Strategies for leaving asbestos-containing materials such as flooring, siding, roofing, or pipe insulation safely in place in or on a building.
Here we explain that where asbestos-containing materials are un-damaged and un-disturbed, usually they can and should be left in place: an approach that is both safe and economical.
Exceptions to that guide include some buildings such as schools where regulations require removal of asbestos materials.
Page top photo: vinyl asbestos floor tiles in the kitchen of a 1970's home - before the author painted over the tiles with black epoxy floor paint in 1999.
The author is a building, environmental & structural inspector and forensic microscopist. A member of ASHRAE and previously ASHI and other professional associations, he has inspected, constructed, repaired, both new and old buildings and diagnosed and has repaired building and building-related environmental problems in the U.S. since the 1970s.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
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In this article we give examples of asbestos-containing or asbestos-suspect materials in buildings that can and should be left alone, in place, perhaps with a coating or encapsulant, and we give for comparison examples of asbestos products that should usually be removed.
Asbestos is safe and legal to remain in homes or public buildings as long as the asbestos materials are in good condition and the asbestos can not be released into the air. - US EPA .
What these government experts are saying is that most asbestos-containing materials that are not friable and that are in good condition can and should be left alone, in place, perhaps covered by an encapsulant, or for flooring, covered by a layer of new flooring material.
Photo: asbestos-cement shingle siding on a 1920s home in Poughkeepsie, repaired by the author.
Asbestos cement siding or roofing is a hard cementious material. It is not friable - not easily made into dust likely to become airborne.
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The US EPA in their "Asbestos NESHAP Adequately Wet Guidance" defines "friable asbestos material" as
Friable asbestos material is any material containing more than 1 percent asbestos as determined using Polarized Light Microscopy (PLM), that, when dry, can be crumbled, pulverized, or reduced to powder by hand pressure. - (EPA p, 3)
Watch out: many InspectApedia readers have told us that they are very frightened by the presence of asbestos-suspect materials in their home. It's normal to be nervous about threats over which we feel we have no control.
But as we warn at OTHER PEOPLE's MONEY, if you sound terrified you may also make your contractor or consultant so nervous that they will spend a lot of your money (not theirs) in an unnecessary expense.
Remember that the hazard from asbestos-containing floor tiles, asbestos cement roofing or siding, and even softer asbestos pipe insulation are not like something that's "radioactive" - that is to say that if the material is not damaged, if you avoid making a dusty mess by demolition, and more, if it the material can be covered and protected from damage, it is not harmful if left in place.
Photo above: an older asphalt shingle on the roof of a New York home. This shingle as well as its felt underlayment may contain asbestos - discussed in more detail
at ASPHALT ROOF MATERIAL ASBESTOS
Excerpt from the US EPA's NESHAP guidance for demolition of building materials that may contain asbestos:
Category I material is defined as asbestos-containing resilient floor covering, asphalt roofing products, packings and gaskets. Asbestos-containing mastic is also considered a Category I material.
Photo above: a transite or asbestos-cement chimney on a New York home - discussed in detail
at TRANSITE ASBESTOS CHIMNEYS, DUCTS, PIPES
Excerpt from the US EPA's NESHAP guidance for demolition of building materials that may contain asbestos:
Category II material is defined as all remaining types of non-friable ACM [Asbestos Containing Material] not included in Category I that, when dry, cannot be crumbled, pulverized, or reduced to powder by hand pressure.
Nonfriable asbestos-cement products such as transite are an example of Category II material.
How are these two categories of non-friable ACM applied to handling them in buildings? Continuing from the US EPA's NESHAP guidance:
The asbestos NESHAP specifies that Category I materials which are not in poor condition and not friable prior to demolition do not have to be removed, except where demolition will be by intentional burning.
However, regulated asbestos-containing materials (RACM) and Category II materials that have a high probability of being crumbled, pulverized, or reduced to powder as part of demolition must be removed before demolition begins.
Watch out: Asbestos cement or "transite" materials may shed harmful asbestos dust if power-washed. Those materials should not be disturbed by demolition or sawing, etc. except by a professional remediation expert. We warn about the power washing hazard
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Photo above: the same building floor as shown at page top, after it was cleaned and then sealed with an expoxy floor paint. That floor has continued in safe daily use for over twenty-five years since the time that the author applied the sealant.
Category I non-friable asbestos-containing materials in good condition and undisturbed do not spontaneously emit harmful particles. These should be left in place.
We defined "Category I non-friable asbestos materials above on this page, followed by Category II - non-friable that are to be removed.
Photo above: vinyl asbestos floor tiles in the same 1970's kitchen as shown at the top of this page, but now twenty five years later, after having been painted over with black epoxy floor paint in 1999.
With this hard high-traffic-tolerant coating, the floor has been completely safe for more than two decades.
At ASBESTOS DEFINITION & COMPOSITION we explain that
Current best asbestos advice is to avoid the dust and mess of demolition of any asbestos-suspect product in a building if you can simply cover it with another material.
Conversely, both regulated asbestos containing materials (generally soft friable materials) as well as category II non-friable materials need to be addressed as a hazardous substance in buildings. That may mean removal in some cases (e.g. asbestos in the air path of an air handler) or removal prior to other building demolition work (both friable and category II non-friable materials).
Photo below: friable asbestos debris from damaged paper asbestos duct insulation. Unlike the intact, un-damaged asbestos floor tile case above, this is an unsafe situation deserving professional remediation.
Some asbestos materials found in buildings should be removed - always by a professional with necessary expertise and in most jurisdictions, licensing. Examples include
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Watch out: if your asbestos-containing floor looks like the one in this photograph, sealing such a floor is not a reasonable approach.
Removal of the flooring is required, and possibly the mastic adhesive needs to be removed as well.
The following U.S. EPA references include some on managing asbestos in place in buildings:
A visual re inspection of all ACM should be conducted at regular intervals as part of the O&M program to help ensure that any ACM damage or deterioration will be detected and corrective action taken.
Above: Except from EPA's Guide to Demolition Practices (for non-friable asbestos material cateogies and handling) cited below.
If the ACM is currently in good condition, increases in airborne asbestos fiber levels at some later time may provide an early warning of deterioration or disturbance of the material. In that way, supplemental air monitoring can be a useful management tool.
If an owner chooses to use air monitoring in an "early warning" context, a knowledgeable and experienced individual should be consulted to design a proper sampling strategy. (See Useful Links for more information on air monitoring, found at http://www.epa.gov/asbestos/pubs/section10.html .)
This air monitoring should supplement, not replace, physical and visual inspection. Visual inspection can recognize situations and anticipate future exposure (e.g., worsening water damage), whereas air monitoring can only detect a problem after it has occurred, and fibers have been released.
Note that the collection of air samples for supplementary evaluation should not use aggressive air sampling methods. Aggressive sampling methods, in which air is deliberately disturbed or agitated by use of a leaf blower or fans, should only be used at the completion of an asbestos removal project inside the abatement containment area.
The most accurate and preferred method of analysis of air samples collected under an O&M program requires the use of transmission electron microscopy (TEM).
Phase contrast microscopy (PCM), which is commonly used for personal air sample analysis and as a screening tool for area air monitoring, cannot distinguish between asbestos fibers and other kinds of fibers which may be present in the air. PCM analysis also cannot detect thin asbestos fibers, and does not count short fibers.
TEM analysis is more expensive than PCM analysis.
However, the more accurate information on actual levels of airborne asbestos fibers that can be derived from TEM should be more beneficial to the building owner who elects to use supplemental air monitoring in the asbestos management program.
TEM analysis is most reliably performed by laboratories accredited by the National Institute of Standards and Technology - http://ts.nist.gov/Standards/scopes/temtm.htm- and who follow EPA’s quality assurance guidelines.
(SeeReferences or Citations , U.S. EPA, Dec. 1989, Transmission Electron Microscopy Asbestos Laboratories: Quality Assurance Guidelines. Washington, DC: EPA 560/5-90-002) found at http://ts.nist.gov/Standards/scopes/temtm.htm
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Below you will find questions and answers previously posted on this page at its page bottom reader comment box.
What type of encapsulation primer/paint you think is best! Fiberlok?
Hello all, wondering what type of encapsulation primer/paint you think is best! I've seen quite a few online for sale, but having a hard time tracking any down. I see perfect prime but its not available in time for my needs.
On amazon I have found serpiex (sp) and a-b-c but they both seem to be made by the same company and I'm not sure if they are for flooring, or just insulation/soundproofing materials as stated in their literature.
Has anyone used a fiberlock brand? All this widom on here has been super helpful. On 2022-09-21 by Anonymous -
Reply by InspectApedia (mod)
@Anonymous,
Johnstone's A-B-C Primer, sold in the U.K. is a "high-performance everyday primer manufactured with acrylic resins.
The company says " It’s water-based, low odour formula means it can be used on a variety of surfaces such as plaster, cement, timber, melamine, masonry, interior stone and ceramic tiles." - this is not a primer designed specifically for asbestos encapsulation.
I found no asbestos encapsulant or sealant product under the "Serpiex" name.
Perfect Primer is an example of a suitable primer paint coating if you're going to then install a new layer of flooring over old asbestos-suspect floor tiles or over asbestos-suspect flooring mastic left on a surface after flooring has been removed.
There are quite a few other useful and recommended encapsulants for asbestos containing or suspect flooring, and other encapsulants and methods for other asbestos-containing materials such as pipe insulation.
Please take a look at the asbestos encapsulation and coating paints and sealers that we discuss in detail atASBESTOS ENCAPSULANTS & SEALERS - coatings, encapsulants, fiber release control for asbestos containing materials
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