1 hour fire wall, 2009 building code

[dustonr]

I converted a home with an attached apartment to commercial FTD flower shop with attached apartment. I have been told by the City of Boise, Idaho, building department that a one hour fire wall must be built between the two units because I converted the home to a flower shop. What constitutes a one hour firewall in this case?

[Jerry Peck - Codeman]

The wall would need to be constructed in accordance with one of the approved UL designs, go from floor to ceiling to roof deck to 18 inches above the roof deck (or instead of 18 inches above the roof deck, the roof deck could be protected out to 4 feet to each side of the fire rated wall - not 4 feet from center of the wall, but from each side of the wall).

Here is one example of a UL 1 hour rated wall assembly: (place cursor over link, right click, select open in new window) http://files.buildsite.com/dbderived-f/ ... 407658.pdf

There are many similar designs and all components *must* be as listed and as shown in the design selected.

[Raquel R]

CodeMan,
In reference to 1 hour fire rated walls (interior walls) how do you know which UL Design to use. There are so many to choose from, so how do you know you are making the right choice?
Thank you in advance!

[Jerry Peck - Codeman]

Hi Raquel,

There are so many choices because there are so many design possibilities that the designers (architects) need choices to select from, such as wood frame, metal frame, masonry partition, whether there are chases or not, single layer or double layer, mechanically attached or adhesive, 1-5/8" stud, 3-5/8" studs, 5-5/8" studs, etc.

Additionally, there are fire rated walls which are STC rated and fire rated wall which are not STC rated, and fire rated walls with various STC ratings.

If you are building a simple structure (and even "simple structure" means many things to many people) then you would most likely the select a fire rated wall design based on the method of construction you were using, then consider if you needed or wanted an STC rating and how high of an STC rating.

Then you need to consider the penetrations "into" or "through" the fire rated wall, i.e., "into" would be a "membrane penetration" which would include items such as electrical boxes, clothes dryer boxes and clothes washer boxes, while "through" would be a "through penetration" and would include items such as duct work, piping, wiring, and the like running one side of the wall through the wall and out the other side of the wall.

While your question may seem like a simple question which should have a simple answer, the answer is really quite complex and depends on what you are building, what you want, and how much money is in the budget.

[Raquel R]

Mr. Codeman,
Thank you for your response. Maybe I should be more specific. This 1 hour fire rated wall is for a warehouse that is being converted into an art gallery. There is only 1 means of egress at the moment so they are in need of a secondary means of egress. Therefore, they are going to build a corridor that is solely to be used as a path to exit the building. That corridor needs to be a 1 hour fire rated wall. The existing wall on the other side of the corridor is a concrete block wall. I guess my problem is that there are so many choices, and many of the walls are so similar in their specs, that I can't really determine which would be THE MOST appropriate.
Thank you again.
Raquel

[Jerry Peck - Codeman]

Hi Raquel,

I guess my problem is that there are so many choices, and many of the walls are so similar in their specs, that I can't really determine which would be THE MOST appropriate.

I can't really tell you which is "THE MOST appropriate" fire-rated wall design either.

Here is a link to the National Gypsum Association FIRE RESISTANCE DESIGN MANUAL (GA-600-2009): (place cursor over link, right click, select 'Open in new window') http://www.gypsum.org/pdf/GA-600-09_Screen_3_Megs.pdf

Start here at page 27: Walls and Interior Partitions, Noncombustible, 1 HOUR . . . 27

Find out what brand of gypsum board is going to be used, and the brand of metal studs, etc., as some of the designs are proprietary everything and the specified products from the specified manufacturers MUST be used for that design to be installed in accordance with that design (i.e., the inspector may ask for documentation that the specified manufacturer's products were used, and the inspector should - if the installation is to meet that specified design). Other designs contain some generic products, others contain all generic products, this allows for flexibility in purchasing the materials when constructing the wall.

Read the differences between these two and you will see what I am saying:
Example, on page 28: GA FILE NO. WP 1049 PROPRIETARY
Example, on page 31: GA FILE NO. WP 1072 GENERIC

I really cannot decide which fire-rated wall design is best for your use and installation. Are you the owner, the tenant, the contractor, or the architect? I would defer this to an architect and let them make the decision based on all the information they will have available to them that I do not.