Paint Booth Door Contacts

bryanc

Member
Location
Tampa, FL
I have a Small Garage that was turned into a paint booth. There is a dry chemical fire suppression system. Are door contacts required to cut power to the fan when the door is opened?? I cannot find anything that says they are??
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
I have a Small Garage that was turned into a paint booth. There is a dry chemical fire suppression system. Are door contacts required to cut power to the fan when the door is opened?? I cannot find anything that says they are??
Given that the fumes and particulates inside the "booth" do not disappear instantly when the door is opened, I would think it might actually be required to keep the fan running until it is shut off manually or with a time delay.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
I have a Small Garage that was turned into a paint booth. There is a dry chemical fire suppression system. Are door contacts required to cut power to the fan when the door is opened?? I cannot find anything that says they are??
No; however, the NEC doesn’t list all the applicable rules, and, depending on your local statutes, there may be more “features” you are overlooking. See NFPA 33 as referenced in Informational Notes (INs) sprinkled throughout Article 516. While INs are not strictly enforceable through the NEC, they are often enforceable through various OSHA rules.
 

Tulsa Electrician

Senior Member
Location
Tulsa
Occupation
Electrician
The last ones I did just months ago.
The door contacts cut the intake and exhaust fans as well as the paint gun air supply. It did leave lights on.
The design was by by a paint booth mfg. The supplied the control cabinet and we wired.
This was also tied into the fire alarm as well. If the bottle was fired it cut all control power to the control cabinet.
This was in Oklahoma so local rules may apply. Check with ahj and for marshall.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
No; however, the NEC doesn’t list all the applicable rules, and, depending on your local statutes, there may be more “features” you are overlooking. See NFPA 33 as referenced in Informational Notes (INs) sprinkled throughout Article 516. While INs are not strictly enforceable through the NEC, they are often enforceable through various OSHA rules.
NFPA 17 is the standard for dry chemical suppression systems. Tulsa Electrician has covered most of what happens, although I'm surprised that power was cut to the control cabinet. Frequently the fan shutdown is done through the booth controller, and only rarely directly via the suppression system.
 

kwired

Electron manager
Location
NE Nebraska
I don't know the rules here but seems the paint is the main concern and at very least ability to dispense paint should be disabled if other safety conditions are not proven.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Everyone I have done has a set of dry contacts to control an air valve that shuts off the air to the sprayer.
Are those contacts on the booth controller or on the suppression system control head? Usually the suppression system control head sends a signal to the booth controller via a "fire" input on the booth controller and the booth controller handles all the rest.
 

Tulsa Electrician

Senior Member
Location
Tulsa
Occupation
Electrician
Here is a pic of an control cabinet I trouble shot. Door errors,drive errors. What a mess. Bunch of mfg defects.
Any way show spray coil in this one.
 

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gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Here is a pic of an control cabinet I trouble shot. Door errors,drive errors. What a mess. Bunch of mfg defects.
Any way show spray coil in this one.
OK, that's definitely not any suppression system controller I've ever seen, either personally or in the literature, and I've seen a lot.
 

Tulsa Electrician

Senior Member
Location
Tulsa
Occupation
Electrician
This one was set up 120 volt control to cabinet thru fa relay.
From there we had all doors in Series. Then if all good lights would come up. They were enclosed led with a blower fan. Had a pressure switch once pressure was detected in light tubes the lights came in and then the drives could be enabled to run. Then a transducer would allow for air supply to spray valve.
If a door opened it would dump spray pressure so there was no stores air supply. Lights would remain on and drive shut down.
The transduce was a DC single to exhaust drive to maintain a set pressure or vacuum in booth.
 

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