Composite Wood Joists

[James Crawford]

We have a project that is using TJI wood joist (composite wood Joists), they
are 16” deep spaces 18” on center and are 20’ long. There is gypsum board
attached directly to the bottom of the joists along with 3” of insulation at
the bottom to reduce sound transmission. The area is about 1400 sq.ft.

 

Reference is NFPA #13 2013 edition section 11.2.3.1.4(4)(j)

 

Light or ordinary hazard occupancies where noncombustible or limited
combustible ceilings are attached to the bottom of composite wood joists
either directly or on to metal channels not exceeding 1” in depth, provided
the adjacent joist space channels are firestopped into volumes not exceeding
160 cubic feet using materials equivalent to ½” gypsum board and at least 3
½” of batt insulation is installed at the bottom of the joist channels when
the ceiling is attached utilizing metal channels.

 

If each channel space formed by two joist is 40 cubic feet, so the adjacent
space is 40 cubic feet, I see no need to fire stop them into volumes less
than 160 cubic feet as they are already less than 160. The AHJ is saying
that we must firestop every 4th joist space with gypsum to create spaces of
160 cubic feet, so we would need to break the space into 12 spaces of 160
cubic feet for the 1400 sq ft area.

 

Am I reading this correctly or do we need to break the space into sections
of 160 cubic feet?

 

Thank you

 

 

James Crawford

Phaser Fire Protection Ltd.

Phone  604-888-0318

Fax 604-888-4732

Cel 604-790-0938

Email  jcrawf...@phaserfire.ca

 

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Re: Composite Wood Joists

[Roland Huggins]

Allow me a bit of a long winded response instead of a simple yes or no.

First off, although your question is not about whether you can omit sprinklers 
but whether you have to have a 3,000 sf remote area (not stated but understood 
since you are referencing chap 11), let’s start in 8.15.1.2.6 that allow the 
omission.  It states - the joist channels are firestopped into volumes EACH not 
exceeding 160 cu ft.  Obviously the volume is per individual channel.  Now 
jumping to 11.2.3.1.4(4)(j) it states - provide the adjacent joist space 
channels are firestopped into volumes not exceeding 160 cubic feet.  I could 
stop here but the coffee is kicking in.  IF it were meant to be a single 
channel, the text would have been copied as stated in 8.15.1.2.6.  Stating 
“adjacent channels” when read without the preconception from 8.15 is pretty 
plain but it was known that the per channel was well ingrained so Annex 
material was provided.  It states - restrict the ability for fire to spread 
beyond 160 cu ft zones covering MULTIPLE joist channels.

Prior to the 2010 edition, you ALWAYS had to use a 3,000 sf remote area with 
unprotected spaces of composite wood joists.  By breaking the overall space 
into volumes of NMT 160 cu ft, it presents a similar risk that that of solid 
wood joists with bigger individual channels.  For our sprinkler scientist, yes 
it is a slightly bigger risk since TJI's burn more vigorously and fail more 
quickly than solid wood joist (thus the prior difference) but for driving the 
need for a bigger remote area, the difference is insignificant.

Roland


Roland Huggins, PE - VP Engineering
American Fire Sprinkler Assn.   ---  Fire Sprinklers Saves Lives
Dallas, TX
http://www.firesprinkler.org <http://www.firesprinkler.org/>





> On Oct 21, 2015, at 5:08 PM, James Crawford  wrote:
> 
> We have a project that is using TJI wood joist (composite wood Joists), they
> are 16” deep spaces 18” on center and are 20’ long. There is gypsum board
> attached directly to the bottom of the joists along with 3” of insulation at
> the bottom to reduce sound transmission. The area is about 1400 sq.ft.
> 
> 
> 
> Reference is NFPA #13 2013 edition section 11.2.3.1.4(4)(j)
> 
> 
> 
> Light or ordinary hazard occupancies where noncombustible or limited
> combustible ceilings are attached to the bottom of composite wood joists
> either directly or on to metal channels not exceeding 1” in depth, provided
> the adjacent joist space channels are firestopped into volumes not exceeding
> 160 cubic feet using materials equivalent to ˝” gypsum board and at least 3
> ˝” of batt insulation is installed at the bottom of the joist channels when
> the ceiling is attached utilizing metal channels.
> 
> 
> 
> If each channel space formed by two joist is 40 cubic feet, so the adjacent
> space is 40 cubic feet, I see no need to fire stop them into volumes less
> than 160 cubic feet as they are already less than 160. The AHJ is saying
> that we must firestop every 4th joist space with gypsum to create spaces of
> 160 cubic feet, so we would need to break the space into 12 spaces of 160
> cubic feet for the 1400 sq ft area.
> 
> 
> 
> Am I reading this correctly or do we need to break the space into sections
> of 160 cubic feet?
> 
> 
> 
> Thank you
> 
> 
> 
> 
> 
> James Crawford
> 
> Phaser Fire Protection Ltd.
> 
> Phone  604-888-0318
> 
> Fax 604-888-4732
> 
> Cel 604-790-0938
> 
> Email  jcrawf...@phaserfire.ca
> 
> 
> 
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RE: Composite Wood Joists

[James Crawford]

Thanks Roland

But my coffee has not kicked in, So I agree with 8.15.1.2.6 allows the omission 
of the sprinkler heads as we meet those requirements, and  11.2.3.1.4(4)(j) 
allows us to not use a 3000 sf design area if we firestop the joist channels 
into 160 cu ft blocks, or in our case about every fourth joist channel and the 
firestop material needs to be 1/2" gypsum or equal


Thank you


James Crawford
Phaser Fire Protection Ltd.
Phone  604-888-0318
Fax 604-888-4732
Cel 604-790-0938
Email  jcrawf...@phaserfire.ca


-Original Message-
From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On 
Behalf Of Roland Huggins
Sent: Thursday, October 22, 2015 9:23 AM
To: sprinklerforum@lists.firesprinkler.org
Subject: Re: Composite Wood Joists

Allow me a bit of a long winded response instead of a simple yes or no.

First off, although your question is not about whether you can omit sprinklers 
but whether you have to have a 3,000 sf remote area (not stated but understood 
since you are referencing chap 11), let’s start in 8.15.1.2.6 that allow the 
omission.  It states - the joist channels are firestopped into volumes EACH not 
exceeding 160 cu ft.  Obviously the volume is per individual channel.  Now 
jumping to 11.2.3.1.4(4)(j) it states - provide the adjacent joist space 
channels are firestopped into volumes not exceeding 160 cubic feet.  I could 
stop here but the coffee is kicking in.  IF it were meant to be a single 
channel, the text would have been copied as stated in 8.15.1.2.6.  Stating 
“adjacent channels” when read without the preconception from 8.15 is pretty 
plain but it was known that the per channel was well ingrained so Annex 
material was provided.  It states - restrict the ability for fire to spread 
beyond 160 cu ft zones covering MULTIPLE joist channels.

Prior to the 2010 edition, you ALWAYS had to use a 3,000 sf remote area with 
unprotected spaces of composite wood joists.  By breaking the overall space 
into volumes of NMT 160 cu ft, it presents a similar risk that that of solid 
wood joists with bigger individual channels.  For our sprinkler scientist, yes 
it is a slightly bigger risk since TJI's burn more vigorously and fail more 
quickly than solid wood joist (thus the prior difference) but for driving the 
need for a bigger remote area, the difference is insignificant.

Roland


Roland Huggins, PE - VP Engineering
American Fire Sprinkler Assn.   ---  Fire Sprinklers Saves Lives
Dallas, TX
http://www.firesprinkler.org <http://www.firesprinkler.org/>





> On Oct 21, 2015, at 5:08 PM, James Crawford  wrote:
> 
> We have a project that is using TJI wood joist (composite wood 
> Joists), they are 16” deep spaces 18” on center and are 20’ long. 
> There is gypsum board attached directly to the bottom of the joists 
> along with 3” of insulation at the bottom to reduce sound transmission. The 
> area is about 1400 sq.ft.
> 
> 
> 
> Reference is NFPA #13 2013 edition section 11.2.3.1.4(4)(j)
> 
> 
> 
> Light or ordinary hazard occupancies where noncombustible or limited 
> combustible ceilings are attached to the bottom of composite wood 
> joists either directly or on to metal channels not exceeding 1” in 
> depth, provided the adjacent joist space channels are firestopped into 
> volumes not exceeding
> 160 cubic feet using materials equivalent to ˝” gypsum board and at 
> least 3 ˝” of batt insulation is installed at the bottom of the joist 
> channels when the ceiling is attached utilizing metal channels.
> 
> 
> 
> If each channel space formed by two joist is 40 cubic feet, so the 
> adjacent space is 40 cubic feet, I see no need to fire stop them into 
> volumes less than 160 cubic feet as they are already less than 160. 
> The AHJ is saying that we must firestop every 4th joist space with 
> gypsum to create spaces of
> 160 cubic feet, so we would need to break the space into 12 spaces of 
> 160 cubic feet for the 1400 sq ft area.
> 
> 
> 
> Am I reading this correctly or do we need to break the space into 
> sections of 160 cubic feet?
> 
> 
> 
> Thank you
> 
> 
> 
> 
> 
> James Crawford
> 
> Phaser Fire Protection Ltd.
> 
> Phone  604-888-0318
> 
> Fax 604-888-4732
> 
> Cel 604-790-0938
> 
> Email  jcrawf...@phaserfire.ca
> 
> 
> 
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> er.org

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Re: Composite Wood Joists

[Roland Huggins]

we are in complete agreement on you latest statement (below).

In your originally question though, weren’t you questioning whether or not ch 
11 applied to a single joist channel or multiple channels.  In other words, you 
were asking if the AHJ was wrong in requiring every 4th channel to be 
firestopped.  The only one that doesn’t occasionally go left instead of right 
are those that don’t do anything.  Good question.

On a related note, the firestopping should run parallel to the joists verse 
being perpendicular to them (provided a single channels isn’t greater than 160 
cu ft.  IF they are firestopping i required for BOTH parallel and perpendicular.


Roland Huggins, PE - VP Engineering
American Fire Sprinkler Assn.   ---  Fire Sprinklers Saves Lives
Dallas, TX
http://www.firesprinkler.org 





> On Oct 22, 2015, at 11:55 AM, James Crawford  wrote:
> 
> Thanks Roland
> 
> But my coffee has not kicked in, So I agree with 8.15.1.2.6 allows the 
> omission of the sprinkler heads as we meet those requirements, and  
> 11.2.3.1.4(4)(j) allows us to not use a 3000 sf design area if we firestop 
> the joist channels into 160 cu ft blocks, or in our case about every fourth 
> joist channel and the firestop material needs to be 1/2" gypsum or equal
> 
> 
> Thank you
> 
> 
> James Crawford

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RE: Concealed Space - composite wood joists

[Dewayne Martinez]

8.15.1.2.6  would normally not require and additional fire stopping on our part 
for typical construction.  For a typical 12in TJI spaced 16in O.C. the required 
run would have to be over 120ft long before the 160ft^3 is exceeded.
  
 8.15.1.2.8 is only requiring the insulation in the space BETWEEN the bottom of 
joist and the ceiling, not the entire space.  Happens a lot with ACT ceiling 
installed 6in below the joists. 

Your right on about 8.15.1.2.7 and the non-3000ft^2 area, unfortunately the 
GC's are never wanting to do  this at their cost.

Dewayne

-Original Message-
From: sprinklerforum-boun...@firesprinkler.org 
[mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of Bobby Gillett
Sent: Monday, January 28, 2013 2:05 PM
To: sprinklerforum@firesprinkler.org
Subject: Concealed Space - compsite wood joists

 

NFPA 13 - 2010:

8.15.1.2.6* <http://codesonline.nfpa.org/a/c.ref/ID1327787/sec>
Concealed spaces formed by ceilings attached to composite wood joist 
construction either directly or onto metal channels not exceeding 1 in.
(25.4 mm) in depth, provided the joist channels are firestopped into volumes 
each not exceeding 160 ft3 (4.53 m3) using materials equivalent to the web 
construction and at least 3 1/2 in. (90 mm) of batt insulation is installed at 
the bottom of the joist channels when the ceiling is attached utilizing metal 
channels, shall not require sprinkler protection.

8.15.1.2.7   Concealed spaces entirely filled with noncombustible insulation
shall not require sprinkler protection.

8.15.1.2.8   Concealed spaces within wood joist construction and composite
wood joist construction having noncombustible insulation filling the space from 
the ceiling up to the bottom edge of the joist of the roof or floor deck, 
provided that in composite wood joist construction the joist channels are 
firestopped into volumes each not exceeding 160 ft3 (4.53 m3) to the full depth 
of the joist with material equivalent to the web construction, shall not 
require sprinkler protection.

 

I have a concealed space formed by composite wood joists with ceiling attached 
directly to the bottom of the joist (no metal channels, so insulation is not a 
requirement). If I'm not mistaken, in order to consider it a space that doesn't 
require sprinkler protection I have to do the
following:

Per 8.15.1.2.6 - Have the joist channels firestopped into volumes not exceeding 
160 ft³ OR

Per 8.15.1.2.7 - Completely fill the space with noncombustible insulation OR

Per 8.15.1.2.8 - Completely fill the space with noncombustible insulation AND 
have the joist channels firestopped into volumes not exceeding 160 ft³ (WHICH 
KICKS 8.15.1.2.7 OUT FOR COMPOSITE WOOD JOISTS ALTOGETHER)

 

I guess what I am misunderstanding is if I have to firestop the joist channels 
into volumes not exceeding 160ft³ either way, why would we want to fill the 
joist space completely with noncombustible insulation? Only thing I could think 
of would be to keep from having to do a 3000ft² RA in the adjacent protected 
space. 

 

Any comments for my understanding would be appreciated.

 

Bobby Gillett

Sr. Project Manager

Key Fire Protection, Inc.

(731) 424-0130 office  (731) 424-9285 fax 

(731) 267-4853 cell

 <http://www.keyfireprotection.com> www.keyfireprotection.com

 

 

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RE: Concealed Space - composite wood joists

[Bobby Gillett]

Dewayne & Greg - Thank you.

That makes more sense, I was misreading 8.15.1.2.8. My ceiling is directly
attached, if they fill the space full of non-combustible insulation
(thankfully my GC is willing) it will not have to be sprinklered and the
3000ft² RA will not apply - and no firestopping into 160ft³ would be
required. 

Bobby Gillett
Sr. Project Manager
Key Fire Protection, Inc.
(731) 424-0130 office  (731) 424-9285 fax 
(731) 267-4853 cell
www.keyfireprotection.com
 
-Original Message-
From: sprinklerforum-boun...@firesprinkler.org
[mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of Dewayne
Martinez
Sent: Tuesday, January 29, 2013 6:54 AM
To: sprinklerforum@firesprinkler.org
Subject: RE: Concealed Space - composite wood joists

8.15.1.2.6  would normally not require and additional fire stopping on our
part for typical construction.  For a typical 12in TJI spaced 16in O.C. the
required run would have to be over 120ft long before the 160ft^3 is
exceeded.
  
 8.15.1.2.8 is only requiring the insulation in the space BETWEEN the bottom
of joist and the ceiling, not the entire space.  Happens a lot with ACT
ceiling installed 6in below the joists. 

Your right on about 8.15.1.2.7 and the non-3000ft^2 area, unfortunately the
GC's are never wanting to do  this at their cost.

Dewayne

-Original Message-
From: sprinklerforum-boun...@firesprinkler.org
[mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of Bobby Gillett
Sent: Monday, January 28, 2013 2:05 PM
To: sprinklerforum@firesprinkler.org
Subject: Concealed Space - compsite wood joists

 

NFPA 13 - 2010:

8.15.1.2.6* <http://codesonline.nfpa.org/a/c.ref/ID1327787/sec>
Concealed spaces formed by ceilings attached to composite wood joist
construction either directly or onto metal channels not exceeding 1 in.
(25.4 mm) in depth, provided the joist channels are firestopped into volumes
each not exceeding 160 ft3 (4.53 m3) using materials equivalent to the web
construction and at least 3 1/2 in. (90 mm) of batt insulation is installed
at the bottom of the joist channels when the ceiling is attached utilizing
metal channels, shall not require sprinkler protection.

8.15.1.2.7   Concealed spaces entirely filled with noncombustible insulation
shall not require sprinkler protection.

8.15.1.2.8   Concealed spaces within wood joist construction and composite
wood joist construction having noncombustible insulation filling the space
from the ceiling up to the bottom edge of the joist of the roof or floor
deck, provided that in composite wood joist construction the joist channels
are firestopped into volumes each not exceeding 160 ft3 (4.53 m3) to the
full depth of the joist with material equivalent to the web construction,
shall not require sprinkler protection.

 

I have a concealed space formed by composite wood joists with ceiling
attached directly to the bottom of the joist (no metal channels, so
insulation is not a requirement). If I'm not mistaken, in order to consider
it a space that doesn't require sprinkler protection I have to do the
following:

Per 8.15.1.2.6 - Have the joist channels firestopped into volumes not
exceeding 160 ft³ OR

Per 8.15.1.2.7 - Completely fill the space with noncombustible insulation OR

Per 8.15.1.2.8 - Completely fill the space with noncombustible insulation
AND have the joist channels firestopped into volumes not exceeding 160 ft³
(WHICH KICKS 8.15.1.2.7 OUT FOR COMPOSITE WOOD JOISTS ALTOGETHER)

 

I guess what I am misunderstanding is if I have to firestop the joist
channels into volumes not exceeding 160ft³ either way, why would we want to
fill the joist space completely with noncombustible insulation? Only thing I
could think of would be to keep from having to do a 3000ft² RA in the
adjacent protected space. 

 

Any comments for my understanding would be appreciated.

 

Bobby Gillett

Sr. Project Manager

Key Fire Protection, Inc.

(731) 424-0130 office  (731) 424-9285 fax 

(731) 267-4853 cell

 <http://www.keyfireprotection.com> www.keyfireprotection.com

 

 

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