Buildings and their indoor environments become more and more complex all the time, and occupants may be exposed to a variety of contaminants (in the form of gases and particles) from office machines, cleaning products, construction activities, carpets and furnishings, outdoor pollutants and a host of other irritants.

Other factors such as indoor temperatures, relative humidity, and ventilation levels can also affect how individuals respond to the indoor environment.

According to NIOSH’s Building Air Quality Action Plan, “understanding the sources of indoor environmental contaminants and controlling them can often help prevent or resolve building-related worker symptoms.” It says that IAQ can be affected both by the quality of maintenance and by the materials and procedures used in operating and maintaining the building’s components.

Keeping IAQ in mind when you plan for operations and maintenance is a good way to prevent IAQ problems.

HVAC Operations: A building operations schedule is basically a daily/weekly/monthly schedule of each individual HVAC component compiled together in a comprehensive whole. This allows for cross comparison of different components schedules and synchronization.

NIOSH says it is imperative that your operations schedule reflect actual use of your building, ensuring that the HVAC system is providing ventilation during all periods of significant occupancy. It is important that this schedule be written and comprehensive, so that there is a “one-stop” reference that is complete, easily updated and accessible to all who need it.

NIOSH recommends ventilating buildings with the maximum volume of outside air that is practical, taking into account your HVAC system capacity and current climatic conditions (refer to the latest publication of ASHRAE Standard 62 for the current ‘best practice’ in HVAC system).

Economizer operations can reduce cooling costs while increasing outdoor air ventilation. However, malfunctioning economizer controls have been known to cause IAQ problems, such as dampers stuck in the closed position. Make sure economizer controls are frequently maintained and recalibrated, especially if you use enthalpy controls (ones that take into account both temperature and relative humidity). Exercise care to ensure that on/off set points are adjusted to avoid indoor relative humidity problems. Enthalpy controls can give the highest energy savings as well as help prevent the potential for excess moisture to be delivered into the building, which is especially important in areas of the U.S. where humid conditions are prevalent. However, the ASHRAE Standard 90.1 User’s Manual recommends that dry bulb (temperature only) controllers be used in dry and mild climates (Southwestern U.S.) because they are less expensive, require less maintenance and are more reliable than enthalpy sensors.

Energy recovery systems may make it feasible to increase outdoor air ventilation rates during temperature extremes. The hotter the outside air, the more energy heat recovery saves. The same is true on the heating side, but only to a point – make sure not to freeze the moisture in the outgoing air stream. Any time you would normally use 100 percent outside air, turn the heat recovery off.

Finally, before building occupants arrive for the day, schedule the introduction of as much outside air as practical to dilute pollutants that may have accumulated over night. Flushing can also provide pre-cooling, or night cooling – another way to contain energy costs. However, make sure that the amount of outside air used is consistent with the proper function of the HVAC equipment (e.g., coil freezing during extreme cold) and maintaining recommended relative humidity levels (30-60 percent, according to ASHRAE 55-1992).

Housekeeping

Inadequate housekeeping can cause IAQ problems, too. Keep your building clean. Also, cleaning materials themselves may be pollutant sources that produce odors and emit a variety of chemicals. Select cleaning methods that are effective for the given need. pan>

Read product labels and Material Safety Data Sheets (MSDS) on all cleaning products in use in your building. Remember, your housekeeping staff will be the most highly exposed to the chemicals in your cleaning products. Buy products with the least adverse impact on human health.

Specific Steps

Prepare and follow written housekeeping procedures that detail the proper use, storage and purchase of cleaning materials.

Be aware of the housekeeping products and equipment used in your building, particularly those that are potential irritants or have other IAQ impacts.

Purchase the safest available housekeeping products that meet your cleaning needs.

Educate housekeeping staff or contractors about proper use of cleaning materials, cleaning schedules, purchasing, materials storage and trash disposal.

It is important that the housekeeping staff, whether they are in-house staff or contractors, be trained on how your housekeeping procedures and products may affect IAQ. In fact, OSHA’s Hazard Communication Standard (29 CFR 1910.1200) requires employers to explain the labels and MSDSs of all hazardous chemicals used, even infrequently, by an employee, and to train those employees in how to protect themselves from emergencies. FSM Reference: “Building Air Quality Action Plan,” a DHHS (NIOSH) Publication, No. 98-123.