OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 18 Personal Protective Equipment

Section 246 Approval of equipment

Respiratory protective equipment must be selected, used, maintained and cared for in the proper manner. Only approved respirators may be used. Approved respirators are those that have undergone testing and have been approved

(a) by NIOSH, or
(b) by another standards setting and equipment testing organization, or combination of organizations, approved by a Director of Occupational Hygiene.

For enforcement purposes, respirators approved by an agency subject to (a) and (b) must bear the registered identifying logo or mark of the agency or organization. All NIOSH-approved respirators, respirator cartridges and filters bear a sequence of approval numbers beginning with “TC”.

Employers having respiratory protective equipment approved for use by a Director of Occupational Hygiene (a member of the staff of Alberta Human Services appointed by the Minister under section 5 of the OHS Act) must have in their possession written permission from the Director indicating that the equipment is acceptable.

For more information
Certified Equipment List
Provided by NIOSH, the Certified Equipment List (CEL) is a database of all certified respirators and coal mine dust personal sampler units.

According to NIOSH, particulate respirators are categorized on the basis of efficiency and on their resistance to penetration by oil. Oil degrades and reduces the filtering efficiency of the filter material. NIOSH certifies the following three classes of particulate filters:

(1) N-series (not resistant to oil);
(2) R-series (resistant to oil); and
(3) P-series (oil proof).

Each of these three classes of particulate filters is also certified according to its level of filter efficiency (rated as 95 percent, 99 percent or 99.97 percent efficient) at removing particles 0.3 micrometres in diameter. For example, a filter marked N95 means that the filter is not resistant to oil and is at least 95 percent efficient at removing particles 0.3 micrometres in diameter. Nine classes of filters are certified as shown in Table 18.3.

Table 18.3 Classes of filters certified by NIOSH

Filter Series

Type Designation

Minimum Efficiency (%)





May be used for any solid or non-oil containing particulate.
"R" Series



May be used for any particulate contaminant. May only be used for one shift if used for an oil-containing particulate.
"P" Series



May be used for any particulate contaminant.
For more information
NIOSH Guide to the Selection and Use of Particulate Respirators