Electrical classification class 1 div 1

[RyanIEC]

Is there a way to change classifications by adding air flow?
We have a new Kiln dryer for concrete going in. The unit itself is located in a 40' container with louvers on the doors. The burner itself is fed by natural gas. There aren't fans feeding air into the container so its just the air coming in from the louvers. Is this considered a class 1 div 1 area? Is there a way to change the class by adding a certain amount of airflow through the container? There is a burner gas valve and burner controls. I have attached a few drawings.

 

[itsmoked]

This isn't a kiln, right?

This would probably NOT be a considered a hazardous space. The inside of an oven is not usually "Divisioned." There is not supposed to be flammable mixtures floating about when humans or ignition sources are present. Nor should there be any normal or abnormal cases where flammable mixes should be present.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[RyanIEC]

I guess it's not a Kiln. It's a type of oven though, they are adding this system because it does get warm enough in the winter. Sorry I need to clarify, it's not in the oven that is the issue. The container that houses the burner and blower is where we are trying to figure out. The burner and blower is outside the building in a container and has ducting that goes into each oven segments. That's where we are having issues.

 

[itsmoked]

Oh, OK. A closer look does show "in a container". Sorry about that.

You are still looking at something that is similar to a furnace. There is not supposed to be fuel in the air around it any more than the unit in your attic heating your home.

Not actually laying eye's on your unit I can't absolutely comment, but if it's as I expect it to be, I would provide ventilation slats in the enclosure,(as exist, and call it a day.

If you're really worried about it, add a flammable gas detector and gate the system enable thru it.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[RyanIEC]

Thank you
That helps

 

[rbalex]

At worst, the inside of the enclosure is Division 2. Assuming, that the fuel gas piping is a closed system except at the point of ignition, there is generally no need to classify a fired system.

From NFPA 58-2006, National Fuel Gas Code:

7.12.5.2 Electrical Requirements. Where gas-mixing machines are installed in well-ventilated areas, the type of electrical equipment shall be in accordance with NFPA70,National Electrical Code, for general service conditions unless other hazards in the area prevail. Where gas-mixing machines are installed in small detached buildings or cutoff rooms, the electrical equipment and wiring shall be installed in accordance with NFPA 70 for hazardous locations (Articles 500 and 501, Class I, Division 2).

As noted above, adequate ventilation can indeed make the difference. What adequate ventilationis is currently going through a debate. Various organizations have differing views; but, in my opinion, the most practical definition in common usage is:

3.3.1 Adequate Ventilation. A ventilation rate that affords either 6 air changes per hour, or 1 cfm per square foot of floor area, or other similar criteria that prevent the accumulation of significant quantities of vapor–air concentrations from exceeding 25 percent of the lower flammable limit.

It has stood the test of time for the last 30 years +.

 

[roydm]

I agree with previous poster, it's Class 1 Div 2, gas not normally present.
Roy