Larry Robertson – IAQA’s First President

Air Date: 2-15-2013| Episode: 274

This week we will have a discussion of Post-Remediation Verification (PRV) on Mold Remediation Projects with Larry Robertson, the Indoor Air Quality Association’s 1st President and founding board member…

Full Description:

This week we will have a discussion of Post-Remediation Verification (PRV) on Mold Remediation Projects with Larry Robertson, the Indoor Air Quality Association’s 1st President and founding board member. Mr. Robertson has been a leader in IAQ research and services for over 2 decades. He is known for establishing Mycotech Biological, Inc. (MBI), one of the first environmental laboratories that specialized in the identification of fungi and their association with HVAC systems. He is currently preparing for a presentation on PRV at the IAQA Conference March 27- Feb. 1, 2013 in Orlando, Florida. We look forward to discussing his experience with PRV in the early days of the mold rush, standards and guidelines that have influenced PRV over the years and current thoughts on PRV.

Z-Man’s Blog:

Post Remediation Verification, we must find better way

As a pioneer in the science of mold sample analysis, Larry Robertson discussed the subject of Post Remediation Verification on today’s episode of IAQradio. There is and always has been a need for definitive guidelines on when a mold remediation project was performed satisfactorily and was considered complete. A common method of PRV involves comparison of outdoor air samples to indoor samples in the areas remediated, with the goal of the air indoors being found to be equal to or cleaner than the air outdoors. Under this scenario the clearance criteria fluctuates up and down on a daily basis. Larry offered examples demonstrating that the success or failure of a project can be dependent upon levels observed in the outdoor air.

Nuggets mined from today’s broadcast:

• The need for PRV was driven by risk management and liability reduction concerns.

• The specific comparison of samples of outdoor air to indoor air is a flawed method for Post Remediation Verification on mold remediation projects.

• Some PRV recommendations are outrageous and unattainable.

• Every remediation project done by professionals should undergo some type of PRV.

• Lab pocket reference guide available on state-by-state basis show Stachybotrys is commonly found in outdoor samples.

• Aspergillus versicolor common in indoor samples of non-water damaged

• Important components of PRV: sensory evaluation/inspection, free from settled dust, cause of the event corrected, water activity of building materials returned to pre-loss levels.

• Most remediation guidelines and standards provide remedial recommendations and do lack recommended specifics of PRV.

• A standardized approach to PRV is needed. Accepted and uniform method of practice.

• Spore trap cassettes have serious precision issues. Lab’s can provide a precision statement on each sample analyzed.

• Citing the use of carbon dioxide as a surrogate for appropriate indoor ventilation, he recommends the use of a particle counter as a surrogate for mold spores within containments. Use of a particle counter to measure particles in the 1-5 micron range indoors and outdoors can provide a contractor with live real time information on which to base decisions.

• There needs to be differentiation in PRV between routine and common projects and unusual and uncommon projects such as operating theatres and ICUs

• To prevent cross contamination, contractors needs to determine that the air within a containment will not have a negative effect on the project when containment is removed and equilibrium occurs.

• Larry is “NOT a proponent of turning AFD’s Off before PRV sampling”.

• Existing tools such as particle counters are becoming more affordable.

• ATP sampling has a place, it is less discriminating on fungi and may miss dead fungi.

• New tools. Portable water activity meters and a chitanase samplers which more accurately detects fungi are available.
Today’s: audio trivia question, “Trust but verify”, YouTube
Today’s Music: “Check on it,” by Beyonce

Z-Man signing off


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