We all know UL systems are very specific in calling out the requirements that must be met in order to have a complete system. What you may not know is that UL allows for certain alterations to be made to the individual UL system, these approved alterations can be found in the UL Guide Information for Through-Penetration Firestop Systems (XHEZ.GuideInfo).
Here is a key highlight from the UL Guide Information to keep in mind the next time you are in the process of selecting or reviewing a through-penetration firestop system.
When searching for a system that allows for concrete over fluted steel deck many of the concrete floor system may be utilized. Even though the fluted steel deck is not specifically called out in the UL System it may be included if two key requirements are met. The two requirements are as follows:
- The minimum concrete thickness measured above the top plane of the steel deck must be equal to or greater than the thickness required per the UL System.
- The firestop system does not require any portion of the firestop system to be installed below the bottom plane of the floor.
A larger majority of systems utilizing mineral wool and sealant in a concrete floor can be installed in a concrete over steel deck assembly. A good example would be STI system C-AJ-1353, since the required packing material does not extend below the bottom surface of the assembly. This may not be the case when considering systems utilizing products such as wrap strip, where it is required to extend below the bottom surface of the floor assembly. Please do not hesitate to contact STI Technical Services for additional information.