Glossary
TSI
Also: Thermal System Insulation
Insulation on pipes, boilers, tanks, ducts, and similar components to control heat transfer or condensation. One of AHERA's three asbestos material categories, and a frequent location for friable asbestos.
Thermal system insulation (TSI) is material applied to pipes, boilers, tanks, ducts, breechings, and other structural components to prevent heat loss or gain, or to control condensation. Pipe lagging, block insulation, and cement on fittings are common forms.
TSI is one of the three material categories AHERA defines, alongside surfacing material and miscellaneous material. In buildings constructed before the 1980s it is one of the most common places to find asbestos, and damaged TSI is frequently friable.
Removal of asbestos TSI is generally Class I work under OSHA 1926.1101 — the most stringent category — because the material is friable and high in asbestos content.