Thermal System Insulation (TSI)

Thermal system insulation is the regulatory name for insulation on pipes, fittings, boilers, tanks, ducts and similar equipment, used to keep heat in or out. Before the late 1970s it often contained asbestos, and it is one of the main sources of asbestos exposure for insulators, pipefitters, boiler workers, shipyard workers and maintenance crews.

Origin

The term comes from EPA's AHERA regulations for schools and OSHA's asbestos standards of the 1980s, which sort asbestos-containing building materials into thermal system insulation, surfacing material and miscellaneous material. The products themselves include pipe covering, block insulation, insulating cement and wrapped or molded coverings used for decades before.

Significance in Asbestos Context

Asbestos TSI was usually friable, meaning it could be crumbled by hand, and installing, cutting, repairing or tearing it out released large amounts of dust. Insulators who applied it, and the pipefitters, electricians, boilermakers and other trades working beside them, are among the groups with the highest rates of mesothelioma and asbestosis. Because so many companies made TSI products, claims often depend on identifying which brands were used at a site, through coworker testimony, purchase records, and product lists. Many former TSI makers went bankrupt and now pay claims through asbestos trusts. OSHA treats removal of TSI as Class I work, its highest-risk category, and buildings built before 1981 must assume such insulation contains asbestos unless tested.

Example Sentence

The ship's engine room was packed with asbestos thermal system insulation on the steam lines, and he spent years working within feet of insulators cutting and fitting it.

Related Terms

Pipe Covering, Boiler Insulation, Insulator, Calcium Silicate Insulation, Surfacing Material, Presumed Asbestos-Containing Material (PACM), OSHA Class I–IV Asbestos Work, Product Identification

Notes

• Brand names, colors, packaging and the trades who installed insulation all help identify products; write down what you remember.
• Many TSI makers' trusts list approved job sites; ask your lawyer whether your workplaces are on them.
• Leave old pipe and boiler insulation alone; have it tested before any repair or removal.