AFDs and Respirators
December 1, 2006
Q: The S500 says that “Restorers can install one or more air filtration
devices...AFDs provide additional airflow while simultaneously removing soils
or contaminants from the air...” So, if we decide to install an AFD to remove
contaminants, should we also have our workers wear N95 respirators while
working in the area?
Q: The S500 says that “Restorers can install one or more air filtration devices...AFDs provide additional airflow while simultaneously removing soils or contaminants from the air...” So, if we decide to install an AFD to remove contaminants, should we also have our workers wear N95 respirators while working in the area?
A: If I am reading between the lines correctly, I assume you are saying that since an AFD is on the water loss there must be contamination present. Therefore, if there is contamination present, shouldn’t workers wear N95 filtering facepiece respirators?
There are two issues to address: first, whether or not there is contamination; and second, whether N95s are appropriate personal protection equipment to be worn by workers while in the area. To begin let’s look at the IICRC S500 Standard and Reference Guide for Professional Water Damage Restoration and see what it says.
The S500 Standard states at 12.1.20:
Airmoving devices inherently tend to aerosolize soils and contaminants present in the environment. As water evaporates from surfaces and materials, such as carpet, more particles often become aerosolized, creating possible health, safety, comfort and cleanliness issues. To minimize or control aerosolization of particles, restorers should consider implementing the following:
Restorers can install one or more air filtration devices or AFDs (scrubbers), depending on the AFD’s size and obstructions within the structure. AFDs provide additional airflow, while simultaneously removing aerosolized soils or contaminants from the air within a room. Restorers should consider repositioning AFDs on each monitoring trip.
The “standard of care” is that the restorer “should consider implementing” what is stated. In order for a restorer to implement these recommendations, a consideration of the available facts would be necessary. Therefore, the use of an AFD in this instance is not part of the “standard of care,” but is based upon the professional judgment of the restorer.
That being the case, what information would a restorer consider? The most obvious consideration is that there is a substantial amount of dust and debris that has accumulated in and under the carpeting. Without knowing or suspecting the makeup of the dust, the installation of an AFD as an air scrubber would be a reasonable precaution. So, the answer to the first question is “possibly.”
Let’s consider a different scenario. If you know that there is contamination, then it would be the “standard of care” to install an AFD, probably as a negative air machine.
At 12.5.2, S500 states:
The most effective way to ensure that gaseous and aerosolized contaminants do not spread is to isolate work areas by establishing critical barriers or by erecting containment (plastic sheeting) and maintaining adequate negative air pressure within contained work areas relative to adjacent areas.
If you have performed an inspection and developed a preliminary determination that contamination does not exist, the use of respiratory protection is not generally necessary. If, however, you have made a preliminary determination that contamination is actually or possibly present and that workers will likely be exposed to aerosolized contaminants, then the use of respiratory protection would likely be a part of the “standard of care.”
Now the question is whether or not an N95 filtering facepiece respirator is adequate to protect workers. A recent article published in the “Journal of Occupational and Environmental Hygiene, entitled Respiratory Protection Provided by N95 Filtering Facepiece Respirators Against Airborne Dust and Microorganisms in Agricultural Farms,” concluded that the assigned protection factor for N95 filtering facepiece respirators against microorganisms (mean aerodynamic size <5 µm) seems to be inadequate. While this information was based upon work protection factors (WPF) and was preliminary, it demonstrated that microorganisms were able to penetrate the filter media or circumvent the facepiece easier than non-organic dust. WPF is a measurement of the protection provided in the workplace by a properly functioning respirator when correctly worn and used. The article further states that “For fungal spores in the mean aerodynamic size of 3.7 to 18.9 µm, the protection factors before correction resulted in the overestimation ranging from 41% to 75%.” The “overestimating” refers to the overestimating of the WPF.
While it is true that we do not know what the levels of contaminants may be while using an AFD as described here, there is a concern about what level of protection is provided while wearing an N95 filtering facepiece respirator. In the case of very little contaminant, an N95 may be adequate. If the levels are considerable, in my opinion, an N95 is probably inadequate. The decision to wear respiratory protection is left to the employer. The level of protection is complicated by the fact that there are not established exposure limits for many microorganisms.
Q: The S500 says that “Restorers can install one or more air filtration devices...AFDs provide additional airflow while simultaneously removing soils or contaminants from the air...” So, if we decide to install an AFD to remove contaminants, should we also have our workers wear N95 respirators while working in the area?
A: If I am reading between the lines correctly, I assume you are saying that since an AFD is on the water loss there must be contamination present. Therefore, if there is contamination present, shouldn’t workers wear N95 filtering facepiece respirators?
There are two issues to address: first, whether or not there is contamination; and second, whether N95s are appropriate personal protection equipment to be worn by workers while in the area. To begin let’s look at the IICRC S500 Standard and Reference Guide for Professional Water Damage Restoration and see what it says.
The S500 Standard states at 12.1.20:
Airmoving devices inherently tend to aerosolize soils and contaminants present in the environment. As water evaporates from surfaces and materials, such as carpet, more particles often become aerosolized, creating possible health, safety, comfort and cleanliness issues. To minimize or control aerosolization of particles, restorers should consider implementing the following:
Restorers can install one or more air filtration devices or AFDs (scrubbers), depending on the AFD’s size and obstructions within the structure. AFDs provide additional airflow, while simultaneously removing aerosolized soils or contaminants from the air within a room. Restorers should consider repositioning AFDs on each monitoring trip.
The “standard of care” is that the restorer “should consider implementing” what is stated. In order for a restorer to implement these recommendations, a consideration of the available facts would be necessary. Therefore, the use of an AFD in this instance is not part of the “standard of care,” but is based upon the professional judgment of the restorer.
That being the case, what information would a restorer consider? The most obvious consideration is that there is a substantial amount of dust and debris that has accumulated in and under the carpeting. Without knowing or suspecting the makeup of the dust, the installation of an AFD as an air scrubber would be a reasonable precaution. So, the answer to the first question is “possibly.”
Let’s consider a different scenario. If you know that there is contamination, then it would be the “standard of care” to install an AFD, probably as a negative air machine.
At 12.5.2, S500 states:
The most effective way to ensure that gaseous and aerosolized contaminants do not spread is to isolate work areas by establishing critical barriers or by erecting containment (plastic sheeting) and maintaining adequate negative air pressure within contained work areas relative to adjacent areas.
If you have performed an inspection and developed a preliminary determination that contamination does not exist, the use of respiratory protection is not generally necessary. If, however, you have made a preliminary determination that contamination is actually or possibly present and that workers will likely be exposed to aerosolized contaminants, then the use of respiratory protection would likely be a part of the “standard of care.”
Now the question is whether or not an N95 filtering facepiece respirator is adequate to protect workers. A recent article published in the “Journal of Occupational and Environmental Hygiene, entitled Respiratory Protection Provided by N95 Filtering Facepiece Respirators Against Airborne Dust and Microorganisms in Agricultural Farms,” concluded that the assigned protection factor for N95 filtering facepiece respirators against microorganisms (mean aerodynamic size <5 µm) seems to be inadequate. While this information was based upon work protection factors (WPF) and was preliminary, it demonstrated that microorganisms were able to penetrate the filter media or circumvent the facepiece easier than non-organic dust. WPF is a measurement of the protection provided in the workplace by a properly functioning respirator when correctly worn and used. The article further states that “For fungal spores in the mean aerodynamic size of 3.7 to 18.9 µm, the protection factors before correction resulted in the overestimation ranging from 41% to 75%.” The “overestimating” refers to the overestimating of the WPF.
While it is true that we do not know what the levels of contaminants may be while using an AFD as described here, there is a concern about what level of protection is provided while wearing an N95 filtering facepiece respirator. In the case of very little contaminant, an N95 may be adequate. If the levels are considerable, in my opinion, an N95 is probably inadequate. The decision to wear respiratory protection is left to the employer. The level of protection is complicated by the fact that there are not established exposure limits for many microorganisms.