Ul Class A Roof Assemblies

Class a b or c roof coverings may be installed over existing classified roof assemblies under the following conditions without additional roof classification tests provided the resulting classification is the lower of the new and existing roof classifications under the following conditions.

Ul class a roof assemblies. Roof systems are segregated into combustible and non combustible construction types. A class a rating is only for external fire performance. Aluminum panels surfacing identified as tee cee lock zee lock zee lock double lock and tee lock. 0 0416 kg m 2 copper sheets installed over combustible decks.

A roof is classified as a class a as the result of one test the external spread of flame test astme 108 or ul 790 standard. Under ul 790 roof systems are evaluated for external fire. A secure online source for increased visibility into your ul project files product information documents samples and services. A class 1 roof has undergone a series of tests that evaluate the entire roof assembly including the external spread of flame test utilized for the class a rating.

While roof assemblies containing polystyrene insulation can meet class a there are no roof assemblies with polystyrene insulation applied direct to a steel deck that qualify as a class 1. Certification database ul product iq. 15 32 thick wood structural panels min. Class a roof assemblies include minimum 16 oz sq.

All class 1 roof assemblies are class a roofs but not all class a roof systems meet the class 1 rating. The ul item number in the following listings has been added as a service to those who have the ul building materials directory. Class a roof assemblies also include ferrous or copper shingles or sheets metal sheets and shingles clay or concrete roof tile or slate installed on noncombustible decks or ferrous copper or metal sheets installed without a roof deck on noncombustible framing. Ul environment sustainability services provide architects designers and professional purchasers a reliable sourcing tool for roofing products that have been evaluated to sustainable and responsible requirements.

A roofing membrane that is classified as part of a class a assembly when installed over a particular insulation may not qualify as part of a class a assembly with another insulation. Contrary to what many think there are no class a roofing membranes. The operative word here is systems. Any ul class a b or c roofing system tgfu or prepared roof covering tfwz layer 2 roof sheathing.

New insulated roof coverings installed over existing uninsulated assemblies only. Grade c d or sheathing. Understand the differences between a class 1 and a class a roof assembly containing foam plastic.