# Noncombustible wall behind cookline



## Ryan Schultz (Aug 3, 2019)

I have worked on Type VB restaurants with full sprinklers. 

I've heard a number of times, through various sources, that the wall behind the cookline needs to be non-combustible. 

It makes sense, but can anyone point me to the code that calls this out specifically.  I'd just like to educated myself on it, as I could not find it.


----------



## TheCommish (Aug 3, 2019)

Try manufactures clearance spec to non combustibles, SS does not count as it transfers heat to the wall behind it. That being said McDs has as a specified design, hood and extingusing for wood wall behind thecooking line.


----------



## Paul Sweet (Aug 3, 2019)

IMC 507.2.6 requires 18" clearance from a type 1 hood to combustibles.


----------



## Builder Bob (Aug 4, 2019)

Mechanical code - it requires 18" to combustible for type I hood.


----------



## mark handler (Aug 5, 2019)

All equipment has clearance listings on the equipment


----------



## Pcinspector1 (Aug 5, 2019)

Clarification on cookline?



Ryan Schultz said:


> I've heard a number of times, through various sources, that the *wall behind* the cookline needs to be non-combustible.





mark handler said:


> All *equipment* has clearance listings on the equipment





TheCommish said:


> SS does not count as it transfers heat to the *wall behind* it



Are we commenting on the OP question, *wall behind* needs 18" clearance? 
Is the *wall behind *considered equipment?

I for one thought that it was normal to see SS (stainless Steel) behind the fryers under the hood system which is a non-combustible material that allows for cleaning. 

What other product do you see in this area behind the fryers? FRP?


----------



## mark handler (Aug 5, 2019)

Pcinspector1 said:


> Clarification on cookline?
> Are we commenting on the OP question, *wall behind* needs 18" clearance?
> Is the *wall behind *considered equipment?
> I for one thought that it was normal to see SS (stainless Steel) behind the fryers under the hood system which is a non-combustible material that allows for cleaning.
> What other product do you see in this area behind the fryers? FRP?



The *wall behind* *equipment is not *considered equipment.
BUT
The code requires the equipment to be installed per the equipment Manufacturer.
Some equipment requires more clearance, some requires less.

We have a lot of kitchen fires, in my jurisdiction, where the "sheet metal" was applied to the wood and the restarant owner or staff, after finals, push the equipment back to touch the wall, so they can gain extra inches in the space.
I now require non-combustible studs if the manufacturer' listing is not provided, or it is
not permanently installed without any movement.

Plan check note


> The back walls of commercial kitchen cook lines require a fire-restive construction, regardless of the building construction type. This wall shall be of non-combustible construction and no wood blocking or backing shall be used in such walls. In existing construction, the back wall of commercial kitchen cook lines is considered combustible unless proven otherwise. In such cases, provide and show on the plans, the clearances that shall be provided for combustible construction per the listing of the appliance as shown on the name plate. No appliance, shelving, or other feature shall be attached to combustible framing in the “Heat Zone”. Applicant must detail on the plan, the appliance, shelving, or other feature attachments located within the heat zone.    2016 CA Mechanical Code sections. 507.3 thru 507.3.3.3.


----------



## mark handler (Aug 5, 2019)

Had one engineer design a vented wall behind to get reduced clearances due to tight spaces.


----------



## mtlogcabin (Aug 5, 2019)

The IMC is the only code that defines noncombustible. Gypsum board does not meet the requirements  of noncombustible in the IMC. That is why there is the exception in 507.2.6 specific for gypsum

507.2.6 Clearances for Type I hood.
A Type I hood shall be installed with a clearance to combustibles of not less than 18 inches (457 mm).
Exceptions:
1.    Clearance shall not be required from gypsum wallboard or 1/2-inch (12.7 mm) or thicker cementitious wallboard attached to noncombustible structures provided that a smooth, cleanable, nonabsorbent and noncombustible material is installed between the hood and the gypsum or cementitious wallboard over an area extending not less than 18 inches (457 mm) in all directions from the hood.

NONCOMBUSTIBLE MATERIALS. Materials that, when tested in accordance with ASTM E 136, have not fewer than three of four specimens tested meeting all of the following criteria:
1.    The recorded temperature of the surface and interior thermocouples shall not at any time during the test rise more than 54ºF (30ºC) above the furnace temperature at the beginning of the test.
2.    There shall not be flaming from the specimen after the first 30 seconds.
3.    If the weight loss of the specimen during testing exceeds 50 percent, the recorded temperature of the surface and interior thermocouples shall not at any time during the test rise above the furnace air temperature at the beginning of the test, and there shall not be flaming of the specimen.


----------



## mtlogcabin (Aug 5, 2019)

We had a fire where the heat transferred through the SS and sheet rock via drywall screw into the wood stud. It took six weeks of cooking operations in this new restaurant before the fire started. We had stand offs on the floor to keep the equipment aligned properly with the suppression system and correct distance from the wall. The problem was the huge wok that was being used forced the heat right onto the wall. Fortunately the guy cleaning the wall 60 minutes after the cooking stopped could feel the wall was still hot and called the FD before it had a chance to get out of the wall.


----------



## Pcinspector1 (Aug 14, 2019)

mtlogcabin,

I've got a hood here with 3-inch clearance on the plans to a gypsum wall with ceramic tile affixed to the wall, no stainless steel. 

I think that's good, do you see this setup in kitchens very often? 

Would install appears to meet the exception?


----------



## Pcinspector1 (Aug 14, 2019)

I have to assume the existing ceramic tiled wall is built with combustible material, but does the 3-inch clearance negate the issue?


----------



## mtlogcabin (Aug 14, 2019)

Only if the hood is listed for a 3" clearance


----------

