Tool Box Talk: Air Monitoring

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Tool Box TalkAir Monitoring

• -James Kaphusman

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Why is it important?

• Air monitoring is very important for the safety
  and well-being of workers in toxic or confined
  areas.
• Between 1996-2005, an average of just more than
  7,000 people have died per year as a result of
  noxious fumes.

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Sources of Fumes

• These toxic fumes can come from a variety of
  sources. Many of these sources are products that
  you can find in a common household.

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Sources of Fumes

• Some sources of toxic fumes are chemicals such
  as asbestos, bleach, chlorine, paint, kerosene,
  paint thinner, pesticides, etc.
• Many of these sources can usually be found at
  construction sites also.

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Sources of Fumes

• Toxic fumes do not just come from chemicals.
  Some products will produce toxic fumes as they
  are heated, in acts such as welding. These may
  not be an issue when the area is well ventilated,
  but in a confined space, these toxins become can
  become deadly. Space heaters are a common source
  known to produce deadly levels of carbon
  monoxide, an odorless killer.

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Sources of Fumes
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Sources of Fumes

• Sewage is another example of a product that just
  creates toxic fumes.

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Sources of Fumes

• Toxic fumes do not just come from chemicals or
  products. Sometimes toxic fumes arise from a
  natural situation. For example, many times in
  confined spaces, the air quality can drop to
  unsafe conditions as a result of the worker just
  using up the available oxygen in the confined
  space. The air in that confined space may have
  never even been safe enough for use in the first
  place.

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OSHA Regulations

• OSHA code 1926.800 (j)
• OSHA requires the monitoring of airborne
  contaminants as often as necessary depending on
  the location of jobsite, geology, previous
  history of contaminants from nearby worksites,
  and work practices that may be occurring nearby
  (running of a diesel engine).
• Oxygen levels must be kept between 19.5-22

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Equipment

• There is a wide variety of equipment used to
  monitor the air quality.
• Most air monitors are created to detect a
  specific toxin in the air.
• There are two standard tests for airborne
  contaminants Time Weighted Average (TWA) or
  Short Term Exposure Limit (STEL)

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Tests

• TWA is the average amount of time that a worker
  is exposed to adverse conditions based on an
  average 8 hour day and 40 hour week, as stated by
  OSHA. This is calculated by usually taking a
  continuous sampling of the workers area over the
  8 hour period
• STEL is a 15 minute TWA that cannot be exceeded,
  even if the 8 hour TWA is below standards. This
  test is usually performed when the toxins are
  known to be short-term hazards.

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Diffusion Tubes

• Diffusion tubes are typically worn on a workers
  lapel, right near their breathing area. These
  tubes are lined with a chemical reagent that
  discolors the tube as it reacts with certain
  airborne toxins. When the worker is done, all
  they need to do is check the extent of the
  discoloration by looking at the tick marks on the
  diffusion tube.

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Diffusion Tubes

• Diffusion tubes are good because they can give an
  instant reading of the air quality. They also
  can be used for both TWA and STEL tests.
• They are not the most accurate way of sampling
  and sometimes can be affected by other chemicals
  in the air.

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Detector Tubes

• Detector tubes are similar to diffusion tubes.
  Instead of being worn on a worker, these are
  little pumps that are used to sample the air.
  Some are read the same way by the markings on the
  side, others look at the amount of pumps that it
  may take the tube to get to a certain color.
  This again gives both the TWA and STEL.

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Vapor Monitor Badge

• VMBs are worn on the workers lapel just like
  diffusion tubes. After the worker is exposed to
  the toxin, the badge is sent to a lab to be
  analyzed. At the lab, they open up the center of
  the VMB and analyze the sample of air collected.
  These tests are more accurate than the detector
  and diffusion tubes, and they also perform both
  the TWA and STEL. However, they need to be
  analyzed by a lab, and are therefore not instant.

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Personal Sampling Pumps

• A personal sampling pump continuously pulls a
  certain amount of air through a special tube,
  usually clipped onto the workers lapel area.
  These specialty tubes are lined with charcoal.
  Some pumps do not have a special tube, they
  instead pull the air through a cassette. Either
  the cassette or tube is then sent to a lab to be
  analyzed.

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Personal Sampling Pumps

• This test can again give both the TWA and STEL,
  but it again needs a lab to do the analyzing.
• These tests can also be very accurate, but the
  pump speed must be precisely set to detect a
  specific toxin, and these can also be very
  cumbersome.

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Electronic Monitors

• There are basically two different types of
  electric monitors hand-held and fixed.
• The main difference is that hand-held monitors
  are carried around by the workers, or a safety
  person and used to sample the area, while a fixed
  monitor is permanently set up at certain
  locations.

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Electronic Monitors

• Electronic monitors are the best for instant
  sampling of an area. They give accurate readings
  of real time situations. Sometimes, as with all
  air monitors, other airborne particles may give
  false readings. Monitors are also typically
  calibrated for one specific toxin, thus a
  competent operator is needed to analyze false
  readings. These can give both the TWA and STEL
  again.