The IRSST's Laboratory Division now offers an analytical determination service for respirable combustible dusts (RCDs). RCDs consist of an indicator (or tracer) for exposure to diesel particulate matter in underground mines as stipulated in the Regulation respecting occupational health and safety in mines (ROHSM, Quebec) as well as in certain other Canadian regulations. It should however be noted that RCDs are not mentioned in the Regulation respecting occupational health and safety (ROHS, Quebec).

Principle of the method:

The respirable fraction of airborne dusts, as defined in the IRSST Sampling Guide, is collected on a preweighed silver membrane 25 mm in diameter. Once returned to the laboratory, the filter is weighed to obtain a result for the respirable dusts. The filter then undergoes a calcination step at 400°C for 2 hours, to then be weighed a second time. Evaluation of the dust lost due to calcination provides a result for the RCDs. The RCD analytical method performed at the IRSST is entirely based on the method described in Schedule VI of the ROHSM, which was developed by the Mining and Mineral Sciences Laboratories (CANMET-MMSL).

Recommended conditions and some analytical performances:

ROHSM reference value (8h): 0.6 mg/m3
IRSST material code: cassette 951
Flow rate: Variable* depending on the respirable fraction selector device used (e.g.: cyclone)
Volume: 400 to 1000 L
Analytical principle: Gravimetric
Minimum reported value (MRV): 10 μg
More information is available on the RCD data sheet on the IRSST's Web site.

* IMPORTANT: For an evaluation of the RCD targeting compliance with the ROHSM standard, a Dorr-Oliver cyclone (prescribed flow rate of 1.7 L/min) must be used for sampling.

Additional information:

Note that the laboratory cannot analyze crystalline silica on samples intended for RCD analysis. The OHS technicians and professionals in the MSSS network will have access to this analysis in SISAT. For private clients, a paper form must be completed. New private clients can open a file with the IRSST's Laboratory Division by completing the on-line form provided for this purpose. Additional information about our laboratory services is available on our Web site. For any questions, please contact our customer service directly at (514) 288-1551, ext. 315.

Simon Aubin, M.Sc., CIH, ROH
Chemist, industrial hygienist
Laboratory Division