ducts
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Solution Overview
Problem
Fire-rated ductwork, typically installed as four-sided ducts without contact to construction walls, results in space inefficiency and reluctance to mount directly to walls due to stringent testing requirements, despite the belief that four identical sides with reinforcing structures are necessary for compliance.
Innovation Solution
A fire-rated duct with a four-sided substantially closed cross-section, where one or two sides contact construction walls using calcium silicate boards of varying thicknesses, with thinner boards (T1 ≥ 20mm) adhering to thicker boards (T2 ≥ 60mm) via fire-resistant glue for secure, air-tight sealing, allowing for reduced wall thickness while maintaining compliance with EN 1366-1 and EN 13501-3 standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fire rated ductwork is mounted directly to construction walls with four identical sides, then fire resistance criteria are met, but space efficiency deteriorates due to lost space between ductwork and construction walls
Solution Approach 1:
The ductwork employs different board thicknesses for different sides: sides contacting construction walls use thinner boards (T1 ≥ 20mm) while non-contacting sides use thicker boards (T2 ≥ 60mm). This local differentiation allows space savings at wall contact points while maintaining fire resistance where needed, directly resolving the contradiction between fire resistance reliability and space efficiency.
2Volume of moving object
If ductwork sides contacting construction walls use thinner boards, then space efficiency improves, but fire resistance may deteriorate
Solution Approach 1:
The invention changes the thickness parameter of calcium silicate boards based on location: T1 ≥ 20mm for wall-contacting sides and T2 ≥ 60mm for non-contacting sides. This parameter differentiation allows thinner boards at wall contacts (improving space efficiency) while maintaining sufficient fire resistance through the adhesive bonding system and strategic thickness distribution.
Solution Approach 2:
The ductwork combines calcium silicate boards of different thicknesses with a fire-resistant adhesive system. This composite construction allows thinner boards at critical locations while relying on the adhesive bonding and thicker adjacent boards to maintain overall fire resistance, resolving the contradiction between reduced thickness and fire safety.
3Reliability
If four identical sides with reinforcing structures are used, then fire resistance is ensured, but device complexity increases
Solution Approach 1:
The invention replaces the traditional symmetric four-identical-sides design with an asymmetric configuration where wall-contacting sides use thinner boards (T1) and non-contacting sides use thicker boards (T2). This asymmetric design eliminates the need for complex reinforcing structures on all sides, reducing device complexity while maintaining fire resistance through strategic thickness distribution and adhesive bonding.
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 solution enables fire-rated ducts to pass stringent tests while saving space by allowing reduced wall thickness contact points, ensuring air-tightness and compliance with relevant fire resistance standards, and optionally supporting self-installation without additional structural support.
Implementation Method 1
a side of said board of said first group of boards adheres at least by means of a glue to the face of the board of said second group of boards
Data Source
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AI summary
A duct having a four sided substantially closed cross section is provided. the duct is mount to one of more construction walls, one or two sides of the duct contacting the one or more construction walls, each side of the cross section being provided by a calcium silicate board. A first group of boards contacting the one or more construction walls by a face of said boards having a board thickness T1 A second group of boards have faces not contacting said one or more construction walls, and having a board thickness T2. T1 is smaller than T2, T1 being more than or equal to 20mm. At the interfaces where a board of the first group of boards is connected to a board of the second group of boards, a side of the board of the first group of boards adheres at least by means of a glue to the face of the board of said second group of boards, which face is facing inwards the duct.