Indoor air quality post-flooding assessment
Download 212.81 Kb.
|
- Navigate this page:
- Background/Introduction
- Discussion Ventilation
- Microbial/Moisture Concerns
- Other Indoor Air Evaluations
- Carbon Monoxide
- Particulate Matter
- Other Conditions
- Conclusions/Recommendations
Background/IntroductionIn response to a request from Martha Goldsmith, Director of Leasing, Division of Capital Asset Management (DCAM) and Roger Tremblay, Human Resources Director, Office of Disabilities and Community Services, Executive Office of Health and Human Services (EOHHS), the Massachusetts Department of Public Health (MDPH), Bureau of Environmental Health (BEH) conducted indoor air quality (IAQ) testing at the Massachusetts Department of Developmental Services (DDS) area office located at 100 Cummings Center, Suite 150B, Beverly, Massachusetts. The office experienced storm-related flooding on October 4, 2011. On October 12, a visit to examine the flood remediation efforts was made by Cory Holmes, Environmental Analyst/Regional Inspector and Ruth Alfasso, Environmental Engineer/Inspector in BEH’s IAQ Program. On October 27, 2011, Ms. Alfasso revisited the DDS office to conduct IAQ testing. The DDS is located in the Cummings Center, which is a large office building complex that was originally built as a shoe machine manufacturing facility in the early 1900s. It was opened to its current use in the mid 1990s. The complex currently houses over 500 tenants in a variety of subdivided spaces. Current use of the space includes medical offices, spa/cosmetic salons, restaurants, other retail, business offices and research and development uses. The DDS office has approximately 10,000 square feet of space located along the eastern edge of the 100 Cummings Center building. The DDS space contains offices, open plan cubicles, conference/meeting rooms, and storage space for files and materials. Windows, found only along the eastern side of the office, are openable. During the course of a few hours in the early morning of October 4, 2011, two and a half inches of rain fell in the North Shore region (Weather Underground, 2011). Flood water reportedly infiltrated the entire 100 Cummings Center building to a depth of at least several inches, damaging nearly all the office space on the first floor. The occupants of the DDS office were relocated while their office space was remediated. During the October 12, 2011 visit, BEH staff observed the extent of removal of water-damaged wallboard, carpeting and other materials from the office. Wallboard was removed and replaced to a height of about 18 inches, well above the extent of the water damage and all the carpeting had been removed. By the time of the October 27, 2011 visit, remediation had been completed; the occupants had returned to the space only three days beforehand.
MethodsAir tests for carbon monoxide, carbon dioxide, temperature and relative humidity were conducted with the TSI, Q-Trak, IAQ Monitor, Model 7565. Air tests for airborne particle matter with a diameter less than 2.5 micrometers were taken with the TSI, DUSTTRAK™ Aerosol Monitor Model 8520. BEH staff also performed visual inspection of building materials for water damage and/or microbial growth and for any other concerns regarding the flood remediation effort. ResultsApproximately 50 people work in the DDS office with up to 100 people visiting each day. The tests were taken during normal operations although unpacking activities were still in progress at the time of the BEH inspection. Test results appear in Table 1. DiscussionVentilationIt can be seen from Table 1 that carbon dioxide levels were below 800 parts per million (ppm) in all areas indicating optimal air exchange at the time of testing (Table 1). Mechanical ventilation is provided by a heating, ventilation and air conditioning (HVAC) system. Fresh air is drawn through a vent on the exterior of the building. Ductwork connects the air handling unit (AHU) to ceiling-mounted supply diffusers (Picture 1). By design, diffusers are equipped with fixed louvers that direct air along the ceiling to flow down the walls and create airflow. Air returns to the AHU through ceiling-mounted return vents via ductwork (Picture 2). Additional exhaust ventilation is provided in bathrooms, via vents activated when the bathroom light is on. The HVAC system is controlled via wall-mounted thermostats located around the office (Picture 3). The thermostats examined at the DDS office were set in the on position which is the MDPH recommended setting to provide continuous air circulation. To maximize air exchange, the MDPH recommends that both supply and exhaust ventilation operate continuously during periods of occupancy. In order to have proper ventilation with a mechanical supply and exhaust system, the systems must be balanced to provide an adequate amount of fresh air to the interior of a room while removing stale air from the room. It is recommended that HVAC systems be re-balanced every five years to ensure adequate air systems function (SMACNA, 1994). The date of last balancing of the HVAC system was not available during the visit. The Massachusetts Building Code requires that each room have a minimum ventilation rate of 20 cubic feet per minute (cfm) per occupant of fresh outside air or openable windows (SBBRS, 1997; BOCA, 1993). The ventilation must be on at all times that the room is occupied. Providing adequate fresh air ventilation with open windows and maintaining the temperature in the comfort range during the cold weather season is impractical. Mechanical ventilation is usually required to provide adequate fresh air ventilation. Carbon dioxide is not a problem in and of itself. It is used as an indicator of the adequacy of the fresh air ventilation. As carbon dioxide levels rise, it indicates that the ventilating system is malfunctioning or the design occupancy of the room is being exceeded. When this happens, a buildup of common indoor air pollutants can occur, leading to discomfort or health complaints. The Occupational Safety and Health Administration (OSHA) standard for carbon dioxide is 5,000 parts per million parts of air (ppm). Workers may be exposed to this level for 40 hours/week, based on a time-weighted average (OSHA, 1997). The MDPH uses a guideline of 800 ppm for publicly occupied buildings. A guideline of 600 ppm or less is preferred in schools due to the fact that the majority of occupants are young and considered to be a more sensitive population in the evaluation of environmental health status. Inadequate ventilation and/or elevated temperatures are major causes of complaints such as respiratory, eye, nose and throat irritation, lethargy and headaches. For more information concerning carbon dioxide, consult Appendix A. Indoor temperatures ranged from 69º F to 73º F, which were within or very close to the MDPH recommended comfort range (Table 1); the two readings below 70º F were in the computer server room (which has a separate air conditioning unit) and the closed/locked library room. The MDPH recommends that indoor air temperatures be maintained in a range of 70o F to 78o F in order to provide for the comfort of building occupants. In many cases concerning indoor air quality, fluctuations of temperature in occupied spaces are typically experienced, even in a building with an adequate fresh air supply. The relative humidity measured in the building ranged from 33 to 46 percent (Table 1). With one exception (the computer room) relative humidity levels were within the MDPH recommended comfort range or slightly below (i.e. 39 percent) during the assessment. The MDPH recommends a comfort range of 40 to 60 percent for indoor air relative humidity. Relative humidity levels in the building would be expected to drop during the winter months due to heating. The sensation of dryness and irritation is common in a low relative humidity environment. Low relative humidity is a very common problem during the heating season in the northeast part of the United States. Microbial/Moisture ConcernsIn order to support microbial growth, a source of water exposure is necessary. Remediation efforts in response to the flood appeared to have been thorough, and no remaining water-damaged wallboard, carpeting, ceiling tiles or other materials were noted during the MDPH visits. Materials that had been removed from and returned to the space, including files, books and personal items were examined for signs of water damage, and no visible signs or musty odors were noted from any of these materials. Most furniture and cubicle dividers were reported to be newly acquired since the flood remediation. A window was found to be damaged in office 2 (i.e., it would not close completely). The occupant reported that this was a new condition and that the window had possibly been damaged during flood-related remediation activities. The outside east edge of the building near the DDS office was examined for breaches and potential water infiltration sources and none were observed; flooding had occurred down the interior hallway and not through windows into the DDS office. The faucet in the kitchen/break room sink was dripping at the time of the inspection. No water leaks were noted underneath the sink and the backsplash behind the sink was intact and sealed. Water leaks from plumbing can provide a source of moisture for building materials and should be repaired promptly. Plants were noted in a few areas (Table 1). Overwatering of plants or keeping plants on porous materials can also provide a medium for mold growth and attract pests. Plants should be kept on washable non-porous drip pans, and the drip pans should be cleaned regularly. The US Environmental Protection Agency (US EPA) and the American Conference of Governmental Industrial Hygienists (ACGIH) recommend that porous materials be dried with fans and heating within 24 to 48 hours of becoming wet (US EPA, 2001; ACGIH, 1989). If not dried within this time frame, mold growth may occur. Once mold has colonized porous materials, they are difficult to clean and should be removed and discarded. Other Indoor Air EvaluationsIndoor air quality can be negatively influenced by the presence of respiratory irritants, such as products of combustion. The process of combustion produces a number of pollutants. Common combustion emissions include carbon monoxide, carbon dioxide, water vapor, and smoke (fine airborne particle material). Of these materials, exposure to carbon monoxide and particulate matter with a diameter of 2.5 micrometers (μm) or less (PM2.5) can produce immediate, acute health effects upon exposure. To determine whether combustion products were present in the building environment, BEH staff obtained measurements for carbon monoxide and PM2.5. Carbon MonoxideCarbon monoxide is a by-product of incomplete combustion of organic matter (e.g., gasoline, wood and tobacco). Exposure to carbon monoxide can produce immediate and acute health effects. Several air quality standards have been established to address carbon monoxide and prevent symptoms from exposure to these substances. The MDPH established a corrective action level concerning carbon monoxide in ice skating rinks that use fossil-fueled ice resurfacing equipment. If an operator of an indoor ice rink measures a carbon monoxide level over 30 ppm, taken 20 minutes after resurfacing within a rink, that operator must take actions to reduce carbon monoxide levels (MDPH, 1997). The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has adopted the National Ambient Air Quality Standards (NAAQS) as one set of criteria for assessing indoor air quality and monitoring of fresh air introduced by HVAC systems (ASHRAE, 1989). The NAAQS are standards established by the US EPA to protect the public health from six criteria pollutants, including carbon monoxide and particulate matter (US EPA, 2006). As recommended by ASHRAE, pollutant levels of fresh air introduced to a building should not exceed the NAAQS levels (ASHRAE, 1989). The NAAQS were adopted by reference in the Building Officials & Code Administrators (BOCA) National Mechanical Code of 1993 (BOCA, 1993), which is now an HVAC standard included in the Massachusetts State Building Code (SBBRS, 1997). According to the NAAQS, carbon monoxide levels in outdoor air should not exceed 9 ppm in an eight-hour average (US EPA, 2006). Carbon monoxide should not be present in a typical, indoor environment. If it is present, indoor carbon monoxide levels should be less than or equal to outdoor levels. Outdoor carbon monoxide concentrations were non-detect (ND) the day of the assessment (Table 1). No measureable levels of carbon monoxide were detected in the building during the assessment (Table 1). Particulate MatterThe US EPA has established NAAQS limits for exposure to particulate matter. Particulate matter is airborne solids that can be irritating to the eyes, nose and throat. The NAAQS originally established exposure limits to particulate matter with a diameter of 10 μm or less (PM10). According to the NAAQS, PM10 levels should not exceed 150 micrograms per cubic meter (μg/m3) in a 24-hour average (US EPA, 2006). These standards were adopted by both ASHRAE and BOCA. Since the issuance of the ASHRAE standard and BOCA Code, US EPA established a more protective standard for fine airborne particles. This more stringent PM2.5 standard requires outdoor air particle levels be maintained below 35 μg/m3 over a 24-hour average (US EPA, 2006). Although both the ASHRAE standard and BOCA Code adopted the PM10 standard for evaluating air quality, MDPH uses the more protective PM2.5 standard for evaluating airborne particulate matter concentrations in the indoor environment. The outdoor PM2.5 concentration was measured at 5 μg/m3 (Table 1). PM2.5 levels measured indoors ranged from 7 to 32 μg/m3 (Table 1), which were below the NAAQS PM2.5 level of 35 μg/m3. The highest level was measured in the copy/mail room during continuous operation of a shredder. No exhaust vent was noted in the copy/mail room; additional exhaust ventilation can be helpful in areas which may produce particles, odors or other pollutants. Frequently, indoor air levels of particulates (including PM2.5) can be at higher levels than those measured outdoors. A number of activities that occur indoors and/or mechanical devices can generate particulate during normal operations. Sources of indoor airborne particulates may include but are not limited to particles generated during the operation of fan belts in the HVAC system, use of stoves and/or microwave ovens in kitchen areas; use of photocopiers, fax machines and computer printing devices; operation of an ordinary vacuum cleaner and heavy foot traffic indoors.
Most occupied areas of the office have wall-to-wall carpeting which was reported to be new. It was unknown if a regular carpet cleaning program is in place, apart from daily vacuuming. The Institute of Inspection, Cleaning and Restoration Certification (IICRC), recommends that carpeting be cleaned annually (or semi-annually in soiled high traffic areas) (IICRC, 2005). A pipe of unknown use was found in one of the women’s restrooms (Picture 7). Pipes or other breaches can provide a pathway for migration of odors and other pollutants from unconditioned areas to occupied areas. This pipe should be investigated to determine its purpose and/or ensure it is properly capped or removed. New furnishings, carpeting and paint were present in all areas of the office. No significant odors related to these items were noted during the visit. However, furnishings, paint and carpet may off-gas volatile organic compounds (VOCs) when they are new/newly applied. Ensuring continuous ventilation during and after paint or adhesive materials are applied will dilute these VOCs. Because construction activities continue in other parts of the Cummings Center, keeping the door closed to the DDS space will also help control migration of odors and dusts from these areas. Conclusions/RecommendationsIt appears that flooding remediation has been completed in a thorough manner and no ongoing problems relating to this event should be expected. In view of the findings at the time of the assessment, the following recommendations are made:
ReferencesACGIH. 1989. Guidelines for the Assessment of Bioaerosols in the Indoor Environment. American Conference of Governmental Industrial Hygienists, Cincinnati, OH. ASHRAE. 1989. Ventilation for Acceptable Indoor Air Quality. American Society of Heating, Refrigerating and Air Conditioning Engineers. ANSI/ASHRAE 62-1989. BOCA. 1993. The BOCA National Mechanical Code/1993. 8th ed. Building Officials and Code Administrators International, Inc., Country Club Hill, IL. IICRC. 2005. Carpet Cleaning FAQ 4 Institute of Inspection, Cleaning and Restoration Certification. Institute of Inspection Cleaning and Restoration, Vancouver, WA. MDPH. 1997. Requirements to Maintain Air Quality in Indoor Skating Rinks (State Sanitary Code, Chapter XI). 105 CMR 675.000. Massachusetts Department of Public Health, Boston, MA. OSHA. 1997. Limits for Air Contaminants. Occupational Safety and Health Administration. Code of Federal Regulations. 29 C.F.R 1910.1000 Table Z-1-A. SBBRS. 1997. Mechanical Ventilation. State Board of Building Regulations and Standards. Code of Massachusetts Regulations. 780 CMR 1209.0 SMACNA. 1994. HVAC Systems Commissioning Manual. 1st ed. Sheet Metal and Air Conditioning Contractors’ National Association, Inc., Chantilly, VA. US EPA. 2001. “Mold Remediation in Schools and Commercial Buildings”. Office of Air and Radiation, Indoor Environments Division, Washington, DC. EPA 402-K-01-001. March 2001. Available at: http://www.epa.gov/iaq/molds/mold_remediation.html US EPA. 2006. National Ambient Air Quality Standards (NAAQS). US Environmental Protection Agency, Office of Air Quality Planning and Standards, Washington, DC. http://www.epa.gov/air/criteria.html Weather Underground, The. 2011. Weather History for Beverly, Massachusetts, October 4, 2011. Available at: http://www.wunderground.com/history/airport/KBVY/2011/10/4/DailyHistory.html?req_city=Beverly&req_state=MA&req_statename=Massachusetts Picture 1 
Ceiling-Mounted Supply Diffuser Picture 2 
Ceiling-Mounted Return Vent Picture 3   \
Thermostat, Fan set to “On” (arrow) Picture 4 
Still Packed Boxes and Items in Office Picture 5 
Decorative Items on Cubicle Divider Picture 6 
Dusty Bookshelf Picture 7  
Unknown Pipe in a Women’s Restroom (Arrow) Picture 8 
Scented Candles
Directory: eohhs -> docs -> dph -> environmental -> iaq -> 2012 iaq -> Protocol for Investigating Odor Complaints Related to Nail Salons iaq -> Indoor air quality assessment iaq -> Indoor air quality assessment iaq -> Indoor air quality assessment iaq -> Board of Health Ice Rink Inspection Sheet 2012 -> Indoor air quality investigation Download 212.81 Kb. Share with your friends:
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
