Mold Inspection

Do you know that if you are taking air samples for a mold inspection, and if they have air scrubbers on during that time, are you supposed to turn them off or are you supposed to leave them on?

Air scrubbers should be turned off at least one hour before a clearance test.

I thought so. The remediation company said that I had to leave them on though.

Do you know where it is stated in the IICRC book?

The scrubbers cannot run during air testing. The only air movement that is allowed is with the blower on the furnace running. That is considered the worst the air gets stirred up normally. You should be testing under normal conditions. Normally the air scrubbers should be turned off at least 24 hours before testing. The mold remediation protocol will state how much time the air scrubbers need to be turned off. There are newer studies that show mold spores settle out way before 24 hour but since very few remediators read studies, most assessors use the old 24 hour rule, so not to confuse the remediator. Different mold species contain more concentrated microtoxins, than other species. The more concentrated the mycrotoxin, the heavier the mold spore is, thus the settling of happens more quickly. If you ever have any mold questions, or just need help interrupting the lab results, please feel free to give me a call at 573-761-3581.

Actually, studies show some mold spores stay sudpended in the air for over six hours.

I am pretty sure that it is not stated in the IICRC S520, 2nd edition. The asseesor determines when the air scrubbers get turned off. The 3rd edition just came out, so I have not read it yet. The remediation protocol will state whst standard was used. If there is no protocol written, I would not take on the liability of the clearance testing.

Don’t know if it’s in the S520, but NORMI has a standard for PRV.

(9) Post-Remediation Verification (PRV) Procedures and Criteria—in the MRP for the project, the assessor shall specify:
a. The method by which the remediation is deemed complete and adequate;
b. The criteria to be used for evaluation analytical results to determine whether the
remediation project passes post-remediation verification;
c. The PRV shall be conducted while walk-in containment is in place, if walk-in
containment is specified for the project, and the air scrubber shall have been sealed and
turned “off” for one (1) hour prior to the PRV assessment sampling. Air scrubber should
be turned “on” immediately following the sampling