any of you practitioners out there have knowledge of two-hour wall assemblies using wood studs that use something other than 2 layers of 5/8 gyp on either side?
like is oft' the case i have a two hour wall meeting a one hour wall in the same plane and i'm looking for a way to keep them as close to flush as possible w/o furring out the other wall to match.
book references, web references, ul or wp #s please.
thanks.
jh
Feb 8, 06 8:00 pm
2-hour wall finished face to face = 5.5":
2″ × 4″ wood studs 16″ on center with metal lath and 7/8″ neat wood-fibered
gypsum plaster each side. Lath attached by 6d common nails, 7″ on center.
Nails driven 11/4″ and bent over.
1-hour wall finished face to face = 5.5"
2″ × 4″ wood studs 16″ on center with two layers 1/2″ regular gypsum wallboarde
applied vertically or horizontally each sidek, joints staggered. Nail base layer
with 5d coolern or wallboardn nails at 8″ on center face layer with 8d coolern or
wallboardn nails at 8″ on center.
cf
Feb 9, 06 9:22 am
As jh:
...
UL Fire Resistance Directory:
Design No. U301, U334, U350, U357
RankStranger
Feb 9, 06 11:26 am
Double up on the 1-hour wall and just make it a 2 hour wall. Shouldn't cost too much more.
ochona
Feb 9, 06 3:26 pm
second that
southpole
Feb 9, 06 4:28 pm
You cold also stager the studs ( ½â€) in the 1hr wall, but labor wise it would be easier just to double up the drywall.
will galloway
Feb 9, 06 5:14 pm
treble the doubling.
RNNR
Feb 10, 06 9:54 am
as a sidenote about alternate fireproofing, check out shigeru ban's highrise in osaka - plywood was used as fireproofing around the columns
and to support his claim of a 'fireproof' wood, the results from tests show that the wood reached a charcoal state and stopped burning at a certain point. i'm not sure of the specifics, but there is some detailed info in his phaidon monograph.
RankStranger
Feb 10, 06 12:52 pm
There are fire-treated plywoods. We did a boathouse below the floodplain and had to use some as a finish material since gyp. bd. & plaster are not allowed. I understand they are made with some nasty chemicals like arsenic and formaldahyde, although I think some eco alternatives have come out in the last few years. What you're talking about sounds like the theory behind heavy timber construction.
DMPArch
Jun 13, 13 1:43 pm
Could someone pass me the UL Design No for a 1 hr exterior wall. Ideally looking for a 5/8" gyp interior, 2x6 stud and 7/16" OSB exterior; or something close; perhaps need another layer of gyp under the OSB?
Thanks for the sites and links. I appreciate the help.
joelane
Dec 16, 19 8:12 pm
existing 2x6 wall is sheeted with 7/16 OSB any way to achieve a 2hr rating without having to remove sheeting. 3 layers of 5/8 typ x gyp on the inside?
Non Sequitur
Dec 16, 19 10:26 pm
What does your architect say?
archanonymous
Dec 16, 19 10:53 pm
3 layers of gyp is definitely not the answer
atelier nobody
Dec 18, 19 2:20 pm
2019 IBC Table 721.1(2)
threeohdoor
Dec 18, 19 2:46 pm
Genuinely Curious Devil's Advocate: Why is 3x Fireshield on either side"definitely not the answer"? UL lists 2x4 assemblies with 2x both sides for 2hr ratings.
Non Sequitur
Dec 18, 19 2:59 pm
^It depends on the situation. Is Joe's 2hr wall a fire separation between 2 suites? If so, laminating gypsum board to one side will not work since the supporting structure (2x6 studs) are unprotected on one side of the assembly. There are not many ways to achieve rated partitions using a one-sided membrane approach. Perhaps you American cowboys have more flexibility, but unless I use a prescriptive ULC assembly, I am limited to 2 layers of 1/2" gypsum board (and 90min) when designing rated walls as per my building code.
atelier nobody
Dec 18, 19 3:06 pm
Many years ago, there used to be some situations in the Code that allowed for a 1-sided assembly, but I honestly don't know whether or not they're still in there, as I've never used one.
Non Sequitur
Dec 18, 19 3:17 pm
^they're called shaft walls now.
threeohdoor
Dec 18, 19 3:57 pm
Ah, yea, I just assumed he was laminating both sides. In the case of asymmetric walls, NYC considers rating the "thin" side as the rating for the assembly. I suppose he'd have to build a shaft wall in front of the OSB and run it horizontally to exterior/demising walls. As for more than two layers each side for a rated wall, I can't honestly say that I've had to do so. I've done super thick isolating walls for acoustic reasons, but that was internal to a space.
atelier nobody
Dec 18, 19 4:41 pm
A shaft wall is asymmetrical, but it still has protection on both sides.
Non Sequitur
Dec 18, 19 4:47 pm
Sorry, I should have added a /s to my shaft wall comment.
archanonymous
Dec 18, 19 5:12 pm
IBC limits calculated resistance with wood studs to 1hr. All 2hr wood studs assemblies I am aware of are two-sided.
any of you practitioners out there have knowledge of two-hour wall assemblies using wood studs that use something other than 2 layers of 5/8 gyp on either side?
like is oft' the case i have a two hour wall meeting a one hour wall in the same plane and i'm looking for a way to keep them as close to flush as possible w/o furring out the other wall to match.
book references, web references, ul or wp #s please.
thanks.
2-hour wall finished face to face = 5.5":
2″ × 4″ wood studs 16″ on center with metal lath and 7/8″ neat wood-fibered
gypsum plaster each side. Lath attached by 6d common nails, 7″ on center.
Nails driven 11/4″ and bent over.
1-hour wall finished face to face = 5.5"
2″ × 4″ wood studs 16″ on center with two layers 1/2″ regular gypsum wallboarde
applied vertically or horizontally each sidek, joints staggered. Nail base layer
with 5d coolern or wallboardn nails at 8″ on center face layer with 8d coolern or
wallboardn nails at 8″ on center.
As jh:
...
UL Fire Resistance Directory:
Design No. U301, U334, U350, U357
Double up on the 1-hour wall and just make it a 2 hour wall. Shouldn't cost too much more.
second that
You cold also stager the studs ( ½â€) in the 1hr wall, but labor wise it would be easier just to double up the drywall.
treble the doubling.
as a sidenote about alternate fireproofing, check out shigeru ban's highrise in osaka - plywood was used as fireproofing around the columns
and to support his claim of a 'fireproof' wood, the results from tests show that the wood reached a charcoal state and stopped burning at a certain point. i'm not sure of the specifics, but there is some detailed info in his phaidon monograph.
There are fire-treated plywoods. We did a boathouse below the floodplain and had to use some as a finish material since gyp. bd. & plaster are not allowed. I understand they are made with some nasty chemicals like arsenic and formaldahyde, although I think some eco alternatives have come out in the last few years. What you're talking about sounds like the theory behind heavy timber construction.
Could someone pass me the UL Design No for a 1 hr exterior wall. Ideally looking for a 5/8" gyp interior, 2x6 stud and 7/16" OSB exterior; or something close; perhaps need another layer of gyp under the OSB?
Thanks.
Pretty useful wall selection widget from USG:
http://www.usgdesignstudio.com/wall-selector.asp?utm_source=Home+Page&utm_medium=direct&utm_term=wall-selector&utm_content=logolink&utm_campaign=Launchpad
Also look at the GA manual online for gypsum rated assemblies
And the damn building code.
Very handy UL assembly search page that I have been using for a number of years. It has recently be revamped to be a little more user-friendly.
http://database.ul.com/cgi-bin/ulweb/LISEXT/1FRAME/FireResistanceWizard.html
Thanks for the sites and links. I appreciate the help.
existing 2x6 wall is sheeted with 7/16 OSB any way to achieve a 2hr rating without having to remove sheeting. 3 layers of 5/8 typ x gyp on the inside?
What does your architect say?
3 layers of gyp is definitely not the answer
2019 IBC Table 721.1(2)
Genuinely Curious Devil's Advocate: Why is 3x Fireshield on either side"definitely not the answer"? UL lists 2x4 assemblies with 2x both sides for 2hr ratings.
^It depends on the situation. Is Joe's 2hr wall a fire separation between 2 suites? If so, laminating gypsum board to one side will not work since the supporting structure (2x6 studs) are unprotected on one side of the assembly. There are not many ways to achieve rated partitions using a one-sided membrane approach. Perhaps you American cowboys have more flexibility, but unless I use a prescriptive ULC assembly, I am limited to 2 layers of 1/2" gypsum board (and 90min) when designing rated walls as per my building code.
Many years ago, there used to be some situations in the Code that allowed for a 1-sided assembly, but I honestly don't know whether or not they're still in there, as I've never used one.
^they're called shaft walls now.
Ah, yea, I just assumed he was laminating both sides. In the case of asymmetric walls, NYC considers rating the "thin" side as the rating for the assembly. I suppose he'd have to build a shaft wall in front of the OSB and run it horizontally to exterior/demising walls. As for more than two layers each side for a rated wall, I can't honestly say that I've had to do so. I've done super thick isolating walls for acoustic reasons, but that was internal to a space.
A shaft wall is asymmetrical, but it still has protection on both sides.
Sorry, I should have added a /s to my shaft wall comment.
IBC limits calculated resistance with wood studs to 1hr. All 2hr wood studs assemblies I am aware of are two-sided.