(a) Elapsed time indicators shall be provided for apparatus with a chemical oxygen source, except:
- (1) Apparatus used for escape only; or
- (2) Liquefied breathing gas apparatus equipped with gages visible to the wearer which indicate the remaining liquid content in the container.
- (b) The timer or other indicator shall be accurately calibrated in minutes of remaining service life.
- (c) Timers shall be readable by sight and by touch during use by the wearer.
- (d) Timers shall be equipped with automatically preset alarms which will warn the wearer for a period of 7 seconds or more after the preset time has elapsed.
- (e) Remaining service-life indicators or warning devices shall be provided in addition to a pressure gage on compressed gas self-contained breathing apparatus, except apparatus used for escape only, and shall operate automatically without preadjustment by the wearer.
- (f) Each remaining service-life indicator or warning device must give an alarm when the remaining service life is reduced to a minimum of 25 percent of its rated service time or any higher minimum percent value or values as specified in the approval. Open-circuit demand and pressure-demand respirators must alarm continuously until depletion of the breathing air supply. The percent value set for indicator activation must be identified by labels and/or markings on each respirator unit.
[60 FR 30355, June 8, 1995, as amended at 78 FR 2622, Jan. 14, 2013]