NFPA 820 Hazardous Location Near Digester

What areas would be C1D1?

  • Only outside the building

    Votes: 0 0.0%
  • Outside building and inside building above grade

    Votes: 0 0.0%
  • Outside building, inside building above grade, and below grade gallery

    Votes: 0 0.0%

  • Total voters
    0

Sclem615

New User
Location
California
Occupation
E/I Technician
I work at a treatment plant built in ‘85. It has two anaerobic digesters with membrane covers. The two digesters extend above and below grade.

Between the digesters on ground level is a building that shares a wall with each digester. The building wall and digester wall are one and the same. This building is divided into an MCC room and a sludge mixing room.

Below grade, between the digesters, is a gallery with the same setup. Two walls that are each tank wall, respectively. This gallery contains sludge pumps, grinders, heat exchangers, and instrumentation.

Finally, the sludge level is maintained above grade in each digester. Gas piping is external to the building.

Reading the NFPA 820, it seems that 5 feet from the walls is C1D1 and 5 feet from that boundary is C1D1. Does this apply only to the areas outside the building? Or does it apply to the building and gallery as well?
 
Top