Appendix E Service Life - 3M SCOTT AIR-PAK X3 PRO Operating & Maintenance Instructions

Each configuration of self-contained breathing apparatus (SCBA) certified by NIOSH is assigned a service life
classification for a duration time of each size of air supply cylinder (30-minute, 45-minute, etc.). The service life
duration time is determined by NIOSH using a breathing machine designed to simulate an average adult user
performing work at a moderate work rate.
Do not expect to obtain the NIOSH rated service life duration time from this respirator on each use. The work being
performed may be more or less strenuous than that used in the NIOSH test. Where work is more strenuous, the
duration may be less than one half the NIOSH rated service life and the time remaining after either end-of-service
indicator alarm actuates may be similarly reduced. The end-of-service indicator alarms actuate when approximately
33% of full cylinder pressure remains in the cylinder and valve assembly. Although all end-of-service indicator alarms
are set to actuate at the set point of approximately 33% of full rated service pressure, they are completely
independent of each other and therefore may not actuate at precisely the same moment. The alarms will continue to
operate until the cylinder is nearly depleted.
The duration time of the respirator will depend on such factors as the following:
•
Degree of physical activity of the user
•
Physical condition of the user
•
Degree to which the user's breathing is affected by emotional factors
•
Degree of training or experience which the user has with this or similar equipment
•
Whether or not the cylinder is fully charged at the start of the work period
•
Possible presence in the compressed air of carbon dioxide concentrations greater than 0.04% normally found in
atmospheric air
•
Atmospheric pressure. For example, if used in a pressurized tunnel or caisson at 2 atmospheres (15 psi gauge or
approximately 30 psi absolute), the duration will be one-half as long as when used at 1 atmosphere; at 3
atmospheres, the duration will be one-third as long
•
Loose or improperly fitting facepiece
•
Condition of the respirator
P/N 595373-01 Rev C
Rev C
202004
P/N 595373-01
202004
APPENDIX E
SERVICE LIFE
55