During fit testing and respiratory training, we ask students how they determine when a cartridge needs to be replaced.  We usually receive these responses:  no answer just a deer in headlight expression, I don’t know, or when I smell something.  None of these meet OSHA regulations.  In fact, OSHA states relying on odors will not be permitted as the primary basis for determining service life.

Did you know your respiratory protection policy must contain a respirator cartridge exchange schedule?  This change schedule indicates how often cartridges need to be replaced and criteria used to make this decision.  The service life of a cartridge is the time it provides protection from chemicals in the air.  Service life depends on amount of contaminants in the air, temperature, humidity, the filtering capacity of the cartridge, air flow through the filter, work rate, other contaminants and the wearer’s breathing rate.

OSHA requires that employers determine this service life using test data, mathematical estimates or information provided by either the chemical or respirator manufacturers.  OSHA further requires that employers should be conservative when determining a realistic cartridge service life. 

The 3 valid ways to estimate a cartridge’s service life are:

1.      Experimental Tests.   This is a more accurate service life, but can take time and money to perform tests.

2.   Manufacturer’s Recommendations.  Accurate estimate, but may not take into account all your workplace variables.

3.   Math Method.  Not as accurate as experimental testing and may result in a shorter service life due to conservative assumptions.

The OSHA website provides a “Rule of Thumb” tool http://tinyurl.com/yfnkp58 that provides an estimate of cartridge service life that can be used in conjunction with one of the 3 methods discussed above.

Service life is critical.  Just wearing a respirator with a cartridge doesn’t provide protection if the cartridge no longer has filtering capabilities.