Marc; you needed to read NFPA 285 to go nuts?
Does anyone have information on a system similar to Centria’s “MetalWrap?” I want at least two credible systems in my spec, if at all possible.
Thanks
When I specified Centria’s MetalWrap as a basis-of-design product, I found that Insulated Panel Systems, Kingspan, and Metl-Span had very similar products.
I think I found the Kingspan system, looks like they call it “KarrierPanel Universal Barrier Wall System”
thanks
Ron, have these others now included NFPA 285 test data when used as a backup system? Last time I looked at listing them as an alternative to the MetalWrap they didn’t really have the documentation.
For a project where we opted to pursue use of a unitized curtain wall for virtually the entire exterior skin, we tried listing a panel from Mapes that could be glazed in as a backup panel. We couldn’t really make the costs work with either the Mapes or the MetalWrap (which didn’t allow for the glazing-in option). Just as well; based on a closer look at how the total system detailing came out, it didn’t really work as true continuous insulation anyway. We had to pursue other options. Still, I like the idea if you can make the detailing work.
Kingspan and Metal-Span have products that have been tested per NFPA 285 (Metl-Span has an ICC-ES evaluation report). NCI Insulated Panel Systems does not, but we included them anyway, as long as they provided the testing prior to submitting submittals for the product.
When researching use of MCM cladding, technical staff at each of the 3 major manufacturers told me their standard core panels will not pass an NFPA 285 test. Have to use their fire-resistant core panels or solid aluminum plate.
The concern is that in a fire, aluminum windows melt allowing fire to get into the construction of the exterior wall with the possibility of propagating through the wall to the next higher story [simplified]. That’s why one-story buildings are exempt from the requirement for NFPA 285 testing. NFPA 285 test assemblies are 2-stories with a window opening on the lower story.
The question is whether there is really a loss history in the US that justifies this code requirement and the extension to all combustible products in the exterior wall construction, regardless of fuel contribution, and the related cost to US commercial construction. Does an air barrier that is typically not more than 40 mils really contribute a significant amount of fuel to a fire?
Louis - I need to understand what you mean about “that’s why one-story buildings are exempt from the requirement for NFPA 285 testing”. While NFPA 285 is a multistory test, the IBC enforcement of NFPA 285 does not exempt 1-story buildings.
A few weeks ago I confirmed directly with ICC that 1-story buildings are not exempt. The closest thing to an exemption is IBC 2603.4.1.4. which governs 1-story buildings, but it requires sheet metal to be placed over the insulation in the wall cavity. I have never heard of this being performed.
You do make an excellent point about “loss history”. Why have the code bodies decided to solve a problem that does not appear to exist?
The test does not include an actual window, just an opening. Therefore, the cladding must have a protection system for the opening and not rely on the window to protect it.
I recently wrote an article regarding NFPA 285: NFPA 285: Flame Propagation in Exterior Walls.
Ron, I could not get the link to the article to work.
Try this one: NFPA 285: Flame Propagation in Exterior Walls
Ed,
I believe the sheet metal covering over the foam plastic insulation is only required IF one desires to not use the thermal barrier required by section 2603.4.1.
Interesting that the Code does not mention if the insulation is required to be covered on one or both faces.
Thanks Ron, that second link worked. Great article.
Ron, you’re correct. The metal is in lieu of a thermal barrier that is required per Section 2603.4. As Section 2603.4 states, the thermal barrier separates the interior from the foam plastic. Therefore, the requirement does require application of the metal to the exterior side of the foam plastic.
Ron (or others),
The question remains whether NFPA 285 compliance is required for one-story buildings. Some sources have repeatedly indicated that NFPA 285 compliance is NOT required for one-story buildings. But as I confirmed with ICC, the only exception for one-story buildings is the Exception to 2603.5.5. This Exception, while exempting the building from NFPA 285, requires compliance with 2603.4.1.4 which, among other requirements, prescriptively requires sheet metal be placed over the insulation. This sheet metal installation in a wall cavity is a practice that I have never heard being performed and does not seem practical. Therefore, reflexively, a one-story building would have to comply with IBC 2603.5.5 (NFPA 285).
If this line of thinking is incorrect, or if there is a practical metal-clad insulation product, please let me know!
If I recall correctly, Type 5 buildings are exempt from this requirement. Since many Type 5 buildings are single-story buildings, this may be where the impression that such buildings are exempt comes from.
Ed:
ICC is correct. Section 2603.5 is titled “Exterior walls of buildings of any height,” which means that one-story buildings are required to comply with the NFPA 285 testing. The exception to Section 2603.5.5 (the requirement for NFPA 285 testing) references complying with Section 2603.4.1.4 for one-story buildings. As I stated, this is a subsection that is essentially an exception to the requirement for a thermal barrier that separates the interior from the foam plastic in the exterior wall. The Code and Commentary mentions that this is for the metal building industry for buildings that may not use gypsum board on the interior. Thus, the only separation between the foam plastic and the building interior is the sheet metal; thereby adding the requirement for the sprinkler system to provide the added protection for equivalency.
The confirmation you received from ICC is just a staff opinion and not a vetted formal interpretation. Although staff opinions carry some weight, they don’t have the level of authority that a full committee interpretation would provide.
I admit this is an imprecise requirement. The use of “foam plastic is covered” in Section 2603.4.1.4 does not stipulate if the cover is to completely encapsulate the foam plastic. That may be the intent, but as specifiers we know that intent does not a requirement make.
I could probably get an alternate means and methods approval by using the sprinkler system per Section 2603.4.1.4 and a gypsum board thermal barrier to avoid the NFPA 285 for a one-story building using the language of Section 2603.4.1.4 against itself by pointing out that full encapsulation of the foam plastic is not stated–just that it is covered from exposure on the interior side (the purpose of a thermal barrier). Since the concern of Section 2603.4.1.4 is the separation of the foam plastic from the interior, the use of gypsum board, per Section 2603.4, will provide that barrier, thus negating the need for the sheet metal. Therefore, a sprinklered one-story building (with either sheet metal or 1/2-inch gypsum board between the foam plastic and interior) would not be required to be tested per NFPA 285.
As to your last statement about a practical metal-clad insulation product, I mentioned several manufacturers above that provide metal insulated panels that can be used.
Hey Ya’ll
I’ve had a question posed to me that I’ve not had to answer before. I have a USACE project where the Exterior Enclosure Assembly is field installed utilizing various components. The components from the inside outward are as follows: (a) 6 metal stud framing, (b) exterior gypsum board sheathing, (c) air barrier membrane, (d) foam plastic insulation board (extruded polystyrene), and (e) metal panel siding. There is no plastic material imbedded within the metal panel siding material. The question is: who would be the manufacturer that has responsibility to have the NFPA 285 test performed?
Currently our Section 07 21 13 - Board and Block Insulation only references ASTM E 84 criteria of FSI at 25 or less and SDI at 450 or less. There is not any reference to the NFPA 285, unless it is just through the general reference to the IBC criteria.
Thanks
Margaret
Margaret,
Many of the Air Barrier manufactures have taken the lead on this. Though any of the material manufacturers could do so, its actually not anyone’s requirement or responsibility. It just makes good business sense that if you market a combustible product for wall assemblies, that you perform as wide a testing as possible for the kinds of applications your products are likely to encounter.
Now, here is the rub - many of the architectural reps for these products don’t know (because they have not been told) that there is information available that tells exactly what materials their product has been tested with and in what configurations. About a year ago now I went to Henry related to what tests they may have performed. Initial response was that there was no list, but that they would check. A short time later I was given a nice brochure that had a printing date of close to a year earlier that listed whole groups of products and manufacturers.
So I went to the Tyvek people and asked them - they said the same thing, and then a week or so passes and I get another nice brochure that shows a wide range of products they have tested with.
This proceeded down the list of other air barrier manufacturers. I remember one that shall remain nameless that when I asked about it was fairly sure that no such lists were being developed. This was one of the more competent reps that I have known for years and respect. So I handed them a brochure from a competitor and said he could keep it. A week or so passed and I got emailed a brochure that bore a printing date of close to a year earlier that ended up being one of the larger comprehensive lists of products from other manufacturer’s tested with this air barrier.
I have not checked in about 6 months or so now, but at that time, none of these were available or even referenced at all on the company web sites. It seems to me that most web sites, even for very technical information, are controlled by the corporate marketing departments. And to marketing types, they think that the professional side wants to see pretty pictures or ‘gee wiz’ type performance information.
Now, one of the short comings for these brochures is that they are only the introduction to what we really need. Well, not what we need but what the project architect needs - that is, the details. Not only do the products in the wall assembly have to be listed as having been tested as an assembly, but the details for the project have to be drawn matching exactly the details used in the assembly tests. Not everyone realizes that, and many of the assembly tests performed ended up with some detailing requirements that have yet to make it into the manufacturer’s standard details.
So, language wise for part 3, might include that where details as shown varies from the manufacturer’s required detail for compliance with NFPA 285, the manufacturer’s detail requirements shall govern.
That might result in some surprises if a PA does not really check into this issue, but better to have to deal with a surprise than to have to tear down a wall. Or worse, no one not even inspectors may realize its not in compliance and after some fire an investigation reveals that the wall is not in compliance with the manufacturer’s assembly requirements.
William
Not much choice but to look for an assembly that has passed the test. So far, insulation manufacturers are leading the way, including a variety of air barrier materials in their tests, but a few other manufacturers have tested their products. My understanding is that because it’s an assembly test, you must use exactly the same materials used in the test, and your details must be exactly the same.
Search for “Dow NFPA 285” “Owens Corning NFPA 285” “Henry NFPA 285” and so on, perhaps starting with the metal panel you want to use.
This is a moving target that can be confusing. UL does not maintain a directory of listed assemblies so manufacturers are the only source of information which may not have the same weight of authority. Because the IBC requires testing, but does not require a “listed assembly”, it should be easily possible to get a variance based on an engineering judgement. It seems to me to leave a lot to the discretion of the AHJ.