Q: I have a question about sanding as it pertains to drywall. I know that the S520 standard does not recommend this practice, but I am preparing to assist on a job where another remediator has suggested it.

Q: How does the S520 define clean? I read an article where the author stated that the S520 defines the target for remediation success as a "return to a normal fungal ecology," and that there is not a clear definition of what is clean.

Q: When the S500 refers to 72 hours for microbial growth, is it referring to mold or bacteria and does the timeframe change if we are in a hot, humid climate?

They have had their carpets cleaned in the past with products that were labeled non-toxic and still had a reaction. How do we determine what is non-toxic?

First of all, I personally believe that heat is an effective method of solving bacterial problems in buildings. However, it is important to clarify what we mean by remediation. Both mold and sewage damage cleanup fall into this category. Let's begin with hot air drying in general and then discuss sewage (bacteria) and mold.

I recently had an adjuster tell me that he would not pay for drying that reduced the moisture content of the building below 20 percent. What would be the consequence of stopping the drying at 20 percent?

If you are following the IICRC S520 Standard and Reference Guide for Professional Mold Remediation, then your remediation project will fall into one of two categories. The first would be that the entire building is contaminated and you need an indoor environmental professional, or IEP. The second is that the building is only partially contaminated and you used an IEP to determine Conditions 1-3.

Q: I recently read that chlorine dioxide was used to remediate mold in a building. Why is it that this process is not mentioned the S520 Mold Remediation Standard?

A: Chlorine dioxide is a biocide that can be used as a gas or as a liquid. In the past, it was created by mixing either sodium chlorite or stabilized chlorine dioxide with another "reactive" chemical, generally an acid such as citric or lactic acid. According to one source, chlorine dioxide is generated for smaller applications by the reaction of sodium chlorite with chlorine, either through gaseous chlorination or the reaction of sodium hypochlorite with hydrochloric acid. The result is chlorine dioxide in a liquid or gas that smells like chlorine bleach.

Q: When the S500 refers to 72 hours for microbial growth, is it referring to mold or bacteria?

Q: In our area, there are a couple of IEPs that are not sampling as part of the post-remediation verification. They are relying on a visual inspection only and then passing or failing the remediation project. How reliable is this method of post-remediation verification?