Hi,
Customer(EPC) has asked us to obtain Hilti`s technical opinion to confirm UL compliance for the proposed Head of Wall (HOW) application.
(*They have a general understanding of the Head of Wall (HOW) conditions. However, since UL–listed systems must be applied to ensure code compliance, they`d like Hilti`s technical review and official opinion on whether the manufacturer’s solution meets the required UL criteria.)
Based on their request, please review and advise on the following points:
1) Dynamic Wall Cladding Penetration
– Can penetrations be made through wall cladding sections where movement occurs (dynamic areas)?
– Customer understands that, in principle, such penetrations are not allowed and would like confirmation.
2) Firestop Selection for Dynamic Sections
– If penetration through a dynamic wall cladding section is unavoidable, how should the firestop product be selected?
– Is it sufficient to match only the HOW and Movement Rating, or are there UL systems specifically certified for penetrations in dynamic areas? If such systems exist, please recommend.
3) Total System Compatibility
– Can you review the overall integrity of the total system, including both the Head of Wall system and the penetration firestopping?
– Specifically:
1) HOW + Penetration Firestopping (Dynamic area)
2) HOW + Penetration Firestopping (Static area)
4) Static Section Penetrations
– For penetrations occurring in static wall sections (below the wall cladding), can a standard firestopping system be applied based on F/T/L ratings only?
– Or should movement be considered even in these static areas? Customer currently understands that compliance with F/T/L ratings is sufficient, but seeks confirmation.
Good afternoon,
I would recommend forwarding this question over to our engineering team either via email (usfirestopeng@hilti.com) or by using the Question feature on our Hilti Construction Platform (information below). When you send over your email or online request, it may be beneficial to request your local Fire Protection Specialist's information as they will be your local firestop expert who can assist with any firestop specific questions.
However, to give a general answer, whether a penetration can/not be made is not really our determination nor can we tell you if movement should be a consideration. We would typically recommend you align with AHJ to make those determinations. We can, however, provide Engineering Judgments for these applications, but we likely cannot specify movement. It's not to say that that joint will certainly be static, but for movement capabilities, we have to rely on the existing data we have, and we do not have any penetrations through wall cladding applications at this time.
Hilti is proud to announce the launch of our engineering website, the HILTI CONSTRUCTION PLATFORM (HCP). This platform will be the home for all of your Fire Protection Engineering needs, including Engineering Judgment requests. You can find more information on how to access this new platform here: https://www.hilti.com/ej (US) or https://www.hilti.ca/ej (Canada.)
Thank you,
Jessica Starks
Senior Fire Protection Engineer