Glossary
ACBM
Also: Asbestos-Containing Building Material
Any material in a building that contains more than 1% asbestos by weight, as defined by AHERA.
ACBM is the AHERA term for any building material that contains more than 1% asbestos by weight, determined by polarized light microscopy (PLM) under the methods AHERA specifies.
The 1% threshold is what makes a material an ACBM at all. Below it, the material is not regulated as asbestos under AHERA. Above it, the material is subject to the rule’s inspection, management plan, and abatement requirements (when work in a school will disturb it).
ACBM includes surfacing materials (sprayed-on or troweled-on), thermal system insulation (pipe, boiler, tank, duct insulation), and miscellaneous ACBM (floor tile, ceiling tile, roofing, siding, joint compound, mastics).
Not every ACBM is also a RACM. RACM is an EPA NESHAP term for ACBM that is friable, or has become friable, or has been crumbled, pulverized, or reduced to powder by the forces of demolition or renovation.