San Francisco County Municipal Code Ch. 26 Plastic

3. Foam plastic insulation that is part of a Class A [ ← ] or B [ ← ], roof-covering assembly provided [ ← ] the assembly with the foam plastic insulation satisfactorily passes NFPA 276 or UL 1256. 2603.4.1.5 Revise this section as follows: 2603.4.1.5 Roofing. A thermal barrier is not required for foam plastic insulation that is 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.
4. 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, and identified as Exposure 1 with edges supported by blocking, tongue-and-groove joints, other approved type of edge support or an equivalent material. [ ← ] The assembly with the foam plastic insulation satisfactorily passes NFPA 276 or UL1256.

Foam plastic insulation meeting the requirements of Sections 2603.2, 2603.3 and 2603.4 shall be permitted as a part of a roof-

covering assembly, provided [ ← ] the assembly with the foam plastic insulation is a Class A [ ← ] or B [ ← ] , roofing assembly where tested in accordance with ASTM E108 or UL 790.