Self-releasing Structural Assembly for Fire-safe Firewall Connections
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Solution Overview
Problem
In multi-level buildings, structural members like floor joists may catch fire, causing them to dislodge and potentially collapse the firewall, which can lead to rapid fire spread, compromising the firewall's protective function and endangering occupants and firefighters.
Innovation Solution
A break-away connector system comprising a support member and a fusible member with a lower melting point than the support member, allowing the structural members to slide and disengage from the firewall when heated, thereby maintaining the firewall's integrity and allowing time for evacuation and fire suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If structural members are rigidly connected to the firewall, then structural stability is improved, but fire resistance is worsened because the firewall cannot remain intact when structural members catch fire
Solution Approach 1:
The connection system is divided into two distinct segments: a support member (fire-resistant) and a fusible member (heat-sensitive). The fusible member acts as a separable connector that can disconnect under thermal stress, allowing the structural member to be released from the firewall during fire while the support member remains intact and anchored to the firewall.
Solution Approach 2:
The fusible member serves as an intermediary element between the structural member and the support member. It transfers the thermal effect from the fire to the connection system, triggering the release mechanism when it reaches its melting point, thereby protecting the firewall from direct thermal damage while maintaining structural integrity under normal conditions.
2Reliability
If a fusible member is used to allow structural members to release during fire, then fire resistance is improved, but connection strength is worsened because the fusible member has lower melting point than the support member
Solution Approach 1:
Different parts of the connection system have different material properties tailored to their specific functions. The support member is made of high-strength, fire-resistant material for structural support, while the fusible member is made of lower-melting-point material specifically for thermal release. This local differentiation allows each component to optimize its performance for its intended purpose.
Solution Approach 2:
The system utilizes a deliberate change in the melting point parameter of the fusible member compared to the support member. By selecting a fusible member with a lower melting point, the system ensures that under normal operating temperatures, the connection remains strong, but under fire conditions, the fusible member melts and releases the structural member, protecting the firewall.
3Strength
If the support member is permanently secured to the firewall, then structural support is improved, but adaptability is worsened because the structural members cannot be released when needed
Solution Approach 1:
The connection system transitions from a static, permanent connection to a dynamic, condition-dependent connection. Under normal conditions, the fusible member maintains a strong bond providing rigid structural support. When exposed to fire temperatures exceeding its melting point, the fusible member dynamically changes state from solid to liquid, automatically releasing the structural member from the firewall without requiring external intervention.
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 system effectively separates structural members from the firewall during a fire, allowing the firewall to remain intact longer, providing time for firefighters to act and occupants to escape, while maintaining structural integrity under normal conditions.
Implementation Method 1
The fusible member is made of a material that will burn or melt when subjected to fire
Implementation Method 2
The consumable member is one that will burn when subjected to fire
Data Source
AI summary
The end of a beam is joined to a wall structure by a self-releasing structural assembly. The self-releasing structural assembly has a first portion that is anchored to the wall. A second portion sticks out from the wall. This portion is fireproof and non-thermally degradable. It defines a seat for receiving the beam end. The assembly also includes a thermally degradable member mounted to the second portion. In normal use the beam fasteners squeeze the end of the beam, the support bracket seat, and the consumable, thermally degradable member in compression. When exposed to heat or flame the consumable, thermally degradable member softens, releasing the compression in the structural sandwich of parts. The end of the beam is then able to translate away from the wall structure. The consumable member can be inspected, replaced if necessary, and the beam fasteners re-tensioned, without removing the beam end from the seat.