GC would like to salvage drywall interior walls damaged by water except for the bottom 12 of stud and track. Which means they would need a splice detail to extend the metal studs down to the new bottom track. Is this something UL has tested and approved?
Im assuming nobody has paid for a test with spliced studs. I would think you could get an EJ pretty easily. I did find this… http://cracometals.com/wp-content/uploads/2017/02/CFSEI-Design-for-Splicing.pdf
I found the same, I do not know if all the walls are cold formed, may not matter. I advised the Architect to check with the manufacturer. Thanks for your quick response. I also searched 4specs Forum to see if this has been discussed in past, it had not.
First reaction is to tell the contractor to use full length studs.
If the contractor still wants to pursue this option treat it as a substitution where the contractor agrees to pay for all costs of the design team.
In terms of fire rating I see no difference between a properly designed splice and the connection of the stud to the top track. Thus I suggest that this is not something that would impact a fire rating. If I am wrong then you have a much bigger problem.
My understanding is that fire ratings can be established by showing compliance with a testing protocol. There is nothing requiring that UL perform the tests or approve the results. You just need to show code compliance.
If UL was the only one who could do this you would have created a monopoly and you would have delegated a governmental function to a private entity.
UL, Intertek, or other testing agency acceptable to authorities having jurisdiction.
As a practical matter what is the basis for determining if a testing agency is acceptable? What is the objective criteria?
Do most jurisdictions even have the ability to evaluate a testing agency? If the jurisdiction does not have the ability to evaluate the testing agency then it is suggested that the jurisdiction is not qualified to fulfill their obligations.
“As a practical matter what is the basis for determining if a testing agency is acceptable? What is the objective criteria?”
29 CFR 1910.7 or NIST NVLAP.
The references to 29 CFR 1910.7 and NIST NVLAP are interesting but they are federal standards and as such are not applicable to building codes unless the adopting entity incorporates them. Nothing compels the agency having jurisdiction to use either one.
Still if designers were to base their claim of code compliance on test results the use of a testing laboratory accredited by one of these systems would help defend against a claim of negligence.
I think the answer to this is much simpler on paper than we are making it out to be. Either the testing for the rated assembly allows for spliced studs, or it does not. If it does, which could be confirmed by looking up the listed design, there should be no issue assuming the splicing is done in accordance with the rated assembly’s tested design.
If there is no allowance for spliced studs in the rated assembly’s design, the code allows for “supplemental features” to be incorporated where “sufficient data [is] made available to the building official to show that the required fire-resistance rating is not reduced.” (see 2015 IBC Section 703.2.4 … your adopted code may differ). The source of, and what would constitute, “sufficient data” is best left to the design professional and the building official to sort out. Trying to guess what the building officials are willing to accept has been hit or miss for me in the past. You may have had better luck than me.
If you believe that the stud splices are not compatible with the fire rating of the assembly then you would also have the same problem with the connections of headers over openings. This would suggest that we have problems with most buildings where metal studs are used. Are you wiling to state that there is a problem with the rating of most metal stud assemblies?
As I understand fire tests they are concerned with transmission of heat across the assembly and whether the structural elements become hot enough that their carrying capacity is significantly reduced. The splice will not impact the temperature on the other side. My understanding is that the temperature of the studs will not impact the capacity of the connection.