Robot Paint Cell

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Sparkyyy

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Location
Comstock Park, MI
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Master Electrician / Electrical Contractor
We have a brush painting robotic cell and need to know if it is Class 1 div 2 Explosion Proof or not?

There is a proposed Robotic Paint Cell with Four Robots in one enclosed Cell. Each robot is fed from a container with an enclosed pressurized canister located outside the room. There is approximately 16oz of Primer or paint that is OSHA Class 2 flammable Rated. A hose comes from the canister to the end of arm to a 2” wide brush. Each Robot coats a panel located on its nest that it will cover with a Primer, or Paint.

There are two Explosion Proof vent fans on the top of the cell roof that together exchange the air in the paint cell 1 or 2x per minute.

Each Nest has switches from cylinders and air cylinder movement via pneumatic valves. There are 4 light fixtures, Area safety laser scanners and Man Machine vision with several lights scheduled for this area.

Question:

  1. Is this a class 1 dive 2 environment as far as the electrical wiring is concerned or not. Due to low volume in the area and no atomization I am hoping it is not.
Of course, even though we are not spraying there could be an accident were the hose line could have a leak and spill or spray the Primer out. We would appreciate any information that would point to a given standard if there is one for the limit of Liquid that could be applied without going to wiring the cell Class 1 Div 2.

Thanks for your help,
 
petersonra said:
My take is if it is enclosed the inside of the paint booth is Class 1 Div 1. But I am by no means an expert in such things.
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This is a rare case where a whole lot of expertise isn't too necessary; robotic or not, the installation is subject to Article 516 and the internal booth/room or direct spray area is Division 1. See Section 516.5
 
rbalex said:
This is a rare case where a whole lot of expertise isn't too necessary; robotic or not, the installation is subject to Article 516 and the internal booth/room or direct spray area is Division 1. See Section 516.5
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Thank you so much for your insight, this is just me thinking. I thought because our canister with the primer is outside the paint cell housed in a metal container (looks like a pressure cooker)and there is a single hose that travels to the end of arm of the Robot directly to the brush from the canister I could use NFPA 34 6.3.2(1) "A flammable gas or a volatile flammable liquid is handled, processed, or used, but any flammable gas, vapor, or liquid is confined within a closed container or a closed system from which it can escape only in case of accidental rupture or breakdown of the container or system or in case of abnormal operation of the equipment. NFPA 70 516.5 "For spray application processes, the area classification is based on quantities of flammable vapors, combustible mists, residues, dusts, or deposits that are present or might be present in quantities sufficient to produce ignitable or explosive mixtures with air." Since this is a brush application I went to NFPA 34 Standard for Dipping Coating, and Printing Processes or Combustible Liquids. Even though this doesn't seem like a spray application the residues part Is important. Please understand I am not trying to force my ideas or thoughts. The Code is the Code and Safety is always first. I do very much value your input what are your thoughts on how I am looking at this.
 
retirede said:
Answers given assumed spray booth, but OP indicates painting method is brush?
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This was indeed a good point and takes it out of the Scope of Article 516. [Section 516.1]

This then brings up an interesting situation that can occasionally occur in such cases: The location is either Division 1 or unclassified but not Division 2. A more detailed analysis is then required to evaluate several process parameters such as total volume of the booth/room, ventilation rates, quantity of paint, service pressures, flow rates, etc.

Those are best left to a person qualified to make the evaluation. Most AHJs are not. They will almost always go for Division 1, “Just to be safe”. I usually recommend either a professional or the insurance company.
 
rbalex said:
This was indeed a good point and takes it out of the Scope of Article 516. [Section 516.1]

This then brings up an interesting situation that can occasionally occur in such cases: The location is either Division 1 or unclassified but not Division 2. A more detailed analysis is then required to evaluate several process parameters such as total volume of the booth/room, ventilation rates, quantity of paint, service pressures, flow rates, etc.

Those are best left to a person qualified to make the evaluation. Most AHJs are not. They will almost always go for Division 1, “Just to be safe”. I usually recommend either a professional or the insurance company.
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Thanks for your feed back and you are absolutely correct in that there is more to look into. Thanks again for the input it has been a pleasure.
 
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