Indoor Air Quality/Mold Investigations

In response to concerns regarding indoor air quality and insurance claims involving mold growth in structures, STC Environmental Services, Inc. began conducting indoor air quality and/or mold investigations in 1996. In 2003 the Texas Legislature passed legislation regulating the businesses conducting mold investigation and remediation activities. The Texas Mold Assessment and Remediation Rules stipulate that as of January 1, 2005 all companies and individuals who perform mold related activities will be licensed by the Texas Department of State Health Services (TDSHS). These rules stipulate that applicants must meet certain qualifications, obtain required training and pass a State exam to be a licensed individual. These rules also set minimum work standards that licensees must follow in addition to providing a code of ethics for the licensees. Complete information regarding the Texas Mold Assessment and Remediation Rules can be obtained from the TDSHS website

STC applied and received a Mold Assessment Company License in January of 2004. STC employs one licensed Mold Assessment Consultant. STC routinely conducts indoor air quality investigations and mold investigations on behalf of tenants, owners, and/or insurance companies in both commercial and residential structures.

STC's role in indoor air quality investigations and mold investigations is to obtain air samples utilizing a high volume pump and a specialized canister with a prepared slide or physical samples of the materials suspected of being impacted. These samples are then shipped to a Texas licensed Mold Laboratory for analysis. The air samples are a direct measurement of particles within the breathing environment and are reported as concentration/meter. The tape or bulk samples from impacted materials are reported as Semi-quantitative concentrations of mold on a prepared slide. STC then reviews and evaluates the laboratory results to develop our recommendations. Details regarding the investigation, type and location of samples, photographs, and the mold consultants conclusions and recommendations are the assembled in a final report.

These investigations are a snap shot in time of the air conditions both inside and outside the building. Samples from the indoor air breathing environment are compared to the outside air. This is required since make-up air for the HVAC unit comes from outside as well as outside air entering with normal door opening during entry and departure events. It should also be noted that there are NO specified levels of mold/fungi that are considered harmful to humans. Each individual has a different tolerance level for molds/fungi species. In addition, different geographical locations also have a wide variance of air quality levels. Therefore what is considered normal outside in one (1) geographical area may never occur in other geographical areas. The Texas rules do not specify a "safe level" of mold.

It is generally accepted that "normal" outside levels are 1,200 or 12,000 concentration/meter depending on the analytical criteria used, with the majority of the particles made up of the common species of Aspergillus/Penicillium and Cladosporium. Based on this outside "normal" level, the inside level that is accepted as "normal" is 300 or 3,000 concentration/meter. Essentially acceptable indoor air quality is normally considered to be 50% of the outside level when the HVAC unit is running. This is why a comparison is always required to establish acceptable indoor levels. With the HVAC system running then the indoor air quality should be less than 2,000 or 20,000 concentration/meter. If the HVAC unit is not running indoor levels may be as high as 80% of the outside level.

In addition to the breathing air environment samples, air samples from the interstitial wall environment may be obtained as well as tape or bulk samples. Interstitial wall samples are obtained by drilling a small opening in the wall inserting a sampling tube coupled to the canister with the prepared slide and then drawing air from the interstitial space. These results are also reported in concentration/meter. In addition, during these investigations STC records relative humidity, temperature, and dew points from both inside and outside the structure at the time of our testing. We will also utilize moisture meters to detect water impacted materials. Finally, photographs are taken to include in the final report.

Should mold remediation activities be necessary, the final report will also provide mold remediation protocol to be followed during any recommended mold remediation activities. The mold remediation protocol specifies the estimated quantities and location of the impacted materials requiring remediation, methods to be used during remediation, and clearance criteria to be met upon completion of the remediation activities. The actual remediation must be conducted by a Texas licensed Mold Remediation Contractor who will also develop the mold remediation work plan which includes operating procedures for how the project will be completed.

If the problem is of a more complex nature STC can obtain air samples of the breathing environment utilizing a SUMMA Canister. The SUMMA Canister is a stainless steel vessel with a sampling regulator which will draw air over a specified time-frame. These canisters come in a variety of sizes varying from 400 ml to 6 liter. Sampling time frames can vary from minute grab samples to 24 hours. After obtaining the appropriate sample, the canisters are then shipped to a laboratory where the air is analyzed using a general Volatile Organic Compound (VOC) scan. STC will then review the results and provide recommendations in a final written report.

Indoor Air Quality / Mold Investigation

What is the cost of a mold investigation?
The cost of these services is dependent on the type of problem and the possible source. A limited investigation of the indoor air quality of a building to include three air samples can typically vary from $500.00 to $ 650.00. More complex problems require additional samples and personnel time
How long do these investigations take?
Depending on the work load and the laboratory turn around time investigations will take between 5 and 10 days from the authorization date. Verbal results can be obtained from 1 to 3 days after the samples are obtained.
If a water leak occurs will I start to see mold immediately?
Generally, mold begins to grow within 8 to 10 days. Mold requires three things to grow a source of moisture, a food source, and to be left alone. If a water leak occurs and receives prompt attention, the likelihood of a mold problem starting is greatly reduced.
Is there an amount of mold that does not fall under the Texas Mold Assessment and Remediation Rules?
Mold impacted materials that are less than 25 square feet contiguously are not subject to the Texas Mold Assessment and Remediation Rules.
How much mold can affect my health?
There are NO specified levels of mold/fungi that are considered harmful to humans. Each individual has a different tolerance level for molds/fungi species. In addition, different geographical locations also have a wide variance of air quality levels.
Where can I find licensed firms to do the remediation work?
The TDSHS website is an excellent source of information regarding the rules and licensed firms in the area.

STC Environmental Services, inc
4754 Research Drive
San Antonio,Texas 78240
Office: 210-696-6288
Fax: 210-696-8761

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