# Know This Shaft Wall UL?



## Francis Vineyard (Dec 18, 2015)




----------



## north star (Dec 18, 2015)

*$ > < $*

Francis,

I cannot see your pictures........It may be the security level on

my work computer..........I wonder if anyone else can see them.

FWIW, ...we do have a link to the U.L. assembly types in our

"Useful Links" thread..........Here is a link to the U.L. databases:

*http://www.thebuildingcodeforum.com/forum/useful-links/17426-u-l-product-specifications.html*



*$ > < $*


----------



## Francis Vineyard (Dec 18, 2015)

Try these links: http://s1105.photobucket.com/user/4justice2/media/Shaft%20Walls_zps4musrl45.jpg.html" target="_blank">

http://s1105.photobucket.com/user/4justice2/media/Shaft%20Walls%20again_zps00prrpn0.jpg.html" target="_blank">


----------



## north star (Dec 18, 2015)

*$ > < $*

Nope !........My work computer has a very high security level

and it will not allow me to view your pics.

Is it possible for you to describe in words what you are seeking ?

Maybe I can search for it that way.



*$ > < $*


----------



## Francis Vineyard (Dec 18, 2015)

It's a slide presentation that shows a 2hr. rated shaft constructed similarly as an exterior wall rated for exposure to both sides with a non-rated floor penetration.  A doulbe row of 2x blocking between the floor joist above the top plate to the underside of the floor deck permitted to continue the fire rating instead of the fire rated gypsum being continuous in the concealed spaces below the floor decking and above the ceiling as typically shown in the code commentary.


----------



## khsmith55 (Dec 18, 2015)

Having been through this exercise a few years ago and after extensive research, I could not find ANY approvals for this detail. What I started doing in these conditions was to do a beam “outside” of the shaft and hanging the joists. On a happy note, Simpson now makes a “listed” hanger that nails thru the two layers of GWB which maintains the continuity of the shaft wall.


----------



## cda (Dec 18, 2015)

north star said:
			
		

> *$ > < $*Nope !........My work computer has a very high security level
> 
> and it will not allow me to view your pics.
> 
> ...


Around page 34

http://www.woodworks.org/wp-content/uploads/TTWB-2014-Podesto-Fire-Resistance-of-Light-Frame-Mid-rise.pdf

Maybe performance or from the build your own section in ibc


----------



## khsmith55 (Dec 18, 2015)

Follow-up, the hangers are Simpson DHU and DHUTF hangers.


----------



## Paul Sweet (Dec 18, 2015)

I have had similar details approved by some jurisdications but disapproved by others.  Some that accepted it required the first bay of floor joists to have the same rating as the shaft if they penetrated the gyp, board.


----------



## steveray (Dec 18, 2015)

Francis Vineyard said:
			
		

> It's a slide presentation that shows a 2hr. rated shaft constructed similarly as an exterior wall rated for exposure to both sides with a non-rated floor penetration.  A doulbe row of 2x blocking between the floor joist above the top plate to the underside of the floor deck permitted to continue the fire rating instead of the fire rated gypsum being continuous in the concealed spaces below the floor decking and above the ceiling as typically shown in the code commentary.


I would bet that it is a rated floor by the concrete topping...


----------



## mtlogcabin (Dec 18, 2015)

steveray said:
			
		

> I would bet that it is a rated floor by the concrete topping...


It is not what is on top of the floor that gives it a rating but what is underneath the floor (ceiling)  that provides protection for the floor

We see gyp-crete all the time for sound not fire


----------



## Sifu (Dec 18, 2015)

So is the idea that the solid lumber will provide a slow enough burn to maintain the 2 hour rating?


----------



## TJacobs (Dec 21, 2015)

The AWC is going under the assumption that if wood burns at a rate of 1.5 inches an hour, then (2) 2x's will last 2 hours.  Just my opinion.  Not a UL-listed assembly AFAIK.


----------



## mark handler (Dec 21, 2015)

Not quite the same construction.

Is it blocked solid in your construction?


----------



## Yikes (Dec 21, 2015)

In the September/October 1982 issue of Building Standards, then-ICBO staff engineer Paul Sheedy proposed this same kind of detail (solid blocking) in Figure 13 of an article called "Area Separation Walls Revisited".  They would typically solid block using three 2x (to get over 3 1/2" thickness of solid wood).  If I remember correctly, this article was referenced in subsequent editions of the "UBC Q and A code Applications Manual" and perhaps even the UBC Commentary.


----------



## steveray (Dec 22, 2015)

mtlogcabin said:
			
		

> It is not what is on top of the floor that gives it a rating but what is underneath the floor (ceiling)  that provides protection for the floorWe see gyp-crete all the time for sound not fire


Correct....but typically when I see that floor/ ceiling design it is for wood framed apartments with the required rated tenant separation...It also usually has resilient channel underneath.


----------



## steveray (Dec 22, 2015)

TJacobs said:
			
		

> The AWC is going under the assumption that if wood burns at a rate of 1.5 inches an hour, then (2) 2x's will last 2 hours.  Just my opinion.  Not a UL-listed assembly AFAIK.


The calculations in IBC 721.6 max out at 1hr for prescriptive wood fire resistance.....IMO beyond that you would need a listed assembly or convince me otherwise...


----------



## mark handler (Dec 22, 2015)

Yikes said:
			
		

> In the September/October 1982 issue of Building Standards, then-ICBO staff engineer Paul Sheedy proposed this same kind of detail (solid blocking) in Figure 13 of an article called "Area Separation Walls Revisited".  They would typically solid block using three 2x (to get over 3 1/2" thickness of solid wood).  If I remember correctly, this article was referenced in subsequent editions of the "UBC Q and A code Applications Manual" and perhaps even the UBC Commentary.


Another history buff It was a good and thorough article. still have a copy, somewhere

This was based on it

http://www.sandiego.gov/development-services/pdf/industry/bnl05-03.pdf


----------



## Francis Vineyard (Dec 22, 2015)

Yikes said:
			
		

> In the September/October 1982 issue of Building Standards, then-ICBO staff engineer Paul Sheedy proposed this same kind of detail (solid blocking) in Figure 13 of an article called "Area Separation Walls Revisited".  They would typically solid block using three 2x (to get over 3 1/2" thickness of solid wood).  If I remember correctly, this article was referenced in subsequent editions of the "UBC Q and A code Applications Manual" and perhaps even the UBC Commentary.


http://www.thebuildingcodeforum.com/forum/attachments/commercial-building-codes/1181d1326487114-fire-rated-construction-sheedy-fig13.jpg

http://www.thebuildingcodeforum.com/forum/commercial-building-codes/7380-fire-rated-construction-3.html


----------



## Builder Bob (Dec 22, 2015)

Alternate means and methods, NDS.... Gives a char rate for southern pine 1.25 inches per hour, so if two 2X's are in place, this would give an approx. burn time of 2.4 hours while maintaining the structural stability for the assembly.


----------

