Modular Fire-Rated Exhaust Duct Assembly for Tight Ceiling Spaces
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Solution Overview
Problem
Existing fire-rated exhaust duct systems face challenges in preventing the spread of flammable or hazardous gases and vapors, require costly rework due to poor welding quality, and have a round profile that limits air volume and fits poorly in conventional building spaces.
Innovation Solution
A modular fire-rated duct system with a rectangular cross-section, comprising inner and outer ducts with insulation and flange connectors for easy field assembly, reducing the need for on-site welding and enhancing thermal resistance and space compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional fire-rated exhaust duct systems are used with round profile, then fire protection is provided, but the volume of air that can be vertically carried is significantly limited and the duct is too large to fit into conventional ceiling spaces
Solution Approach 1:
The patent changes the duct profile from a conventional round shape to a rectangular cross-section. This asymmetric shape optimization allows the duct to fit into conventional ceiling spaces and building footprints while maximizing the air carrying volume within the available space constraints.
Solution Approach 2:
The patent transitions from a round cross-sectional geometry to a rectangular one, effectively changing the dimensional arrangement of the duct. This allows better utilization of horizontal ceiling spaces and vertical building footprints, accommodating standard building dimensions more efficiently.
2Reliability
If sections are welded together at installation location to form continuous conduits, then fire-rated duct assembly is achieved, but welding quality is poor due to limited space and setup conditions requiring expensive rework
Solution Approach 1:
The duct system is divided into modular sections that are pre-assembled and pre-tested at the manufacturing facility. Each module contains pre-installed fire dampers and is designed to connect via mechanical coupling mechanisms, eliminating the need for complex field welding operations and ensuring consistent assembly quality.
Solution Approach 2:
Critical assembly operations including welding, fire damper installation, and sealing are performed in advance at the manufacturing facility under controlled conditions. The modules are pre-assembled with high-quality welds and pressure-tested before shipment, so that field installation only requires simple mechanical coupling without requiring expensive rework.
3Reliability
If additional gypsum fire-rated enclosure is installed around the duct, then fire protection is enhanced, but installation complexity increases and requires coordination with another trade
Solution Approach 1:
The fire protection functionality is integrated directly into the duct assembly itself rather than being provided by a separate gypsum enclosure. The duct modules incorporate fire-rated materials and fire dampers as integral components, combining the duct function and fire protection function into a single unified assembly that simplifies installation and eliminates coordination with additional trades.
4Reliability
If fire dampers are installed within the fire separation section to prevent fire spread, then fire protection is provided for ventilation ducts, but exhaust ducts for flammable or hazardous materials cannot be configured with fire dampers
Solution Approach 1:
Fire protection is provided at specific locations within the duct system rather than requiring fire dampers throughout. Fire-rated modules are strategically positioned at fire separation points and hazardous locations, while other sections maintain full configurability for exhaust applications. This localized approach provides necessary fire protection while preserving duct configuration flexibility in non-critical areas.
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 modular system effectively contains flammable materials, minimizes thermal transfer, and fits within standard building dimensions, reducing installation costs and ensuring safe discharge of hazardous gases while maintaining fire-rated standards.
Implementation Method 1
a void being formed between at least a portion of space between said inner duct liner and said outer casing, said void being configured for receiving an insulation material
Data Source
AI summary
A fire-rated exhaust duct system comprising a modular configuration or structure. The fire-rated exhaust duct system comprises a plurality of exhaust duct sections. Each of the exhaust duct sections is configured to be joined or connected with other exhaust duct sections in the field or at an installation site, e.g. in building housing a kitchen facility or a laboratory facility to form longer sections or runs for exhaust duct system.