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Draftstopping in a commercial building
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Re: Draftstopping in a commercial building By  cda

Posts: 0

7/26/2007 1:07:00 PM

Is there combustible construction in the floor area???

Is it a rated assembly???


"Are we correct in our interpretation of this dead space between the suspended ceiling and the drywall under the trusses as being considered an attic area"

does not sound like attice area, are you going to require attic access 1209.2?? to this area??


"with the dead space created between the drywall and suspended ceiling left as one large open area?"
sounds like yes to the arc e tech.


   

Re: Draftstopping in a commercial building By  MLowery

Posts: 0

7/26/2007 1:12:00 PM

mv,

I''m not at the code book, but I think you would need to first look at the definition of "attic" and apply that, but also, if its not an attic, then I would call it void space. That has to be dealt with as well.

Also, is it sprinklered? that makes a difference on how void spaces and attics are handled.


   

Re: Draftstopping in a commercial building By  mvanberlo

Posts: 0

7/26/2007 1:16:00 PM

An attic area is created in this building between the underside of the trusses and the roof area above. There is no floor area above the drywall ceiling. The drywall ceiling is not part of a rated assmebly. The area in question is between the drywall at the bottom of the trusses and the suspended ceiling located approximately 24 inches below the drywall. Is that area required to have draftstopping too.


   

Re: Draftstopping in a commercial building By  mvanberlo

Posts: 0

7/26/2007 1:18:00 PM

As noted in the original post " This is not a suppressed building."


   

Re: Draftstopping in a commercial building By  Builder bob

Posts: 0

7/26/2007 1:34:00 PM

mv77 - IMHO, no. Reasoning:

While concealed spaces is not readily identified or defined in the IBC, another I-code the IFGC does define concealed space/location.

THE IFGC offers the following definition:
CONCEALED LOCATION. A location that cannot be accessed without damaging permanent parts of the building structure or finish surface. Spaces above, below or behind readily removable panels or doors shall not be considered as concealed.


Also, per the Energy Code, Acoustical ceiling tiles are not an effective air barrier for an permanable barrier .... thus would allow the passage of smoke at - light fixtures, vents, registers, etc.


of course , opions differ and vary widely.

a.k.a Builder Bob - pending MCP certificate in the mail


   

Re: Draftstopping in a commercial building By  cfisher

Posts: 0

7/26/2007 2:26:00 PM

Bob is correct. But it''s that "readily removable panels" that''s the hang up for me. I''d guess that ceiling is probably around 18'' minimum above the floor. In my mind, that''s not "readily anything" since it would take bringing in a very big ladder. The fire crew that shows up isn''t exactly going to just be able to peek up there quickly to gauge the conditions.

Also know that I worked on a grocery store fire where no draft stops had been provided. It took a whole of 20 minutes from the spark to a full structural collapse. But, in mine everything was exposed, had years of dust, and paper faced insulation to feed that fire. Mine was also 50,000 sf and the void was 7'' high and constructed under the ''73 UBC codes (remodelled in ''97).

I never was called to the stand, because the opposing expert and the fire marshall testified that had the draftstops been present, the fire probably would not have spread as fast.

Note that the definition of draft stop is provided, at least in the ''97 ubc as:
" Draft Stop is a material, device or construction installed to restrict the movement of air within open spaces of concealed areas of building components such as crawl spaces, floor-ceiling assemblies, roof-ceiling assemblies and attics." So they aren''t limited to attics only.

During the deposition, lots of stuff came up. I interpret an attic to be the space between the ceiling and roof diaphram. Some will disagree.
If you determine clg tiles way above the floor aren''t "readily removable", then in my opinion you have concealed space or attic. It could be a plenum, but only if it''s treated as such and there are codes on that too.

It''s all very grey area open to interpretation and intent and I was working with totally different codes. But I thought I''d share because it was a large retail store without draftstops that quickly fell to the ground once a fire got into this concealed space and rolled along above the fire suppression gutting out the structure.. No deaths were involved.


   

Re: Draftstopping in a commercial building By  trunks82

Posts: 0

7/26/2007 9:06:00 PM

MY take is this. Draftstopping is required in

"In combustible construction, draftstopping shall be installed to subdivide attic spaces and Concealed roof spaces"

I personally feel this is a concealed space but even if it is an attic space there is no combustible construction in this area.

It sounds to me that the space between the hard lid and the ceiling tile is not made up of combustible materials and therefore no draftsop would be required. After all what fuel is their for the fire is in this space? Sounds like nothing? What good will a draftstop do in this area? IF thier is nothing to promote the horizontal spread then what are you protecting? In fact to install the draftstop one may up putting wood framing in this space thus giving something to burn.

While I am certain someone can slam this thought lets look at intent draftstop is required to slow the spread of fire, if thier is nothing combustible in the space then what are your preventing?


   

Re: Draftstopping in a commercial building By  mvanberlo

Posts: 0

7/27/2007 6:53:00 AM

Let me throw this thought into the mix. Code definition of an attic - " the space between the ceiling beams of the top story and the roof rafters." In this case the top chord of the trusses form the top of the roof rafters. The suspended ceiling grid work creates the ceiling beam of this single story building. as such, all space between the ceiling beam - the grid work, and the top of the roof rafters - top chord of the trusses, can be considered as the attic area. It just happens to be that this space is broken up into two areas, the attic above the suspended ceiling, and the attic above the drywall placed on the under side of the bottom chord of the trusses.
In answer to cda''s question, the attic access to the area above the drywall passes through the attic area between the drywall and the suspended ceiling.
As to the comment by Good Guy, the ceiling tile and paper facing on the drywall are both combustible materials. Both can and would aid in the spread of fire across the 9200 square feet of area between the drywall and the suspended ceiling area. And so the question remains, is the area between the drywall applied to the underside of the roof trusses and the suspended ceiling considered a part of the attic area, thereby requiring that the area be considered part of the attic? If not considered an attic space, perhaps a concealed roof space? See the code commentary on section 717.4 " draftstopping is required in attic and concealed roof spaces "


   

Re: Draftstopping in a commercial building By  Builder bob

Posts: 0

7/27/2007 7:42:00 AM

The ceiling grid components are by the code an architectural component a not a structural component.
They have low flame spread capability and can be readily replaced, changed, installed at various heights above finish floor grade,etc. Very similar to furniture in a building. Draft stopping is generally required to be installed in structural components of a more permanent nature. Now, once thing that can be of assistance to you is if you are in a seismic area, if the ceiling grid is required to be a seismic ceiling grid, most people install a gypsum bulkhead to cut down on the ceiling grid areas to less than 2500 S.F. to do away with isolation joints in the ceiling grid systems.

cfisher, I bet the grocery store had a plenum air return system which was very common in that time and age of construction. The fire department failed to be proactive in requiring the plenum areas to be cleaned on a regular basis.


As far as ceiling tiles being 18 feet off of the floor, a 12 foot pike poke with a 6 foot FF should be able to remove or check the space.


   

Re: Draftstopping in a commercial building By  maniac

Posts: 0

7/27/2007 7:48:00 AM

2003 INTERNATIONAL BUILDING CODE? COMMENTARY
ATTIC. The space between the ceiling beams of the top story and the roof rafters.
The definition of ?Attic? identifies the specific portion of a building or structure for the purposes of determining the applicability of requirements that are specific to attics, such as ventilation (see Section 1202) and draftstopping (see Section 716). Additionally, the code has access requirements (see Section 1208) and uniformly distributed live load requirements (see Table 1607.1) for attics.
An attic is considered the space or area located immediately below the roof sheathing within the roof framing system of a building. Pitched roof systems, such as gabled, hip, sawtoothed or curved roofs, all create spaces[b] between the roof sheathing and ceiling membrane, which are considered attics.[/b]


   

Re: Draftstopping in a commercial building By  maniac

Posts: 0

7/27/2007 7:48:00 AM

2003 INTERNATIONAL BUILDING CODE? COMMENTARY
ATTIC. The space between the ceiling beams of the top story and the roof rafters.
The definition of ?Attic? identifies the specific portion of a building or structure for the purposes of determining the applicability of requirements that are specific to attics, such as ventilation (see Section 1202) and draftstopping (see Section 716). Additionally, the code has access requirements (see Section 1208) and uniformly distributed live load requirements (see Table 1607.1) for attics.
An attic is considered the space or area located immediately below the roof sheathing within the roof framing system of a building. Pitched roof systems, such as gabled, hip, sawtoothed or curved roofs, all create spaces[b] between the roof sheathing and ceiling membrane, which are considered attics.[/b]


   

Re: Draftstopping in a commercial building By  FoxCode1

Posts: 0

7/27/2007 10:02:00 AM

mv77,your much better off getting the opionions of some of your fellow code officals,contacting the ICC will not resolve the issue as even though they will answer code questions they also will always put in the disclaimer that the final interpretation is up to the AHJ,and I can tell you from experiance that I have personally called them before and i have had someone else call them with the exact same question and we have got two different answers from them.


   

Re: Draftstopping in a commercial building By  TJacobs

Posts: 0

7/29/2007 1:57:00 PM

My SOP on this is that as long as all exposed surfaces in the void space are covered with drywall or the exposed suspended ceiling materials have the same flame-spread & smoke-developed properties as drywall, no draftstopping would be required.

I''d ask for the specs of the ceiling tile.


   

Re: Draftstopping in a commercial building By  trunks82

Posts: 0

7/29/2007 9:27:00 PM

"the ceiling tile and paper facing on the drywall are both combustible materials."

mv tell me since exposed paper on the drywall does not meet flame spread then why is it an approved draftstopping material. If the space is draftstopped we will now have more vertical combustable components (studs and drywall facing). And we are not certain the facing is left exposed or not just as we are uncertain the actual flame spread on the tile in use. I personally do not think the construction materials would warrant this being "combustable construction".


   

Re: Draftstopping in a commercial building By  paulk

Posts: 0

7/31/2007 3:57:00 PM

Since you asked for opinions, I would say that a grid ceiling is fairly accessible. I would vote that this is not an attic.

I also agree with maniac''s comments- if this is an attic, then you also need to consider those items (venting, attic floor loading, etc)


   

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