Walkin coolers Sprinklers required?

[mtlogcabin]

I have an existing 400 sq ft walk in cooler located inside a 1,200 sq ft V-B building used to store seeds. They want to add 240 sq ft to the existing walkin cooler bringing the sq ft of the cooler to 640 sq ft. The cooler walls are 2 x 6 with 4 inches of foam and 1/2" OSB on both sides(similar to a SIPS panel. Question does the 640 sq ft walkin cooler need to be sprinklered or is the 1/2" OSB thermal barrier sufficient?

2009 IBC

2603.4.1.2 Cooler and freezer walls.

Foam plastic installed in a maximum thickness of 10 inches (254 mm) in cooler and freezer walls shall:

1. Have a flame spread index of 25 or less and a smoke-developed index of not more than 450, where tested in a minimum 4 inch (102 mm) thickness. Compliant

2. Have flash ignition and self-ignition temperatures of not less than 600°F and 800°F (316°C and 427°C), respectively. Compliant

3. Have a covering of not less than 0.032-inch (0.8 mm) aluminum or corrosion-resistant steel having a base metal thickness not less than 0.0160 inch (0.4 mm) at any point. Installed over the OSB, Compliant



4. Be protected by an automatic sprinkler system in accordance with Section 903.3.1.1. Where the cooler or freezer is within a building, both the cooler or freezer and that part of the building in which it is located shall be sprinklered. Non-Compliant

2603.4.1.3 Walk-in coolers.

In nonsprinklered buildings, foam plastic having a thickness that does not exceed 4 inches (102 mm) and a maximum flame spread index of 75 is permitted in walk-in coolers or freezer units where the aggregate floor area does not exceed 400 square feet (37 m2) and the foam plastic is covered by a metal facing not less than 0.032-inch-thick (0.81 mm) aluminum or corrosion-resistant steel having a minimum base metal thickness of 0.016 inch (0.41 mm). A thickness of up to 10 inches (254 mm) is permitted where protected by a thermal bar Exceeds the 400 sq ft limitation

 

[Dr. J]

These two sections are the exception to 2603.4 which otherwise would require a thermal barrier. If it doesn't meet these two sections it needs a thermal barrier.

2603.4 defines the thermal barrier - equivalent to 1/2" gyp. bd. or pass specified tests. So, your real question should be, "is 1/2" of wood equivalent to 1/2" of Gyp. Bd?". Unless they got some of that magic paint, probably not.

They need to either enclose the cooler in drywall or paint the wood with magic paint to meet 2603.4, or they need to sprinkler it to meet 2603.4.1.2 (it will never meet 2603.4.1.3 due to the aggregate sf limit).

 

[TimNY]

The building is not sprinklered?

 

[Dr. J]

A bit facetious on the magic paint thing. A remote possibility is that the assembly of metal over wood has an ICC ES report showing equivalency to gyp bd.

 

[mtlogcabin]

Thanks Dr. J They should be able to add a layer of 1/2" gypsum board pretty easily.

TimNY No this building is not sprinklered.

 

[SCBO1]

My two cents worth, OSB is only 7/16" thick and plywood is not a full 1/2" thick. 2603.4 requires a 0.5-inch interior thermal barrier. I too agree it should be gyp bd. like the Dr. sez.

But does the code take into consideration that building materials do not match up to sizes required?

Am I splitting hairs?

pc1

 

[Dr. J]

The issue is not the dimension, it is the material. Gyp Bd is a thermal barrier because it absorbs the heat of a fire by releasing bound water, wood burns and thus is not, by itself, a thermal barrier. If anything besides 1/2" (nominal) gyp bd is proposed, ask to see the ICC ES.

 

[brudgers]

Are you suggesting coolers migrate?

 

[north star]

* * * *

What rating is required on the separation?......One layer of 1/2"

gyp. board is going to only provide [ at most ] a 15 minute

"burn thru" time.

In this AHJ, we had an project where the RDP spec'd. a layer

of 5/8" on a Walk-In Cooler enclosure from the rest of the building.

* * * *

 

[peach]

why would anyone want wood exposed inside a cooler (which will experience temperature flux everytime the door is opened).. don't we learn from freezer burn at home?