ANSUL System

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davedottcom

davedottcom

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Is anyone familiar with the NFPA rule for killing lights located under Comm. Kitchen Hoods during a fire?

I just installed a Control panel for an existing hood that had a new section added to it. I hooked all 4 fan motors into the Ansul system and everything is working perfectly...Exhaust fans stay running & Supply fans are "killed" during a fire.
I'm getting different opinions about the lights under the hood being turned off in a "fire" situation. The control panel is set up to keep the lights On (In the new section of hood). but I was told by the installer that the lts. in the old section will have to be turned off!
His reason was because the 1/2" EMT & boxes for the lts. are mounted "under" the hood. The EMT & boxes for the lts. in the new section are mounted on "top" of the hood with only the lights "under" the hood.

Anyone else ever run into this?

Dave
 
Re: ANSUL System

Only the cooking equipment and supply fan(s) need to shut down, I've heard in some locations the exhaust fan(s) is required to shut down too.

Roger
 
Re: ANSUL System

The Exhaust fan is required to keep running(push ansul chemical into the duct where fire has usually spread) the make up air unit must shut down(so doesn't feed fresh air to the fire) EVERYTHING under the hood including Lights Must be shut dn. If Gas stove it must shut dn gas feeding stove. Has to be Manually turned on after ansul is done spraying.If just a limit is used after tanks empty the the units would start up again if still in operationing condition.
 
Re: ANSUL System

Originally posted by roger:
Only the cooking equipment and supply fan(s) need to shut down, I've heard in some locations the exhaust fan(s) is required to shut down too.

Roger
Click to expand...
I heard that the exhaust fans sometimes are required, and I've had specs for it. However, the inspector would not pass our drawings because he didn't see why the exhausts fans needed to be shut down. I told him that it was what the manufacturer requested. He said that he's never seen that in 42 years, I said...you've got a lot of catching up. He laughed!! :)
 
Re: ANSUL System

Here is the PDF on this subject if you want to take the time to download it.

Check out page #19 exaust fans 8.2.3.1 :)

http://www.free-the-abbott.org/nfpa96-01.pdf


site1033.GIF


[ January 09, 2005, 01:47 AM: Message edited by: ronaldrc ]
 
Re: ANSUL System

In the above NFPA code it says listed equipment.

For example I think they might want to shut the exaust fan down if you had a large gas heating system nearby to keep from causing a backdraft and filling the area with carbon monoxide things of this nature.

[ January 10, 2005, 07:00 PM: Message edited by: ronaldrc ]
 
Re: ANSUL System

If the exhaust fan shuts down when the fire suppression system is activated it will not pass final inspection. There is not ANY circumstances that could change this, it is a must that they stay on for the UL300 systems.
 
Re: ANSUL System

Then if we have the case I described above would we have to shut the main gas to the Bldg. off with the fire suppression system instead of the gas just suppling the cooking units involved?
 
Re: ANSUL System

According to NFPA 96 Page 20 Para.10.4.3 the gas to the heating unit would have to be shut down.

But I don't understand why NFPA 96 says the exhaust fans can be shut down if a listed component calls for it?

Are you saying that particular unit want allow it to be shut down because of electrical interlocks or are you saying the inspector is in contradiction to the NFPA 96 code?

Or does this just apply to this particular system because of its design? :confused:
 
Re: ANSUL System

I need to vent if this where a question about a 25 amp. breaker on a 20 amp. conductor we would be flooded with response of why it couldn't be and how it might be a fire hazard.

Then when something like this hood fan exhaust fan issue pops up which could be one of the reasons some are overcome by toxic flumes in burning Bldgs. and don't get out no one takes an interest. :confused:

Can you honestly tell me there is not a contradiction between code enforcing authorities?
 
In a building we did about a year ago. The Exhaust remained on, Make up air turned off, Gas valve closed, Electric Equipment Tripped Off.

Our Fire Marshal made us go back and add a shunt trip breaker for the lights under the hood.
 
Gas shut off

Gas shut off

The gas to the appliances under the hood is supplied thru a gas valve...either a spring-loaded manual valve or a solenoid valve.

When the Ansul is pulled:
1. The manual valve is connected via their little cable to the suppression system and it trips/closes the gas valve OR
2. A shunt trip arrangement opens the circuit to the solenoid valve.

Either way, the gas supply is interrupted along with the power to the affected area.
 
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