Roof Ceiling Fire Rating

A question has come up concerning sloped roof trusses and fire assembly ratings.

Roof ceiling fire rating.

Fire tests may be conducted at any one of several recognized facilities. Both ul and ga include specific guidance regarding the use of insulation in assemblies. You can use only the specific type size and minimum. The slope of the test specimen is preselected and since steeper slopes are more of a challenge due to melting material feeding the fire the rating applies to the maximum slope passed.

Astm e119 standard test methods for fire tests of building construction and materials is the test standard for determining the fire resistance rating of partitions floor ceiling assemblies roof ceiling assemblies beams and columns. Fire rated ceiling assemblies suspension ceiling designs floor ceiling designs a003 3 hr. However the total depth of the systems with either directly attached or suspended ceiling membranes shall be permitted to extend greater than 36 inches. Do you have any information regarding the suitability of the fire rated ceiling assemblies for sloped roof trusses.

3 4 fr 83 12 x 12 z runners fluorescent type none 2 1 2 concrete. Don t be left hanging understanding how the nec regards suspended ceiling designs and supports is critical for proper design and installation of electrical wiring and equipment. No ceiling or suspension system product alone constitutes a fire rated assembly. Roof ceiling and floor ceiling construction assemblies which are tested and assigned hourly ratings mandated by building codes or other building safety requirements.

Urb concealed grid system and tile. Time temperature ratings the third major roof system fire test is astm e 119. Refer to our roof ceiling assembly documents which includes ul fire rated roof assemblies for easy guidance through the assembly of a roof or ceiling on your next project. Some are reluctant to rely on test results from flat parallel chord trusses applied to sloped roof trusses.

Ul and fm list many roof ceiling systems in their publications. This is a system test that includes structural members such as beams trusses and roof deck. As a designer and installer you should know the fundamental differences between a suspended ceiling which is an integral part of a fire rated floor ceiling or roof ceiling assembly and the far more. Helpful documents and resources for usg s roof assemblies can be found on this page.

In the world trade tower collapse heat load on the connections of steel trusses is suspect. Floor ceiling and roof ceiling systems were fire tested at less than 36 inches total depth. The maximum flame spread is 6 feet for a class a rated roof 8 feet for class b and 13 feet for class c. Ul tests rate an entire assembly.