| Author |
Message |
Marc C Chavez
Senior Member
Username: mchavez
Post Number: 463
Registered: 07-2002
| | Posted on Monday, January 21, 2013 - 02:54 pm: |    |
new fun from the ICC. .....if your "water-resistive barrier" is combustible your entire assembly must go thru NFPA 285 testing. and remember what we have all learned about NFPA 285...
to give credit where it is due Chris Dixon brought this to my attention when some folks from WJE were on stage talking about it.
Does anyone have the ICC's definition.
? |
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 1076
Registered: 03-2003
| | Posted on Monday, January 21, 2013 - 03:21 pm: | |
Applies only to Type I, II, III, and IV construction, and only if the exterior walls are greater than 40 ft. above the grade plane.
Ron Geren, AIA, CSI, CCS, CCCA, SCIP
www.specsandcodes.com |
anon (Unregistered Guest)
Unregistered guest
| | Posted on Monday, January 21, 2013 - 03:38 pm: | |
check this discussion out:
http://www.thebuildingcodeforum.com/forum/commercial-fire-codes/7126-code-definition-combustible.html
Evidently ASTM E 136 is the IBC measure of combustibility unless the material under consideration is a "composite." note that aluminum is combustible using this ASTM standard as the benchmark.
Why stop at weather-resistive barriers, IBC? What about aluminum curtainwall with it's "combustible" aluminum framing, sealants, glazing gaskets, and thermal breaks? Doesn't this represent more of a fire hazard than a thin layer or weather-resistive material over the sheathing?
Crazysauce. |
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 1077
Registered: 03-2003
| | Posted on Monday, January 21, 2013 - 04:50 pm: | |
ASTM E 136 and NFPA 285 are two completely different standards that test for different characteristics.
It is rumored that aluminum cannot pass the ASTM E 136 test. That is a falsehood. The Aluminum Association had a variety of common aluminum alloys tested per this standard and the results are that aluminum is noncombustible. Here is the link to those test results: http://www.aluminum.org/Content/NavigationMenu/TheIndustry/BuildingConstructionMarket/Combustibility/default.htm
NFPA 285 test the fire propogation of a wall assembly and not just one material or wall component.
The Air Barrier Association of America (ABAA) has a good presentation of NFPA 285 and air barriers, which sometime provide double-duty as a weather-resistive barriers. the presentation can be found at http://www.airbarrier.org/conference/NFPA%20285%20and%20What%20it%20Means%20for%20Air%20Barriers%20-%20Jess%20Beitel.pdf.
The IBC requirement is only for water-resistive barriers, so if the air barrier is not also the water-resistive barrier, then an air barrier is not required to be tested per NFPA 285.
Ron Geren, AIA, CSI, CCS, CCCA, SCIP
www.specsandcodes.com |
anon (Unregistered Guest)
Unregistered guest
| | Posted on Monday, January 21, 2013 - 07:30 pm: | |
The IBC requires exterior walls to be nonconbustible for buildings of construction types I-IV.
ASTM E 136 is the test method that the IBC identifies in determining a material's "combustibility." I put that in quotation marks because this is an arbitrary term in the way the code currently defines it - ASTM E 136 is not meant to test anything in proximity with other materials, not anything with any coating, and not anything that melts and pools - i.e. aluminum framing in a curtainwall.
Aluminum is indeed combustible. Take a look at the aftermath of the Chinese TVCC tower in Bejing - you can actually watch the aluminum panels going up in flames on youtube. The Aluminum Association test results Mr. Geren provided do not test aluminum as it would be used on a building, but a stack of four approximately 1 inch thick pieces of raw, uncoated aluminum. ASTM E 136 is not an appropriate test for determining combustibility of building materials because it is not meant to test thin materials or materials as they are used in a building - as stated in the standard (!).
The reason that NFPA 285 and ASTM E 136 are related to one another, in the context of the IBC, is that NFPA 285 is all about ascertaining whether or not a wall will burn - its "combustibility - and to what extent. The code requires that all exterior walls be "noncumbustible" but seemingly ALLOWS materials such as thin-walled fluoropolymer coated aluminum, plastic thermal breaks, EPDM/Neopprene/Silicone glazing gaskets, and sealant joints and backer rod materials - all standard components in a curtainwall assembly - to pass as "noncombustible."
Building code officials are introducing requirements via NFPA 285 into the code with specific focus on individual materials - to date foam plastic, MCM, and now weather-resistive barriers in a highly arbitrary way. Their rationale is that these materials are "combustible" - but instead of applying this rationale across the board for ALL materials in an exterior wall, instead they have picked three and required that, not only the individual MATERIAL be tested to NFPA 285, but also the ENTIRE ASSEMBLY it is a part of. So, while the glazed aluminum curtainwall with all of its "combustible" components gets to skate on that "aluminum passes ASTM E 136 so we're good" position, every other assembly that has even the slightest amount of MCM, foam plastic, or a weather-resistive barrier must be tested, in accordance with the literal reading of the code, to NFPA 285.
If there were any consistency in the code, the NPFA testing requirement would required for all exterior wall assemblies, because they all have SOME degree of combustibility in today's exterior wall assemblies...
I am not saying that one way is better than another to arrive at the intended place, but I am alarmed and peeved that the IBC is as inconsistent as it seems to be and being incredibly arbitrary in its requirement for full scale wall assembly testing per NFPA 285.
It seems like a little common sense is needed here. |
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 1078
Registered: 03-2003
| | Posted on Tuesday, January 22, 2013 - 10:54 am: | |
The building code is inconsistent? That's news to me! ;-)
I won't agrue the point that aluminum has a lower melting point than other construction metals and will combust eventually over time when a fire's temperature reaches a certain point, which is probably at a time when occupants in the vicinity have already evacuated or are dead from the extreme heat.
The intent of NFPA 285 is to prevent the rapid promulgation of a fire through a building's exterior wall that leaves little time for occupants to evacuate. Unlike floor/ceiling systems, which are required to have protected penetrations of shaft assemblies to slow a fire's progress from floor to floor, some exterior walls do not have a means of stopping the vertical spread of fire. With the push for energy efficiency and the use of continuous insulation in the exterior walls, the problem of vertical flame spread at the exterior has been compounded.
Water-resistive barriers and continuous insulation provide uninterrupted or moderately interrupted planes of combustible material that once they're ignited will have uncontrolled burning, like a curtain in a room. The NFPA 285 test ensures that the surrounding construction of the wall gives sufficient protection to the combustible material, thus the need to test the entire assembly.
The metal covering of MCM conducts radiated heat to the plastic core causing the plastic to melt and ignite (at a lower temperature than the metal), therefore, it is subject to the same test. However, there are options that do not require MCM to comply with the NFPA 285 test.
If something in the code does not make sense to you, you are given the means to propose changes. The entire code development process is public and anyone can proposed a change to any one of the ICC codes. Members of ICC get to vote on proposed changes during the preliminary hearings; however, only ICC governmental members get to vote on surviving proposals at the final action hearings.
Although I have not personally submitted a change proposal, I have followed some that have interested me to see how they make it through the system. It appears that changes with a strong case and good, factual data backing it up, have the best chance of survival through the process.
Ron Geren, AIA, CSI, CCS, CCCA, SCIP
www.specsandcodes.com |
Wayne Yancey
Senior Member
Username: wayne_yancey
Post Number: 560
Registered: 01-2008
| | Posted on Tuesday, January 22, 2013 - 11:22 am: | |
Ron,
First, your postings in 4Specs dicussion forums are amoung the best. They are clear and concise in language my injured brain can understand. To many collisons with the ice surface.
My understanding is NFPA 285 addresses exterior wall assemblies with continuous foam plastic insulations. Not wall assemblies with continuous mineral wool which can tolerate temperatures up to 2000 deg F (1000 deg C) plus/minus.
In your opinion, in assemblies with mineral wool, does NFPA 285 apply when the mineral wool insulation is over a self-adhesive air/water barrier or a torch-on air/water barrier or fluid applied air/water barrier?
Torch-on air/water barriers from Soprema are essentially the same as their torch-on roof membranes. If a torch-on roof membranes can provide a Class A rating, can torch-on air/water barriers then be used in walls without NFPA 285 testing?
Thanks,
Wayne |
ken hercenberg
Senior Member
Username: khercenberg
Post Number: 415
Registered: 12-2006
| | Posted on Tuesday, January 22, 2013 - 11:42 am: | |
Anon, it seems like you have issues with MCM. That's fine, I prefer aluminum plate. But wait, it's still aluminum so I guess that gives you heartburn too. Oh well.
I suppose you would like to see all windows and curtain wall framing be fabricated from HM steel. Should all glass be fire-rated as well?
Frankly I'm still hoping that Code officials will make firestopping requirements more stringent at junctions between rated horizontal assemblies to non-rated vertical assemblies but that doesn't sound like it's going to happen either. I guess they're still hoping the sprinklers will work.
There is no question that IBC went too far when they started requiring NFPA 285 for just about every condition imaginable on a commercial or institutional project without providing any sensible or practical way to comply. The industry has wasted too much money and too much time trying to make sense of this. I appreciate the desire to get something into the Code as quickly as possible. I don't think the ICC did their usual due diligence in this case.
Testing assemblies vs. components seems to come up in many aspects of construction. Somehow the concept seems hard to grasp by some. |
Robert W. Johnson
Senior Member
Username: bob_johnson
Post Number: 193
Registered: 08-2004
| | Posted on Tuesday, January 22, 2013 - 11:58 am: | |
Second to Wayne on Ron's great postings on code issues - always to the point, clear, and informative!! |
Lynn Javoroski FCSI CCS LEEDŽ AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1604
Registered: 07-2002
| | Posted on Tuesday, January 22, 2013 - 12:05 pm: | |
If we need a third for Ron's postings, I couldn't agree more. |
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 1079
Registered: 03-2003
| | Posted on Tuesday, January 22, 2013 - 12:47 pm: | |
Wayne, Bob, and Lynn: Thanks for the compliments and for overlooking my typos and grammatical errors.
Wayne, to answer your questions, there are only six conditions in the 2012 IBC where NFPA 285 is required:
1. Section 718.2.6, Exception 3, which allows testing per NFPA 285 in lieu of providing fire blocking in combustible exterior walls.
2. Section 1403.5 for combustible water-resistive barriers.
3. Section 1407.10.4 for full-scale testing of MCM (Alternate conditions, which do not require NFPA 285 testing, are specified in Section 1407.11).
4. Section 1409.10.4 for full-scale testing of high-pressure decorative laminate (HPL) exterior panels (Alternate conditions, which do not require NFPA 285 testing, are specified in 1409.11).
5. Section 1509.6.2 for mechanical equipment screens installed on the roof.
6. Section 2603.5.5 for exterior walls containing foam plastic insulation.
Therefore, if the conditions of an exterior wall do not fall into one or more of these conditions, then NFPA 285 testing is not required. Mineral wool insulation itself would not trigger a requirement for NFPA 285 testing. However, if the insulation covers a combustible water-resitive barrier or an air barrier that also performs the function of a water-resitive barrier, then the NFPA 285 testing is required.
Membranes that are horizontal do not promulgate the spread of fire as quickly as do vertical membranes. There is no exception to the NFPA 285 test for water-resistive barriers, even if the material is the same as that used on a roof.
As I mentioned earlier, air barriers are not mentioned in the code as being required to pass NFPA 285. So, if an air barrier is installed, but is not used as a water-resistive barrier, then NFPA 285 testing is not required. But give it time, the code folks will eventually realize this and a proposal will be offered to include air barriers.
Ron Geren, AIA, CSI, CCS, CCCA, SCIP
www.specsandcodes.com |
Louis Medcalf, FCSI, CCS
Senior Member
Username: louis_medcalf
Post Number: 8
Registered: 11-2010
| | Posted on Wednesday, January 23, 2013 - 08:51 am: | |
Last May the ICC reviewed comments on the new requirements for NFPA 285 testing for walls with combustible water barriers. Various industry experts questioned the requirement on the basis of 1) is it based on actual loss experience and 2) how much fuel does a membrane less than 1/16" thick contribute to a fire inside the exterior wall construction. ICC reaffirmed the NFPA 285 testing requirement.
The biggest problem now is that various product manufacturers have tested assemblies with their proprietary products, but there aren't many tests that are practical for use by designers. NFPA 285 testing is too costly in money and time for custom pre-construction tests to be practical.
BTW, it's still a mystery to me why EIFS is permitted on walls that are otherwise required to be "non-combustible" by Code. There was a fire at a casino in Tunica, MS a few years ago when I lived in Memphis where the EIFS was ignited by heat from exterior building illumination lights. |
Joseph Berchenko
Senior Member
Username: josephberchenko
Post Number: 36
Registered: 08-2003
| | Posted on Wednesday, January 23, 2013 - 10:11 am: | |
Although NFPA 285 is not directly invoked by name for EIFS, IBC Section 1408 requires EIFS systems to be constructed to meet the performance requirements of ASTM E 2568 in which NFPA 285 is mandated by Table 3.
Joseph Berchenko AIA CSI CCS
Assistant Director of Architectural Specifications
ARCOM |
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 1080
Registered: 03-2003
| | Posted on Wednesday, January 23, 2013 - 10:14 am: | |
Louis:
An interesting point regarding EIFS. For building codes prior to the 2009 IBC, the code did not address EIFS directly, which is interesting considering how long the product has been available. However, the requirement for NFPA 285 testing for foam plastics in exterior walls has been a part of the IBC since the very first one in 2000. Therefore, even though there was no EIFS-specific criteria in the earlier editions of the IBC, EIFS would have still needed to comply with the general requirements for foam plastic in exterior walls.
Per recent IBC (2009 and 2012 editions) requirements, EIFS is required to comply with ASTM E 2568, which is a standard specification for PB EIFS. As part of that standard, full-scale multistory testing per NFPA 285 is required.
You're correct that that the NFPA 285 will likely require testing on a per project basis depending on the project's construction type and number of stories. It is impossible for manufacturers to test every conceivable exterior wall assembly. They may test commonly used wall assemblies, but even that might be pushing it, since wall types are regional--what is used here in Phoenix will not be used in Minneapolis.
I've successfully worked around the issue by specifying an insulated metal panel system as the building's continuous insulation. The metal panel system had passed the NFPA 285 test on its own, so any added wall coverings--interior or exterior--was added protection. Also, the metal panel inself created the water-resistive barrier, so a separate material was not needed. It is not an ideal continuous insulation system from an energy-performance perspective, but you have to consider all factors, like the NFPA 285 test.
Ron Geren, AIA, CSI, CCS, CCCA, SCIP
www.specsandcodes.com |
Wayne Yancey
Senior Member
Username: wayne_yancey
Post Number: 561
Registered: 01-2008
| | Posted on Wednesday, January 23, 2013 - 10:32 am: | |
Mark stated above "if your "water-resistive barrier" is combustible your entire assembly must go thru NFPA 285 testing"
If I play with semantics and call the water-resistive barrier an air barrier, combustible or noncombustable, is the product exempt from NFPA 285 testing?
When DuPont Tyvek hit the market in the 80's in Canada it was as a sheet air barrier. Same for the eventual comparables that followed in quick sucession.
Ron said above "As I mentioned earlier, air barriers are not mentioned in the code as being required to pass NFPA 285. So, if an air barrier is installed, but is not used as a water-resistive barrier, then NFPA 285 testing is not required."
Not to challenge Ron, but show me an air barrier that does not also act as a water-resistive barrier. Many products provide several functions. Omit vapor barrier from the equation as may are vapor permeable, the question is still valid.
Are all bets off if the continuous insulation is mineral wool made from basalt rock and slag?
The thlot pickens. |
Wayne Yancey
Senior Member
Username: wayne_yancey
Post Number: 563
Registered: 01-2008
| | Posted on Wednesday, January 23, 2013 - 02:30 pm: | |
I should have been clearer when I wrote "show me an air barrier that does not also act as a water-resistive barrier".
What I meant was when the air barrier is located on the exterior face of a substrate with or without continuous insulation. Air barriers can be in other locations within the exterior wall assembly. |
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 1081
Registered: 03-2003
| | Posted on Wednesday, January 23, 2013 - 03:16 pm: | |
Wayne:
Water-resistive barriers are required by the code, unless exempted because of wall material. So, if your wall assembly requires a water-resistive barrier and you propose using the air barrier as the water-resistive barrier, then it is a water-resistive barrier and must comply with the code requirement for testing per NFPA 285.
Ron Geren, AIA, CSI, CCS, CCCA, SCIP
www.specsandcodes.com |
Sheldon Wolfe
Senior Member
Username: sheldon_wolfe
Post Number: 604
Registered: 01-2003
| | Posted on Wednesday, January 23, 2013 - 08:10 pm: | |
Code guys are no fun. |
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 1082
Registered: 03-2003
| | Posted on Thursday, January 24, 2013 - 11:02 am: | |
Maybe, Sheldon.
But I did help a client defend his option not to install a fire sprinkler when the AHJ was requiring it without any basis in code.
And I helped a small jurisdiction by educating them on the code in order to reign in a rogue fire marshal who completely misinterpreted the code and overstepped his authority.
So, every now then we do some good. ;-)
Ron Geren, AIA, CSI, CCS, CCCA, SCIP
www.specsandcodes.com |
Paul Gerber
Senior Member
Username: paulgerber
Post Number: 142
Registered: 04-2010
| | Posted on Friday, January 25, 2013 - 11:30 am: | |
All I can say is from what I read about the ICC, I'm glad I don't have to deal with it in Canada, yet!
But as with all things Canadian, eh? I'm sure that eventually some of these absurd sounding requirements for minuscule portions of the building envelope will find their way into our codes too! Effective January 2012, Ontario Building Code adopted requirements of ASHRAE 90.1-2010. Suddenly we are on the leading edge of energy-conscious design requirements!
Another example is CaGBC's adoption of USGBC LEED requirements (although thankfully we are usually a full version behind you guys so some of the bugs get worked out before we have to use it).
I wholeheartedly agree with Louis' comment above..."how much fuel does a membrane less than 1/16" thick contribute to a fire inside the exterior wall construction"???? Things that make you go hmmmmmmmmmm...
Ride it like you stole it!!! |
ken hercenberg
Senior Member
Username: khercenberg
Post Number: 419
Registered: 12-2006
| | Posted on Friday, January 25, 2013 - 12:02 pm: | |
Hey Paul, have the brainiacs decided that roofs in Canada should be white reflective to reduce A/C loads?
Must be a big deal up in the Great White North, especially this time of year. I guess with the snow it is white and reflective.
Hope all is well.
Ken |
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