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Type I Hood fan shut down?

Wouldn't the running exhaust fan pull the suppression agent up the vent instead on letting it suppress the fire at its source?

with a normal fixed pipe set up, you have

1. nozzles protecting the cooking area

2. nozzles protecting behind the filters

3. nozzles protecting into the duct work to the roof

the nozzle that protects the duct to the roof normaly has a unlimited length coverage

t
 
Let me ask a question, does 610.4 of the IFC say this:

610.4 Inspection and maintenance. Commercial kitchen exhaust hoods shall be inspected and maintained in accordance with NFPA 96.

Or is that a NY enhancement only?
 
This is from the Ansul UL300 manual (type l duct systems were required to be retrofitted to UL 300 standards, CO2 or Automatic fire sprinkler systems in California by Jan. 1st 2008. Around here, 99.9999 % of the new systems are UL300, actually.... I've never seen a new system that was other than UL300) :

"Exhaust fans in the ventilating system should be left on. The forced

draft of these fans assists the movement of the liquid agent

through the ventilating system, thus aiding in the fire suppression

process. These fans also provide a cooling effect in the plenum

and duct after the fire suppression system has been discharged.

The system is UL listed with or without fan operation.

Make up or supply air fans, integral to the exhaust hoods being

protected, shall be shut down upon system actuation"
 
Get what changed? Section 511.2.3 (California Mech. code) states ".... A hood exhaust fan(s) shall continue to operate after the extinguishing system has been activated, unless fan shutdown is required by a listed component of the ventilation system or by the design of the extinguishing system"

This is California code, mind you, I'm not sure of the others......the Ansul manual makes sense and the system is UL approved either way
 
"IBC 904.11.2: System interrconnection. The actuation of the fire suppression system shall automatically shut down the fuel or electrical power supply to the cooking equipment. The fuel and electrical supply reset shall be manual."

Not familiar with the model IBC.... if you were refering to the above quoted IBC section, I believe that relates to the actual "cooking equipment" such as electric salamanders, electric fryers, etc. not the electrical for exhaust fans.
 
since the electrical supply also applies to the lights in the hoods, it includes the fan.
 
Not in my opinion, I believe the IBC wants the actual "Cooking equipment" (as you stated in IBC section 904.11.2)I read "cooking equipment" as the equipment that cooks the food .... to turn off. It makes sense to me that if the food that is being cooked is on fire, it doesn't need the heat source that started it to still be on, of course.........

I can't get rid of "read read" it only shows up after the post.....
 
Valid opinion there Beach. Back in the day sat in on some initial 300 testing and additional rationale to require all fuel and power shut down (with exception to exhaust fan) was to prevent re-ignition of ignitable vapors when equipment was moved and nozzles or flow points were being dialed in for angular coverage. Eliminating heat and fuel sources aids in the prevention of potential re-ignitions if equipment gets moved.
 
we are talking about an exhaust fan that sets outside the building

and the electric power runs on the outside of the unit

most fires I have seen are before the filters, unless the filters were not in place prior to the fire
 
we are talking about an exhaust fan that sets outside the buildingand the electric power runs on the outside of the unit

most fires I have seen are before the filters, unless the filters were not in place prior to the fire
Click to expand...
Exactly, CDA and FMWB!
 
If you really want to understand the issues, travel back into time when " saponification" (spelling?) was what put the fire out - The dry powder from the extinguishing system would mix with the animal fat to create soap ...otherwise known as foam. It did not really matter with the appliances prior to the energy conservation movement along with healthy alternatives to animal fat. Several buildings were burnt to the ground when the cooking medium was changed from animal fat to vegetable oil and the appliances became more energy efficient.( better insulated to retain heat )

(BTW, in the old days of animal fat, fuel source or electrical power was required to be removed from the cooking equipment - so nothing new.)

The more energy efficient appliances keep the temperature of the vegetable oil above ignition temperature for a long time, thus re-ignition of the new fangled vegetable oil would occur, thus defeating the one-time shot of a hood suppression system.

That is a brief outline why UL-300 systems are required today.....

The basic concepts of how exhaust systems should act are basically unchanged in 25 years of code enforcement ---- the only (new) question is what does the manufacture's installation instruction state?

http://www.nafed.org/resources/library/ul300.cfm
 
well, Bob.. the ICC hasn't kept up with the technology (or should I say, Ansul hasn't lobbied the ICC to make a code change). The IBC is pretty clear.

By the way, I don't see NFPA 96 as a referenced standard in either the IBC or IFC (2006)

My humble opinion
 
Last edited by a moderator:
Nfpa 96----

Be sure to read previous post - I never did state that 96 was referenced, only that the testing standard for UL is based upon NFPA 96...... The IMC also states that equipment and appliances shall be installed in accordance with manufacture's specifications...... which means for every hood you are inspecting, you better have that model's installation guide to determine the proper sequence of operations for the hood when the fire suppression system activates.

Just saying..... IMHO the manufacture's guide is going to mirror NFPA 96's requirements in order to get UL or FM certified.
 
1. The IBC states that the suppression system shall shut down the fuel or electrical power supply to the COOKING EQUIPMENT

2. The CMC states that the exhaust fan(s) shall continue to operate.

3. The manufacturer (Ansul) states that the exhaust fans should be left on(with the approval of UL).

4. An exhaust fan is not COOKING EQUIPMENT.

5. The exhaust fan(s) is located on the roof.

What code change does Ansul need to make????

If someone wants to do it their own way, with their own interpretation, and they consider themselves the AHJ........... by all means, do whatever you want!

I'll stick with common sense, IMHO
 
your state says one thing beach.. not everyone agrees with you. Let's agree to disagree and let this thread die.

Thanks
 
West Des Moines Fire Department

FIRE PREVENTION BUREAU

TYPE 1 HOODS & SUPPRESSION

WDM Fire Code and IMC 2006

May 14, 2007

1. Type I Hoods shall be installed where cooking appliances produce grease vapors or smoke.

2. See all applicable provisions pertaining to installations of Type I hoods and grease ducts under the 2006 International Mechanical Code, Section 506, 507 and 508.

3. Sufficient make up air shall be provided to all hoods. Supply air openings shall be a minimum of 6'-0" from any part of a Type I Hood. The supply air unit and /or a fire-smoke damper installed in the supply air opening may be interconnected to the fire extinguishing system to shut down upon activation of the extinguishing system.

4. All equipment located under a Type I Hood shall be interconnected with the fire extinguishing system and make-up (supply) air system so that all fuel and energy sources shall be terminated upon activation of the fire extinguishing system. The exhaust fan for the Type I Hood shall continue to operate unless fire extinguishing system requirements state otherwise. Supply air within 6-feet of the hood shall shut down upon system activation.

5. If the building has a fire alarm system, then activation of the hood extinguishing system shall activate the building fire alarm system.

6. Pull stations to activate the hood suppression system shall be no closer than 10-feet to the hood and no more than 20-feet from the hood (unless approved by the Fire Marshal. The “K” class extinguisher with signs shall be mounted next to the pull station.

7. Plans and fees shall be submitted for the hood suppression system by a licensed contractor to the Fire Marshal.

For mechanical questions call the Mechanical Inspector at 515-222-3630.

For additional information, please contact the Fire Marshal at 515-222-3420.
 
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