Controlling Fungi

Moisture, heat, and dirt or dusts are the ingredients needed to grow fungi. Remove one or more, and you'll likely have a healthier building.

Furnace filters—often used in homes, schools, and small office buildings—don't catch and trap all the microbes and the dust the microbes feed upon. Consequently, the filters transmit the microbes and catch large particulates for a time and release a certain percent­age of the smaller particles (including spores). Then as the filters become dirtier, the filter material itself begins to catch more of the microbes, provides a growth location, and trans­fers some of the microbial contamination into the airstream.

Another hot spot for microbial growth is the humidifier assembly on furnaces. Typical humidifier reservoirs are pools of standing, stagnant water throughout much of the year that allow mold to grow and infiltrate the ducts.

In many buildings, fiberglass-lined ductwork (often used for noise or thermal control) is used in lofts because of continual airflow. These lofted spaces collect dirt and become "microbial nests." The microbes grow and multiply and then are blown all over the build­ing to infest other areas.

ABATEMENT

Should removal of contaminated items be the only option, workers and building occu­pants must be protected during the abatement. Control of airstreams in and out of the con­taminated area is a requirement to limit contamination in other areas of building.

These biologicals grow and reproduce; therefore concentrations of biologicals are not equivalent to such things as chemical concentrations. A dilute concentration of biologicals in a good growth environment will result in a concentrated level of contamination over time.

All abated buildings must be sampled and certified as suitable for reentry prior to nor­mal building usage. This certification states that the building's biological contamination has been diminished through abatement activities and is now in equilibrium with the ambient exterior conditions or interior baseline conditions previously agreed upon.

Certification does not state that the building cannot be recontaminated in the future. Always ask for recommendations for preventing future recontamination of your facility. Any porous materials that have been contaminated, removed from the facility, and returned must be decontaminated; facility users must be advised that recontamination may be inevitable.

CHAPTER 7

Дата добавления: 2015-11-16