About Asbestos-Containing Materials (ACM)
What the exam tests
This domain checks whether you can classify a material as ACM or RACM, recognize the six regulated fiber types, and apply friability and category rules before work begins.
Core rules and concepts
- ACM means any material containing more than 1% asbestos by weight, determined by an accredited laboratory using PLM with dispersion staining. A result of 'none detected' or 'trace' is not the same as ACM.
- Regulated fiber types are chrysotile, amosite, crocidolite, tremolite, anthophyllite, and actinolite. Chrysotile is the most common in Indiana buildings; amosite appears in older pipe insulation and ceiling tiles.
- Friable means the material can be crumbled, pulverized, or reduced to powder by hand pressure when dry. RACM is regulated asbestos-containing material and includes friable ACM and nonfriable ACM that will be or has been crumbled, ground, or cut.
- NESHAP categories: surfacing material (sprayed-on or troweled-on ceilings, walls, structural members), thermal system insulation (pipe, boiler, duct insulation), and miscellaneous material (floor tile, mastic, gaskets, roofing, cement products).
- Nonfriable categories: Category I includes packing, gaskets, resilient floor covering, and asphalt roofing products; Category II includes all other nonfriable ACM.
Worked example
A contractor finds a pipe elbow with 2% chrysotile by PLM. It is TSI, friable, and therefore ACM and RACM. Removal triggers NESHAP work practices and, if the project exceeds 260 linear feet, Indiana notification. If the same material were a gasket containing 2% chrysotile and remained intact, it would still be ACM but might be Category I nonfriable and outside certain work-practice requirements unless cut, sanded, or ground.
Traps
Do not treat 1% as a de minimis threshold; do not assume nonfriable material is exempt if it will be damaged. Do not confuse ACM with RACM. In schools, PACM (presumed asbestos-containing material) must be treated as ACM until sampled.