By Tim Turney According to estimates from the International Labor Organization, one worker dies every 30 seconds from exposure to toxic chemicals, pesticides, and other hazardous substances. Of 160 million cases of work-related disease reported, 35 million are due to chemical exposure, a rate of around 21.9 percent. With over 100,000 different chemicals in use in industries across the globe, correct monitoring and reporting procedures have perhaps never been more vital in ensuring worker safety and legal compliance.  It is understood that high chemical concentrations can pose an immediate (acute) risk to life; however, repeated and prolonged exposure can have detrimental and long-term consequences for workers, even when they’re subjected to relatively low concentrations. Continued exposure can cause long-term chronic illness such as cancers and even hearing loss (in the case of ototoxic chemicals such as nitriles). Effective monitoring and reporting of exposure levels is integral to maintaining high standards of worker safety and legal accountability. Personal monitoring is the preferred solution when the average concentration of chemical exposure must be determined. The Right Tool for the Job As with all data recording, good intentions are a great starting point, but they need to be reinforced with effective, well-maintained, and properly utilized equipment. There are three main points to consider when selecting and operating personal monitoring equipment for chemical exposure sampling: the specific type of unit, legal and internal compliance, and correct operating procedure.  A low-flow pump is smaller and lighter than a medium-flow pump with a low-flow adapter. Newer units will not only meet the standards by default but will also offer benefits including Bluetooth or similar wireless connectivity, allowing for digital flow calibration to be performed automatically, saving the occupational hygienist’s time and eliminating the potential for user error. This increased connectivity also allows for the pump to be checked remotely, reducing any potential worker disruption and increasing site efficiency.  Considering Compliance In terms of compliance, it is important that the intrinsic safety (IS) approvals of all units meet the requirements of the facility where they are in use (for example, ATEX, IECEx, and so on). Pumps must also meet the latest version of ISO 13137:2013, Workplace Atmospheres—Pumps for Personal Sampling of Chemical and Biological Agents—Requirements and Test Methods. The superior flow control and error detection features of newer pumps meet this relatively new standard. Sampling methodology must be consulted to determine the appropriate flow rate is set before and after use and the correct sorbent tube is used based on the chemical being sampled.  Correct operating procedure falls under the purview of both the company and individual workers. Pumps and equipment must be used consistently and regularly, and must be fully serviced in accordance with manufacturers’ recommendations, normally after a few thousand hours of use. Maintenance and expiry dates must be adhered to, sample trains checked for leaks, and samples sent to the laboratory as soon as possible to avoid conditions that might damage the integrity of the sampling (rough handling, excess heat)  and provide a control sample to test against.  The Ten Commandments of Sampling In addition to the considerations raised above, those carrying out low-flow sampling should bear in mind the following tips:
  1. When using a flow calibrator with a suitable flow range, check that it is within the calibration date.
  2. Consult the method and determine the appropriate sorbent tube to use (for the chemical being sampled) along with the required flow rate.
  3. Always check that the sorbent tube is in date.
  4. Calibrate the flow rate (as indicated in the method) both before and after use.
  5. Just before sampling, use a scorer or breaker tool to uniformly break the ends of the sorbent tube to a 2 millimeter diameter or half the diameter of the tube body.
  6. Ensure that the arrow on the tube indicates airflow direction and points to the tube holder and pump. If no arrow is present, the smallest section should be near the tube holder.
  7. Check that the open end of the tube holder is placed in the breathing zone, a 30 centimeter radius centred on the nose and mouth.
  8. Use flexible, inert plastic tubing and check that it has the correct internal diameter.
  9. Check and double-check the sample train for leaks.
  10. Keep the tube in a vertical position during sampling to prevent the possibility of channelling that can otherwise lead to under-sampling.

Sampling is a means of measuring and avoiding potential hazards to health. It is key that best practices are followed when sampling so that it is also an effective means of capturing data.

Tim Turney is Casella's global sales manager. For more information about Casella, visit the company website.  

Go with the Flow
Essential Tips for Low-Flow Sampling