Non classified becoming Class 1Div 1?

[hirscr]

ok here is the scenario:

I have a 3 walled shelter housing one box (class 1 div 2) that is purged into another box (class 1 div 1) but are isolated other than the purge flow. The C1D1 box purges into the enclosure which is 6x6x8 (8 ft is the height), but as I said only has 3 walls and a roof.

Here is my question: if I want to install a set of doors, or a roll down shutter on the open wall, so that if someone is maintaining the unit in the dead of winter, he can keep the wind off his back, have i just made my open area into a class 1 div 1 area? What if the roll down shutter stops, say 2 feet abovce the ground? Or if the doors leave big gaps?

 

[rbalex]

Re: Non classified becoming Class 1Div 1?

I have a few questions about the installation:

1. Where is the source of gas / vapor with relation to the installation in the first place. For example, is it already inside one of the ?classified? enclosures?
2. If it is from an outside source, why isn?t the immediate area already classified ? at least Division 2?
3. What is the combustible material involved? What is the flow rate of the combustible material?

 

[hirscr]

Re: Non classified becoming Class 1Div 1?

Originally posted by rbalex:
I have a few questions about the installation:

1. Where is the source of gas / vapor with relation to the installation in the first place. For example, is it already inside one of the ?classified? enclosures?

The liquid is fed to the class 1 div 1 box, via a steel tube from a 'fast loop' or tank. . The area is likely to be class 1 div 2. The other box is a class 1 div 2 box. The class 1 div 1 box, needs to be opened for maintenance. During maintenance there could be a drip or two. During maintenance is when I'd like to close the 'leaky' door.

2. If it is from an outside source, why isn?t the immediate area already classified ? at least Division 2?

it probably is.

3. What is the combustible material involved? What is the flow rate of the combustible material?

mostly fuels (gas, deisel, jet fuel, you name it). The flowrate through this enclosure is in two forms, the filters allow a large flow rate through them, mostly unfiltered, and the filtered flow is only say at most 2 gallons per minute. The bypass flow could be 10's of gallons per minute.

 

[rbalex]

Re: Non classified becoming Class 1Div 1?

The topic title seemed to indicate the 6x6x8 volume has been considered unclassified; however, from what you have described so far, the exhaust port from the "Class I, Division 1" box already makes the 6x6x8 volume(or most of it) Division 1 anyway, so a door or shutter would make no difference.

Now, if you had said the products involved were only deisel or jet fuel, I probably would have gone the other direction and said NOTHING needed to be classified at all; that "... you name it ..." really clouds the issue.

 

[hirscr]

Re: Non classified becoming Class 1Div 1?

Originally posted by rbalex:
The topic title seemed to indicate the 6x6x8 volume has been considered unclassified; however, from what you have described so far, the exhaust port from the "Class I, Division 1" box already makes the 6x6x8 volume(or most of it) Division 1 anyway, so a door or shutter would make no difference.

I am going to be making the output of the C1D1 box to be catalyzed or filtered, so there shoudl be no vapors coming out of that box, or I can port that box to the outside of the enclosure.

Now, if you had said the products involved were only deisel or jet fuel, I probably would have gone the other direction and said NOTHING needed to be classified at all; that "... you name it ..." really clouds the issue.

could you elaborate more on this? The worst case is that there is any fuel coming into or out of the box. But perhaps I can constrain it to diesel and gasoline. Why would it not have to be classified?

Thanks for your continued feedback!

 

[rbalex]

Re: Non classified becoming Class 1Div 1?

My original statement about diesel and jet fuels was based on the concept that they are Class II or III Combustible Liquids and are very rarely the basis for classifying a location. Check the appropriate Material Safety Data Sheet [MSDS]. Unfortunately, the same cannot be said for gasoline, it would definitely cause a classified location.

I still don?t understand your process well enough yet to make too many definitive comments. What other electrical equipment is in the 6x6x8 volume that you would be worried about classifying the area in the first place? Venting outside the volume may or may not make a difference. Rendering it non-flammable before exhausting certainly would. Other considerations such as the amount and reliability of ventilation in the 6x6x8 volume could affect it.

 

[hirscr]

Re: Non classified becoming Class 1Div 1?

OK, thanks! Then one final question. Once we have a design, who do I call to see if the venting/exhaust/fluid issues are going to pass before we go and build this thing?

Originally posted by rbalex:
My original statement about diesel and jet fuels was based on the concept that they are Class II or III Combustible Liquids and are very rarely the basis for classifying a location. Check the appropriate Material Safety Data Sheet [MSDS]. Unfortunately, the same cannot be said for gasoline, it would definitely cause a classified location.

I still don?t understand your process well enough yet to make too many definitive comments. What other electrical equipment is in the 6x6x8 volume that you would be worried about classifying the area in the first place? Venting outside the volume may or may not make a difference. Rendering it non-flammable before exhausting certainly would. Other considerations such as the amount and reliability of ventilation in the 6x6x8 volume could affect it.

 

[rbalex]

Re: Non classified becoming Class 1Div 1?

As this thread has developed, it appears you actually have multiple applications in mind. I have found many people well qualified to install / inspect classified location installations once they have been classified. But truthfully, I've found very few that actually know how to properly classify a location in the first place. In the general tradition of this forum I recommend you find a qualified engineer to assist you if you want a general solution (other than make everything Division 1) rather case-by-case. Area classification is a very complex subject.