Location of gasoline station seal-offs.

Prefabricated modular service station. Gasoline despencers out front. Ridgid conduit from dispenser, under store, up out of poured concrete on rear of building, seal-off, entry into proper equipemnt.

BUT: Once the large foundations piles were set, no dirt was backfilled. The conduit enters an open void under the building.

If the conduit was in free air all the way, the seal off could be at the 20' boundry of the Class 1 Division 2 around the dispenser. If it was in burried all the way, the seal off could be 'the first fitting as the conduit emerges from grade'

In this situation, is there not a danger of vapor traveling down the conduit, accumulating in the unventilated void under the building, and creating a hazard? And it does not have a seal-off 'where it emerges from grade' ? comments?

Lynn Adams

Hmmm...I would ask for the riser and sealoffs to be on the modular side before going underneath the unit if that were 20ft. or more from the dispensers. I would ask for a w.p. wireway above 18" at that point and appropriate Class I bonding at that wireway. They could then route under or thru the modular as necessary. Propane and gasoline vapors settle at the low points. The void beneath the modular should not be approved. I would speak with the jurisdiction Fire Marshal.

I'd agree with Ron and ask the fire marshal to help investigate further. Perhaps there is a fire code to prevent this.

A little more information (I have been 500 miles away due to a family medical situation) There is a 20 minunite timer activated ventilation fan for the sump area. BUT it is only for activation and min. 20 minute ventalation of the area before entry into 'confined space'.

That solves the entry into question. But if the whole station and convienicence store is lifted into the air, will we have cameras operating so we can send it to U-Tube?

L A