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Some devastating fires have occurred in commercial cooking establishments.  We all know the history of fast food restaurant fires and the toll they can have on a fire department if the fire is not found early.

Kitchen suppression systems are designed to activate to limit the effects of a grease fire in these establishments. It is important to note that when these fires occur and the system is activated, the return air should shut off and the hood vent should activate if it is not already on.

When these systems are designed they are equipment specific. Meaning that the flow points are determined by the type of cooking appliance and its location under the hood and suppression system. Moving or replacing any appliance requires reevaluation of the system and could mean an alteration to keep the system adequate.

As you can see in the picture, the appliance shown has wheels.  This could create a problem in the future when the ownership wants to move things around a bit and could be detrimental to the effectiveness of the system. One suggestion is to adopt a local ordinance that requires these wheels to be removed or locked. I have seen it both ways and it is up to your jurisdiction on how to do that.

Secondly, you want to ensure that the suppression system is hooked into a monitored fire alarm system or on a direct dial alarm system.  We, the fire department, want to know if this system activates.  Even if the system puts the fire out, there is a possibility of fire being pulled into the vent duct. If there are any penetrations or gaps in that duct, fire could smolder above for a long time or it could be burning the uncleaned grease.  We also want to make sure that if that system activates it gets put back in service appropriately and prior to cooking commencing again.

In the video it shows a "dump" test where we make sure that the correct amount of product is being flowed and that all utilities are shut off with the activation.

I know this is not a tactical post, but it gives you a little insight of why these systems are important.  I may not have touched on all of the aspects of these systems, so if you have additional comments or suggestions, please feel free to comment.

Thanks, stay safe and be careful.


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Jason, I like the post because it gives company level guys an basic understanding of how things work if the bosses don't. Back to basics, how often do we really check these hood systems thoroughly during our company inspections like we should be, to add to that where is the class "K" extinguisher at and is it properly installed?


Nicely done as usual Brother! Take Care Jeff

1. Fire suppression systems are listed to operate with the exhaust fan on or off

2. There is a requirement in NFPA 96-2008 12.12.3 & that covers the placement of appliances with or with out wheels.

    I think there is a similar requirement in the Mechanical Specialty Code, 2006, but that code book is in my van.

3. NFPA 72 has  a requirement that the suppression system be wired to a fire alarm, if the premises are equipped with a fire alarm.  It is also a requirement that is often neglected

4. I have never seen a requirement for a "dump test" in the NFPA standards, the IFC standards or the Mechanical Specialty Code standards or any manufactuer installation manuals.  I have not seen any information in the installation manuals that gives any indication that a certain amount of chemical is to be applied to any appliance.  If the requirments of the installation manual are followed, and the right nozzles at the right orientation and height are followed, the UL300 Fire Test Standard will be met. All the dump test does is increase the cost to the owner of the resturant.  After the test, all the piping needs to be flushed using water or a special chemical supplied by the system manufacturer.  Then air needs to be blown through the piping in an effort to dry the pipe and prevent rust.  And the tank/tanks need to be recharged with new chemical.  If you can quote a national code or standard requirement, I would like to know. 


Jeff, after 30 years of doing installs and servicing suppression systems, I stll need get out the manual to make sure the components are installed correctly. And I often talk to others in hte trade for their advice.  But Jason did a good job of explaining the basic function of  chemical fire suppression system.  There are state orgs, such as those in GA, OR, PA, WA, FLA that offer classes in fire suppression systems and portable fire extinguishers.  Go to for information on state orgs.


 Thanks for the comments and your expertise.  You are correct with the codes. We operate many of these requirements from local ordinances that were established years ago. One of the things we have done in our jurisdiction is teamed up with our city building commissioner to mirror each others codes as best as possible to eliminate any contradictions between the two AHJs.

  I can't remember a day when we didn't request a dump test, and I can say that in 99% of the cases, the contractor doing the  work is expecting it.  As far as the quantity issue, this information is handed to us by the engineer firm when they seal the shop drawings with flow points and calculations.  It has been explained to me that each flow point should provide a minimum amount of product to protect the specific surface area below.  When we do the dump test, we require only water.  I never recall a time that this was an issue.

  The only reason we require the alarm, which is local ordinance, is because we had instances where systems were set off by fire and we were never called, nor was the health department.  We want to insure that no fire breached the void space above, that the system gets back in service prior to cooking starting again and that the facilities are clean enough for human consumption.

  I am not an expert and typically have to get into the books on a regular basis as well.  The only reason I posted was to bring some things for companies to look at when they do inspections.  I really appreciate your information, it will only help to educate others about these topics that are not regularly discussed.  If someone learns something from this post, than we did our job. : )

  If you have more to offer, please keep the comments coming.


Thanks and take care,



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