Mold Standards: Do They Exist?

We have stated that there are no accepted numerical standards for mold concentrations. Several previous attempts at suggesting numerical concentrations have failed due to the enormous diversity of the thousands of mold species that naturally occur, and to the wide variability in human responses to these species. Most professional doubt that we will ever have a set of exposure limits like we have for other indoor contaminants such as radon, asbestos and lead.

This does not mean, however, that there are no standards with which to conduct a competent assessment or remediation project. Numerous public and private agencies in the US have written standards for biological contaminants, starting with the Environmental Protection Agency (EPA) and the American Conference of Governmental Industrial Hygienists (ACGIH) in the late 1980’s. The body of professional standards has grown steadily since. A sampling of the evolution of professional industry standards is shown below. [Read more…]

Mold Remediation Procedures

We reference the industry standard Bioaerosols: Assessment and Control (1999), published by the American Conference of Governmental Industrial Hygienists (ACGIH). The ACGIH standard is the current authority on biological contamination, and is a practical guide for identifying and correcting suspected sources of microbiological amplification. Several other industry guides have been published in recent years, including:

  1. Environmental Protection Agency (EPA) Mold Remediation in Schools and Commercial Buildings, EPA 402-K-01-001, March 2001.
  2. Environmental Protection Agency (EPA) Guide for Building Owners and Facility Managers, ISBN-0-16-035919-8, published in December, 1999.
  3. Institute of Inspection, Cleaning and Restoration (IICRC), Standard and Reference Guide for Professional Water Damage Restoration, IICRC S500, 1999.
  4. New York City Department of Health (NYCDOH), Guidelines on Assessment and Remediation of Fungi in Indoor Environments, May 1993, Revised March 2004.
  5. American Industrial Hygiene Association (AIHA,) Field Guide for the Determination of Biological Contaminants in Environmental Samples 1996.
  6. American Industrial Hygiene Association (AIHA), Assessment, Remediation and Post Remediation Verification of Mold in Buildings, AIHA Guideline 3, 2004.

As described by EPA and ACGIH, and supported by publications by the American Industrial Hygiene Association and the National Institute of Occupational Safety and Health, the amplification of biological populations should not be tolerated in occupied buildings. The presence of amplification requires mitigation measures to remove the biological growth. Existing industry standards indicate the need to remove affected porous materials, clean affected non-porous materials, and thoroughly clean all surfaces in the area of the contamination. Caution is advised in the use of disinfectants, to ensure that building occupants are not exposed to chemical biocides that can be hazardous with uncontrolled use.

[Read more…]

Mold Inspection: How is it Done?

The inspection process includes a general understanding of the building, including age, number of stories, roofing and siding type, and presence of basements or crawlspaces.

The behavior of moisture in the structure is the critical component of the assessment. The grading around the building should be reviewed to ensure the water flows away from the foundation. This is especially important in the area of roof leaders and drains. Some grading issues are a challenge by definition. For instance, if a home has a walk-out patio door on one side of the basement and the rest of the basement is below grade, this implies that the grade slopes toward the house on the other side. [Read more…]

Mold Air Testing: Is there any value?

When folks call our office with a mold concern, they invariably ask for an air test. They say, “I need to know what we are breathing! Can you help us?”

Our response is invariably, “Yes, we can help you. But an air sample for mold is not the proper diagnostic tool.” We go on to describe the more powerful, albeit simple, tools we have available to figure out a mold problem. These tools include a thorough visual inspection, targeting areas where moisture can commonly occur, moisture and humidity testing, and source testing of suspected materials. The goal, after all, is to determine whether an active mold condition exists in the building, not just to identify (usually inaccurately) what is flying around in the air. [Read more…]

Indoor Air Quality Assessment – Walk Through Inspection


A thorough walk through inspection of each floor is conducted to investigate and determine potential sources of Indoor Air Quality contamination. The mechanical room air handling systems are visually inspected for microbiological contamination on the cooling and heating coils, drip pans and other system components. The maintenance records also are reviewed for each facility. Experienced field technicians qualitatively review the delivery capacities of the air handling systems to determine if air flow appears sufficient for the size and type building under investigation. [Read more…]