I need a UL fire rated assembly (walls and interior partitions, shaftwall head-of-wall, floor-ceiling systems, etc.), which assembly should I use?

The Architect of Record and Engineer of Record should be able to tell you which UL file No. is required for the project. There are several other resources to help you in choosing the correct fire rated assembly for your project. You can search the UL database of fire rated assemblies here. The number to search should begin with the UL designated letters for the type of assembly you are looking for:

Prefix Letters	Group of Construction
A	Floor-Ceiling Designs - Concrete with Cellular Steel Floor Units and Beam Support
D	Floor-Ceiling Designs - Concrete with Steel Floor Units and Beam Support
I	Non-load-bearing Horizontal Barrier
J or K	Floor-Ceiling Designs - Precast and Field Poured Concrete
L	Floor-Ceiling Designs - Wood or Combination Wood and Steel Joist Assemblies
N	Beam Designs for Floor-Ceiling Assemblies
P	Roof-Ceiling Designs
S	Beam Designs for Roof-Ceiling Assemblies
U or V	Wall and Partition Designs
X or Y	Column Designs

For instance, Search U* will list all UL rated wall assemblies. From there you can click "Refine Your Search" and enter all of your project design criteria (1HR vs. 2HR) and enter applicable Keywords such as 1" for 1" deflection. Additionally, UL architectural services can assist by calling 1-877-854-3577 (option 5 or extension 49590). National Gypsum Co. has excellent fire rating technical services and can be reached at 1-800-National. The Gypsum Association Design Manual GA-600-12 has several fire-rated assemblies. As always, our engineering team is available at 206-725-2500.