The Preparation of Mold Remediation Protocols: Part 3
The following is Part 3 of a 4-part series on the Preparation of Mold Remediation Protocols that discusses Remediation Techniques, waste disposal, and methods for cleaning. The goal of a Mold Remediation Protocol (MRP) document is to provide a guideline for the remediation contractor to complete the project in accordance with current industry standards and demonstrate that the building is safe to occupy.
The MRP specifies the methods for removing the microbial contamination from a containment area. For example, the exact location of demolition of porous materials (i.e. gypsum board) the method of demolition, or the technique to remove mold colonies from wood surfaces that are not to be removed may be specified. Note that the MRP may specify that contaminated semi-porous materials that are being removed are cut beyond the visibly contaminated area by a specified distance (i.e. 2 feet beyond visual contamination).
If it is most cost effective to use a chemical cleaner, scrub, or use dry ice blasting equipment to remove the mold contamination from building materials that will not be removed, the MRP should be vague enough to allow the contractor some liberties to make the decisions for using the appropriate equipment and addressing the health and safety issues associated with the
remediation method. A MRP that is too detailed may be so restrictive to actually place the Consultant and Owner in a position of liability. The Contractor is ultimately responsible for accomplishing the remediation to meet the requirements of the Post Remediation Verification (PRV), meet the expectations for discretion by the property owner, and satisfy the goals of the
If there are concrete surfaces that are to be cleaned, it may be prudent to include the type of liquids to be used to remove the mold from the surfaces (i.e. antimicrobial agent or soap). Some contractors are focused on killing mold colonies rather than removing the contamination, which is incorrect and should never be allowed. For example, using an antimicrobial cleaning agent on concrete without then using a liquid that has a strong surfactant property during the cleaning process will most often not afford the possibility of passing the PRV.
If mold contamination cannot be removed, then a method of encapsulation may be considered if all of the stakeholders agree on this course of action. This is often required when removing a few square inches of contamination would cost thousands of dollars in reconstruction fees. For example, in a basement, where mold is on the overhead subfloor and the floor joists, there is probably mold contamination between the wood surfaces of the seam where they meet. These areas may be sealed with caulk to prevent an exposure potential. However, note that there are no national industry guidelines that allow for the use of encapsulation as a method of remediation. At best, one must make a best effort to remove the mold to natural background values before encapsulation is considered. Prior to the beginning of a project, the property owner must be made aware in writing that the Contractor is not expected to remove all of the mold (below background values), regardless of its location, and that steps will be taken to minimize the potential exposure to future occupants.
If a specialty remediation technique is required, then specialty considerations for using such equipment should be presented in the MRP. For example, the use of soda blasting requires the use of a collection sock, special pre-filters on the NAMs, and the use of a powered air purifying respirator or a supplied air system. The use of dry ice blasting will require storage considerations for the dry ice and possibly oxygen depletion considerations. A specialty technique may not be possible in a confined space without using an external and independent air supply system.
Note that there are no guidelines that allow for the use of a chemical product to simply kill mold contamination and leave it in place as the method of remediation. For example, the use of Fogging an area and then painting over the contaminated surfaces is not an accepted remediation technique and opens all stakeholders to potential liabilities after the property is re-occupied.
Waste must be removed from the containment area in a way that does not spread the contamination and provides the discretion that is expected by the property owner. The MRP should specify the method of packaging the waste and how the surfaces of the package are cleaned before it is removed. Generally, the standard protocol is to place the bagged materials in the egress chamber. The surfaces are then HEPA vacuumed and then wiped with a cloth soaked in a soapy solution. This process is repeated three times.
After the waste is removed from the containment area, the MRP should identify if there is any special method that the waste packages are to be handled to meet a third party expectation (i.e. property owner or health department). For example, if a roll off box is used, is it to be covered with a tarpaulin? Is the contractor required to build an enclosure that connects the containment area to the roll off box so that the public cannot see the waste being handled before it is placed in the roll off? If so, then the MRP should include statements to address these issues.
The MRP should specify that all surfaces inside the containment area be HEPA vacuumed and then wiped with a cloth soaked in a soapy solution typically three times. It is important to stress in the MRP that this activity must be accomplished in detail to pass the PRV. Everything that leaves the containment area must be cleaned in accordance with the protocols (except personnel which will be wearing disposable suites) to prevent the spread of contamination outside the remediation area.
There is considerable discussion regarding whether to have the HVAC System cleaned as part of a standard remediation project. Some consultants feel that when the HVAC system is not part of the mold contaminated areas, then cleaning the HVAC dislodges debris and creates unnecessary post remediation cleanup. If the consultant feels that the HVAC system be cleaned as part of the project, then the method should conform to National Air Duct Cleaners Association General Specifications for the cleaning of commercial Heating, Ventilating, and Air Conditions Systems, Publication 1992-01.
In Part 4 of this 4-part series, we will discuss the post remedial verification testing, project file documentation, and examples of inappropriate protocol content.