CHICAGO - The question of how much mold remediation should be enough to hold up in court has been a deep one for all trades involved ever since the lawsuits started. Is "no measurable mold" a reasonable goal? (No.) Should indoor levels be comparable to outdoor levels? What if you live in South Carolina, Florida, or Hawaii?

Standard S520, the Mold Remediation Standard, has been developed by the Institute for Inspection, Cleaning and Restoration Certification (IICRC) in order to address these questions, as well as to provide a "standard of care" for the many industries involved in mold and moisture remediation, including HVAC contractors. It uses the term "fungal ecology" to describe the mold content of a particular area.

Acknowledging that we live in - and have always lived in - a fungal ecology, the standard describes varying degrees of the ecology and provides input on fungal ecologies that may or must re-quire remediation. In short, it uses common sense.

In addition to IICRC, the standard is being created and reviewed by committee members from the Indoor Air Quality Association (IAQA), the National Air Duct Cleaners Association (NADCA), and the Indoor Environmental Institute (IEI). According to IAQA president Tom Yacobellis, "It's going to be the international mold remediation standard ... it's going to be the standard of care." The association reviewed the document at its annual convention.

"You know when people pay attention to a standard?" Yacobellis asked. "When the job's over and it wasn't done correctly. The time to study it is way, way before you need it."

Author Carl Grimes discusses S520 with a participant at the IAQA National Convention.

Drawing Lines

In addition to references, definitions, principles of remediation, contractor qualifications, safety and health, and structural and HVAC remediation, the standard will provide information on inspections and preliminary determinations. This is a particularly sticky area that leaves many contractors debating, "Where do we draw the line?" said Yacobellis.

"What do we say? We at IAQA also are working on a mold remediation manual."

Carl Grimes, author of Starting Points for a Healthy Habitat and president of Healthy Habitats in Denver, described the standard as a living document. "It will go out to the industry for comments and review. We want to know what works in real life."

The peer review process, Grimes said, led to a shift away from quantifiable levels. "S520 is not intended for establishing procedures," he said. Therefore, it does not establish limits based on quantifying visible levels of mold growth alone.

Establishing a standard of care for the industries involved in all aspects of mold remediation was of critical importance to the standards team. "The standard of practice is so broad, and [often] so unethical and wrong, we don't want to do that," said Grimes. "We also don't want a ‘best practices' standard."

What they wanted was a standard of care: practices common to reasonably prudent members of the trade, who are recognized in the industry as being competent. (If the definition sounds like legal jargon, that's because it is often used in negligence cases.) It will apply to professionals involved with the mechanical systems, building envelope, substructures, content cleaning procedures, and post-remediation verification.

Levels Of Contamination

By offering a standard of care, Grimes said, this will make it easier for the standard to be incorporated into legislation and written into future specs. "You may be specifying it," he commented.

The urgency of remediation actions is described at three different levels:

  • Must - Mandatory due to natural law or regulatory requirements.

  • Highly recommended - Not required by law, but part of the standard of care. (May as well be "must," Grimes indicated.)

  • Recommended - Advised or suggested.

    Levels of contamination are also ranked in three levels:

  • Condition I - Normal fungal ecology; may have traces of fungal or mold growth.

  • Condition II - The fungal ecology shows settled spores with trace growth.

  • Condition III - The fungal ecology shows traces of actual growth; there is growing mold, most likely visible; however, it can be either visible or hidden and still be at Condition III.

    "Each building is unique in its own regard," Grimes said. "Each fungal ecology is different from region to region, zone to zone, and climate to climate."

    Types Of Growth

    The standard also describes various types of fungal/mold growth:

  • Surface mold - If it's on the surface, on the condensation level, and it's not into matrixes, it usually can be cleaned through regular maintenance, Grimes said. This is a Condition I situation.

  • Limited mold growth - This could show settled spores and trace growth. Professional judgment is advised.

  • Extensive mold growth - No two ways about it; it is highly recommended to call in an Indoor Environmental Professional (IEP), Grimes said.

    What is an IEP? A person who can verify Condition I, II, or III, and also can verify a return to Condition I. (Note: "IEP" is not a trademarked term; there is no intention of developing an IEP designation, Grimes said.)

    The document also sets forth "Five Principles of Remediation," which may be multi-disciplinary:

    1. Provide for the health and safety of occupants and workers, including the use of engineering controls and personal protective and respiratory protective gear to protect workers. (In short, meet OSHA regulations.)

    2. Document conditions and work processes throughout the project, not just at the beginning and the end.

    3. Control the contaminant at its source.

    4. Physically reduce contamination to Condition I status.

    5. Correct the moisture problem to prevent recontamination.

    In addition, a reference guide covers the following topics:

    Chapter 1 - Fungal Ecology of the Indoor Environment.

    Chapter 2 - Principles of Mold Remediation.

    Chapter 3 - Health Effects Associated With Contamination.

    Chapter 4 - Administration, Processing, and Insurance.

    Chapter 5 - Limitations, Complexities, Complications, and Conflicts.

    Chapter 6 - Inspections.

    Chapter 7 - Structural Remediation.

    Chapter 8 - HVAC Remediation.

    Chapter 9 - Contents Remediation.

    Chapter 10 - Tools, Equipment, Materials.

    Chapter 11 - Safety and Health.

    Chapter 12 - Indoor Environmental Professional (IEP) Assessment.

    Getting Others Involved

    Many new pieces of state legislation are requiring that the companies assessing mold cases cannot perform the remediation. This is not a huge hardship for many HVAC contractors, who do not want to perform mold remediation work (although they may be called in to perform system repairs related to moisture control).

    The standard, however, gives them better guidelines for their technicians on what to do when they perceive that there may be a problem.

    Once it is determined that there is a problem (that is, a situation that looks like it could involve Condition II or Condition III mold contamination), Grimes said, ask yourself if it is out of your level of expertise. "If so, you need to recommend someone else," he said.

    "The preliminary determination also dictates the need for further assessment by an IEP or other appropriate professionals."

    There are still questions. For instance, how do you determine what types of respirators workers should wear without knowing specific mold levels? There is an appendix on respiratory protection, Grimes said.

    For more information on the standard, visit or

    Publication date: 11/03/2003