Tank Gauging Respirator Use

We had the following question come in:

“I have a crew of guys who are going to location to gauge tanks. When they open the hatch, there is a chance they could get a blast of H2S or Benzene. This is a process that only takes a few minutes. Can you recommend a respirator that would  work for this project? I don’t think we need to go full SCBA, but more than the filtered masks.”

There are a few different options for protecting these employees:

  1. Obviously the safest thing we could do is remove them from the equation. They make equipment that allows you to gauge tanks remotely. This keeps employees from even having the possibility of exposure. While this is the safest option, it may not be feasible and it might be cost prohibitive.
  2. Positive pressure SCBA are potentially the best option if this is going on in a large number of locations or if locations change. This give the employees the ability to move freely to work locations with a large supply of air  so risk of exposure to toxins is almost completely eliminated. They would need to refill their bottles frequently and their work duration would only be around 30 minutes before they would have to refill their tank.
  3. Another option if employees are going on a large number of locations or if locations change would be a truck mounted SAR setup. We could rig up several large air tanks in the bed of the truck with a manifold and hose reels. As long as the truck could make it within close proximity of the work area the employees could hook up their SAR units to the truck and have a very large supply of air. They would be limited to 300 feet of travel from the truck because the hose length can only be 300 feet long per 42 CFR 84 Subpart J Table 8.
  4. If there are only a few locations that do not change frequently we can make SAR setups to sit next to the tank battery. This eliminates the issue of needing to get the truck close to the work area. It is limited in that it will be a somewhat permanent to each location so you would need several.
  5. The most comprehensive respirator solution would be to mix options 2 and 3. We could do the truck mounted SAR system but use SCBA rather than SAR packs as respirators. Some SCBA have a hookup for an airline hose, so employees could breathe off the hose wherever possible, but if they need added mobility they could disconnect from the hose and use their bottle (which they cannot do with a SAR pack unless it is an emergency for escape only). This gives them the extended time SAR provide, the mobility that SCBA provide, and if they drain their SCBA tank they could refill it off the truck rather than having extra tanks or needing to drive somewhere to refill.

* Due to the nature of the work, APR and PAPR should not be used. These respirators can only be used when known concentrations of a substance are present to ensure the Maximum Use Concentration is not exceeded. This is not realistic for production tanks because the concentration can change on a continual basis.

** Unless specific citations are shown, all answers are based on interpretations provided by authorized officials. As such, all information is deemed reliable, but not guaranteed.