Asbestos - Asbestos Air Monitoring Requirements - EH: Minnesota Department of Health

Asbestos Air Monitoring Requirements

Who can perform asbestos air monitoring?

You must meet the following qualifications to perform air monitoring for an asbestos-related work project in Minnesota:

  • The Minnesota Department of Health (MDH) must license your company as an asbestos contractor.
  • You must be certified as an asbestos worker or supervisor by the MDH. A site supervisor from your company must be present while any workers perform air monitoring.
  • Any site supervisor or worker whom you do not directly employ, but who are independent contractors, must be certified and licensed by MDH.

You must also:

  • have completed a Minnesota 2-Day Asbestos Air Sampling course; or
  • be a certified industrial hygienist (CIH); or
  • have completed a National Institute for Occupational Safety and Health (NIOSH) 582 course or an equivalent course (582E) before July 1, 1996.

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When is asbestos air monitoring needed?

Indoor air monitoring must be performed during every asbestos-related work project. Air sampling must be performed during work area preparation if asbestos materials will be disturbed during the preparation. Demolition projects that are occurring according to Minnesota Rules, part 4620.3585, also known as "The Demolition Rules", have special air monitoring requirements. Please see the "Demolition and Asbestos" website.

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What about preliminary air monitoring?

If you suspect elevated fiber levels in the area where asbestos work is going to be performed, you have the option of taking five preliminary air samples to establish an alternative indoor air standard. These preliminary air samples must be taken before any other asbestos-related work begins, including area preparation. The samples must be taken within ten feet of where the work area will be. An alternative indoor air standard can be established for full containment, glove bag or mini-containment work. Each full containment needs a separate alternative indoor air standard. For glove bag or mini-containment operations, you may establish an alternative indoor air standard in each room, or in some industrial facilities, each 15,000 square foot area of floor space. The analytical results of at least one sample must be greater than the Minnesota indoor air standard, 0.01 fibers per cubic centimeter (f/cc), in order to establish an alternative indoor air standard.

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Where do I need to collect air samples during asbestos work in a full containment?

You need to collect a minimum of two air samples, simultaneously outside of each containment, for each zero to five-hour period. One of these two air samples must be within 10 feet of the entrance to the decontamination unit. The other air sample must be within 10 feet of the containment. You will need another sample, every four hours, to monitor the negative pressure exhaust, if it is being vented indoors. The analytical results of these samples must be less than or equal to 0.01 f/cc or the alternative indoor air standard, if one has been established.

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What clearance air sampling is needed in a full containment?

Before any clearance air sampling may take place in a full containment, the asbestos contractor performing abatement must remove all walls and floors and the containment must pass a visual inspection. Critical barriers must remain in place, negative pressure must be maintained and the worker decontamination unit must also remain in place and be operational until final clearance is achieved. For regulated non-residential projects, you need to collect five clearance air samples in the containment. For residential projects, you need to collect three clearance air samples. You must select air sampling sites at random. Air sampling must also be performed in an aggressive manner using a leaf blower and stationary fans. You need to have one fan for every 10,000 cubic feet of containment area. You must decontaminate all air sampling equipment, including fans and leaf blowers, before you remove them from the containment. The analytical results of clearance air sampling must be less than or equal to 0.01 f/cc or the alternative clearance standard. If the samples are analyzed by transmission electron microscopy (TEM), the analytical results must be less than or equal to 70 structures per square millimeter (s/mm2). If these standards are not met, the containment must be re-cleaned and another set of final air clearance samples must be collected.

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Is air sampling needed during a glove bag or mini-containment operation?

You need two air samples in each room during work with glove bags or mini-containments. These air samples need to be collected within 10 feet of the glove bags or mini-containments. The analytical results of these air samples must be less than or equal to 0.01 f/cc or the alternative indoor air standard, if one has been established, before these areas can be reoccupied. In the event that the air samples collected during the glove bag or mini-containment operation are above 0.01 f/cc, a process of cleaning and resampling must be started in the area until the clearance standard is met. This is described in Minnesota Rules, part 4620.3592, subpart 5. Five clearance air samples must be taken inside of a mini-containment if the mini-containment cannot be collapsed using a high efficiency particulate air (HEPA) filtered vacuum.

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Who can analyze air samples?

Air samples must be analyzed by phase contrast microscopy by:

Air samples, analyzed by transmission electron microscopy, must be analyzed by:

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How do I find out more information?

For more information about asbestos, contact the Asbestos Program at MDH through the internet or by telephone at (651) 201-4620.

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Updated Monday, March 05, 2018 at 08:16AM