Personal H2S Monitors Protect the Air We Breathe
OSHA designates that personal monitors for atmospheric monitoring, including H2S monitors, should be worn within what is called the breathing zone. The breathing zone is 9 inches from the mouth and nose but not behind the shoulders. By wearing H2S badges within the breathing zone the detector is allowed to sample the atmosphere closest to the air the worker is breathing as possible.
Poor Choices Give Less Optimal Protection
One common area that workers have been found to wear H2S monitors has been on the back of the hard hat. The back of the hard hat does not sample the breathing zone because people do not breathe out of the back of their head! Coaching the worker to inform them of the breathing zone can help them remember to place their H2S badge in a proper location.
Another common area in the completions and well servicing industry has been on or around the belt. The reason given has been that since hydrogen sulfide is heavier than air they believe that wearing the monitor low on the body will alert the worker earlier. This may not be the case when we are dealing with hydrogen sulfide as a petroleum fluid. Although hydrogen sulfide does have a higher specific gravity than air there are two additional factors which can cause the gas to rise under specific circumstances. The heat of the gas as well as the combined mixture of lighter than air methane can cause hydrogen sulfide gas containing solutions to rise.
Proper H2S Monitoring
Properly monitoring the atmosphere for H2S will require some combination of stationary and personal H2S monitors. Personal gas monitoring is needed to protect the breathing zone.
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