»

Lagging: Adhesive, Cloth and Tape

Lagging is an insulating material which is used to cover plumbing and boiler components and heavy equipment parts, to both contain and reserve heat and to prevent scalding and other injury from contact with heated components. Lagging is commercially available in three forms: as an adhesive, and as a woven material in lagging cloth and lagging tape. Used individually and in combination, these versatile materials are prevalent in many commercial and residential buildings, and comprise an essential component of effective plumbing and heating systems. One of its most common uses is as a sealant at the juncture of heating ducts, where it is installed to close gaps and keep heated, flowing air contained within the ductwork.

Lagging materials and asbestos

As with many products which were manufactured to be used in situations where heat retention was a prime concern, lagging materials were for years embedded with asbestos fibers. Offering high insulative value and both heat and corrosion resistance, asbestos seemed the ideal fiber to use to give lagging materials the added qualities to make it an even more effective construction material.

It all sounded good. However, what manufacturers and construction workers did not know was that asbestos added something more than efficient insulation to the lagging materials they routinely processed and applied. It also added the deadly risk of asbestos contamination, including the risk of mesothelioma and other cancers. When first applied in its pristine, semi-moist or tacky state, the asbestos in lagging products posed no problems. But over time, as the material was exposed to the drying effects of warm air or water, the lagging materials begin to break down, releasing tiny fibers of asbestos to the surrounding air. That danger is compounded by the air currents flowing through the ductwork, which may come in contact with loose and degraded lagging material, filling air ducts with potentially deadly fibers. And it can also pose a serious health risk any time renovation or upgrading of structural systems takes place, in both residential and commercial settings. Although legislation made it illegal to add asbestos to these products in 1977, existing stocks were not depleted until the mid-1980s, meaning any building constructed prior to those years presents a potential hazard.

Last modified: December 09 2009.