Forms of Asbestos Commonly Found in Homes
Asbestos materials were used in many building materials starting at the turn of the 20th century (1900's) when industry became available to mine it as a mineral and refine it as a fiber to be used in hundreds of applications.
An asbestos inspection is meant to identify those materials in a household and determine if there is a risk associated with the content and form of asbestos. As you know, asbestos is linked with causing cancers and disease with a strong correlation to occupational exposure (exposure through mining, refining, or installation activities). There is no good data regarding incidental exposure of asbestos fibers in a residential setting, but we do know that identifying and limiting exposure through prevention is the best course of action.
The following are common building materials which may contain asbestos and their characteristics relative to exposure:
Floor tile: Installed from 1930's to 1960's vinyl floor tile is the most common form found in housing. It usually is identified as a 9 inch square tile with a low concentration of asbestos bound up in a matrix of vinyl (some larger tiles are also suspect). The mastic or glue which was used also typically contains asbestos. This is a relatively low risk material given the form and durability and can be left in place if it's in good condition.
Pipe Wrap Insulation: Installed
mainly in the 1920's through 1950's. This is a thermal system insulation usually found on heating system pipes associated with boilers. Often older boilers are also insulated with an asbestos jacketing material. The asbestos content in these materials is usually high with a typical content of 40% to 60%. This material is also easily disturbed and will produce airborne fibers with hand pressure. When in poor condition, this material is usually removed with abatement methods.
Duct Connectors: This is a textile form of asbestos often overlooked or unrecognized as an asbestos material. It is found as part of a duct manifold system which connects an HVAC unit to the rest of the duct work. It is literally part of the duct where the air stream flows across it. It was meant to allow of connecting and isolating vibration. The risk is difficult to define although the fibers are usually tightly bound in the textile fabrication and not often considered to be high risk.
Structural Blown-on insulation: This is the worst kind of material to encounter given it is loose and easily disturbed. It is often found in commercial buildings or larger apartment buildings (the World Trade Center in NY City had this insulation on the structural steel). It is usually of very high concentration of fibers 50% to 80% and goes airborne by simple contact. This material is rare to find in single family households. Larger apartment buildings built in the 60' and 70's often have this applied to the structural steel.
Other forms to consider: Here is a list of other forms of asbestos commonly found in households:
- Transite board- A hard cementious board often installed on walls surrounding boilers
- Duct Canvass- A paper-like covering used to cover metal ductwork.
- Exterior Shingles- Hard cementious siding found on many neighborhoods in northern states.
- Asbestos Duct Pipe- Found embedded in concrete slabs, this material gas a textile core impregnated with cement and is was used to duct air through slabs of concrete.
Let us know if you are interested in knowing what you have in your home. The time to know is especially important prior to major renovations or changes to older heating and HVAC systems.
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