Ventilation Duct Section With External Frame for Fire Sealing
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Solution Overview
Problem
The existing methods for sealing metal sheet ventilation/smoke exhaust ducts through fire-rated walls are time-consuming and restrict airflow, and the use of vertical stiffening pipes and L-shaped frames can compromise the seal and structural stability, especially under fire conditions.
Innovation Solution
A rigid metal frame formed by U- or T-shaped bars is positioned around the duct, spaced from the metal sheets by a heat insulating material to prevent heat transfer and deformation, with screws or bolts used for attachment to maintain structural integrity and seal effectiveness without the need for vertical pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If vertical stiffening pipes are mounted inside the duct to maintain structural stability, then the duct stability is improved, but the mounting process becomes time-consuming and restricts free airflow through the duct
Solution Approach 1:
The invention extracts the stiffening function from the interior of the duct by removing vertical pipes and relocating it to the exterior through a frame made of bar members. This eliminates the need for time-consuming interior mounting operations while maintaining structural stability during fire conditions.
Solution Approach 2:
The stiffening structure is moved from the vertical dimension (internal pipes) to the horizontal/external dimension (external frame). The frame members extend around the duct perimeter rather than vertically inside, fundamentally changing the spatial arrangement while achieving the same stabilizing effect.
2Stability of the object's composition
If vertical stiffening pipes are mounted inside the duct to maintain structural stability, then the duct stability is improved, but the free flow of air through the ventilation duct is restricted
Solution Approach 1:
The stiffening function is extracted from the air flow path by relocating it to the exterior of the duct. The external frame structure provides structural support without occupying interior space, thereby eliminating restriction on air flow through the duct.
3Stability of the object's composition
If an L-shaped stiffening frame is applied on the outside of the duct, then structural support is provided, but the seal between the duct section and the wall is compromised
Solution Approach 1:
The frame members are positioned at specific locations away from the sealing area, with heat insulating material placed between the frame and duct surface. This local arrangement provides structural support where needed while preserving the seal integrity at the wall interface.
Solution Approach 2:
Heat insulating material serves as an intermediary element between the frame members and the duct surface. This intermediary layer prevents direct contact that could compromise the seal, while still allowing the frame to provide structural support.
4Ease of manufacture
If bar members are placed close to the metal sheets for structural support, then attachment is simplified, but heat transfer between bar members and duct increases causing temperature-induced deformations
Solution Approach 1:
Heat insulating material acts as a thermal intermediary between the bar members and the metal duct sheets. This prevents direct heat transfer while maintaining the structural connection, thereby reducing temperature-induced deformations of the bar members.
Solution Approach 2:
The heat insulating material is placed locally at the contact points between frame members and duct surface, providing thermal insulation where needed without complicating the overall attachment process.
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
This solution reduces the need for vertical pipes, maintains structural stability, and ensures a tight seal during normal operation and fires, while minimizing airflow restriction and heat-induced deformations, thus meeting fire regulations without the drawbacks of traditional methods.
Implementation Method 1
the heat insulating material is arranged between the frame and the ventilation/smoke exhaust duct metal sheets, preferably to act as a spacer ensuring the proper spacing between the frame and the metal sheets such that heat transfer between the bar members and the duct is restricted
Data Source
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AI summary
The invention relates to a metal sheet (15) ventilation/smoke exhaust duct section (10) for incorporation into a metal sheet ventilation/smoke exhaust duct, said metal sheets (15) being covered on the outside by a heat insulating material (20) and said duct section (10) including elongated stiffening bar members (30) located on the outside of the duct and attached to said metal sheets (15), the invention being characterised in said bar members (30) being located at a distance from said metal sheets (15), said bar members (30) being attached to said metal sheets (15) at discrete locations along the length of the bar members (30).