Perhaps as a facility manager you have encountered this scenario: You return from lunch to find your desk littered with phone messages and your email inbox brimming with terse, distressed messages. Quickly reading through them you notice one recurring theme: indoor air quality complaints. You begin wondering what the problem might be. Did we not just finish a total renovation of that work area? Or perhaps the complaints are originating from a newly constructed and freshly occupied research wing. Shouldn’t they be ecstatic about their new surroundings? Well, welcome to the world of indoor air quality, or IAQ.
Indoor air quality, and in a broader sense and perhaps more accurately, indoor environmental quality, IEQ , has risen to the top of the list for worker complaints over the last decade. IEQ encompasses many different parameters, from temperature to odors to lighting and even ergonomics in addition to potential contaminates. IEQ has received the most attention stemming from mold concerns—the media baby of the twenty-first century. Nonetheless, research and, unfortunately, major health disasters during the last couple of decades have increased our knowledge and understanding of the indoor environment. From the infamous outbreak of Legionnaires’ disease during that ill-fated 1976 convention in Philadelphia to the multitude of Sick Building Syndrome cases during the 1990s and dozens of major mold infestations discovered during the beginning of this century, our awareness of and perspective about indoor air quality for building occupants have grown tremendously.
The US Green Building Council (USGBC) and the US Environmental Protection Agency now estimate that Americans spend an average of 90 percent of our time indoors where levels of potential contaminates and pollutants may be two to five times higher than outdoor levels.1 Add to this the fact that an estimated seventeen million Americans suffer from asthma and forty million have allergies, and you can see indoor air quality is nothing to sneeze at. (Sorry, we couldn’t resist.)
There is some good news, though, and that is the focus of this article. The USGBC, in developing its Leadership in Energy and Environmental Design (LEED®) program, has come up with a comprehensive strategy for optimizing indoor environmental quality and minimizing potential problems from poor indoor air quality. The LEED IEQ strategy addresses many areas. These include meeting minimum indoor air quality performance standards, controlling environmental tobacco smoke, using lowemitting materials, increasing ventilation effectiveness, controlling chemical and pollutant sources, addressing thermal comfort, and optimizing use of daylight, among others. We highly recommend using the LEED strategy for all your construction projects. But whether you are going for LEED certification or not, use of one particular strategy can go a long way in ensuring good indoor air quality following construction, and that is implementing a construction IAQ management plan. Let’s take a deeper look into what this plan does and how it can prevent your building occupants from flooding your desk and inbox with those pleas for help.
The LEED construction IAQ management plan (EQ Credit 3)
The construction IAQ management plan is basically a simple protocol for ensuring that indoor air quality is acceptable following construction and prior to occupancy. We all know how dusty construction can be. In addition to the normal heavy particulate loads from all the activity, other potential contaminates can accumulate during the project. These include chemical pollutants or volatile organic compounds (VOC) given off by building materials and biologicals such as mold spores, pollens, etc., that enter from outside. The goal of the construction IAQ management plan is to reduce potential indoor air quality problems resulting from the construction or renovation process. Under the LEED rating system this is achieved by one of two methods— either a building flush out or air testing.2
Building flush out
The building flush out is achieved by running the heating, ventilating, and air-conditioning (HVAC) systems until a large amount of outside air has been delivered to the space. In following the LEED for new construction or major renovations, the HVAC system is set for 100 percent outside air and operated continuously until 14,000 cubic feet of outside air is delivered for each square foot of new floor space. This can take a period of weeks, depending on HVAC system design, even running 24/7. During flush out, the temperature must remain at least 60 degrees F, and the relative humidity cannot exceed 60 percent.
An alternate procedure is provided under LEED-NC, which allows faster occupancy. This option permits the space to be occupied after flushing just 3,500 cubic feet of outside air per square foot of floor space, provided ventilation continues each day beginning three hours prior to occupancy and throughout normal occupant hours until the goal of 14,000 ft3/ft2 is reached.
Baseline air quality testing
Because of the time and expense of conducting a building flush out, most owners opt to go with the second option of air quality testing. Performing baseline indoor air quality testing demonstrates that certain common indicator contaminates do not exceed recommended maximum concentrations. Following the LEED rating system, indoor air is sampled for formaldehyde, total particulates, total volatile organic compounds, carbon monoxide, and 4-phenylcyclohexene (4-PCH). Sampling for 4-PCH is required only if carpets and fabrics containing styrene-butadiene rubber latex backing were installed as part of the base building systems.
In order to collect accurate and representative samples to ensure the best possible results, a few guidelines must be followed. First, the testing must be conducted prior to occupancy and during hours of normal occupancy. All HVAC systems must be operated at the normal daily settings, including the minimum outside air flow rate during testing. All interior finishes must be installed. The number of sampling locations depends on the building size and number of separate ventilation systems. Sampling should be done for each portion of the building served by a separate HVAC system and include at least one location for every 25,000 ft2. Please note the “at least”— more samples or sampling locations may be required to assess the area with confidence. Finally, all samples should be collected from between three and six feet above the floor, representing the occupant breathing zone.
A downside to performing the baseline IAQ testing is the possibility of exceeding the recommended limits. Should this happen, additional flushing and retesting must be conducted for the specific contaminates found above the maximum levels.
Whether building a new structure or renovating an old space, construction activities can have serious impacts on indoor air quality. Heavy dust, off-gassing chemicals, and stray particles from outdoors can accumulate, leading to potential problems for future building occupants. However, implementing a simple indoor air quality management plan during construction and prior to occupancy can go a long way toward preventing these from occurring. The USGBC’s LEED-NC rating system establishes one such construction IAQ management plan. A future article will look at the details of the LEED IAQ testing parameters and provide a recommended building commissioning protocol for construction projects.