IAQ Trends: Conundrum In The Air
Energy efficiency has become one of the most prized sustainability attributes in a long list of aggressive environmental goals for facilities managers (fms). With increasing pressure to reduce the use of fossil fuels and resulting greenhouse gases along with the expense associated with rising energy prices, there is clear cause for reducing energy use.
Market drivers are pushing fms to build and operate high performance facilities with energy saving spaces that are healthy for all occupants. In order to accomplish this, many attempt to “tightly seal” buildings to minimize the escape of heated or cooled air, reduce outdoor air infiltration, and curtail unnecessary use of HVAC systems.
Unfortunately, these tactics can negatively impact indoor air quality (IAQ), a key sustainability issue quickly rising up the list of concerns. Prior to the 1990s, indoor spaces were considered havens to protect people from outdoor air pollution. However, since then we have become increasingly aware of the danger that indoor air pollutants present to human health. A 2011 report, Climate Change, the Indoor Environment and Health, from the Institute of Medicine of the National Academies, predicts that indoor environments, where most people already spend 90% or more of their time, will shelter occupants—particularly vulnerable populations such as the elderly, impoverished, immune compromised, and children—even more often than in the past, as they escape harsh weather conditions, extreme temperatures, and increased moisture.
Modern technology, materials, and lifestyles have significantly impacted the levels and types of pollutants in indoor air. Chemicals used in consumer products, furnishings, construction materials, and decorative items can emit volatile organic compounds (VOCs), formaldehyde, and ultrafine particles into the air, exposing occupants to a cocktail of chemicals that can have allergic and more serious health implications. Activities conducted in a space can also contribute to indoor air pollution. And construction defects common today can allow liquid water and moisture to infiltrate roof and wall systems, triggering moisture and potentially mold problems. New construction materials used in building envelopes and wall systems do not allow for free airflow and further exacerbate the problem. The implications for IAQ are enormous.
Can Good IAQ And Energy Efficiency Coexist?
Some of the fundamental tenets of energy efficiency and good IAQ are at odds. Energy efficiency calls for tightly sealed buildings and minimal ventilation; good IAQ calls for sufficient quantities of clean air to enable a sense of well-being in spaces without toxic pollutants. Energy efficiency calls for minimized use of energy to condition air; good IAQ calls for carefully controlled temperature and humidity. Energy efficiency calls for use of construction materials minimally processed and locally available; good IAQ calls for low emitting products that contribute minimally to indoor air pollution.
To achieve both goals, a balance is required. It is not appropriate to compromise human health in the name of protecting the outdoor environment. Nor is it appropriate to throw caution to the wind with regards to the use of limited natural resources. Fms must consider both and maximize each without compromising the other. A balanced approach can successfully improve energy efficiency and maintain good indoor environmental quality. Fms who are looking to achieve that balance should employ the following strategies.
Ventilate. Equipment such as printers, copiers, fax machines, and computers have become a mainstay in commercial buildings and schools. While this technology is essential, this equipment can generate VOCs, formaldehyde, and ultrafine particles that can adversely impact health. Building ventilation should always be operating when this equipment is in use. Myriad activities such as cleaning, cooking, and painting can also release pollutants into the indoor air.
Ventilation is critical to minimizing the impact of these activities on IAQ. Facility spaces that house these activities should be outfitted with exhaust systems to carry pollutants directly outdoors especially in copy rooms, cleaning supply closets, kitchens, science laboratories, and even art classrooms. If this type of investment is not possible, it is best to limit these activities to defined areas and to open windows whenever possible.
Control moisture. Mold growth can greatly compromise indoor environmental quality, releasing microbial VOCs (MVOCs) that can trigger allergic reactions, asthma, and other health problems. One of the root causes of the indoor mold growth, in many cases, is building envelopes and wall systems that do not allow for the free flow of air, a byproduct of poorly designed and maintained HVAC systems and tighter buildings. However, many of the sources of mold growth are preventable with regular moisture control and management.
Fms concerned with these issues should keep these basic practices in mind:
- Minimize water used in mopping to prevent excessive moisture being left along baseboards at the floor edges.
- Check for and immediately address spills and potential water leaks.
- Dry any damp areas and any other visibly moist areas, including condensation on windows and windowsills.
- Clean bathroom areas routinely to reduce or prevent mildew growth.
- Routinely check for plumbing fixture leaks. Repair leaks, and dry the area.
- Routinely check ceilings, walls, and floors for discoloration or water stains. These potential indicators of water leaks should be addressed immediately.
- Keep return air vents clear of furniture for proper airflow.
- Close all windows and doors, especially during periods of inclement weather.
- Check emergency overflow, plumbing, and HVAC systems pans for signs of water leakage.
- Routinely inspect the integrity of the weatherstripping and its seal around windows, skylights, and sliding doors.
Ultimately, these efforts reduce the energy required to dry and clean out a mold contaminated facility.
Limit pollutant sources. By selecting low emitting construction materials and furnishings, fms can limit the VOCs in their facilities. For example, when choosing adhesives and sealants (which are used to achieve energy efficiency), fms should try to select low emitting options.
Programs such as the GREENGUARD Environmental Institute and Blue Angel provide third-party verification that a product meets key standards and contributes minimally to indoor air pollution. Programs like Energy Star, EcoLogo, and Energy Saving Recommended provide third-party verification of energy efficiency and other environmental criteria. Fms can strive to select products that achieve both goals.
Manage HVAC wisely. These systems are responsible for a major portion of energy use in large facilities. However, seeking to reduce energy use by turning equipment on and off can greatly compromise IAQ. Thermostats should be set between 70°F and 80°F during summer months. Setting them higher than this will reduce equipment run times and limit the effectiveness of the equipment in controlling humidity. Operating lower than this means cold temperatures could cause moisture condensation on interior surfaces. During the winter, thermostats should be set no lower than 55°F. Setting them any lower can lead to low indoor temperatures that could allow water pipes to freeze and burst.
It is important to maintain HVAC systems, replacing filters regularly to ensure clogged filters do not limit airflow or damage equipment. Operation of temperature control systems should be checked monthly. This can be performed using a simple device, such as an analog thermostat, or with a more extensive energy management system that oversees hundreds of sensors and control devices. For simple unitary or split system equipment, the fan should be set to the “auto” mode. This allows the fan to cycle on and off with the compressor, a situation beneficial for preventing introduction of unconditioned outside air or the reintroduction of moisture from the cooling coil.
To check thermostat operation, the air conditioner should turn off in the cooling mode (summertime) when the setpoint temperature is raised above the actual temperature. Conversely, the air conditioner should turn on when the setpoint temperature is lowered below the actual temperature. A similar test should be performed in the winter.
Condensate drainpipes in air conditioning systems should be flushed. This will require the use of an effective cleaning agent that can be poured into the drains. Regular maintenance and proper use of the HVAC system will extend equipment life and support good IAQ.
By being aware of IAQ issues and how they might impact energy efficiency strategies, fms can ensure they do not sacrifice one for the other. After all, facilities are meant to be safe places for occupants, and good IAQ is required for healthy indoor environments.
Black is president of UL AQS, an Atlanta, GA-based provider of consulting and product emissions testing for product development studies, certifications, specifications, legal review, and risk assessments. She is a global expert on indoor air quality and product emissions and holds a Ph.D., a master’s degree, and bachelor’s degree in chemistry and environmental health.