Recent heightened media attention on public health provides a good wake-up call to revisit best building practices. Because people spend approximately 90 percent of their time indoors, building owners and facility managers have several available strategies to promote healthier indoor environments. Combining contaminant source control, good maintenance practices, and adequate ventilation offers a strong plan of attack against poor indoor air quality (IAQ).
A Good Offense
Chemicals can lead to respiratory illness and weaken the immune system. Remove existing contaminants from your building and have a plan in place to prevent them from entering in the future. Assess the chemicals being brought into your building from new building materials, furnishings, and paints. Many toxins, such as volatile organic chemicals (VOCs) and formaldehyde used in the manufacture of these products, off-gas pollutants into the interior environment for years – something that even good ventilation can’t undo. Create building specifications that prohibit VOCs from coming into the facility when repairs or tenant improvements take place.
According to the Centers for Disease Control, one of the best ways to prevent the spread of disease is frequent hand washing, but not all hand cleaners are created equal. Hand cleaners, such as soap, are a different classification than hand sanitizers. It’s important to note that those with antimicrobial – as opposed to antibacterial – properties kill good bacteria as well as bad. Under LEED for Exiting Buildings: Operations & Maintenance, the credit available in EQc3.4-3.6 requires that hand soaps meet one or more of the following standards: Environmental Choice CCD-104, Green Seal GS-4, or no antimicrobial agents. Many alcohol-based hand sanitizers evaporate on contact, so they don’t put residue into the sewer system, which is another benefit to using the product.
Be sure your janitorial service is working with green-cleaning products, using the right equipment, and providing preventive maintenance. The majority of building and site maintenance products, such as sealants, fungicides, insecticides, and cleaning products, contain harmful chemicals that can become airborne. Work with your suppliers and create a new contract that specifies which products are allowed in your building and on-site. Craft an integrated pest-management plan rather than relying on monthly maintenance. Have your janitorial service use hepa-filter vacuum cleaners rather than the bag type, which tend to simply redistribute the dust within a space.
Practice preventive maintenance. Investigate spots on the wall from water seepage, and repair small breaks and cracks. Responsive action to these seemingly minor damages is especially important in hot and humid climates where mold and mildew quickly establish a foothold.
Mind the Systems
Without adequate airflow exchange, it’s easy for occupants to breathe in contaminants. Outside air supply is extremely important to dilute germ concentrations, but the cost to condition 100-percent outside air is cost prohibitive for building owners. Instead, a 20-percent (+/- 10 percent) introduction of outside air is the norm. With 80 percent of all air recirculating in a building, having effective ventilation and a good filtration strategy become extremely important.
While standard filters aren’t effective against germs and bacteria, they remove other contaminants, such as dust and mold. The Minimum Efficiency Reporting Value (MERV) is the rating of a filter in terms of its ability to collect and trap particulate matter. LEED for Commercial Interiors suggests that facilities use a MERV 13, which is 90- to 95-percent efficient in capturing particulate matter. At this high rating, the MERV 13 will actually filter bacteria, but not viruses. MERV 8 provides the accepted minimum efficiency, capturing 60 to 65 percent of particles. Costs rise in proportion to the MERV rating because filters become more expensive, and the larger pressure drop needed to push more air through the filters results in greater fan energy consumption. The best strategy is to strike a balance between operational costs and air quality need.
Make a habit of changing your filters on a regular basis, and routinely test your exhaust systems to make sure they’re operational during the occupied mode.
By their very nature, variable air volume handlers take in less outside air in the winter when the cold and flu season is at its peak. Make sure your systems are air balanced, even in these conditions. Review the air-balancing report that was generated when the building was built, and verify that the dampers are in the recommended position. Programming overrides, control-system component failures, human interaction, and wear and tear can affect damper positions. Incorporate a review of outside air damper positions and exhaust fans into your maintenance program.
Building operators in climates that don’t have outside economizer possibilities or climates with extreme seasonal temperatures have to be even more sensitive to how much outside air is supplied because of the costs to condition the air. In fact, it’s common that commercial heating and cooling systems are programmed or a manual override is performed to close the outside damper completely in extreme temperatures so as not to lose the building’s temperature control. In some cases, this strategy is solely to save energy. Facility managers need to be cautious that this mode of operation isn’t resulting in poor air quality. It might be necessary to rethink the standard programming for densely occupied spaces, like large conference rooms; at minimum, have your ventilation system cycle air at a higher rate to disseminate the contained air throughout the building.
As building owners and facility managers examine their specification, maintenance, and operational practices, it becomes clear that their decisions can have a great influence on indoor air quality. As we refocus our attention on safeguarding tenant and building occupant well being, sustainable frameworks, like LEED, and green product guidelines, such as Green Seal, can help point the way to providing healthy working environments.