Remediation
Cleaners, antimicrobials and coatings (S520)
In plain English
The S520 is clear that chemicals are helpers, not the cure. Removing the mold physically "should always be the primary means of remediation," and no liquid product (antimicrobial, stain remover or cleaner) should be used as an alternative to it. Antimicrobials shouldn't be relied on to remove mold's allergenic or toxic properties, and even repeated aggressive cleaning and treatment may not remove endotoxins and similar residues. Indiscriminate use of antimicrobials, coatings, sealants and cleaners is not recommended, and before using any of them the remediator should weigh whether it fits the job and what it could cause.
Bioburden and soil come off first, then any disinfecting. On thoroughly cleaned non-porous materials, antimicrobials are generally not needed. Disinfectants are a supplemental treatment the remediator should justify to the client, for example on rough surfaces that can hide microorganisms; they should be registered as fungicides, and the remediator shouldn't claim any lasting effect unless the EPA-registered label does. Stain removers are cosmetic and come only after cleaning; a client who wants only the stain treated is asking for a deviation from the standard. Chemicals can also damage things in wall cavities, such as CPVC pipe, flexible plumbing, wire jackets and electronics, so manufacturers' compatibility lists should be checked.
Label directions "shall" be followed. If an application method isn't on the EPA label, using it is illegal; the S520's example is electrostatic spraying. Remediators should explain what a product does, document every chemical and coating used, and give the client the label and safety data sheet before use. They should not use a disinfectant or fungicide instead of removing growth, a stain remover before or instead of cleaning, a product against an organism or in a situation it isn't registered for, or a gas or vapor (fogging, misting) to kill microbes without cleaning first or without registration for that use. Plant-based or "green" products are allowed to meet customer or LEED requirements, with proof of plant-derived content such as USDA BioPreferred (at least 25%) or EPA Safer Choice.
Dust raised during the work should be controlled at the source, with a HEPA vacuum on or near the tool or a light mist, and what escapes caught with HEPA air filtration devices (with the air gently circulated through them) or a water-based, non-antimicrobial fog that drops it to surfaces. Either way, the residue that settles has to be physically cleaned up to get back to Condition 1.
Fungicidal and mold-resistant coatings can protect some materials, but not in place of removal, moisture control and ordinary cleaning. They should go on only after the post-remediation evaluation or verification confirms Condition 1, and after demolition, drying and cleaning; be water-based and low-odor; resist regrowth in industry tests; and not add fire risk or trap moisture. The S520 gives ASTM tests for comparing products: a Class A flame-spread rating (ASTM E84), at least 2 perms of vapor permeability (ASTM D1653; a vapor barrier is under 1 perm), VOCs under 100 grams per liter (ASTM D6886), and a "0" (no growth) rating under ASTM G21 or D3273. Fungicidal coatings must be registered as antimicrobials with the EPA and state regulator.
Coatings only work on what they cover. Their active ingredients inhibit growth on or in the coating film, so a substrate left wet can keep growing mold underneath. They go on surfaces that have been cleaned (and disinfected where appropriate), never as a "sealant" or "encapsulant" over growth, and where there's a worry that a coating could hide mold, a clear or translucent product lets the surface be inspected later. Heat and cold are no substitute either: the S520 says temperature extremes should not be relied on to eliminate mold or its allergenic or toxic properties.
Key points
- Physical removal first; chemicals never replace it.
- Clean before disinfecting; cleaned non-porous surfaces usually need no antimicrobial.
- Follow the label; an unlisted method (like electrostatic spraying) is illegal.
- Give the client the label and SDS; document every product.
- No fogging to kill mold without cleaning first and label registration for it.
- Coatings only after the area is verified clean and dry: Class A, 2+ perms, <100 g/L VOC, no-growth rating.
- Heat or cold treatment doesn't replace physical removal.
Official text
This topic is covered in our own words because the standard behind it is copyrighted; we cite it below rather than reproduce it.
Citations
- IICRC S520, ANSI/IICRC S520 Standard for Professional Mold Remediation — Secs. 2–2.1.3, cleaners, stain removers, antimicrobials and airborne particulate knockdown, pp. 25–26. Best practice
- IICRC S520, ANSI/IICRC S520 Standard for Professional Mold Remediation — Secs. 2.2–2.3, fungicidal and mold-resistant coatings, Chart 1, limitations, extremes of temperature, pp. 27–28. Best practice