Following are descriptions of type, class and grade designations for ASTM C1289, "Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board":

• Type I: Foil-faced foam core
  • Class 1: Non-reinforced foam core
  • Class 2: Glass fiber reinforced or non-reinforced foam core
• Type II: Faced foam core
  • Class 1: Reinforced cellulosic mat facers
    • Grade 1: 16 psi minimum compressive strength
    • Grade 2: 20 psi minimum compressive strength
    • Grade 3: 25 psi minimum compressive strength
  • Class 2: Coated fiberglass facers
  • Class 3: Uncoated fiberglass facers
  • Class 4: High-density foam core, 1.2-inch thick maximum, with coated or uncoated fiberglass facers
    • Grade 1: 80 psi minimum compressive strength
    • Grade 2: 110 psi minimum compressive strength
    • Grade 3: 140 psi minimum compressive strength
• Type III: Faced with perlite board on one surface and a reinforced cellulosic mat facer or a coated or uncoated fiberglass facer on the other surface
• Type IV: Faced with wood fiberboard on one surface and a reinforced cellulosic mat facer or a coated or uncoated fiberglass facer on the other surface
• Type V: Faced with OSB or plywood on one surface and a reinforced cellulosic mat facer or a coated or uncoated fiberglass facer on the other surface
• Type VI: (withdrawn)
• Type VII: Faced with glass mat-faced gypsum board on one surface and a reinforced cellulosic mat facer or a coated or uncoated fiberglass facer on the other surface

For additional information regarding polyisocyanurate insulation, view Tech Today, "Too many options," in Professional Roofing's March 2013 issue by clicking here.

This Web exclusive information is a supplement to Tech Today.