Fire-rated ventilation duct and a method of manufacturing and/or installing such ventilation duct in a fire-rated ventilation duct structure penetration arrangement
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Solution Overview
Problem
Existing ventilation duct systems face challenges in achieving a tight seal during fire-rated penetrations, especially in tight spaces where there is little room for installation of stiffening bar members, which can compromise the structural stability and fire protection of the duct.
Innovation Solution
The solution involves a ventilation duct with elongated stiffening members arranged substantially within the opening of the building structure, providing a compact penetration arrangement that maintains structural stability and meets different fire protection ratings. The stiffening members are attached to the ventilation duct before installation, allowing for easier installation in tight spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stiffening bar members are mounted on the outside of the fire protection material after duct installation, then the structural stability of the ventilation duct is improved, but the installation space requirement increases and the installation complexity increases
Solution Approach 1:
The stiffening bar members are nested within the opening of the building structure, with the fire protection material covering both the duct and the stiffening members. This nesting arrangement allows the stiffening members to be positioned inside the building structure opening rather than requiring external space, thereby maintaining structural stability while reducing installation space requirements.
Solution Approach 2:
The stiffening bar members are prepared and positioned within the opening before the fire protection material is applied. This preliminary arrangement of stiffening members within the opening simplifies the installation process by eliminating the need for post-installation mounting operations in tight spaces.
2Strength
If stiffening L-shaped frame is applied to reinforce the duct, then the structural stability is improved, but the seal between the duct section and the wall deteriorates
Solution Approach 1:
The stiffening bar members are nested within the building structure opening and covered by fire protection material that abuts the wall, creating a flush arrangement. This eliminates the protruding L-shaped frame that caused seal deterioration, while still providing structural reinforcement through the stiffening members positioned within the opening.
3Strength
If bar members are moved further out from the ventilation duct, then the risk of duct wall bending is reduced, but the installation space requirement increases
Solution Approach 1:
The stiffening bar members are nested within the building structure opening, positioned at an optimal distance from the duct to provide bending resistance. The fire protection material covers both the duct and stiffening members, allowing the stiffening members to be positioned far enough out to prevent duct wall bending while maintaining a compact overall arrangement that fits within the building structure opening.
Data Source
AI summary
A fire-rated ventilation duct structure penetration arrangement includes a ventilation duct and a building structure, such as a wall, ceiling or floor, through which the ventilation duct extends. The ventilation duct has one or more metal sheets forming the duct. The metal sheet duct is covered on the outside by a fire protection material, and the duct includes elongated stiffening members located on the outside of the duct and attached to the metal sheets. The stiffening members are arranged substantially within the opening of the building structure.