2009 IBC. Rigid roof insulation sheets, reflective faced. Section 719 describes the requirements for insulation. In 719.1 there are four exceptions. Exception 2 requires foam plastic insulation to comply with Chapter 26. Exception 4 requires "All layers of single and multilayer reflective plastic core insulation shall comply with Section 2613."
Rigid insulation is a plastic insulation. So must it meet Chapter 26 requirements? Or, if it has a reflective membrane, is it ONLY required to meet Section 2613?
the intent of the question is to determine if reflective faced rigid roof insulation is required to have a thermal barrier on the exposed to room side.
thanks for your input!