Hi
We are reviewing firestop requirements for insulated mechanical pipe penetrations on the confidential project and would like to confirm available tested systems.
Please confirm whether Hilti has a tested and listed through-penetration firestop system (UL 1479 / ASTM E814) achieving both F and T ratings for the following conditions:
- Pipe size greater than 4
- Elastomeric (closed-cell) insulation maintained at penetration
- Floor penetration conditions requiring T-rating
If no such system is available, please confirm:
1. Whether elastomeric insulation must be removed or modified at the penetration to achieve a T-rated system
2. The required insulation type and configuration per UL-listed systems (e.g., mineral wool batt, density, thickness, extent)
3. Applicable Hilti system numbers and installation requirements
Please provide supporting UL system references or listings for verification.
We are not requesting a design solution—only confirmation of available tested assemblies and limitations.
---------- RFI question from Contractor ---------------
Hilti does not offer a judgement for T-rated firestop systems on elastomeric for pipe > 4". Assuming the VE option for switching to fiberglass is approved, T-rated systems is achievable throughout. However, if the VE option is not accepted, please advise whether it's acceptable to insulate mechanical pipe penetrations in rated wall/floor assemblies with fiberglass to meet T-rated system requirements using Hilti System No. C-AJ-5091. Fiberglass sections would consist of a 6" to 12" section on both sides of the pipe penetrations. This change would be a zero impact to cost and schedule. If Retro is unable to utilize fiberglass at pipe penetration, please advise acceptable product/method to meet T-rating requirements per spec 078413/1.2C at elastomeric insulated pipe penetrations.: Asked by Alisha Sevilla-Slider at 05/06/2026 12:44 PM
----------- RFI question from contractor ---------
Thank you,
JJ
Hello,
Thank you for reaching out to the Hilti Fire Protection Design Team to assist you with your firestop engineering needs.
We do not have a listed system for a large pipe insulated with AB/PVC insulation through a floor with a T-rating. We can only support up to 4" pipes with this type of insulation intact through the floor, any larger size and it will need to be removed through the opening. We can support larger than 4" metallic pipes, exclusive of copper, for a T-rating. We can address your application through an Engineering Judgment, which will be a custom detail showing your exact application with the firestop components required to maintain the stated ratings.
We are proud to announce the launch of the HILTI CONSTRUCTION PLATFORM (HCP), our company’s new engineering service website. This platform will be the home for all of your Fire Protection Design needs. Instead of emailing a PDF form for a request, the platform enables you to create new Engineering Judgment (EJ) requests, submit revisions to previously completed EJs or connect with an FPE on a question. HCP also enables you to track the status of your request.
You can find more information on how to access this new platform here: http://www.hilti.com/ej (US) or http://www.hilti.ca/ej (Canada.) If you have any questions or require assistance navigating the platform, please call Customer Service for help at 1-800-879-8000 (US) or 1-800-363-4458 (Canada.)
Along with HCP, Hilti is excited to announce our new mobile app for all your firestop needs: Hilti Firestop Selector. Using the Firestop Selector app gives you easy access to the Hilti Fire Protection Design Team from the jobsite, on the road, or in the office to request a new EJ, an EJ Revision, or a Question anytime, anywhere. You can download the app using the appropriate link below.
Hilti Firestop Selector App – Google Play Store
Hilti Firestop Selector App – Apple App Store
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.
Best regards,
Zach Rezazadeh
Fire Protection Design Team
Hilti North America