Intumescent Head-of-Wall Fireblock Systems
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Solution Overview
Problem
Current fire blocking and containment systems in building construction, particularly dynamic head-of-wall joints and gaps, are labor-intensive and expensive, with limited effectiveness in preventing smoke and fire penetration, especially in steel stud wall constructions.
Innovation Solution
A fire retardant head-of-wall assembly comprising an elongated sheet-metal footer and header track with an intumescent strip affixed to the sidewalls, allowing for ceiling deflections and featuring vertically aligned slots for secure fastening, which expands to seal gaps when exposed to heat, preventing the spread of smoke and fire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fire blocking materials (mineral wool, spray coatings, caulk) are used to seal head-of-wall gaps, then fire resistance is achieved, but labor intensity and installation cost increase significantly
Solution Approach 1:
The fire blocking function is segmented into two components: a structural metal track system that provides the framework, and intumescent strips that provide the fire-resistant sealing. This division allows the structural and fire-resistant functions to be implemented separately and efficiently.
Solution Approach 2:
The intumescent strips are pre-attached to the metal tracks during manufacturing, creating a pre-assembled fire blocking system. This preliminary action eliminates the need for on-site application of fire-resistant materials, significantly reducing labor intensity and installation time while maintaining fire resistance.
2Adaptability or versatility
If metal framing assemblies with studs spaced from the ceiling are used to allow ceiling deflections, then adaptability to structural movement is improved, but fire sealing effectiveness deteriorates due to gaps
Solution Approach 1:
The metal track system is designed with flexibility to accommodate ceiling deflections and structural movements. The tracks can move dynamically with the ceiling while maintaining continuous contact with the intumescent strips, ensuring fire sealing is preserved even during structural movement.
Solution Approach 2:
The system combines metal framing members with intumescent fire-resistant strips to create a composite structure. The metal provides structural integrity and adaptability to movement, while the intumescent material provides fire sealing, achieving both adaptability and fire resistance simultaneously.
3Reliability
If intumescent strips are affixed to metal track sidewalls with offset positioning, then fire sealing effectiveness is improved, but manufacturing complexity increases
Solution Approach 1:
The intumescent strips are merged with the metal tracks by pre-attaching them during track fabrication. This combining of components into a single pre-assembled unit simplifies the overall manufacturing process and eliminates the need for complex on-site assembly, despite the offset positioning requirement.
Solution Approach 2:
The offset positioning of the intumescent strips is optimized to achieve the best fire sealing effectiveness. By carefully selecting the offset distance and position, the system achieves superior fire blocking while maintaining manufacturability through standardized attachment procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The assembly effectively seals head-of-wall construction joints, accommodating ceiling deflections and withstanding high temperatures, as demonstrated by passing Underwriters Laboratories' standards for fire resistance, including UL 2079, without allowing smoke or fire penetration.
Implementation Method 1
an intumescent strip affixed lengthwise on at least one of the outer sidewall surfaces of the pair of sidewalls, the intumescent strip being positioned on the upper sidewall portion
Data Source
AI summary
A fire retardant head-of-wall assembly configured to seal a linear head-of-wall construction joint or gap when exposed to a heat source such as a building fire is disclosed. The inventive fire retardant head-of-wall assembly comprises a header track having an elongated intumescent strip affixed lengthwise on at least one of the outer sidewall surfaces of the header track. The intumescent strip comprises expandable graphite and a fire retardant (C2-C8 alkyl diamine phosphate). When exposed to a heat source such as a building fire, the intumescent strip expands so to fill the head-of-wall construction joint or gap, thereby retarding or preventing the spread of smoke and fire. The inventive fire retardant head-of-wall assembly has been certified as complaint with respect to Underwriters Laboratories, Inc.'s standards set forth in its Tests for Fire Resistance of Building Joint Systems—UL 2079.