Services & Maintenance: Indoor Air Concerns
Michael P. Menz, CET
From the November 2013 issue of Today's Facility Manager
A facility manager (fm) returns to the office after a week-long vacation and begins reviewing the backlog of e-mails and maintenance requests. And then there’s the e-mail detailing a situation that all fms dread. An occupant has reported feeling ill and believes it to be the result of poor indoor air quality (IAQ) from their work area. What steps can be taken to address this very broad and very vague allegation?
The first step in diagnosing the situation is to discuss it with the affected parties. Is the concern being expressed by one person or multiple persons? Does the person have a history of health issues, and are they taking medications? People with suppressed immune systems may easily be symptomatic while their fellow occupants are symptom free. It is also possible for individuals to become hypersensitive to an allergen or chemical after repeated exposure. During the interview with the occupant, it is paramount for fms to not dismiss their health concern and to investigate in a sound manner.
It is worth noting that many agencies and professional associations are replacing “IAQ” with the term indoor environmental quality (IEQ), which refers to the quality of the facility’s interior environment as it relates to the health and comfort of occupants. IEQ encompasses all aspects of a building interior including air, chemicals, particulates, dampness, thermal comfort; and lighting—all of which impact facility occupants.
Although identifying IEQ issues can be a very complex undertaking, the majority of the investigative efforts can be targeted to five fundamental areas: the heating, ventilation, and air conditioning (HVAC) system; building dampness; chemicals/contaminants; maintenance practices; and occupancy patterns.
Where To Look
HVAC systems have a major influence on a facility’s IEQ. These systems directly control fresh air intake, relative humidity levels, and thermal comfort. An inspection of these systems should include confirmation that the air filters have the proper efficiency and are being replaced at appropriate intervals. Air filters should have a dust-spot rating between 35% and 80% or a Minimum Efficiency Rating Value (MERV) of between 8 and 13. Also a contributing variable to airborne particulates is interior duct insulation, which should be avoided if possible for new construction and may require supplemental maintenance procedures.
Fresh air intakes should be inspected to confirm these are not blocked or near a source of contamination. These issues have historical recurrence for air intakes located near ground level common with “unit ventilators” and during renovation projects, respectively. While it is important for the HVAC system to provide sufficiently filtered air, it is also important for the system to supply enough fresh air for human comfort. An inadequate supply of fresh air can be identified by measuring carbon dioxide (CO2) levels, which can then show that further investigation may be warranted for elevated levels of other contaminants.
Relative humidity can be controlled with modern HVAC systems. ASHRAE recommends indoor humidity levels from 30% to 60%. Low relative humidity, often encountered during winter months, can lead to drying of mucous membranes and has been theorized to increase air concentrations of infectious aerosols. Elevated humidity can allow fungal growth, increase populations of mites, increase allergens, exacerbate asthma, and decrease comfort.
Dampness in buildings has been shown to have direct impact on respiratory symptoms in occupants. The first and foremost issue with dampness, and the one that receives the most media attention, is the likely presence of mold. Building dampness can be the result of numerous causes. Water intrusion can easily be identified with roof leaks and failing foundations. Sources of moisture more difficult to identify include faulty design, improper construction of wall and window systems, or elevated relative humidity resulting from imbalanced HVAC systems. Water stained components should be replaced, but more importantly, the means for the water intrusion must be corrected.
Building dampness has twofold consequences: adverse health effects on occupants, and increased facility costs due to the increased frequency of replacing deteriorated components and decreased insulation performance.
It should be understood that short-term or acute events involving moisture or water are normal and do not automatically result in detrimental effects on occupant health or building materials. Should an event occur, such as spilling a bucket of cleaning solution or leaving a window open during a rainstorm, it is recognized that if the water is quickly cleaned up and the materials dried in 24 to 48 hours there is minimal chance of adverse effects. It is only with chronic moisture intrusion (from faulty foundation or migration from moisture reservoirs to other susceptible materials) that more serious effects may occur.
In addition to increased fungal concentrations, building dampness is a precursor to increased populations of bacteria, dust mites, cockroaches, and rodents; all pose significant negative impacts on IEQ. If the initial site evaluation identifies these, the investigator should then evaluate the potential use of pesticides in contrast to an integrated pest management (IPM) system.
Preventing vectors by management and maintenance practices through an IPM system is significantly better for a facility’s IEQ than introducing toxic chemicals to control their populations. Pesticides should be used as a last resort only, and if required these should be approved by a health and safety professional.
Tools For Inspection
The vast majority of fms can initiate an IEQ investigation by interviewing the affected person (or people) and the maintenance staff as well as conducting a thorough visual and olfactory inspection. What are probably not within most fms’ capabilities are the proper equipment and knowledge of sampling. Industrial hygienists have experience in using both direct read instruments and collecting samples for laboratory analysis. These tools may include moisture meters, air quality monitors, infrared cameras, and air sampling equipment.
Moisture meters can assist in locating point sources for water intrusion through building envelopes. Interpreting moisture content in materials is dependent on the material itself. Many moisture meters were intended to be used to determine the percent moisture content in wood, with an industry accepted cautionary level of 15%. However, some inexperienced assessors use this threshold for drywall, where a content of as little as 1% can allow certain fungal growth on the paper facing.
Air quality monitors are commonly used for IEQ investigations to provide readings for levels of oxygen, CO2, temperature, and relative humidity. These parameters provide information useful in evaluating the operation of the HVAC systems as it relates to the dehumidification of the indoor air and the amount of fresh air supplied to occupants. Photoionization detectors (PIDs) are used to monitor volatile organic compounds (VOCs), which can be emitted from numerous sources including aerosol sprays, cleaning supplies, pesticides, office equipment, paints/strippers, and microbial sources. PIDs can allow the industrial hygienist to identify specific areas during their walk-through, which permits a more focused, efficient investigation.
An experienced IEQ consultant can collect air samples for laboratory analysis, targeting contaminants identified during investigation. The sampling strategy can vary greatly from fungal concentrations, particulates, VOCs, asbestos, and fumes from maintenance areas. Regardless of the type of quantitative data collected, it is critical that equipment is properly calibrated, sample procedure accurately followed, laboratory appropriately accredited, and data interpreted correctly.
Menz is environmental training manager for EMSL Analytical, Inc., a Cinnaminson, NJ-based environmental testing firm with a network of laboratories nationwide. He has been in the environmental consulting and indoor environmental industry since 1987.
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