Segmented Stairwell Pressurization for High-Rise Smoke Control
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Solution Overview
Problem
High-rise buildings above 60 meters face challenges in maintaining homogeneous pressure in stairwells due to flow resistance, leading to excessive door opening forces and potential smoke ingress during fires, especially with temperature differences causing shaft effects that hinder door operation.
Innovation Solution
The stairwell is vertically divided into sub-rooms by bulkheads with controlled air supply, allowing targeted pressure management and reducing the shaft effect, ensuring door operability and smoke containment through strategically placed barometric flaps and valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the stairwell is kept as a continuous vertical space, then the structure is simple and construction is easier, but pressure homogeneity deteriorates and door opening forces become excessive
Solution Approach 1:
The stairwell is divided into multiple sub-rooms vertically using bulkheads at regular intervals (e.g., every 10-20 floors). Each sub-room is independently pressurized by dedicated supply air shafts and fans, ensuring homogeneous pressure distribution within each segment while avoiding the excessive pressure buildup that would occur in a continuous tall stairwell.
2Length of stationary object
If the stairwell height increases beyond 60m, then the building can accommodate more floors, but flow resistance increases and pressure homogeneity is lost
Solution Approach 1:
The tall stairwell is segmented into multiple shorter sub-rooms using bulkheads, preventing the accumulation of flow resistance effects over the entire building height. Each sub-room maintains independent pressure control, ensuring homogeneous pressure distribution even in buildings exceeding 60m in height.
Solution Approach 2:
Bulkheads with barometric flaps act as intermediaries between sub-rooms. These flaps allow controlled air exchange to maintain pressure equilibrium while preventing direct communication between distant floors that would cause pressure heterogeneity.
3Reliability
If the stairwell is continuously pressurized to prevent smoke ingress, then smoke protection is improved, but door opening forces become excessively high
Solution Approach 1:
The pressurization system is segmented into independent sub-room zones, each maintaining a controlled excess pressure (e.g., 50 Pa). This localized pressurization prevents smoke ingress while keeping door opening forces within acceptable limits compared to pressurizing the entire stairwell height.
Solution Approach 2:
Each sub-room receives tailored pressurization based on its specific requirements, with supply air delivered locally through dedicated shafts. This ensures adequate smoke protection at each level without creating excessive pressure that would make door operation difficult.
4Manufacturing precision
If bulkheads with small leak rates are used to divide sub-rooms, then pressure control precision is improved, but the complexity of the structure increases
Solution Approach 1:
Barometric flaps in the bulkheads automatically self-regulate air flow between sub-rooms based on pressure differences, eliminating the need for complex active control systems. The flaps open or close passively in response to pressure changes, maintaining precision pressure control while minimizing structural complexity.
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 maintains standard door opening forces and ensures smoke-free escape routes by controlling air pressure and flow, neutralizing the shaft effect and ensuring compliance with safety standards even in tall buildings.
Implementation Method 1
strategically placed barometric flaps and valves
Implementation Method 2
supply air is blown in at the lowest point of the stairwell and parallel to it via the supply air shaft via the inlet openings
Implementation Method 3
the shaft effect caused by the temperature difference between the inside and outside temperatures
Data Source
Figure 1
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AI summary
The invention relates to a high rise building with a stair well (38), an intake air shaft (74), inlet flow openings (76) that connect the intake air shaft to the stair well and a pressure system for keeping the stair well smoke-free. The stair well is subdivided vertically into a plurality of partial spaces by way of at least one bulkhead (58), and each bulkhead has a door that enables passage from a partial space of the stair well to the adjacent partial space.