Aerodynamic Sub-Duct Layout for Vertical Shaft Exhaust
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Solution Overview
Problem
In multi-story buildings, existing solutions for penetrating fire-rated shafts with exhaust ducts are cumbersome, occupy excessive space, and increase pressure drop, failing to meet aesthetic and cost requirements while ensuring compliance with fire codes.
Innovation Solution
A sub-duct system with hollow first and second portions, featuring a rectangular cross-section and aerodynamic configurations, is designed to minimize space occupation and pressure drop by aligning flush with the main shaft's inner wall, allowing for efficient exhaust passage while meeting fire code requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a steel sub-duct protrudes into the shaft to meet fire code requirements, then fire safety compliance is improved, but the pressure drop increases and space occupation increases
Solution Approach 1:
The sub-duct incorporates a curved aerodynamic configuration instead of a straight protruding design. This curvature allows exhaust gases to flow more smoothly around the sub-duct, reducing turbulence and pressure drop while still maintaining the required 22-inch protrusion into the shaft for fire code compliance.
Solution Approach 2:
The sub-duct cross-sectional area is reduced compared to traditional designs. By changing the dimensional parameters while maintaining the aerodynamic shape, the sub-duct occupies less space in the shaft and creates less resistance to exhaust flow, thereby reducing pressure drop while still meeting fire safety requirements.
2Reliability
If a steel sub-duct protrudes into the shaft to meet fire code requirements, then fire safety compliance is improved, but the space occupation increases
Solution Approach 1:
The curved aerodynamic configuration allows the sub-duct to achieve the required 22-inch protrusion into the shaft with a more compact overall form. The curved shape occupies less volumetric space compared to a straight cylindrical protrusion of the same length, thereby reducing space occupation while maintaining fire code compliance.
Solution Approach 2:
The sub-duct uses reduced cross-sectional dimensions and an optimized aerodynamic shape to minimize the volume it occupies within the shaft. By changing these geometric parameters, the sub-duct meets fire safety protrusion requirements while occupying minimal space that would otherwise be available for shaft functionality.
3Reliability
If a traditional sub-duct design is used to meet fire code, then fire safety compliance is improved, but the device complexity increases
Solution Approach 1:
The sub-duct is designed as a modular assembly with distinct components including the curved aerodynamic portion, the attaching wall section, and connection interfaces. This segmentation allows for simplified fabrication, easier handling during installation, and simpler maintenance while maintaining the integrated aerodynamic shape required for fire code compliance.
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 sub-duct system reduces pressure drop and occupies less space, enabling more efficient exhaust gas flow and potentially reducing the main shaft's size, thereby recovering valuable space without compromising compliance with building codes.
Implementation Method 1
a bottom side that has an aerodynamic configuration
Data Source
AI summary
Sub-ducts and methods of exhausting into a generally rectangular and vertical main shaft are disclosed herein. A sub-duct of one embodiment includes hollow first and second portions. The first portion presents a generally flat attaching wall, a top side that defines an opening, and a bottom side that has an aerodynamic configuration; the second portion defines an intake opening, meets with the first portion attaching wall at approximately a ninety degree angle, and has a configuration complementary to a configuration of an exhaust duct. The first and second portions collectively define a continuous channel between the intake opening and the top side opening. The first portion may have a section of generally constant cross section extending from adjacent the second portion to the top side opening, and the second portion may have a generally constant cross section extending from the intake opening to the first portion.