Asbestos-Containing Material Identification and Assessment
Categories and condition
Assessments classify material as surfacing (sprayed-on or troweled fireproofing/acoustical), thermal system insulation (TSI), or miscellaneous, and as friable (crushable by hand pressure) or non-friable. Friability, condition (intact versus damaged), accessibility, and vulnerability to air or water erosion drive the hazard rating and the required response action.
Inspection and sampling
In NYC the survey is performed by a DEP-licensed asbestos investigator. NYS Rule 56 and NESHAP presume suspect materials to be ACM until sampling proves otherwise. Bulk samples are analyzed by polarized light microscopy with dispersion staining; the definition of ACM is 1% or more asbestos by weight, and results near that line should be confirmed by point counting (400 points) or gravimetric methods, with TEM/SAED available for verification. Collect enough samples per homogeneous area - a common rule is at least three, with more when layers separate or results disagree - and never composite samples across different homogeneous areas.
The report
A usable survey identifies each homogeneous area with material type, quantity (linear or square feet), location, condition, accessibility, and layer-by-layer analytical results. That inventory sets quantities for notification, cost estimates, and the abatement specification or design.
Traps
- Confusing percent by weight with percent by area.
- Treating “under 1%” as automatically safe without confirming the analysis.
- Forgetting that demolition, renovation, or disturbance of presumed material requires handling it as ACM when sampling is not feasible.
- Mixing up an investigator's bulk survey with post-abatement clearance, which is air sampling.
Rule of thumb: three bulk samples per homogeneous area, sampled layer by layer, and anything presumed rather than sampled is treated as ACM.