Asbestos and Drywall Systems

Author: Pacific Northwest Inspections Group, LLC   Date: 19-Aug-2015.   Category: Asbestos   Add to Favorites 


Is the The point Count "Loop Hole" Sampling best for an AHERA Survey?


AN AHERA inspector MUST use the strictest of the requirement set by the State, Local, EPA or Clean Air Act


Joint Compound/Wallboard

When joint compound and/or tape is applied to wallboard it becomes an part of the wallboard and in effect becomes one material forming a system. Therefore, where a demolition or renovation impacts such a wall system, a composite analysis of the wall system (percent of asbestos in the joint compound, tape and wallboard) should be conducted. If the analysis shows an asbestos content of greater than one percent and at least 160 square feet of the wall system is involved in the demolition or renovation activities (whether planned or unplanned, during a calendar year), then the activities would be subject to the asbestos NESHAP.

First, a sample in which no asbestos is detected by polarized light microscopy (PLM) does not have to be point counted. However, a minimum of three slide mounts should be prepared and examined in their entirety by PLM to determine if asbestos is present. This process should be carefully documented by the laboratory.

Second, if the analyst detects asbestos in the sample and estimates the amount by visual estimation to be less than 10%, the owner or operator of the building may (1) elect to assume the amount to be greater than 1% and treat the material as asbestos-containing material or (2) require verification of the amount by point counting.

Third, if a result obtained by point count is different from a result obtained by visual estimation, the point count result will be used.