Additional Definitions from Occupational Safety and Health Administration
"Homogeneous area" means an area of surfacing material or thermal system insulation that is uniform in color and texture.
"Industrial hygienist" means a professional qualified by education, training, and experience to anticipate, recognize, evaluate and develop controls for occupational health hazards.
"PACM" means presumed asbestos containing material.
"Presumed asbestos containing material" means thermal system insulation and surfacing material found in buildings constructed no later than 1980. The designation of a material as "PACM" may be rebutted pursuant to paragraph (j)(8) of this section.
"Regulated area" means an area established by the employer to demarcate areas where airborne concentrations of asbestos exceed, or there is a reasonable possibility they may exceed, the permissible exposure limits.
“Surfacing ACM" means surfacing material which contains more than 1 percent asbestos.
"Surfacing material" means material that is sprayed, troweled-on or otherwise applied to surfaces (such as acoustical plaster on ceilings and fireproofing materials on structural members, or other materials on surfaces for acoustical, fireproofing, and other purposes).
"Thermal System Insulation (TSI)" means ACM applied to pipes, fittings, boilers, breeching, tanks, ducts or other structural components to prevent heat loss or gain.
"Thermal System Insulation ACM" means thermal system insulation which contains more than 1 percent asbestos.
Courtesy of OSHA