Sick building?
To solve indoor air quality (IAQ) problems, go directly to the source ... go to the building's ductwork.
Sources of IAQ Problems
One of the major causes of poor indoor air quality in commercial buildings is inadequate maintenance of air conveyance systems. For this reason, government agencies and indoor air consultants commonly endorse a "building systems" approach to indoor air quality. In order to reduce the threat of indoor air pollution, the building systems approach calls for a dedicated environmental maintenance program for air conveyance systems.
There are three main areas to consider in the building systems approach to good indoor air quality.
1. Ventilation. The efficiency of the ventilation system has a direct correlation to the quality of the air within a building. Occupants within a building where air is not properly distributed to all occupied areas or where there is an inadequate infusion of fresh air into the system are likely to have indoor air pollution complaints. Also, ventilation systems which have accumulated large deposits of dust and debris may have air flow restrictions, which can seriously affect the comfort of building occupants and the efficiency of the system.
2. Filtration. Most of the air filters found in today’s commercial buildings are low efficiency filters. Thus, a large percentage of the dust, chemical residues, grease and other foreign matter carried in the airstream cannot be stopped by the filters, and ends up adhering to the interior surfaces of the air conveyance system.
3. Maintenance. A good maintenance program for mechanical components in an air conveyance system is the key to preventing IAQ problems. For existing systems, however, steps must first be taken to clean the air conveyance system and its components.
The Air Conveyance System
A building’s air conveyance system provides conditioned air to occupied spaces within the facility. The system is comprised of several complex components which work together to maintain an acceptable level of temperature and humidity for the building occupants.
Typically, air from within an occupied space, along with fresh air drawn from outdoors, is channeled through ductwork. to the air conditioning unit, where it is either heated or cooled. Before the air gets to the unit, it usually passes through a low efficiency filter which does not adequately protect the system from dust and debris.
In the course of normal budding operations, the humidity level within an air conveyance system can vary greatly. High humidity allows moisture to combine with dust and debris in the system, resulting in the growth of microbial contamination.
Microbial contamination in an air conveyance system (such as mold, fungus and spores) may cause allergic reactions among budding occupants. Condensate drain pans and other system components often become heavily contaminated with microbial slime, which in a few cases has led to more serious forms of contamination, such as legionella.
In order to maintain acceptable indoor air quality, mold, fungi, dust and other contaminants must be cleaned out of the air conveyance system.
Cleaning air conveyance systems provides many benefits. It lessens the likelihood of indoor air pollution in the budding, and may help to alleviate complaints of "budding related illness" by occupants. A dean system performs more efficiently, decreasing energy costs. Also, well maintained mechanical components are likely to last longer, reducing the need for costly system replacement or repairs.
To some, the term "air duct cleaning", implies that just the ductwork in a system needs to be cleaned. However, only a total system cleaning, including all ductwork, fans, coils and other components, will yield positive results. Naturally, if only a portion of the system is cleaned, the areas which were not will quickly re-contaminate the rest.
The National Air Duct Cleaners Association (NADCA), a non-profit membership organization headquartered in Washington, DC, has introduced the first industry standard that quantifiably measures the cleanliness of an air conveyance system.
The NADCA Standard provides instructions on how to test surfaces within an air conveyance system for the maximum acceptable level of contamination after a cleaning job. This test can be performed by any qualified industrial hygienist, and serves to assure the building owner that the services he contracted for were performed successfully. The NADCA Standard also prescribes safety requirements which were written to protect both building occupants and cleaning technicians from exposure to contaminants removed from the system during the cleaning process.
There are several methods for cleaning air conveyance systems. NADCA recommends "source removal" air duct cleaning. Through the use of tremendously powerful, highly efficient vacuum units and various devices designed to dislodge debris within a system, Source Removal methods thoroughly extract contaminants from air conveyance systems.
The National Air Duct Cleaners Association
Formed in 1989 by a group of 22 cleaning professionals, NADCA now has over 400 members throughout the United States, Canada, Europe and Australia.
NADCA was formed to promote integrity, training and competence in the industry. NADCA is setting national standards and developing an education and certification program for its members. These programs give the building owner the assurance that the building will be cleaned with the utmost diligence and quality.
NADCA was also formed to help educate the public about the need for cleaner indoor environments. To obtain more information about the NADCA membership, or to receive a listing of qualified firms in your area, simply contact NADCA Headquarters.
We subscribe to the NADCA's Code of Ethics.
© NADCA 1518 K Street, NW Washington, DC 20005 (202) 737-2926 FAX (202) 638-4833
