Thermal Barrier requirement on metal shop with spray foam.

[Jonathan Earnhart]

Is a thermal barrier required on a metal shop with spray foam under IBC Chapter 26? The shop is actually block with a metal roof. I used this exemption but the city says no:

Elimination of Thermal Barrier According to building codes, roof assemblies incorporating foam plastic insulation installed on a steel deck must include a thermal barrier, typically 1/2 inch gypsum board or equivalent, between the deck and the foam plastic insulation. The thermal barrier may be eliminated if the complete roof assembly passes either FM 4450 or UL 1256. Note that although both FM 4450 and UL 1256 are conducted on a specific roof assembly, passing either test without a thermal barrier in one tested roof assembly does not mean the thermal barrier may be eliminated in all roof assemblies. Specific roof assemblies that have passed FM 4450 may be found in the FM Approval Guide or the web-based FM RoofNav roof assembly search tool. Those that have passed UL 1256 may be found in the UL Roofing Materials & Systems Directory.

 

[cda]

Welcome

So what section of the building code did they tell you to comply with??

and what year edition of building code

 

[Jonathan Earnhart]

Welcome

So what section of the building code did they tell you to comply with??

and what year edition of building code

2012 IBC 2603.4. Or just said chapter 26

 

[classicT]

Do you have documentation that your proposed assembly passes either NFPA 276 or UL 1256? Did you provide it to them?

Do note that the IBC specifies NFPA 276, not FM 4450. This could be a local amendment, not sure.

2603.4.1 Thermal Barrier Not Required
The thermal barrier specified in Section 2603.4 is not required under the conditions set forth in Sections 2603.4.1.1 through 2603.4.1.14.

2603.4.1.5 Roofing
A thermal barrier is not required for foam plastic insulation that is a part of a Class A, B or C roof-covering assembly that is installed in accordance with the code and the manufacturer's instructions and is either constructed as described in Item 1 or tested as described in Item 2.

1. The roof assembly is separated from the interior of the building by wood structural panel sheathing not less than 0.47 inch (11.9 mm) in thickness bonded with exterior glue, with edges supported by blocking, tongue-and-groove joints, other approved type of edge support or an equivalent material.
2. The assembly with the foam plastic insulation satisfactorily passes NFPA 276 or UL 1256.

 

[Paul Sweet]

I believe the exception is for foam insulation installed above the deck, not sprayed on the underside of a metal roof.

 

[Tim Mailloux]

I believe the exception is for foam insulation installed above the deck, not sprayed on the underside of a metal roof.

that's how I understand it.