Plywood used in high-piled racking, Type II Building

[classicT]

Any thoughts on allowing plywood for the construction of the horizontal barriers specified in NFPA 13 for Class I, high-piled racking in a Type II building?

My gut says not permitted, but NFPA 13 specifically says that plywood is allowed.

Nothing fits as per IBC 603.1 though...

16.1.9* Horizontal Barriers and In-Rack Sprinklers​

16.1.9.1​

Where required by other sections of this standard, horizontal barriers used in conjunction with in-rack sprinklers to impede vertical fire development shall be constructed of sheet metal, wood, or similar material and shall extend the full length and depth of the rack.

16.1.9.2​

Barriers shall be fitted within 2 in. (50 mm) horizontally around rack uprights.

 

[e hilton]

Does any code give a time rating for the barrier? 20 min for example.

 

[classicT]

Does any code give a time rating for the barrier? 20 min for example.

No. All it serves to do is contain the heat long enough to activate the sprinkler head.

 

[classicT]

3.9.3.5 Horizontal Barrier​

A solid barrier in the horizontal position covering the entire rack, including all flue spaces at certain height increments, to prevent vertical fire spread.

The above definition is provided as well.

 

[RLGA]

NFPA 13 clearly indicates wood, so it must be acceptable. The wood must be of sufficient thickness to avoid sagging under load, so the plywood sheet would likely be something more substantial than your standard 1/2-inch-thick plywood panel. (You also have to consider the items stored on the shelving will also consist of combustible materials, shuch as wood pallets and cardboard packaging.)

Per the NFPA Fire Protection Handbook, the horizontal barriers "help to activate the in-rack sprinklers and reduce the number of in-rack sprinklers needed." The barriers trap the heat close to the in-rack sprinkler heads allowing them to reach their activation temperature. Without the solid barriers, open shelving, such as metal grating, will allow the heat to rise through the racks.