Fire Safety Control for Buildings with Overhead Fans
Solution Overview
Problem
Current fire safety systems for buildings with overhead fans struggle to quickly and accurately detect the location of a fire and efficiently control ceiling fans and overhead sprinklers to extinguish it, often leading to wastage of high-pressure water and potential spread of the fire.
Innovation Solution
A fire safety system that utilizes a combination of smoke and heat detectors to deactivate fans and activate sprinklers selectively, using sensors positioned near the ceiling and floor to determine the fire's location and control the operation of fans and sprinklers, ensuring precise and efficient water distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fans continue operating during a fire to circulate air, then air circulation is maintained for normal building function, but fire detection accuracy deteriorates and fire spread is accelerated
Solution Approach 1:
The fan operation is dynamically controlled based on fire detection status. The controller monitors sensor inputs and automatically adjusts fan operation mode - maintaining circulation during normal conditions but stopping fans when fire is detected, thus adapting the system behavior to current conditions to resolve the contradiction between air circulation and detection accuracy
Solution Approach 2:
The harmful effect of fan operation on fire detection is eliminated by extracting the fan from operation during fire conditions. The controller selectively stops fan motors when fire is detected, removing the air circulation function temporarily to prevent interference with accurate fire location determination while maintaining it during normal operation
2Reliability
If sprinklers are activated without accurate fire location detection, then fire suppression coverage is expanded, but water wastage increases and limited high-pressure water supply is depleted
Solution Approach 1:
The sprinkler system applies water locally and selectively based on detected fire location rather than activating all sprinklers uniformly. The controller identifies which specific sprinklers are nearest to the fire and activates only those, providing concentrated suppression where needed while leaving other areas dry, thus achieving reliable fire suppression with minimal water wastage
Solution Approach 2:
The sprinkler system is divided into independently controllable zones or individual sprinkler units. The controller can selectively activate specific sprinklers based on fire location detection, rather than treating the entire system as a single unit. This segmentation enables precise water application to the fire area while preventing wasteful activation of distant sprinklers
3Measurement precision
If multiple sensors are deployed throughout the building to accurately locate fire, then fire location precision is improved, but system complexity and cost increase
Solution Approach 1:
The sensor system uses multi-functional detectors that can sense both smoke presence and provide location information through their spatial arrangement. The same sensors that detect fire conditions also contribute to location determination by their position in the matrix, eliminating the need for separate location-tracking devices and reducing overall system complexity while maintaining precision
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 system effectively identifies the fire's location, deactivates fans to allow direct heat detection, and activates sprinklers with high-pressure water only where needed, minimizing water wastage and enhancing fire suppression efficiency.
Implementation Method 1
Smoke particles, however, can scatter the light beam into the sensor and trigger the smoke detector.
Implementation Method 2
The fusible link holds a valve of the sprinkler closed until sufficient heat from the fire melts or otherwise destroys the link, thereby activating the sprinkler.
Data Source
AI summary
A fire safety system includes a sensor arrangement and control scheme for quickly sensing a fire, accurately identifying its location, and controlling a set of ceiling fans and overhead sprinklers to efficiently extinguish the fire. The fire safety system is particularly suited for large buildings such as warehouses, factories, gymnasiums, retail stores, auditoriums, convention centers, theaters or other buildings with large open areas. In some examples, the overhead fans are disabled prior to activating the sprinklers. The placement of the fire sensors, in some cases, are selected upon first considering the location of the overhead fans.