Respiratory Protection

UNB Reference Number: 7840
Authorized by: E. Parr Johnston, President,
Effective Date: November 2001
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To outline the hazards and regulations pertaining to respiratory protection.


Any person performing a function which could result in exposure to any of the following hazards shall wear respiratory protection, if:

  • the concentration level of an air contaminant may exceed 50% of the Threshold Limit Value (T.L.V.) in conditions which are part of a normal work procedure;
  • there is reasonable risk of accidental exposure in excess of the T.L.V. for the air contaminant; and
  • the oxygen content of the atmosphere is less than 19.5% or greater than 23% by volume. (At normal atmospheric pressure, oxygen content is 21% by volume.)


  1. Where practical, engineering controls shall be used to remove air contaminants at their source.
  2. Where it is suspected that the level of concentration of an air contaminant is approaching 50% of the T.L.V., the air shall be tested by a competent person to determine the concentration.
  3. Where individuals are required to wear respiratory protection, the Department shall develop a written Code of Practice for the proper selection, care, use, maintenance and fitting of the equipment in conformance with the CSA Standard.
  4. The Code of Practice shall be readily available to all users.
  5. Users shall be familiar with and adhere to the Code of Practice; users shall be appropriately instructed in the use and fit of respiratory protection.

Note: T.L.V.s are published annually in the "T.L.V.s & B.E.I.s (Threshold Limit Values for Chemical Substances & Physical Agents; Biological Exposure Indices) by the American Conference of Governmental Industrial Hygienists (ACGIH), Cincinnati, Ohio.

(N.B. Occupational Health & Safety Regulations)