Occupied Compartment Fire Detection With Occupancy-Based Smoke Control
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Solution Overview
Problem
Fire detection systems in transport vehicles, such as toilets, often trigger false alarms due to passengers smoking or vaping, leading to unnecessary alerts and potential delays in detecting real fires.
Innovation Solution
A fire detection system that deactivates smoke detectors when the compartment is occupied and waits for a predetermined time after the compartment becomes unoccupied to resume monitoring, using a combination of heat detectors and occupancy sensors to differentiate between smoke from smoking/vaping and actual fires, thereby reducing false alarms and ensuring timely detection of genuine fire threats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If smoke detectors are used to detect fires in occupied compartments, then fire detection capability is improved, but false alarms increase due to smoking or vaping
Solution Approach 1:
The system dynamically adjusts the operational state of the smoke detector based on occupancy detection. When the compartment is occupied, the smoke detector is deactivated to prevent false alarms from smoking or vaping. When unoccupied, the smoke detector is activated to provide fire detection capability. This dynamic switching resolves the contradiction by adapting the detection system to the actual usage context.
Solution Approach 2:
An occupancy sensor acts as an intermediary between the fire detection system and the smoke detector. The occupancy sensor detects whether the compartment is occupied and uses this information to control the smoke detector's operation. This intermediary component enables the system to distinguish between smoke from legitimate fire hazards and smoke from personal activities like smoking or vaping.
2Object-generated harmful factors
If smoke detectors are deactivated in occupied compartments to reduce false alarms, then false alarm rate decreases, but fire detection capability is reduced
Solution Approach 1:
The system implements dynamic control where the smoke detector's operational state changes based on real-time occupancy information. During occupancy, the smoke detector remains inactive to avoid false alarms. Upon detecting that the compartment becomes unoccupied, the system reactivates the smoke detector after a predetermined time delay, thereby restoring fire detection capability when the risk of false alarms has subsided.
Solution Approach 2:
The system introduces a predetermined time delay before reactivating the smoke detector after occupancy ends. This preliminary waiting period allows any residual smoke from recent smoking or vaping activities to dissipate, ensuring that the smoke detector is reactivated only when the environment is clear, thus preventing false alarms while maintaining fire detection readiness.
3Object-generated harmful factors
If the system waits for a predetermined time after unoccupancy before resuming smoke detection, then false alarms from residual smoke are reduced, but detection response time increases
Solution Approach 1:
The predetermined time delay serves as a preliminary action that proactively clears residual smoke from the compartment before smoke detection is resumed. This waiting period is calculated based on typical smoke dissipation times, ensuring that the detector is activated only when the air is clear, thereby preventing false alarms while maintaining an acceptable response time for actual fire events.
Solution Approach 2:
The system changes the operational parameters of the smoke detector based on the occupancy state and time elapsed since unoccupancy. By adjusting the detection sensitivity and activation timing according to these parameter changes, the system optimizes the balance between avoiding false alarms from residual smoke and maintaining rapid response capability for genuine fire threats.
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 approach effectively reduces false alarms caused by smoking or vaping, allowing for timely detection of real fires by prioritizing heat detection when occupied and resuming smoke detection after the area is vacated, ensuring the system's accuracy and reliability in transport vehicles.
Implementation Method 1
A heat detector has the purpose of reacting to heat
Implementation Method 2
An optical smoke detector has the purpose of reacting to smoke
Data Source
Figure 1~2
AI summary
A fire detection system comprises a heat detector configured to monitor a fire detection volume; a smoke detector configured to monitor the fire detection volume; and an occupancy sensor configured to detect the presence of at least one person within the fire detection volume. The fire detection system is configured to monitor for the presence of a fire within the fire detection volume using the heat detector and the smoke detector responsive to determining, using the occupancy sensor, that the fire detection volume is unoccupied. The fire detection system is configured to monitor for the presence of a fire within the fire detection volume using the heat detector and not using the smoke detector responsive to determining, using the occupancy sensor, that the fire detection volume is occupied.