Motor Fuel Dispensing - Outside

[ptonsparky]

Small fuel tanks now require a containment system around them and essentially are an open box that the fuel tank sits in. The dispenser is mounted to the top of the tank. I have not measured the one we will be working with but will guess that it is about 24" tall and hopefully the wall to wall dimensions to the tank are >= to 18" on all sides. That being True would indicate to me that the area outside that box is not a Hazardous area. Ref: 514.3(B)(1) and Fig 514.3(B). 2014 NEC.


Yes, No?

 

[rbalex]

First - why didn't you post this in the Hazardous (Classified) Locations forum? AND why didn't you ask this BEFORE Public Input for the 2017 NEC?

My opinion is Figure 514.3(B) is incomplete.

That said, if you read Table 514.3(B)(1), (line: Tank, Aboveground) carefully you will see that the dike (wall) location may cause a problem. That is, the "[e]ntire space within dike, where dike height exceeds distance from tank shell to inside of dike wall for more than 50 percent of tank circumference" is Division 1.

Since Section 500.5(B)(3) requires locations adjacent to Division 1 to be classified Division 2 you may find it difficult to not classify at least 18" beyond the wall. EDIT ADD: Remember the space above the Division 1 must be classified as well.

 

[ptonsparky]

First - why didn't you post this in the Hazardous (Classified) Locations forum? AND why didn't you ask this BEFORE Public Input for the 2017 NEC? HUA Syndrome? I had may nose in the NEC, you can't expect me to think further than that.:slaphead:

My opinion is Figure 514.3(B) is incomplete.

That said, if you read Table 514.3(B)(1), (line: Tank, Aboveground) carefully you will see that the dike (wall) location may cause a problem. That is, the "[e]ntire space within dike, where dike height exceeds distance from tank shell to inside of dike wall for more than 50 percent of tank circumference" is Division 1.

Since Section 500.5(B)(3) requires locations adjacent to Division 1 to be classified Division 2 you may find it difficult to not classify at least 18" beyond the wall. EDIT ADD: Remember the space above the Division 1 must be classified as well.

I am mostly concerned about the area 18" above ground and 20' around the tank or in this case the containment. The area inside the containment is Div 1. So now the area 18" above the containment wall, outside the wall and within a 20' radius is now Div 2. Prior to the containment I would not have had a Div 1, just Div 2.

 

[rbalex]

I am mostly concerned about the area 18" above ground and 20' around the tank or in this case the containment. The area inside the containment is Div 1. So now the area 18" above the containment wall, outside the wall and within a 20' radius is now Div 2. Prior to the containment I would not have had a Div 1, just Div 2.

I would generally analyze it that way as well. However, it is conceivable that Division 2 only extends 18" beyond the wall, if the wall is at least 18 high. It would simply be the "run off" of the Division 1 envelope. Its "source" would no longer be the tank.