Air Cell insulation is both a brand name for a specific type of insulating material and a generic term. Resembling gray corrugated cardboard, air cell insulation is frequently and effectively used to wrap steam pipes, HVAC ducts and furnace systems. This material is available in several different thicknesses, and is sold in sheets measuring about three feet in length, with different widths based on the type of pipe or ductwork to be covered.
Prior to the mid 1980s, air cell-type insulation was manufactured with asbestos; and in addition it was (and in some cases, continues to be) affixed to the pipe surfaces with asbestos cement. This type of insulation may also be found held in place with metal bands such as hose clamps.
Air cell insulation becomes friable as it ages and deteriorates. A material is defined by the EPA as “friable” if it can be crushed and reduced to a powder by using hand pressure alone. Air Cell insulation that is friable has the potential to spread millions of microscopic asbestos fibers into the air. Once breathed into the lungs, these fibers may injure the inner surfaces of the alveoli, or air sacs, causing the build-up of scar tissue. Ultimately, this results in the condition known as asbestosis, and is associated primarily with chrysotile, or “white” asbestos—a softer and more common variety.
Some types of air cell insulation may contain the hard amphibole variety of asbestos, such as crocidolite, or “blue” asbestos. These fibers literally bore through lung tissues from the inside out, causing cellular mutation as they do so, and resulting in the cancer known as mesothelioma.
In either case, old, deteriorating air cell insulation presents a serious health hazard, particularly when it is found in and around HVAC systems. Several school districts and university websites have photographs of this material (see Sources) to assist contractors and maintenance workers in identifying this material. Old air cell insulation should only be removed by trained, certified asbestos abatement personnel. If the building in question is open to the general public, EPA regulations and the federal Clean Air Act, as well as numerous state and municipal codes, require that such work be performed only by licensed asbestos contractors. Building owners who attempt to do this on their own or hire unlicensed, untrained personnel can be charged with a felony and can face fines of up to $250,000 and prison terms of up to five years.