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Anonymous
 
Posted on Monday, February 09, 2009 - 12:34 pm:   Edit PostDelete PostPrint Post

We have a project with a rated floor/ceiling assembly constructed of open-web wood joists. The Project Arch is being told by the AHJ, that he will not allow open joists in that situation. He wants either the entire cavity filled with batt insulation, or place sheathing on the joists to close the webs (lose all flexibility with services), or paint the joists with intumescent paint, or sprinkler the cavity. I-joists have been considered, but dropped due to the service flexibility issue.

Are we missing something? Are any of these options standard? Why wouldn't the UL assembly be enough? Any help appreciated.
Mark Gilligan SE, CSI
Senior Member
Username: mark_gilligan

Post Number: 117
Registered: 10-2007
Posted on Monday, February 09, 2009 - 03:29 pm:   Edit PostDelete PostPrint Post

What code section does he reference? What does he say is wrong with the assembly?

Some fire fighters believe that these systems are unsafe. Refer to the following link http://www.cdc.gov/niosh/docs/2005-132/#7

You can probably get some informtion on this from the Wood Truss Council of America. http://www.sbcindustry.com/

If fire is the issue and there is not any special provisions in the building code the architect may be able to tell the building official no thanks.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman

Post Number: 723
Registered: 03-2003
Posted on Monday, February 09, 2009 - 06:09 pm:   Edit PostDelete PostPrint Post

What UL assembly did you use?
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
RLGA Technical Services
www.specsandcodes.com
Anonymous
 
Posted on Tuesday, February 10, 2009 - 01:40 pm:   Edit PostDelete PostPrint Post

UL L576 or L528

There was no code reference given. Only the statement from a reviewer, "AHJ DID NOT PERMIT OPEN WEB TRUSSES WITHOUT SOME MODIFICATION"

We don't believe "No Thanks" is an option.
Ralph Liebing, RA, CSI
Senior Member
Username: rliebing

Post Number: 943
Registered: 02-2003
Posted on Tuesday, February 10, 2009 - 02:05 pm:   Edit PostDelete PostPrint Post

You have the right to go back and ask for the code references on which they are basing their contentions-- book, chapter and verse, in writing!

How can you ever begin to comply when things are so abstract and undefined?

As to modifications, they should be able to tell you what is worng with your design and what you need to do-- at least within a range of things, since code departments are not authorized as "design" agencies and can only offer broad solution possibiltiies-- not specific design services.
Mark Gilligan SE, CSI
Senior Member
Username: mark_gilligan

Post Number: 118
Registered: 10-2007
Posted on Tuesday, February 10, 2009 - 02:23 pm:   Edit PostDelete PostPrint Post

Why is "No Thanks" not an option?

If no code reference is provided, when requested, one must assume that this "requirement" is not in the adopted building code and thus you are not legally required to comply with this request. You then have two options exercise your legal rights or comply with whatever the building department asks for. Would you pay them $5,000 if they asked for it?

Prior to complying with the building officials request I would suggest writing a letter to the Building Official requesting an explination of which code provision requires these changes. Then if no code requirement is provided the Architect should notify the Owner of the building official's response and that it is the Architects belief that this requirement is not required by the building code. At this point it is the Owner's decision on how to proceed.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman

Post Number: 724
Registered: 03-2003
Posted on Tuesday, February 10, 2009 - 04:37 pm:   Edit PostDelete PostPrint Post

To parrot the other posts above, the plans examiner should be able to cite the specific code reference they're using to support their comment.

The assemblies that you're using are acceptable "as is," provided you've designed the actual floor/ceiling assembly as stipulated in the UL assembly.

I did a cursory check of the Florida Building Code and could not find where open web joists are not permitted in fire-resistance-rated horizontal assemblies.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
RLGA Technical Services
www.specsandcodes.com
Mark Gilligan SE, CSI
Senior Member
Username: mark_gilligan

Post Number: 119
Registered: 10-2007
Posted on Tuesday, February 10, 2009 - 05:13 pm:   Edit PostDelete PostPrint Post

If the building official cannot establish a basis in the code for a requirement Owners have been able to fairly easily obtain a court order requiring the building official to issue a building permit.

The reason you need to involve your client, if you believe you are being required to do something not required by the building code, is that you could have some liability if you did what was asked and the client did not agree to pay the added costs. I am aware of an actual case with some strong similarities.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman

Post Number: 726
Registered: 03-2003
Posted on Tuesday, February 10, 2009 - 07:14 pm:   Edit PostDelete PostPrint Post

Mark is correct. And to add to that, the building department may be liable, as well, on the grounds of "misfeasance," or the improper performance of an act that a person may lawfully do.

The building department can only enforce compliance with the code and not features beyond the code.

The assembly you've provided satisfies the requirements of the code for a 1-hour horizontal assembly: it has been tested by an approved lab (UL) in accordance with ASTM E 119. The alternative methods your plans examiner is providing will affect the performance of the assembly, which requires additional data per Section 703.2:

"...Where materials, systems or devices that have not been tested as part of a fire-resistance-rated assembly are incorporated into the assembly, sufficient data shall be made available to the building official to show that the required fire-resistance rating is not reduced..."

This is like the experience of another architect who posted on the ICC Bulletin Board stating that his plans examiner would not allow aluminum curtain wall on his Type IIA (noncombustible) building because the plans examiner read "somewhere" that aluminum was combustible.

And building officials wonder why architects don't like working with the building department.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
RLGA Technical Services
www.specsandcodes.com
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec

Post Number: 641
Registered: 05-2003
Posted on Tuesday, February 10, 2009 - 10:54 pm:   Edit PostDelete PostPrint Post

anonymous
which municipality in Florida are you dealing with?
Tim Werbstein, AIA, CSI, CCS
Senior Member
Username: tim_werbstein

Post Number: 6
Registered: 09-2006
Posted on Wednesday, February 11, 2009 - 08:17 am:   Edit PostDelete PostPrint Post

The comment was probably from the mechanical plan reviewer. The 2006 IMC requires in 602.2.1 that materials exposed within air plenums are noncombustible or have a flame-spread and smoke-density ratings not exceeding 25 and 50, respectively. This requirement is mirrored in NFPA 90A. There are numerous other requirements for plenums in both standards.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman

Post Number: 727
Registered: 03-2003
Posted on Wednesday, February 11, 2009 - 10:44 am:   Edit PostDelete PostPrint Post

Tim, that may be possible, but the plans examiner's suggestion to place sheathing on the joists to cover the webs would likely defeat the purpose of an air plenum. If the project has ducted returns, then there is no air plenum.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
RLGA Technical Services
www.specsandcodes.com
(Unregistered Guest)
Unregistered guest
Posted on Wednesday, February 11, 2009 - 11:05 am:   Edit PostDelete PostPrint Post

I concur with the above statements regarding the liabilities to various entities. Keep in mind, however, it is the owner who ultimately is responsible for the permit. That's why the owner must be involved in this discussion and decision making. Owner's building, owner's permit, owner's citation for violations.
(George Everding)
Anonymous
 
Posted on Wednesday, February 11, 2009 - 01:54 pm:   Edit PostDelete PostPrint Post

The floor/ceiling assembly is not being used as a plenum. Penetrations within the ceilings for mechanical purposes are limited in area as permitted by the UL assembly and are ducted directly from the device (exhaust fan and clothes dryer) to the exterior.
(Unregistered Guest)
Unregistered guest
Posted on Tuesday, February 24, 2009 - 03:20 pm:   Edit PostDelete PostPrint Post

INQUIRY UPDATE:
The reviewer cited NFPA 13 - 8.14.1.1 through 8.14.1.2.15 for the concealed spaces formed by the open web trusses. The floor/ceiling assemblies prescribed by UL U576 or U528 does not (seem) to fall within any of these exceptions to not require sprinkler protection. On its face the reviewer seems to be correct. If anyone knows of some esoteric reference within NFPA that trumps this and gives us a leg to stand on your input will be appreciated. Thanks in advance.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman

Post Number: 740
Registered: 03-2003


Posted on Tuesday, February 24, 2009 - 08:53 pm:   Edit PostDelete PostPrint Post

Question 1: Do you indicate on the drawings that the building is sprinklered?

If yes, then:

Question 2: Is the building required to be sprinklered due to occupancy type (Section 903.2)?

If yes, go to Question 4:
If no, then:

Question 3: Is the sprinkler used for some other purpose (e.g. area increase, 1-hour substitution, height increase, etc.) that requires the building to be sprinklered throughout?

If yes, then sprinklers are required in concealed spaces as the plans examiner indicates.

Question 4: What is the occupancy and the condition (e.g. fire area exceeds maximum, occupant load exceeds maximum, etc.), if applicable, that triggered the sprinkler requirement?

It's hard to respond if we don't have all the essential data.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
RLGA Technical Services
www.specsandcodes.com
Randy Cox
Senior Member
Username: randy_cox

Post Number: 52
Registered: 04-2004
Posted on Tuesday, February 24, 2009 - 09:00 pm:   Edit PostDelete PostPrint Post

This is a whole different issue. You are creating a combustible concealed space and unless you have one of the exceptions that you noted it must be protected by sprinklers to comply with NFPA 13. Some residential projects can use NFPA 13R,which doesn't require all concealed spaces to be sprinklered.
(Unregistered Guest)
Unregistered guest
Posted on Wednesday, February 25, 2009 - 09:39 am:   Edit PostDelete PostPrint Post

Ron -
R-2 Use / 5A Type
Sprinklers are required.
Fully Automatic Sprinkler System (NFPA 13 provided).
Height and Area Increases taken therefore NFPA 13 system is required (13R not permitted).
Hope that helps.
It is becoming apparent that this seems to be an AHJ issue since we have and have not had to meet installation requirements of NFPA 13 for concealed spaces in other projects around the country.
Learn something new every day!
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman

Post Number: 741
Registered: 03-2003


Posted on Wednesday, February 25, 2009 - 10:40 am:   Edit PostDelete PostPrint Post

From the information you've provided, the plans examiner is correct. I suggest sprinklering the concealed spaces--it's definitely less expensive than the other alternatives provided, and it doesn't alter the rated assembly.

The reason it may not have been picked up in other locations may be due to the timing of submitting sprinkler drawings to the AHJ for plan review. For many years here in Phoenix, sprinkler systems were generally a performance specification, requiring the contractor to design the system in accordance with NFPA 13 and submit the sprinkler drawings for review. The contractor would get any comments--not the A/E--therefore, the contractor would have been told to sprinkler the concealed spaces if they didn't include it in their submittal drawings. That may be the case in your past projects.

Now in Phoenix, with the sprinkler ordinance in place, the sprinkler system must be fully designed by a qualified engineer concurrent with the building design and submitted to the AHJ along with all the other construction documents. Therefore, the A/E sees all the comments from the AHJ.

Good luck!
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
RLGA Technical Services
www.specsandcodes.com
Steven Hauk
Senior Member
Username: sh1net

Post Number: 11
Registered: 12-2004
Posted on Sunday, March 01, 2009 - 11:21 am:   Edit PostDelete PostPrint Post

Here in Dallas, there's a good-sized multi-family contractor who volunteers filling the cavity with insulation as the solution to this NFPA 13 issue. It adds acoustical benefit, so it's not entirely a waste. It's probably a good solution.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman

Post Number: 742
Registered: 03-2003


Posted on Sunday, March 01, 2009 - 06:06 pm:   Edit PostDelete PostPrint Post

You have to be careful about providing additional insulation. If the assembly stipulates a maximum thickness, then you cannot add more than what the assembly shows; otherwise, you've modified the assembly and it will likely not perform as tested.
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
RLGA Technical Services
www.specsandcodes.com
Steven Hauk
Senior Member
Username: sh1net

Post Number: 15
Registered: 12-2004
Posted on Monday, March 02, 2009 - 02:09 am:   Edit PostDelete PostPrint Post

UL Design L521 seems to address what needs to be done in order to allow an unlimited depth of insulation.
(Unregistered Guest)
Unregistered guest
Posted on Tuesday, March 03, 2009 - 10:05 am:   Edit PostDelete PostPrint Post

I have probably gathered too much information for my own good, but this has proven very useful moving forward. UL L521...that one's a needle in a haystack and seemingly in agreement with NFPA 13. Up until that reference I was convinced UL did not permit for full (vert) depth of insulation.

The minor distinction I have now made is that UL addresses fire separation between spaces and not necessarily what (additional) construction shall be used to effectively inhibit heat and smoke development within the assembly. This is where NFPA 13 enters the picture and prescribes what to do in concealed (uninhabited) spaces. One of the exceptions that does not require sprinklers is filling the full depth of the void with non-combustible insulation. Specific to the use of insulation in the assembly it seems like NFPA and UL need to come to some agreeable details meeting the NFPA 13 exceptions for concealed spaces like UL L521...just an observation. That said, our tact is that the AHJs direction trumps the requirements of the UL assembly.

QUESTION: All that said, and in an effort to always push the envelope of interpretation (and upset reviewers), IF rather than completely filling the void with insulation one was to use the non-combustible insulation of some thickness to "clad" the web of the truss AND limit the volume to 160 cu ft max would I have essentially accomplished the intent of what is described in some of the exceptions in NFPA 13 - 8.14.1.2.1 through 8.14.1.2.15?
Steven Hauk
Senior Member
Username: sh1net

Post Number: 16
Registered: 12-2004
Posted on Wednesday, March 04, 2009 - 12:34 am:   Edit PostDelete PostPrint Post

It is my understanding the exceptions mean the joist channels are to be firestopped into 160 cu ft with materials equivalent to the joist construction.

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