OHS Code Explanation Guide

Published Date: February 23, 2012
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Part 18 Personal Protective Equipment

Section 249 Quality of breathing air

The air delivered to a person wearing a self contained breathing apparatus or remote supplied air apparatus must be as free of contaminants as possible. Contaminants may harm the person breathing the air or may damage the respiratory protective equipment being used. As a result, the employer must ensure the air is of a quality that complies with Table 1 of CSA Standard Z180.1-00 (R2005), Compressed Breathing Air and Systems, shown as Table 18.4.

Despite the table, the employer must also ensure that the air does not contain a substance in a concentration greater than 10 percent of its occupational exposure limit as listed in Table 2 of Schedule 1 of the OHS Code unless it is already listed in Table 1 of the CSA Standard. So, in the case of carbon monoxide, this means an allowable concentration of ≤5 ml/m3 (ppm) even though 10 percent of the 25 ppm occupational exposure limit would be 2.5 ppm.