The Growing Trend for UL and cUL Full-Scale Fire Tested Horizontal Membrane Assemblies


Mitchell Schittler, LEED AP® BD+C, WELL® AP, Technical Marketing Manager, CertainTeed Gypsum

The demands of building product performance are constantly increasing. Everything from material quality to product lifespan to life safety is under growing scrutiny to help make sure the built environment is safer and more livable. As a result, the testing and certification of building products are becoming more rigorous.

Today’s commercial, multi-family, and institutional buildings must comply with myriad fire safety issues, as defined by the International Building Code and National Building Code of Canada. Because fire safety issues are not limited to vertical separations, specifiers need to address horizontal fire and smoke separation when working on multi-story building projects.

Floor-Over-Floor Protection

Horizontal shaftwall assemblies are key building components in many commercial, multi-family, and institutional buildings, and they require specific design and specification attention to ensure both code compliance and the safety of the people who occupy these spaces. As an increasing number of projects utilize horizontal membranes, there is a growing demand for full-scale fire-rated assemblies, per ASTM E119 and CAN/ULC-S101.

As non-loadbearing structures, horizontal membrane assemblies are unique in that they provide a fire resistance rating for projects that can’t incorporate a typical floor/ceiling or roof/ceiling assembly. Floor/ceiling assemblies typically include subflooring or concrete floor toppings, while roof/ceiling systems typically include the roofing system, as specified in the UL and cUL assembly. Horizontal membranes provide alternative fire rated assemblies to use in corridors, occupied space and plenum separation, exit stairways, and other areas where a standard floor/ceiling or roof/ceiling assembly is not architecturally feasible.

The Benefit of Full-Scale Testing for Fire-Rated Horizontal Shaft Liner Assemblies

While horizontal membrane assemblies are not new within the industry, full scale tested horizontal membrane assemblies, per ASTM E119 and CAN/ULC-S101, are newer assemblies for the industry. Moreover, awareness among specifiers of full-scale tested products remains limited because they have not yet become an industry norm. 

Architects and Specifiers are no longer limited to evaluation reports, which are often based on small-scale testing. Architects and Specifiers have the ability to — and should — specify UL and cUL full-scale tested fire-rated horizontal membrane assemblies. Thanks to stringent and more thorough procedures, full-scale testing offers a more accurate representation of how fire-rated horizontal membrane assemblies will actually perform in real-life applications. They will also not only help meet code requirements, but ensure life safety for the occupants.

Fortunately, CertainTeed provides multiple full-scale testing options. In fact, the company is the first manufacturer to offer full scale tested, one and two-hour horizontal shaftwall systems that meet ASTM E119 and CAN/ULC-S101.

Testing Details

UL/cUL I507 provides a one-hour fire resistance rating, using a minimum 6”, 33 mil steel stud, and three layers of 5/8” CertainTeed Type X, 5/8” CertainTeed M2Tech® Type X, or 5/8” CertainTeed Type C.  


UL/cUL I514 provides a two-hour fire resistance rating, using a minimum 6”, 33 mil steel stud, four layers of 5/8” CertainTeed Type C, with resilient channel between the third and fourth layer.

CertainTeed is also the first manufacturer with full scale tested, one and two-hour horizontal shaftwall systems.  UL/cUL I515 provides utilizes C-T studs, GlasRoc® or M2Tech® Shaftliner and two layers of 5/8” CertainTeed Type X, 5/8” CertainTeed M2Tech® Type X, or 5/8” CertainTeed Type C for a one-hour rating.  The two-hour rating utilizes C-T studs, GlasRoc® or M2Tech® Shaftliner, three layers of 5/8” CertainTeed Type C, with resilient channel between the middle and face layers.

One Hour

Two Hour

The Value-Add: Health, Sustainability & Specification Tools

The use of CertainTeed fire-rated assemblies can also help achieve your project’s health and sustainability goals. CertainTeed continues our Sustainability commitment.  All CertainTeed Gypsum panel products have Health Product Declarations (HPDs), many third-party verified, which provides added product transparency. Many products also offer product-specific Type III Environmental Product Declarations. Plus, all CertainTeed Gypsum Panel products meet GREENGUARD Gold and CDPH V1.2 requirements.

CertainTeed also provides additional tools. Our Sustainability page can be accessed at  CertainTeed’s BIM and CAD page is available at  We also provide quick access to our 3-part specifications, substitution requests, data submittals, and more at

Additional Accredited Learning Opportunities

Interested in learning more about the growing trend for horizontal membrane assemblies?  CertainTeed now offers a lunch-and-learn CEU, AIA accredited for 1 LU|HSU. 

Email us at to schedule your company’s lunch and learn presentation.

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