Storage tank

[augie47]

Upfront: Hazardous Locations are one of my weak points as an inspector.
Situation: A small Municipal fleet maintenance facility has a desiel and a gasoline above ground storage tank (piped tgo dispensers) each with a low "dyke" concrete wall surrounding them. Its seems overkill, to call this bulk storage, but it appears to me that the gasoline tank would fall under Art 515. Is that correct ?
Also if I read correctly that my calssified area in reagrd to the tank would be Class II within 10 ft of the shell, and Class I withing 5 ft of the vents ??

 

[rbalex]

Upfront: Hazardous Locations are one of my weak points as an inspector.
Situation: A small Municipal fleet maintenance facility has a desiel and a gasoline above ground storage tank (piped tgo dispensers) each with a low "dyke" concrete wall surrounding them. Its seems overkill, to call this bulk storage, but it appears to me that the gasoline tank would fall under Art 515. Is that correct ?
Also if I read correctly that my calssified area in reagrd to the tank would be Class II within 10 ft of the shell, and Class I withing 5 ft of the vents ??

The gasoline dispenser is within the scope of Article 514. The gasoline storage tank is within the scope of Article 515, overkill or not. The diesel can probably be ignored unless it is stored or handled above its flashpoint. That may be a consideration if the tanks are in direct sunlight, but it is still unlikely.

Within classified locations, ?Class? refers to the nature of the hazard (gasses, dusts, fibers, etc.); ?Division? refers to the degree of hazard. Gasoline is a ?Class I? material. Diesel would be too if is stored or handled above its flashpoint.

From Table 515.3:

Division 1 locations:

• The area inside the dike where the dike height is greater than the distance from the tank to the dike for more than 50 percent of the tank circumference. The dike height is probably low enough that it can be ignored with regard to Division 1 classification; but check it anyway.
• Within 5 ft of the open end of a vent.

Note: the inside of the tank is also Division 1; however, unless there is wiring inside, it is probably moot.


Division 2 locations:

? Inside the dike
? 10 ft from the shell, ends, or roof of the tank
? An additional 5 feet (10 foot total radius) from the open end of a vent.

​

Other Notes:

1. It does not matter if the vent has an inline relief valve in it; the radii described still apply to the open end of the vent.
2. Both Articles 514 and 515 also have significant wiring method requirements beyond those described in Article 501.

 

[augie47]

tank

tank

Thanks, much (PM sent also)