| abstract |
According to one embodiment, a halogen free roof system is described. The roof system includes a structural deck that is positioned above joists or other suppor members. Polyisocyanurate foam insulation is positioned atop the structural deck. The polyisocyanurate foam insulation has an isocyanate index greater than 200 and includes a polyisocyanurate core having a halogen free fire retardant. A water proof membrane is positioned atop the polyisocyanurate foam insulation. The polyisocyanurate core is able to form a sufficiently stable char when exposed to flame conditions such that the polyisocyanurate core is able to pass the ASTM E-84 test. |