How to approach applying a UL assembly to an existing structure

[KHL]

I have a current project that is an assisted living (I-1), Type VA,1 story, fully sprinkled NFPA 13 (dry system), 13,665 sf, built in 1999. Its a typical H-design assisted living floor plan.
The entire building is a gabled/hip roof that is a combination of wood trusses, and part is stick framed (2x rafters and 2x ceiling joists). Currently blown-in insulation at the ceiling plane. Ceiling is (2) layers of type X gyp. bd. All interior partitions terminate at the ceiling plane (not what would happen if we were building today, but it is what it is).

At the time it was built (not certain what codes applied at the time) it was common to utilize 2-layers of 5/8" type X gyp bd fastened to the bottom of the roof framing. I've seen this approach on many assisted living facilities of that time period, it seems to have been an acceptable practice at least in several States.

The owner is looking to convert the dry sprinkler system to a wet system which will require removing all the blown-in insulation and installing open-cell spray foam insulation at the roof deck. This conversion of dry to wet and creating a tempered attic is one we've done before in different jurisdictions. Typically the AHJ has seen it as a positive improvement.

This project AHJ applicable codes are 2012 IBC and 2012 NFPA 101 Life Safety. They do not utilize the IBC existing building code.
The AHJ is requesting that we identify the UL assembly that allows there to be foam installed in the attic. So I'm trying to determine how to approach this. This AHJ is historically sticklers for requiring that the identified UL assembly be followed to the letter - for example, if the assembly doesn't specifically say National Gypsum, you will have a problem at inspection.
The existing construction does not fit nice and neat into a UL roof/ceiling assembly.
The specific items are:
No UL assembly includes (2) layers of 5/8" type X at the ceiling plane - they all are steel channels with (1) layer of 5/8" typically type C
No UL assembly includes the option for non-truss roof construction.
No UL assembly includes the specific spray foam that the contractor is planning on utilizing (we can work on this one )

Has anyone had a similar situation? And what approach did you take?

 

[Yankee Chronicler]

U.L. listed assemblies are typically required when a structural element (wall, floor-ceiling, or roof-ceiling assembly) is required to have a fire-resistance rating. If this sprinkler system and the insulation are in the ceiling cavity of a roof-ceiling assembly, what code provision requires the roof-ceiling assembly to have any fire-resistance rating?

 

[KHL]

Good question - 2012 IBC requires the corridor walls and walls separating dwelling units are required to be fire partitions (708.4 & 1018.1)
Fire partitions are required to be continuous from top of slab to bottom of roof deck OR to a fire-resistive roof/ceiling assembly. (708.4)
This building was originally reviewed, built, inspected and licensed as an assisted living in 1999 - apparently at that time it was acceptable to use 2-layers of 5/8" type x at the ceiling and not be required to extend any of the interior partitions up to the roof deck, as ALL the interior partitions terminate at the ceiling plane.

At this point it would be extremely difficult, maybe not possible, to go in and try to build fire partitions in the attic at all the corridor walls and walls separating dwelling units.

We are looking to leave the existing fire resistive features of this building as they are, basically just move the insulation from the ceiling to below the roof deck -

 

[TheCommish]

Consideration should be give in the sprinkler design for the combatable attic and combustible insulation, along with separation of foam plastic from the occupied space

 

[Yankee Chronicler]

Can you utilize the IEBC? Does Kansas adopt the IEBC? Even if not, perhaps you can use the IEBC as the basis for a modification request.

In the back of the IEBC is a voluminous appendix (Resource A) that includes not only fire resistance ratings for "archaic" building materials, but also a set of rules for using multiple materials (or multiple layers of one material) to increase the rating. This document has been around, essentially unchanged, for as long as I can remember (and I've been practicing architecture for 49 years). At various times it has been published by HUD, the NFPA, BOCA, probably the ICBO and maybe the SBCCI, and now it has found a home as an appendix in the IEBC. It's based on "Harmathy's Ten Rules" (whoever Harmathy was) and, grossly over-simplied, it boils down to "If some of something is good for resisting fire, more of that something is better at resisting fire."

 

[Yankee Chronicler]

Update: I guess my memory isn't as good as I would like to think, because it turns out this document has only been around for 23 years. I thought I remembered having discussions about Harmathy's Rules with the boss I worked for in the 1990s, but this link says the document was first published by HUD is 2000. At any rate -- it has been around for awhile, and it has been accepted by multiple model code organizations so, even if your jurisdiction hasn't adopted the IEBC, it may still be worth asking if your AHJ is willing to accept an approach based on this document.

Guideline on Fire Ratings of Archaic Materials and Assemblies | HUD USER

Aha! In the introduction to the 2000 edition, it states that it dates to 1980. I wasn't crazy (at least, not about this).

 

[KHL]

Can you utilize the IEBC? Does Kansas adopt the IEBC? Even if not, perhaps you can use the IEBC as the basis for a modification request.

In the back of the IEBC is a voluminous appendix (Resource A) that includes not only fire resistance ratings for "archaic" building materials, but also a set of rules for using multiple materials (or multiple layers of one material) to increase the rating. This document has been around, essentially unchanged, for as long as I can remember (and I've been practicing architecture for 49 years). At various times it has been published by HUD, the NFPA, BOCA, probably the ICBO and maybe the SBCCI, and now it has found a home as an appendix in the IEBC. It's based on "Harmathy's Ten Rules" (whoever Harmathy was) and, grossly over-simplied, it boils down to "If some of something is good for resisting fire, more of that something is better at resisting fire."

This project happens to be in TN, and they indicated they have not adopted the IEBC.
I really like "if some of something is good for resisting fire, more of that something is better at resisting fire"! Sometimes it seems like with projects that don't fit cleanly into a check-marked box, the ahj just needs to use some common sense!

 

[KHL]

Update: I guess my memory isn't as good as I would like to think, because it turns out this document has only been around for 23 years. I thought I remembered having discussions about Harmathy's Rules with the boss I worked for in the 1990s, but this link says the document was first published by HUD is 2000. At any rate -- it has been around for awhile, and it has been accepted by multiple model code organizations so, even if your jurisdiction hasn't adopted the IEBC, it may still be worth asking if your AHJ is willing to accept an approach based on this document.

Guideline on Fire Ratings of Archaic Materials and Assemblies | HUD USER

Aha! In the introduction to the 2000 edition, it states that it dates to 1980. I wasn't crazy (at least, not about this).

 

[KHL]

Update: I guess my memory isn't as good as I would like to think, because it turns out this document has only been around for 23 years. I thought I remembered having discussions about Harmathy's Rules with the boss I worked for in the 1990s, but this link says the document was first published by HUD is 2000. At any rate -- it has been around for awhile, and it has been accepted by multiple model code organizations so, even if your jurisdiction hasn't adopted the IEBC, it may still be worth asking if your AHJ is willing to accept an approach based on this document.

Guideline on Fire Ratings of Archaic Materials and Assemblies | HUD USER

Aha! In the introduction to the 2000 edition, it states that it dates to 1980. I wasn't crazy (at least, not about this).

I'm certainly downloading that document! if not this project, I know it will come in handy in the future!

 

[steveray]

The owner is looking to convert the dry sprinkler system to a wet system which will require removing all the blown-in insulation and installing open-cell spray foam insulation at the roof deck. This conversion of dry to wet and creating a tempered attic is one we've done before in different jurisdictions. Typically the AHJ has seen it as a positive improvement.

Doesn't help if you can't get to the IEBC, but it sounds like a repair...

[A] REPAIR. The reconstruction, replacement or renewal of any part of an existing building for the purpose of its maintenance or to correct damage.

401.2 Compliance​

The work shall not make the building less complying than it was before the repair was undertaken.

 

[KHL]

Doesn't help if you can't get to the IEBC, but it sounds like a repair...

[A] REPAIR. The reconstruction, replacement or renewal of any part of an existing building for the purpose of its maintenance or to correct damage.

401.2 Compliance​

The work shall not make the building less complying than it was before the repair was undertaken.

We submitted it as a "repair". But the AHJ has decided that it is a "major renovation". My correspondence with them will continue to emphasize exactly that - "the work shall not make the building less complying than it was before the work was undertaken". If looking at the big picture, the conversion from a dry to a wet sprinkler system ultimately is going to make for a more efficient system and increase the pressure safety margin. Its just trying to communicate to the ahj that the fire-resistive measures of 24yrs ago still meets the intent of the code. If the ahj recognized the IEBC, I think we'd already have this project completed.

 

[Yankee Chronicler]

So make a formal request for modification based on the Guidelines for Fire Resistance Ratings of Archaic Building Materials. Be sure to include that the document originated with the federal government (NIBS and HUD), has been around for 43 years, and has at one time or another been accepted and incorporated by just about every code writing organization in the country. The AHJ can accept it as a modification even if the jurisdiction hasn't adopted the IEBC.

 

[Penguin87]

Good question - 2012 IBC requires the corridor walls and walls separating dwelling units are required to be fire partitions (708.4 & 1018.1)
Fire partitions are required to be continuous from top of slab to bottom of roof deck OR to a fire-resistive roof/ceiling assembly. (708.4)
This building was originally reviewed, built, inspected and licensed as an assisted living in 1999 - apparently at that time it was acceptable to use 2-layers of 5/8" type x at the ceiling and not be required to extend any of the interior partitions up to the roof deck, as ALL the interior partitions terminate at the ceiling plane.

At this point it would be extremely difficult, maybe not possible, to go in and try to build fire partitions in the attic at all the corridor walls and walls separating dwelling units.

We are looking to leave the existing fire resistive features of this building as they are, basically just move the insulation from the ceiling to below the roof deck -

I just did one of these - 1 story, assisted living facitly, 40 units, sprnklered, type VB construction w/ prefab truss roof. Was a repair of fire damaged units which killed a few residents. Shame, but the building had no sprinklers and a resident fell asleep smoking with an O2 tank...

I digress. Anyway, our fire partitions terminated at the bottom of the ceiling, at the unit and corridor side. 1/2 hour for the unit to corridor, 1 hour between units.

I used a 1-hour fire rated ceiling - roof assembly from one of the UL listed assemblies. I believe it has hat channels over 2x ceiling joists w/ gyp board.
Above the ceilings throughout the attic space, we did smoke partitions for every (2) units. The HVAC system had fire dampers in the corridor, and all of the units have their own minisplits.

The UL assembly I went with was: RC 2602

We passed permitting without a hitch.