Flammables Cabinet DIY or alternatives?

[mishima]

Hi, I was looking into building a flammables cabinet for our high school lab. Flinn suggests a 1 inch thick plywood cabinet is superior to a metal cabinet because it will not warp under heat. I was curious if that'e true, or of any other alternatives to a flammables cabinet. Thanks.

 

[Borek]

No regulations, fire codes, that will deal with the requirements?

 

[mishima]

Yes, OSHA:

regulations also provide an option for wood cabinets. 1910.106(d)(3)(ii)(b) states that wood cabinets must be constructed in the following manner:

Bottom, top and sides of cabinet shall be at constructed of exterior grade plywood at least 1" thick
Plywood shall not break down or delaminate under fire conditions
Joints shall be rebutted and fastened in two directions with flathead wood screws
When more than one door is used, they should have a rebutted overlap of not less than 1"
Doors shall be equipped with latches and hinges that are mounted to not lose their holding capacity when subjected to fire
Door sill or pan shall be raised at least 2" above the cabinet bottom to retain spilled liquid within the cabinet
Cabinet must have a "FLAMMABLE—KEEP FIRE AWAY" legend
In addition to the requirements listed above, the UFC also requires self-closing doors. Most local authorities use one or more of these standards as a foundation for establishing local codes.

There is a similar list for metal type cabinets. I am curious if wood is better than metal. I am also looking for alternatives. Basically, I need a simple and cheap way to do it.

 

[ChrisJA]

I assume you are required to use a UL listed type cabinet and can't just build your own, unless you want to spend $100K getting your new design tested.

One good and cheap way to build a fire resistant box is with "X" type wall board. There is a type of sheetrock that is fire rated. It's very inexpensive compared to plywood. Cut it by scoring with a utility knife then snapping it. It you will find a few layers of this stuff in large fire proof safes glued to the steel walls. I think this has replace asbestos boards. Building code sometimes requires this kind of wall boards. They sell a special kind of caulking that is also fire resistance that you have to use to seal the edges. It is abut $10 a tube.

Is wood better? No. as in all engineering it is just a matter of meeting a requirement at the lowest cost. If the goal is to survive a fire for 15 minutes you either need so much metal or some much wood or so much concrete. Which is cheaper depends on the details

Is wood good for heat? There was an early Chinese spacecraft that dropped some small part back to Earth (likely film??) and the heat shield that survived reentry was made of solid oak. Wood is good stuff. Notice the fire codes for building don't allow you to use steel structural members unless you pack them with solid wood on both sides. The wood provides insulation. In larger buildings they spray on a kind of foam but in residential construction they bolt lumber to the steel and not just for nailing, fire codes requires it.

 

[HelperChuck]

This is years old, but I want to put this link here so others can find it.

This link has a full plan showing how to build a home-sized fire cabinet out of one sheet of 1" plywood. This flammables storage cabinet has been designed to meet the code requirements of the National Fire Protection Association.

The link and story originally appeared in American Woodworker October 2000, issue #82.

http://www.popularwoodworking.com/projects/flammables-cabinet