| (ii) Exhaust vents should be located to avoid contaminants being drawn back into the building and no closer than 25 feet from an air intake. (L) Comfort. Adequate temperature and humidity control with proper air velocity should be provided to maintain comfort, process requirements, and minimize microbials and contaminants in all occupied areas. (M) Humidity. The maximum relative humidity should be maintained below 60% throughout the year to prevent mold growth. Ideal relative humidity levels are generally between 30% and 60%, however between levels 30% and 50% will decrease the chance of mold growth. In climates where outdoor humidity levels are often less than 30% and building occupants do not complain of health effects or discomfort from the lower humidity, then lower humidity inside buildings is acceptable. (N) Air diffusers. Air diffusers should be used to manage air flow volumes, mixing, and patterns for occupant comfort. Normal occupied spaces should have an average air velocity between 20 and 50 feet per minute in the occupied zone. (O) Controls. Proper controls and energy management systems should be installed to maintain recommended interior conditions. Thermostats in each occupied room and conference room are preferred. Humidistats should be used in rooms where humidity control is important. (b) Maintaining acceptable IAQ during renovation. Building occupants should be protected from airborne contaminants that may be disturbed, generated, or released during mitigation and/or renovation, including irritating or toxic substances such as asbestos, lead, pesticides, heavy metals, mold, cement dust, paint vapors, and roof tarring vapors. (1) Asbestos Survey. Prior to any renovation or dismantling, assure that the asbestos surveys for the building in question are up-to-date. If such survey information is not available, engage a licensed asbestos consultant or other licensed professional to conduct an asbestos survey and plan for the building as per the Texas Asbestos Health Protection Act, Article 4477-3a, V.T.C.S. and Rules, §§295.31-295.73 of this title (relating to Texas Asbestos Health Protection Act), and the National Emission Standards for Hazardous Air Pollutants, 40 CFR 61 Subpart M, National Emission Standards for Asbestos. (2) Lead-based paint concerns. Lead-based paint, used in many buildings built prior to 1978, may create an exposure risk for young children occupying or visiting the building, if the paint is deteriorating or is disturbed. Prior to any renovation or remodeling project in such a facility that is occupied or frequented by young children, a lead inspection by a state-certified person to determine the presence of lead-based paint is recommended, if the presence of such has not already been determined. If lead-based paint will be disturbed during a renovation or remodeling project, lead-safe work practices should be used to avoid unnecessary lead exposure to workers and building occupants. In a "child-occupied facility" as defined in §295.202 of this title (relating to Definitions), any "lead based paint activity", i.e. lead inspection, risk assessment or abatement, must be conducted in accordance with the Texas Environmental Lead Reduction rules, §§295.201-295.220 of this title. (3) The IAQ Coordinator should review designs and construction activities for all proposed remodeling and renovation activities prior to their initiation. (4) Minimize volatile organic compounds (VOCs) by purchase and use of low-emitting products, such as paints, varnishes, building materials, furnishings, etc., and processes (wet-sanding drywall). Minimize emissions from new furnishings by airing out the product before installation. Water-based solvents, when available, are preferred. (5) Hazardous chemicals and substances. Hazardous chemicals as defined in the Health and Safety Code, §502.003 and hazardous substances as defined in the Health and Safety Code, §361.003, should be managed and disposed of in accordance with all applicable state and federal laws. (6) Scheduling. Occupant exposure to contaminants should be minimized by scheduling renovations that may produce contaminants or uncomfortable conditions when the building is unoccupied. (7) Isolation. Ventilation and barrier control strategies to isolate construction areas from the occupied areas should be used. Increase ventilation in occupied areas if necessary to control odors from construction area. The area of renovation should be kept under a negative pressure relative to occupied areas during renovation periods. (8) Remediation of toxic contaminants. Procedures appropriate for toxic contaminants (lead, microbial, asbestos, hazardous chemical, etc.) should be utilized if such contaminants are expected or discovered during renovation and in some cases must be utilized under state and federal law. (9) Filters. Filters should be changed more frequently during contaminant-generating activities, and also replaced after work is completed. The highest possible MERV rated filters should be used during renovation and for a few days after to minimize exposure to renovation related particulates and dust. (10) HVAC equipment. Ensure that HVAC equipment is protected from damage and entry of contaminants. (11) Water-damage. Porous building supplies that become water-damaged should be discarded to avoid the potential for mold contamination. (12) Re-occupancy. All renovated areas should be thoroughly cleaned utilizing high-efficiency particulate air (HEPA) filtered vacuuming and adequately ventilated prior to re-occupancy. (c) HVAC system testing. For new construction and major remodeling, the HVAC systems in those areas should be tested and balanced by an independent certified contractor at the completion of construction or remodeling. (d) Commissioning of building. Building commissioning of new and/or renovated buildings should be provided by a trained and knowledgeable commissioning authority according to recognized national standards to assure proper operation of all building systems. (e) Design Documentation. Design documentation including the owner's project requirements (design intent), and basis of design should be retained for the life of the facility. As-built documents should be prepared during construction and retained at the facility. (f) Monitoring activities. Construction and renovation activities should be monitored by the owner's representative, facility IAQ coordinator, and commissioning authority. (g) Ventilation Protocols. Ventilation protocols should be developed to include proper area exhaust rates and pressurization requirements to be used during repairing and remodeling. During initial occupancy of a new area and during re-occupancy following repairs or renovations, the fresh air rate and the total air supply rate may need to be increased until any out gassing of the new material has decreased to a level that will not cause adverse heath effects to the occupants. |
