. Air handlers should be designed and selected to accommodate the pressure drops required for adequate filtration. Low capacity systems may use lower efficient filters (MERV 6 - 8) if it cannot be retrofitted for the more efficient filters. Filters should be installed to minimize air bypass around the filters and maintained per the manufacturer's recommendations.

    (D) Access doors/ports. Convenient access doors/ports to facilitate inspection, maintenance and cleaning of air handling units and ducts should be provided.

    (E) Coils. Coils with adequate heating and/or cooling capacity and with features to facilitate maintenance should be used.

    (F) Drain pans. Insulated drain pans with proper slope and drainage to prevent standing water should be installed on all new cooling (wet) coils.

    (G) Drain lines and traps. Drain lines need to be adequately sloped to provide proper drainage. Drain traps should be properly installed when drain lines from condensate pans connect to sewer systems.

    (H) Ducts. Ducts with internal surfaces that are easily cleaned, not damaged by typical cleaning methods, do not harbor dust and microbials, and that will not emit materials or gases that can harm the occupants should be provided on all new HVAC systems.

    (I) Return air. Ducting of return air is recommended.

    (J) Positive building pressure. The rooms of the buildings should be maintained at a net positive pressure (minimum of 1 Pascal) with respect to the wall cavities and plenums, and the wall cavities should be maintained at a net positive pressure (minimum of 1 Pascal) with respect to the outside atmospheric pressure. Some areas in buildings that have isolation or process requirements, such as print shops, darkrooms, and restrooms, may require defined pressure relationships to adjacent areas.

    (K) Exhaust systems. Adequate exhaust systems for restrooms, storage rooms, copy rooms, animal areas, chemistry labs, computer rooms, industrial arts rooms, kilns, home economics rooms, locker rooms/showers, swimming pools and other areas with contaminant sources should be provided. These areas should be under negative pressure with respect to adjacent areas, such as classrooms, offices and hallways.

      (i) Exhausts should be vented directly to the outside.

Cont'd...

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