Tool Box Talk: Air Monitoring

1. Tool Box Talk:Air Monitoring -James Kaphusman

2. 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.

3. 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.

4. 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.

5. 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.

6. Sources of Fumes

7. Sources of Fumes Sewage is another example of a product that just creates toxic fumes.

8. 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.

9. 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%

10. 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)

11. 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 worker’s 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.

12. Diffusion Tubes Diffusion tubes are typically worn on a worker’s 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.

13. 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.

14. 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.

15. Vapor Monitor Badge VMBs are worn on the worker’s 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.

16. 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.

17. 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.

18. 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.

19. 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.