Asbestos in Calcium Silicate Insulation

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Today’s calcium silicate insulation is asbestos-free and provides fire-resistant insulation practical for a wide variety of construction applications. However, this was not always the case.

Calcium silicate insulation used for pipe lagging once contained asbestos, making it strong and durable. This was a common practice until the mid-1980s, meaning that older structures are likely to contain some of this type of insulation, most likely surrounding steam pipes, but it was also available in sheets used in walls and between ceilings and floors.

Despite their durability and strength, asbestos-containing materials are prone to become brittle and deteriorate as they age. In this condition, also known as friable, materials can be reduced to powder with the use of hand pressure alone. Friable asbestos is far more likely to release microscopic fibers that can be inhaled and cause tremendous damage to the respiratory system.

At its worst, asbestos disease becomes a form of cancer, either as mesothelioma, or cancer of the pleural lining, or in the lung tissue itself. The variety of asbestos known as amphibole–meaning crocidolite (“blue”), amosite (“brown”), or tremolite–consists of microscopic needles that bore through lung tissue from the inside out. Medical researchers have yet to discover exactly how it works, but they do know that amphibole fibers interact with living cells on the DNA level, causing them to mutate and become malignant.

The other form of asbestos, chrysotile (“white”) asbestos, was used in about 95 percent of all building materials containing asbestos. The fibers are softer than amphiboles, but just as dangerous: they cause tiny abrasions on the inner surfaces of the lungs, resulting in the build-up of scar tissue that reduces lung capacity over time. Known as asbestosis, the condition causes the person to suffocate. The good news is that the disease’s progression can be stopped by taking the sufferer out of the asbestos-containing environment or removing the asbestos itself.

There is no way to tell whether calcium silicate insulation contains asbestos simply by looking at it–a small sample must be sent to a laboratory for testing.