I have an existing electrical switchgear room that was believed to be 1-Hour rated via block CMU walls and a ceiling construction of metal deck with concrete. Upon further investigation, the ceiling is just metal deck and no concrete was ever poured on it.
How can I achieve a 1 hour rated ceiling assembly without pouring concrete? Can the interior be spray-applied fireproofing that has a UL certified assembly? Someone mentioned fire-rated plywood on top of the metal deck but I have never seen this accomplished before.
Hi Daniel! Thank you for checking out ASK Hilti!
It is outside the scope of HILTI to provide direction on fire-resistance rated construction. That would need to be directed towards the drywall manufacturers, design team, building official and/or UL to determine the correct design intent of the floor/ceiling assembly.
Hilti can certainly provide support on locating and providing tested and listed firestop systems and/or engineering judgments of penetrations or joints of the fire-resistance rated floor/ceiling assembly once the assembly is determined that the fire-resistance rating is justified.
You can find more information on how to our access our firestop selector and our engineering judgment platform here: https://www.hilti.com/firestops (US) or https://www.hilti.ca/firestops (Canada) and https://www.hilti.com/ej (US) or https://www.hilti.ca/ej (Canada.)
If you have any questions, please reach out to our customer service team at 1-800-879-8000 (US) or 1-800-363-4458 (Canada) for assistance.
Thank You for choosing Hilti as your Firestop Experts!
Joe Newbanks,
Fire Protection Engineering Team