Cast-In-Place Firestop Shutters for Thin-Wall Conduits
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Solution Overview
Problem
Conventional firestop devices using intumescent materials struggle to effectively seal larger-diameter conduits with thin walls, particularly during high-pressure fire testing, due to the intumescent material being located far from the metal deck and delaying heat penetration, which can prevent timely expansion and closure of the void left by melting conduits.
Innovation Solution
A cast in place firestop device with a mechanical design incorporating spring-loaded shutter flaps and thermal fuses, where the shutter flaps are held open by thermal fuses and pivot to close the void upon heat activation, using compression springs to ensure rapid closure without relying solely on intumescent material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If intumescent material is used for firestop devices, then fire-stopping function is provided, but the material is located far from the metal deck causing delayed heat penetration and slow expansion for larger-diameter conduits
Solution Approach 1:
The patent replaces the chemical-based intumescent material system with a mechanical shutter system. The shutters are held open by thermal fuses and spring-loaded mechanisms, and close mechanically when the thermal fuses fail under heat exposure. This mechanical substitution eliminates the delay associated with intumescent material expansion, providing immediate closure for larger-diameter conduits.
Solution Approach 2:
The invention extracts the fire-stopping function from the intumescent material and implements it through a separate mechanical shutter system. The shutters are positioned close to the metal deck and can close the void left by melting conduits independently of any intumescent material, thereby solving the problem of delayed heat penetration and slow expansion.
2Device complexity
If intumescent material is positioned far from the bottom of the metal deck, then the device structure is simplified, but the heat penetration is delayed and the void closure is not timely
Solution Approach 1:
The shutters are pre-positioned in an open state, held ready by thermal fuses, with spring-loaded mechanisms prepared to drive them closed. This preliminary positioning ensures that when heat activates the thermal fuses, the shutters can close immediately without delay, achieving timely void closure while maintaining a relatively simple device structure.
Solution Approach 2:
The thermal fuses act as intermediaries between the heat source and the shutter closure mechanism. They are positioned close to the metal deck to detect heat early, and when they fail, they release the shutters to close the void. This intermediary mechanism bridges the gap between heat detection and void closure, minimizing time loss.
3Speed
If spring-loaded shutter mechanism is used, then rapid closure of void is achieved, but the device complexity increases compared to simple intumescent material
Solution Approach 1:
The invention uses spring-loaded mechanisms to change the force parameter applied to the shutters. The springs store mechanical energy in an open state and release it rapidly when the thermal fuses fail, providing the high closure speed needed for larger-diameter conduits. This parameter change (from static to dynamic force) achieves rapid closure while keeping the overall device structure manageable.
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 device provides efficient and rapid closure of voids left by melting conduits, ensuring effective fire-stopping without the need for additional intumescent material, particularly suitable for larger-diameter conduits with thin walls.
Implementation Method 1
at least one thermal fuse for releasing at least one of the first shutter flap or the second shutter flap in case of heat
Implementation Method 2
the spring-loaded shutter mechanism comprises a first shutter flap pivotably connected to the first web, a second shutter flap pivotably connected to the second web
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Cast in place firestop device for installation on corrugated metal decking, comprising an insert, which comprises a flange, a first web for being inserted into a rib of the corrugated metal decking, wherein the first web projects from the flange, and wherein the first web has a first web distal end, and a second web for being inserted into the rib of the corrugated metal decking, wherein the second web projects from the flange, and wherein the second web has a second web distal end, wherein a mouth is formed between the first web distal end and the second web distal end, and a spring-loaded shutter mechanism, wherein the spring-loaded shutter mechanism comprises a first shutter flap pivotably connected to the first web, a second shutter flap pivotably connected to the second web, and at least one thermal fuse for releasing at least one of the first shutter flap or the second shutter flap in case of heat.