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Asbestos – How Many Samples are Right?

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At RPF Environmental, we encounter customers that are confused and frustrated by different information they receive from inspection companies regarding the amount of sampling required. This begs the question, “How many asbestos samples is the right amount?” Too few samples can get you in trouble, too many can needlessly chew up your budget. In this blog, we explore the requirements for asbestos sampling.

Contact RPF Environmental now for affordable asbestos testing and inspection services in the New England region and beyond! We offer customized solutions to meet your specific needs.

About Asbestos

Historically, asbestos was used in a wide array of applications due to its resistance to heat and corrosion and its durability. Once it became clear that asbestos at any level of exposure is harmful to humans, laws were put in place to reduce people’s contact with this hazardous substance. This includes partially banning its production, laws about safe management and construction practices, and improving awareness of its presence. Asbestos remains in buildings that existed prior to the origination of these rules and it is still available in some products on the market.

Beware of the fox watching the henhouse and take more than one bite of a chocolate chip cookie!

When is Asbestos Sampling Required?

Renovation or demolition of buildings, or any other activity that might disturb suspect asbestos-containing material requires an inspection by certified individuals to inform work practices that must be followed. Sometimes, OSHA requires these inspections regardless of the activity, and EPA requires periodic inspections for K-12 Schools.

Who Performs Asbestos Sampling?

Many of us have heard the term “the fox watching the henhouse.” It comes into play with asbestos inspections when the abatement contractor companies think to do their own testing. The EPA has a conflict-of-interest requirement that consultant firms independent of the abatement contractor complete the inspection in schools. Additionally, states require that the individuals conducting the asbestos assessment obtain the proper certification and licensure.

Sampling should only be completed by an experienced testing firm, ideally with a Certified Industrial Hygienist (CIH) on staff, and the company should show proof of professional liability (errors & omissions) insurance coverage.

Asbestos Sampling Requirements & Rules

During an asbestos assessment, the EPA, along with other regulatory agencies (it varies by location), requires that each homogeneous group of suspect asbestos-containing material be inventoried and categorized. This involves items that are of different types, colors, and sizes. A certified inspector must then collect separate sets of samples from each type of material or assume that the material contains asbestos.

Here is an overview of how those samples should be categorized and taken:

  • The “Miscellaneous” category includes such products as flooring, ceiling tile, caulking, mastics, wallboard, shingles, glazing, grout, etc. From this category, two to three samples of each homogenous group are typically required. Some states require at least three samples.
  • The “Thermal Systems Insulation” category includes materials that are put around products such as boilers, pipes, ducts, or tanks to avoid heat loss. For this category, three samples are typically required of each group except for small quantity patches.
  • In the “Surfacing” materials category, materials that have been sprayed on or otherwise applied to surfaces such as those for acoustical or fireproofing purposes are included. Even more sampling may be required depending on the volume of material that has been applied and may include up to nine random samples per group.

If you are wondering why more than one sample needs to be taken of a homogenous group, consider the chocolate chip cookie analogy. When you bite into a chocolate chip cookie, you might not actually get a chocolate chip, or you might get several. The same is true with asbestos-containing material – you may or may not get what you are looking for with just one sample due to the manufacturing process or limitations of analytical methods.

To add to this, depending on the types of material there may be a need for different types of analysis and analytical tools to meet all the regulatory requirements and latest industry standards. One thing is for sure, if your inspection firm also completes the asbestos removal work, and they only take one or two samples of all the materials, you may have a problem.

The rules discussed above are just an overview. In the end, it truly takes a qualified, accredited inspector from an independent firm to know what is right for asbestos sampling. Requirements can also vary by state and for some materials, it really requires an experienced professional to ensure proper sampling methods and numbers of samples. It is never really possible to determine the exact number of samples required until the entire inspection process has been completed.

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How many asbestos samples do I need?

Two to three or more samples are usually taken for each homogenous group depending on the type of material being tested, area covered, and local or state laws. Only a professional will know how many samples are right to ensure accurate tests and assessments.

What is the sampling method for asbestos?

This depends on the sampling method: air sample testing or bulk sampling. For bulk sampling, Polarized Light Microscopy (PLM) is done while Phase Contrast Microscopy (PCM) is used for air sampling.

How big does an asbestos sample need to be?

Some recommend a quarter size and others up to two square inches. A certified asbestos inspector will know what sample size is sufficient to make sure that the sample is representative of the parent material.

How do you sample asbestos drywall?

We recommend taking samples from the drywall seams (the point where two pieces of drywall are joined together). It is best to collect up to three samples from a couple of areas and then place them in separate airtight containers.

Questions About Asbestos Sampling Methods & Requirements?

RPF Environmental has thirty years of experience with asbestos inspections. Our expertise with the applicable regulations, knowledge of how to assess an environment and the materials within, and solid practice with sampling techniques allow us to hold strong to our philosophy of providing the most efficient services possible while meeting the appropriate regulatory needs of our clients. Click here to learn more about our asbestos services.

Call us at 603-942-5432 today to find out how RPF can support your industrial hygiene control program.

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