Area and separation limitations of light-transmitting plastics.

[Ryan Schultz]

Hi, I'm trying to get a grasp of the area and separation limitations of light-transmitting plastics.

The R-2 building is a 3 story, Type VB with a 20,000sf footprint, and is fully sprinklered.

Per 2607.4 Area Limitation and Separation exception 1:

2. Veneers of approved weather-resistant light-transmitting plastics used as exterior siding in buildings of Type V construction in compliance with Section 1406.

... it appears this building would not be limited by 2607.4, but section 1406 instead.

All the exterior walls are 10ft or more away from a property line, or right of way.

We are proposing 2x wood stud construction behind the light-transmitting plastic panel (polycarbonate panel ) at each seam in the panel. The clip for the polycarbonate will be attached to the stud for lateral support.

These studs will be exposed to the interior space. That is, no concealed space.

There will be a horizontal alum profile supporting the top and bottom of the plastic panel at each floor.

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Question: From what I can understand of Section 1406, assuming the incident radiant heat flux of these panel is less than 8.9(kW/m2), we are not limited in the maximum area, or the vertical separation of these polycarbonate panels. Since there is not a concealed space behind the panel, there is not a fire blocking requirement either.

Would this be a correct interpretation?

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Also a related question, are these polycarbonate wall panels, with supporting studs behind, considered an 'opening protective'?

That is, would they fall under the restrictions of 705.8 Openings in exterior walls?

My interpretation is that they are not considered 'opening protectives'

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If curious, this is the product we're looking to use: http://gallinausa.com/arcoplus/arcoplus-547/

Images below of the proposed design.

 

[RLGA]

What code edition?

 

[Ryan Schultz]

Hi. 2015 ibc.

 

[RLGA]

An opening protective is an opening that requires a fire-protection rating. Light-transmitting plastics would never qualify as part of an opening protective. Opening protectives are only required when the exterior wall that they’re located within is required to be fire-resistance-rated. If the walls are required to be fire-resistance-rated, then light-transmitting plastics would not be allowed per Section 2607.1.

I don’t think Section 1406 would apply in your situation as this section applies to exterior wall coverings and projections. By definition, an exterior wall covering is applied to an exterior wall. Without the light-transmitting plastic, you do not have an exterior wall by definition. Therefore, your only option is with Section 2607 and, thus, Table 2607.4.

Are these “walls” enclosing conditioned space? If so, do you have any energy code adopted and how are these “walls” in compliance?

 

[Ryan Schultz]

How is exception 2 of 2607.4 applied?

"Veneers of approved weather-resistant light-transmitting plastics used as exterior siding in buildings of Type V construction in compliance with Section 1406."

Note: I said exception 1 above, but meant 2.

 

[Ryan Schultz]

Per the energy compliance, we plan on running an energy model to make sure we're in compliance. Will require dialing in on u values and overhangs distances.

 

[RLGA]

How is exception 2 of 2607.4 applied?

"Veneers of approved weather-resistant light-transmitting plastics used as exterior siding in buildings of Type V construction in compliance with Section 1406."

Note: I said exception 1 above, but meant 2.

Although not italicized, veneer is defined in Chapter 2. In my opinion, the application of light-transmitting plastic panels per your design would not meet the definition of a veneer.

 

[Ryan Schultz]

"VENEER. A facing attached to a wall for the purpose of providing ornamentation, protection or insulation, but not counted as adding strength to the wall."

It appears this might be open to interpenetration, as the polycarbonate panels we're using provide insulation, and do not add additional strength to the wall.

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Viewed another way, what would be an example of a light transmitting veneer which satisfies exception 2?

If Veneers and panels are view differently, why is this expectation about veneers in Section 2607--a section about Light-Transmitting Plastic Wall Panels?

 

[Builder Bob]

Ryan,

What does your area require for wall bracing etc. , In our area (seismic D) you would have to provide braced wall panels at various locations and the sketch provided does not appear to have any braced wall panels for the second and third floor.

You may not have to provide as much "braced Wall" design as we do down here since you are a "B" seismic for commercial.

 

[Ryan Schultz]

Hi Bob, we are in Wisconsin, but they still require bracing. If you see on the elevation drawings above, we're proposing diagonal bracing inside.

 

[RLGA]

Viewed another way, what would be an example of a light transmitting veneer which satisfies exception 2?

If Veneers and panels are view differently, why is this expectation about veneers in Section 2607--a section about Light-Transmitting Plastic Wall Panels?

Panels can be applied to walls to provide a continuous material over solid and open areas of the wall. I just went through this with a client and had to get an ICC opinion to confirm that the panels over the solid walls were veneer and can be subject to Chapter 14 and the panels over openings were actually used as windows with light-transmitting material subject to Chapter 26 limitations. I had to get the ICC opinion because the local plans examiner wouldn't accept my opinion.

Also, the panels could be back-lit with lighting for graphics and/or signage.

You need to look at the intent of the code. There are a couple of concerns that the code is trying to address: exposure of plastics on the interior (from a flame-spread/smoke-developed perspective) and exposure on the exterior (from a flame propagation perspective -- think London's "Grenfell Tower" -- and from fire exposure to and from adjacent properties). When used as a veneer over a solid wall, the exterior exposure concern is significant, thus the height limitations; but not as significant when actually used as a light-transmitting plastic panel where both interior and exterior concerns are at play, thus the height and area limitations. Your use of light-transmitting plastic panels falls into the latter.

To be honest, I don't know why Exception 2 of Section 2607.4 references Section 1406 for Type V construction, because Section 1406 hasn't even addressed Type V construction since the 2009 IBC (The 2012 IBC relocated the general requirements applicable to all construction types entirely within the section that is applicable only to construction types other than Type V). In other words, there are no requirements for Type V construction in Section 1406 unless the light-transmitting plastic panels are applied to balconies, projections, and bay/oriel windows.

 

[Ryan Schultz]

Thanks Ron! So it goes.

Assuming we're within the area limitations outlined in Table 2607.4, it appears the only way we can stack these panels directly above one another, floor to floor, (0' separation) is to have an approved flame barriers extending 30 inches (760 mm) beyond the exterior wall in the plane of the floor?

Would that be a correct assessment?

 

[Ryan Schultz]

Also, I assume, if we have a plastic panel on the 2nd floor, for example, we can have window directly above on the 3rd, without this 30" flame barrier. Would that be a correct assumption as well?

 

[RLGA]

Thanks Ron! So it goes.

Assuming we're within the area limitations outlined in Table 2607.4, it appears the only way we can stack these panels directly above one another, floor to floor, (0' separation) is to have an approved flame barriers extending 30 inches (760 mm) beyond the exterior wall in the plane of the floor?

Would that be a correct assessment?

Yes, that would be correct.

Also, I assume, if we have a plastic panel on the 2nd floor, for example, we can have window directly above on the 3rd, without this 30" flame barrier. Would that be a correct assumption as well?

Yes, that would be correct, too.