Abstract

When it comes to microbial sampling for remediation and restoration projects, there are no set criteria as to when to sample and how to sample. It is important to note that there are no recognised industry Standards or Guidelines that provide what acceptable levels are for any specific bacteria or mould species in the air or on surfaces. This is especially the case when it comes to sections of properties that have been partially stripped and are considered to be a construction site or non-inhabited spaces such as subfloors, wall cavities and ceiling voids.

As there is little to no consensus as to what constitutes acceptable levels of any particular microorganism, the determination is left to the consulting Indoor Environmental Professional (IEP) to make in context with the project. This article explores the necessity of professional independence and the specific conditions under which sampling provides genuine scientific value.

 

The Importance of Independent Analysis

Some consulting companies in Australia provide both onsite assessments as well as analytical analysis of samples in their own laboratory, which is a potential conflict of interest. This conflict arises when a business can take samples from a site and then report the findings of those samples in a way that might bias a particular outcome for that client’s interests.

Furthermore, businesses that own a laboratory tend to oversell the importance of microbial sampling, including how it should be done on all remediation projects and the amount of sampling that should be done. Much of this is not supported by science. Professional, experienced and certified indoor environmental consultants and microbial investigators only sample when it is deemed to be actually required.

 

The Hypothesis-Driven Approach

Microbial sampling should only be done to prove or disprove a specific hypothesis. Valid examples of when microbial sampling may be required include the following:

• To determine if a surface has abnormal levels of microbiological loadings
  
• To determine an airborne exposure risk (though this is very rarely required as if there are water-damaged and microbially contaminated materials present, that is what constitutes a risk)
  
• To determine if a surface has been cleaned to a satisfactory level as part of Post Remediation Verification

 

The “Clearance” Scenario

For mould growth from target spores or mould genera to occur in a water damaged building, viable spores from those target genera must have been present in the building prior to the wetting of materials. Regardless of what genera and levels of mould are on surfaces, especially structural elements within interstitial spaces, prior to the wetting event, that is the normal mould ecology for that unaffected area or surface. In my opinion, this constitutes Condition 1 according to the IICRC S520 definition. It is unreasonable and even unfair to restoration contractors to expect the cleanliness of structural elements, especially in interstitial spaces, to be evaluated in a way that does not account for this pre-existing ecology.

 

Industry Standards and Regulatory Excerpts

To ensure compliance and defensibility, RIC Solutions adheres strictly to the recognised industry definitions provided by the ANSI/IICRC.

 

From the ANSI/IICRC S500-2021: Standard for Professional Water Damage Restoration

Where elevated risk factors are present on a Category 2 or 3 remediation project, an IEP should be retained by one of the materially interested parties. Risk factors include, but are not limited to:

• occupants are high-risk individuals
• a public health issue exists, for example, elderly care or childcare facility, public buildings, hospitals
• a likelihood of adverse health effects on workers or occupants
  
• a need to identify a suspected contaminant
  
• contaminants are believed to have been aerosolized
  
• a need to determine that the water actually contains contamination

The S500-2021 defines an indoor environmental professional (IEP) as:

• an individual with the education, training, and experience to perform an assessment of the microbial ecology of structure, systems, or contents at a job site, create a sampling strategy, sample the indoor environment and submit to an appropriate laboratory, interpret laboratory data and determine Category of water or Condition 1, 2, and 3 for the purpose of establishing a scope of work and verifying the return to a normal microbial ecology (e.g., Condition 1).

 

From the ANSI/IICRC S520-2015: Standard for Professional Mold Remediation

The S520-2015 defines post-remediation verification as:

• A process performed by an IEP after a remediation project, which can include but is not limited to visual inspection, odor detection, analytical testing, or environmental sampling methodologies to verify that the structure, system, or contents have been returned to a level that no longer poses a substantial risk from dermal, ingestion, or inhalation exposure.

 

The S520-2015 defines an assessment as:

• A process performed by an indoor environmental professional (IEP) that includes the evaluation of data obtained from a building history and inspection to formulate an initial hypothesis about the origin, description, location and extent of Condition 2 or 3. If necessary, a sampling plan is developed, and samples are collected and sent to a qualified mycology or microbiology laboratory for analysis.

 

Summary

In an industry often clouded by commercial interests, RIC Solutions remains committed to research-led integrity and strict regulatory compliance. By applying the IICRC standards precisely and maintaining absolute laboratory independence, we provide defensible data that protects all stakeholders from unnecessary costs and health risks. Our goal is to replace industry madness with professional building science and accountability.