A pump room is suspected of accumulating gases after a ventilation machinery breakdown. Where should the combustible gas indicator case be placed when testing the pump room atmosphere for combustible gases?

Correct Answer: Option D — On the deck outside the pump room

Combustible gas indicators must be operated in a safe atmosphere to prevent the device itself from becoming an ignition source. Placing the unit outside the space and using a sampling line ensures the operator remains in a safe environment while drawing a representative sample from the potentially hazardous pump room.