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INDOOR AIR QUALITY ASSESSMENT - MassGov

By Roberto Hunt,2014-02-01 06:36
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INDOOR AIR QUALITY ASSESSMENT - MassGovAIR,air,Air

    INDOOR AIR QUALITY ASSESSMENT

    Ipswich Public Library

    44 School Street

    Ipswich, Massachusetts

    Prepared by:

    Massachusetts Department of Public Health

    Bureau of Environmental Health Emergency Response/Indoor Air Quality Program

    August 2007

Background/Introduction

    At the request of Coleen Fermon, Health Director for the Ipswich Board of Health (IBOH), an indoor air quality assessment was done at the Ipswich Public Library (IPL), 44 School Street, Ipswich, Massachusetts. The assessment was conducted by the Massachusetts Department of Public Health (MDPH), Bureau of Environmental Health (BEH) and prompted by concerns about mold and water damage to carpeting in the ground level of the 1940 wing.

     On June 22, 2007, Michael Feeney, Director of Emergency Response/Indoor Air Quality (ER/IAQ), made a visit to the IPL. The IPL was built in 1869 as a two-story, free-standing, red brick building. The first addition was constructed on the south wall of the building in 1940 (Picture 1). A second edition was added to the rear of the building in 1997 (Pictures 2 and 3). Windows are openable in a number of areas in the building.

     At the time of the assessment, the building was undergoing restoration of plaster and re-painting ceiling on the second floor of the original building due to water damage. Although minor paint odors were detected, no reports of symptoms related to the restoration work was received by BEH staff.

Methods

    BEH staff performed a visual inspection of building materials for water damage and/or microbial growth. Air tests for carbon dioxide, temperature and relative humidity were taken with the TSI, Q-Trak, IAQ Monitor, Model 8551.

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Results

     The IPL has a daily employee population of approximately 16 and an estimated 200 other individuals who visit on a daily basis. The tests were taken under normal operating conditions. Test results appear in Table 1.

Discussion

     Ventilation

     It can be seen from Table 1 that carbon dioxide levels were below 800 parts per million (ppm) in all but one area surveyed, which are indicative of an adequate fresh air supply throughout the IPL. The Archive room had a slightly elevated carbon dioxide reading after a short occupancy by the assistant library director and Mr. Feeney.

    Ventilation is provided by a heating, ventilating, and air-conditioning (HVAC) system. Fresh air is supplied by rooftop-mounted air handling units (AHUs) (Picture 4). Fresh air is distributed to offices and other areas by ceiling and wall-mounted fresh air diffusers and returned to the rooftop units via ductwork. The Archive room has an AHU that does not introduce fresh air nor does it exhaust air. Therefore, normally occurring pollutants (e.g., carbon dioxide and water vapor) will tend to build-up in this area.

     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 ventilation system, the systems must be balanced subsequent to installation 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

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    every five years to ensure adequate air systems function (SMACNA, 1994). The date of the last balancing of these systems was not available at the time of the assessment.

    The Massachusetts Building Code requires a minimum ventilation rate of 20 cubic feet per minute (cfm) per occupant of fresh outside air or have openable windows in each room (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 MPDH 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