hood equipment

[nizak]

Could someone please post the NFPA article that gives the shutdown procedure for a commercial kitchen hood. i.e power under hood, exhaust, make up air, etc. Thank You.

 

[mdshunk]

It's in a few of them, but basicly gas off, makeup air off, exhaust on, lights off, under hood electric power to appliances off. Notification of local FA sometimes req'd.

 

[LarryFine]

I just did one yesterday, a re-fit of a fairly big one. Existing kitchen, with two intake fans and two exhaust fans. Each of the four fans has a separate power switch. The fire-supression guys re-piped and put in a new tank and control box, and a plumber installed the solenoid gas valve.

I added the gas-valve reset box and a horn-strobe. I was able to maintain the four individual switches and still have everything operate as required (outlined my Marc above) with the additional requirement that the gas shut off if either (or both) exhaust fan is turned off manually.

I had to use four contactors. One 2-pole shuts down the two intake fans, one 2-pole energizes the two exhaust fans, and two 1-poles monitor the two exhaust fans to de-energize the gas valve. The shut-off-the-gas-with-manual-operation is in the fire code they use here. Customers hate it.

 

[adavey]

NFPA 96 and you local Mechanical code (if there is one)

 

[benaround]

Manual 'reset' is also required, but I have seen a lot of systems without it.

If the 'Ansul ' man comes and recharges the system, without a manual reset

for the electrical equipment, it will reenergize everything possibly starting

another fire. IMO that's why a lot of EE's use shunt breakers.

 

[LarryFine]

So far, at least, here only the gas requires a manual reset, thus the box.

 

[benaround]

Larry,

Have you ever done a kitchen that was all electric ?

 

[nizak]

Is it a requirement that the hood exhaust and make-up air start with the same switch or can each one be started seperatetly?

 

[benaround]

nizak, Normally they want both to come on at the same time, think about it

this way, if the make-up air ran by itself, the outside doors wouldn't close and

if just the exhaust fan ran the doors would be real hard to open with both

running you have a balanced system.

In the area I work in they want the exhaust fan to come on whenever the

Ansul system is activated, even if the exhaust fan/ MAU switch is off.

Remember, different parts of the country have their own way of doing things,

so, whoever is going to inspect this system is the one to ask.

 

[nizak]

benaround, thanks for the input. Do you have a link to NFPA 96 that clearly states the requirements? On this retro job there are many aspects(improper duct insulation, inadequate fire alarm system, etc) that is being overlooked but I get stuck with making the existing hodge podge of 3 seperate Ansul systems, 2 make up air units, and 3 exhaust fans work "per code" and these components are all spread out over a 70'x30' foot kitchen.

 

[BryanMD]

On this retro job there are many aspects(improper duct insulation, inadequate fire alarm system, etc) that is being overlooked but I get stuck with making the existing hodge podge of 3 seperate Ansul systems, 2 make up air units, and 3 exhaust fans work "per code" and these components are all spread out over a 70'x30' foot kitchen.

If you want to be a hero contact a fire equipment company to spec the components the WHOLE system needs to be compliant and functional; maybe sub contract them to install some things.

If the owner won't cooperate with doing it right on his own...
drop a dime to the fire marshal and let the FM order him to do it right.

 

[LarryFine]

Larry,

Have you ever done a kitchen that was all electric ?

Oh, yes! I've used contactors for appliances, I've used shunt-trip branch-circuit breakers, and I've used shunt-trip main breakers. There's no one best choice.

It all depends on several factors, such as existing or new kitchen, if new is it still in the design phase, the quantity and amperage of the appliances, and so forth.

Who is doing the engineering of the system? Are you given a schematic, or do you need to design the circuitry yourself, like I often do since many are retrofits?

 

[LarryFine]

Is it a requirement that the hood exhaust and make-up air start with the same switch or can each one be started seperatetly?

I've seen plenty done both ways. Sometimes, use of the intake fan depends on the outside temperature, as I'm told by cooks.

When I design the system, recommend using a single switch, because both the operation and the wiring are easier.

 

[nizak]

Where would I find out if "manual" reset is required for the electrical portion of the hood shutdown? It appears the gas valve would have to be manually reset, is simply the location of the limit switch arm moving back into position once the Ansul is re-cocked satisfactory? Thanks much.

 

[cschmid]

man now for the monkey twist..leaving the hood exhaust on spreads fire through the upper areas of the building..when using contactors on the electrical appliances do you put them in a sperate panel and does all the power in the panel disconnect when you open the door of the panel..so now I will go to bed and tomarrow I will come back to this..I have more questions and maybe more than answers..:grin:

edited to add..a manual reset is required for everything..