Proper Removal of Mold is Not Rocket Science—But Must be Science Based

Not All Mold Remediation Is The Same (Part 2 of 3)

By Michael A. Pinto, CSP, CMP

This is part two of three, please read part one if you have not already so.

Proper Removal of Fungal Sources is Not Rocket Science—But Must be Science Based

Currently there are very few federal or state regulations that actually control the mold remediation process (Texas being the notable exception, but even in that state there is a current push to deregulate those activities). Therefore, true industry professionals must be aware that their efforts are subject to an industry standard of care. Unlike a regulation, a standard of care must be pieced together from a number of different documents. While there is some debate about which references really form the core of the mold control industry, the following seven documents are cited frequently:

1. American Conference of Governmental Industrial Hygienists; Bioaerosols: Assessment and Control; 1999

2. American Industrial Hygiene Association; Report of Microbial Growth Task Force; 2001

3. Environmental Protection Agency; A Guide for Mold Remediation in Schools and Commercial Buildings; 2001

4. Canadian Construction Association; Mould Guidelines for the Canadian Construction Industry; 2004

5. New York City Department of Health; Guidelines on Assessment and Remediation of Fungi in Indoor Environments; 2008

6. Institute of Inspection Cleaning and Restoration Certification; Standard and Reference Guide for Professional Mold Remediation S520; 2008

7. Occupational Safety and Health Administration; A Brief Guide to Mold in the Workplace; Safety and Health Information Bulletin, updated November 2013

Despite the fact that guidance for mold situations is coming from a variety of sources, there is a surprising consistency in the overall tone and approach. Since many mold remediation contractors come from a background of dealing with other hazardous contaminants such as asbestos or lead, all of the accepted reference documents emphasize understanding that mold is a biological agent. Since it has the ability to grow under the right conditions, isolation and deferred action to remove the source of the problem may not be possible, as it is with asbestos materials. With mold a delay may allow contamination inside a building to grow to a point where it poses a hazard greater than when initially discovered.

Another key point emphasized by all of the documents is that the presence of mold growth means that there is or has been moisture intrusion in the building. Removing surface mold contamination and not identifying and correcting the underlying moisture problem would be tantamount to a doctor treating symptoms rather than the disease that is causing them. This aspect of the mold remediation process has taken on even greater importance since we have recognized that other contaminants present in water-damaged buildings are also contributing to the problems experienced by occupants.

A third element that makes up the standard of care for the removal of fungal sources is that the work be done in such a way as to avoid cross-contamination. As is stated in bold type at the beginning of the remediation section of the New York City guidelines: The goal of remediation is to remove or clean mold-damaged materials using work practices that protect occupants by controlling the dispersion of mold from the work area and protect remediation workers from exposures to mold.

Even though it should not be necessary to add this warning, a word about chemical use is important. Too many advertisements related to mold remediation fall into the category of “spray and pray.” Despite the fact that the advertisements and sales pitches talk about how the product is “all-natural,” “developed by NASA for the space station,” “used by the military to decontaminate anthrax,” and a number of other impressive statements, such an approach does not fit the industry standard of care. More important, fogging, spraying, or atomizing chemicals into a structure occupied by a sensitized individual can be downright dangerous. Spraying such materials into a building and praying that they take care of the problem the first time, divert energy and financial resources away from the real work of physical removal of fungal sources and reservoirs.

The Basics of Source Removal When There are Sensitized Occupants

Proper isolation, engineering controls, and work practices must be employed on every project focusing on contaminant removal from water-damaged buildings because bad remediation can be worse than no remediation at all. Activities that disturb sources of biological growth and distribute bacteria, spores, fragments, and byproducts such as mycotoxins into the air where they can migrate to other areas of the structure must be done under controlled conditions. While failure to understand or follow this standard of care may create some problems for the average individual, conducting such work without proper controls can literally create a life-threatening situation for one who is genetically susceptible or previously sensitized to contaminants from water-damaged buildings.

Although entire books have been written on proper remediation, a typical project involving individuals who have known or suspected mold sensitization utilizes these sequential steps:

A. Isolation from the rest of the structure of the specific work area where visible or hidden contamination will be removed, utilizing sheet plastic or other materials sealed tightly against structural components.

B. Sealing off of supply and return air ducts for the duration of the remediation effort.

C. Installation of a decontamination chamber that acts as both a transition zone between the contaminated work area and the rest of the structure and a device that controls the amount of air flow into the workspace.

D. Creation of negative pressure inside the isolated workspace through the use of exhaust fans. In most cases the exhaust air is pushed through HEPA filters before being exhausted out-of-doors in order to create a pressure differential of 0.02” of water column (equivalent to 5 pascal).

E. Minimization of spore deposition through HEPA vacuuming or sealing of visible mold with adhesive plastic prior to disturbing the visible colonies.

F. Careful planning of the demolition aspects of the work so that sections of drywall or other finish material are kept small enough to fit into bags without having to be broken.

G. Requiring individuals working inside the isolated area to wear protective suits with hoods, slip-on safety boots, gloves, and respiratory protection is an important means of preventing cross-contamination. When the workers remove those items in the decontamination chamber it keeps contaminants from being carried into other areas of the building.

H. Utilization of dust free demolition techniques, such as panel saws with a dust collection cowl around the blade, connected to a HEPA-filtered vacuum for cutting of plaster or drywall.

I. A work sequence that follows the air flow, generally starting at the decontamination unit and finishing at the area closest to the negative air machine.

J. Immediate bagging of debris and careful attention to frequent cleanup of dust with a HEPA vacuum.

K. Wiping plastic bags of debris at the entry to the work area and then double bagging the material in the decontamination unit into bags that have never been inside the work area.

L. Transport of double bagged debris out through occupied areas of the structure in solid containers with tightfitting lids, such as Rubbermaid garbage cans.

M. Thorough cleaning of the isolated work area following the removal of all contaminated materials, using the “HEPA sandwich,” a three-step process consisting of HEPA vacuuming, damp wiping with an antimicrobial, and a second HEPA vacuuming.

N. Air scrubbing for 8 to 24 hours following completion of removal and cleaning activities. During this air scrubbing one HEPA-filtered unit should be used to maintain negative pressure, with a second unit set up inside the isolated work area with an exhaust tail to diffuse the air.

O. Post-remediation review of the work area by means of a thorough visual inspection, collection of air samples with proper analysis, and comparison of data to a stringent evaluation criteria.

Dealing With the Often Forgotten Transport Mechanism

Although it seems difficult for the layperson to imagine, many remediation projects in water-damaged buildings emphasize sealing the supply and return vents in the isolated work area with poly sheeting and then simply allow the plastic to be removed after successful sampling results are received. No testing or cleaning of the register vents, ductwork, or mechanical components of the heating, ventilating, and air conditioning (HVAC) system is ever considered. Given that the microscopic particles that cause so many problems for sensitized individuals are present prior to the remediation effort, the default position should be to consider all HVAC mechanisms to be contaminated and in need of cleaning rather than being ignored.

Proper cleaning of HVAC systems is a sub-specialty, even in the remediation field. While many service providers claim to clean ductwork, few have the equipment and experience to do it well when the work is part of a remediation process in a water-damaged building with sensitized individuals. A thorough understanding of the cleaning guidelines put out by the National Air Duct Cleaners Association (NADCA) is a bare minimum starting point.

Above and beyond the basics, sensitized individuals require a thorough cleaning of the HVAC system that typically involves isolation of all supply and return points. Negative pressure is then installed at the mechanical unit, with the preferred method being a van- or truck-mounted filtration device connected to the HVAC unit by a long flexible duct. One at a time, starting at the supply and return vents farthest from the mechanical components, the grilles are uncovered and cleaning brushes, wands, or other specialized equipment is inserted into the ductwork. This process dislodges contaminants and pushes debris and microscopic impurities downstream, where it can then be sucked to the outside capture device in the specially-equipped vehicle.

Duct cleaning in the homes of sensitized individuals adds a number of complexities that are not present in the typical project. There is significant debate in the HVAC cleaning industry about the practicality and effectiveness of cleaning flexduct (polyethylene tubing that has spiral wire ribs in it—like a Slinky toy—that allow it to expand and contract). For occupants suffering from biotoxin illness or other sensitivities that are triggered by microscopic contaminants, it is best to remove and replace flexduct as part of the cleaning process. Such clients should also have the fan and coils actually disassembled from the unit. Although this requires the use of a licensed mechanical contractor, it allows those critical pieces to be taken outside and thoroughly cleaned, while enabling access to inspect and completely sanitize the drip pan and associated piping.

If the main trunk lines are constructed of fiberglass duct-board rather than sheet metal, a thorough cleaning will roughen the interior surface. Unless addressed at the time of the cleaning, the damaged interior will shed more particulates when the system is used and provide many more areas where moisture can be trapped and support future fungal growth. Therefore, as much as excess chemical use is avoided in homes with sensitized individuals, this is one situation where application of a low odor, EPA-approved coating inside the ductwork is imperative as part of the cleaning process.

The use of spray or gaseous sanitizers in ductwork as an adjunct to cleaning is also controversial. For sensitized individuals, the general industry preference is to avoid adding additional chemicals to the HVAC system—even those that are expected to quickly break down to inert materials. As noted in the remediation section, the focus of the cleaning should be on removing the small particulates to as low a level as practical, not on killing or inactivating the contaminants.

Continue reading Part Three…

Not All #Mold Remediation Is The Same (Part 2 of 3) @moldsensitized http://t.co/pFdCWhDlMZ PLEASE RETWEET

— Mold Sensitized (@moldsensitized) March 11, 2015