Series on Mold and Buildings – Part 3.
When mold growth has been identified within a building, certain steps must be taken to isolate the contaminated materials and to make proper repairs. Appropriate Engineering Controls must be considered to control the mold and prevent the spores and dust from spreading during mold remediation.
Mold Remediation Containment and Equipment
Containment is used to isolate the areas of mold contamination, usually behind plastic sheeting. The goal of establishing an effective containment strategy is to control the spread of spores during repairs and to protect uncontaminated areas as well as mold remediation workers and building occupants that may still be present during the repairs. It is necessary to design these containment systems to allow for an entry/exit area. This is where workers can remove their protective clothing without risking cross contamination outside the work zones. This area is called a clean room. Usually, workers put on their Personal Protective Equipment (PPE) prior to entering the clean room. They then perform their work shift, exit through the clean room taking off their PPE and then enter the unaffected portion of the building. This is a very specific process requiring advanced training. Untrained persons should not perform mold remediation. This is because it may result in a significant release of mold spores into the unaffected areas of the building and extensive cross-contamination.
Further adding to the engineering controls is the use of a High-Efficiency Particulate Air (HEPA) filtered negative air machine. This is more correctly called Air Filtration Device (AFD). A HEPA AFD is used to create negative air pressure within the work zone. It attracts mold spores and construction dust towards the filter. This device, working in conjunction with the containment plastic, creates an effective engineering control that minimizes the spread of mold and dust from the work zone to adjacent uncontaminated areas. At the same time, it filters out a large portion of the spores released during mold remediation. The HEPA filter, when functioning properly, will remove essentially all mold spores from the exhaust air stream.
Mold Remediation Contractor Safety
The use of controlled demolition is recommended. This avoids unnecessarily disturbing microbially contaminated building materials during removal. The use of hammers, sawzalls, and other coarse demolition methods can all significantly increase mold spore levels within the containment. This may overload the filtering capacity of the respirators designed to protect the workers. Tools such as utility knives, drywall saws and vacuum-attached circular saws have all proven effective as mold remediation tools.
The capture zone of a negative air machine is from one to three feet in front of the intake of the filter. Locating the filter close to the work zone ensures that much of the dust created during removal of contaminated materials will be captured. The farther away the filter is from the work zone, the more dust will be released into the air. When implemented properly, controlled demolition and engineering controls can reduce the airborne concentrations of mold and dust tremendously.
A final line of defense for a mold remediation contractor is the use of PPE. This involves the use of respirators and protective clothing to prevent inhalation and dermal exposure to spores during remediation. It is very important to understand that not everybody is able to wear a respirator. A medical evaluation and fit testing are required. This will ensure that all persons using these types of PPE are medically fit and have the lung capacity to handle the resistance created by the respirator filters.
There are different types of respirators for different applications. Depending on the conditions observed, the appropriate type of respirator is chosen. It is usually recommended that a full-face respirator be used when involved in mold remediation projects that require the removal of contaminated materials greater than 10 square feet. Those wearing respirators must get the proper training and fit testing to ensure proper protection.
Protective clothing is used to protect the skin and clothing of the workers. This usually consists of a Tyvek-type material. This material is sufficient to prevent the penetration of spores through the suit. The suit usually consists of a hood and boots incorporated into a jumpsuit-type garment. This suit, in conjunction with rubber gloves taped to the wrists and a full-face respirator, will protect workers against exposure.
During hot summer months, these suits will add significantly to the heat load of the worker. Often, frequent breaks are required. This is to ensure worker safety against heat stress. These and other health-related safety issues are discussed in much greater detail in classes offered for certification in mold remediation.
A basic knowledge of microbiology, health and safety issues, engineering controls and mold remediation skills is needed to complete an effective remediation project. The skills and disciplines necessary to perform these types of tasks can be developed while working under a qualified microbial remediation technician, or learned at certification courses taught throughout the country.
These various types of disciplines are referenced in current published industry standards listed below.
Mold Remediation Protocol
Indoor Environmental Technologies (IET) conducts a full mold investigation. This is designed to determine the extent of water/mold damage to the property and to create a mold remediation protocol for the removal and repair of the damaged and affected areas. As we do not perform any remediation ourselves or have direct connections with remediation companies, we function as an “honest broker” providing defendable and dependable information.
Should you have any questions regarding this subject or would like to schedule a service, please feel free to contact us.
Additional posts on this topic:
ACGIH Bioaerosols Assessment and Control www.acgih.org
IICRC Standard and Reference Guide for Professional Water Damage Restoration S500 www.iicrc.org
IICRC Standard and Reference Guide for Professional Mold Remediation S520 www.iicrc.org
EPA Mold Remediation in Schools and Commercial Buildings www.epa.gov/molds