SummaryAs the construction industry expands and skyscrapers increase, the frequency of electrical fire safety accidents also rises. To ensure the safety of residents and users, enhancing the design and research of electrical fire monitoring systems in high-rise buildings is of great significance. The paper analyzes the electrical fire monitoring systems in high-rise buildings.
KeywordsHigh-rise buildings; electrical; fire; monitoring system
Introduction
As living standards improve, the consumption of commercial and residential electricity continues to rise. Due to inadequate electricity management and maintenance, the incidence of electrical fires is on the rise annually, causing significant economic losses to businesses and individuals. According to relevant surveys, the probability of electrical fires occurring in high-rise building fires is quite high. In response, relevant departments have formulated a series of standards and specifications, laying a solid foundation for the design and application of electrical fire monitoring systems. Electrical fire monitoring systems are an effective means of preventing electrical fires in high-rise buildings. When the relevant parameters of electrical lines or equipment within the monitoring range exceed the alarm threshold, the system can promptly emit sound and light alarm signals, allowing monitoring personnel to grasp the operation status of the electrical system and take effective measures to control it, thus preventing electrical fire accidents and reducing unnecessary losses.【l】Therefore, the research and application of electrical monitoring systems for high-rise buildings hold significant practical importance.
Principle of High-Rise Electrical Fire Monitoring System
Basic Components of Electrical Fire Monitoring System
Generally speaking, high-rise building electrical fire monitoring systems mainly consist of several components, including electrical fire detectors, electrical fire monitoring equipment, and centralized monitoring devices. Electrical fire monitoring detectors are primarily used to detect residual current in the protected electrical circuits.
Electrical parameters related to fires, such as flow and temperature. Electrical fire monitoring equipment primarily collects relevant information from fire monitoring detectors, emits alarm signals such as sounds and lights, identifies the fault location, and then sends control signals. Electrical fire monitoring in high-rise buildings...
The entire operation process of the fire monitoring system, as shown in Figure 1, is as follows: Detectors collect current information from the circuit and transmit it to the on-site processing equipment. Through analysis and computation, a comprehensive judgment is made on the current information. If an electrical fire hazard is detected, the alarm information is transmitted to the centralized monitoring equipment via two-wire communication. The centralized monitoring equipment then issues corresponding control commands to promptly and effectively resolve the fault issues.
Graded Protection for Electrical Fire Monitoring Systems
The core of electrical fire monitoring systems is the residual current fire alarm system. According to "Installation and Operation of Residual Current Protection Devices" (GB13955-2005), electrical protection equipment must implement a tiered protection mechanism to minimize electric shock incidents and power outages caused by grounding faults, thereby ensuring the stable operation of the electrical fire monitoring system. High-rise building electrical fire monitoring systems should consider their own power usage and distribution system configurations to select appropriate protection methods, typically using Level 2 and Level 3 protections. The residual current protection devices should be installed at the main power source, the start of branch lines, and the end of lines. Additionally, in a tiered protection setup, the action time interval between the upper and lower tier residual current protection devices should be over 0.2 seconds.
High-rise Electrical Fire Monitoring System Design and Installation
Electrical Fire Detector Design and Installation
Detectors commonly used in electrical fire monitoring systems include residual current-based electrical fire monitoring detectors and temperature-based electrical fire monitoring detectors. In system design and installation, the application location of detectors can be designed in one of the following three ways: (1) Installed externally on the electrical distribution cabinet, which is the most commonly used installation design in electrical fire monitoring systems. Generally, a dedicated fire monitoring box is required to facilitate the installation of detectors. Additionally, a residual current transformer is installed on the power bus, and wires with adjustable shielding range are used to connect the transformer and the detector; (2) Installed internally within the electrical distribution cabinet, which is more suitable for new high-rise buildings. In the design and installation, the detectors and power bus should be kept at a certain distance, and transformers and shielding wires need to be installed; (3) Embedded design, where detectors are installed embedded in the surface of the electrical distribution cabinet, avoiding any impact on the internal structure of the cabinet. The installation of transformers follows the same method as the first two options.[2]。
Electrical Fire Monitoring Equipment Design and Installation
Electrical fire monitoring equipment must prioritize performance during the selection phase, including sensitivity, reliability, and adaptability to harsh weather conditions. Additionally, the monitoring equipment should be capable of continuous operation and automatic patrol inspections. In the event of data reaching critical warning levels, an immediate response is required, along with the issuance of an alarm signal. Analysis of the adaptability of monitoring equipment to harsh weather conditions reveals that the equipment must analyze different regional climate conditions and construction site situations, adjusting alarm thresholds flexibly to meet system operation requirements in various work environments. The monitoring equipment must also be capable of continuous operation, as electrical fire monitoring systems require uninterrupted 24/7 operation and should minimize downtime for maintenance when certain components fail. Moreover, the automatic patrol inspection function of monitoring equipment is evident in its 24-hour continuous monitoring of relevant lines and equipment within the electrical fire monitoring system, promptly detecting faults and reporting their locations and abnormal conditions to monitoring personnel for timely identification and resolution of issues.
Electrical Fire Monitoring System Wiring Design
Electrical fire monitoring system wiring design must also ensure mold prevention, moisture resistance, and salt mist resistance. Strictly follow relevant specifications for the laying and connection of cables, and pay attention to avoid reverse wiring and overloading issues at the terminal connections. Additionally, attention should be given to the N and PE lines...
On the connection, strict distinction should be made and not mixed, especially the N-line passing through the transformer, which is strictly prohibited from being used as the PE line. Similarly, the PE line should also be strictly prohibited from passing through the transformer. The installation of communication lines for monitoring detectors connecting to monitoring equipment should be effectively controlled. The line selection should strictly use twisted pair cables with a wire diameter standard, controlling the diameter to be above 0.5mm. Additionally, the interference shielding capability of the twisted pair cables should be set based on the interference factors of the environment. Meanwhile, the electrical fire monitoring equipment is connected to the monitoring graphic display system using a 3-core RS232 communication cable. The equipment of the electrical fire monitoring system is connected to the bus isolator with a cross-sectional area greater than 1.0mm².2Flame-retardant twisted pair cable connections.
Key Applications of High-Rise Electrical Fire Monitoring Systems
Electrical fire monitoring systems are bound to encounter issues in practical application, necessitating adjustments and repairs. Specifically, this involves the following points.
System Grounding
Detectors and residual current transformers have just been installed. There will be a large number of wiring issues on the construction site, leading to frequent false residual current alarms, wasting inspection time. This requires strict adherence to the wiring guidance in "Installation and Operation of Residual Current Protective Devices" (GB13955-2005), selecting appropriate grounding methods according to different wiring requirements, and ensuring proper grounding connections for the system.
Electromagnetic Interference Resistance Test
The high-rise building's electrical fire monitoring system must have a certain degree of electromagnetic interference resistance. If there is a complex electromagnetic field around the electrical system, it can easily lead to the failure of the fire monitoring system to operate properly, and the electrical equipment itself lacks electromagnetic shielding measures.
Leakage not only affects the normal operation of equipment but also leads to reduced lifespan. The working environment of building electrical fire monitoring systems varies greatly, and the appropriate equipment specifications should be selected based on the specific application location.
Residual Current Detection
Electrical fire monitoring systems predominantly rely on residual current detection as the primary method, with temperature detection as a supplementary measure. Residual current detection should ideally be increased by no more than 500mA. Based on the specific application and the importance of electrical equipment within the building, temperature monitoring detectors can be installed on other critical equipment such as electrical circuits, motors, and distribution boxes.
Ankele Electric Fire Monitoring System
The Acre1-6000 Electrical Fire Monitoring System is a fully digital, independently-operated system developed by Ankorui Electrical Co., Ltd. in accordance with the current national standards. It has passed the fire product testing certification by the National Fire Product Quality Supervision and Inspection Center and has also successfully undergone rigorous EMC electromagnetic compatibility tests. This ensures the safe and normal operation of the series in low-voltage distribution systems. The system is now in mass production and widely used across the country. By collecting and monitoring signals such as residual current, overcurrent, overvoltage, temperature, and fault arcs, it enables early prevention and alarm of electrical fires. It can also disconnect the distribution circuits with excessive residual current, temperature, and fault arcs upon necessity. Additionally, it can meet user requirements for data exchange and sharing with the AcreIEMS corporate microgrid management cloud platform or fire automatic alarm systems.
Application Scenario
Ideal for intelligent buildings, high-rise apartments, hotels, restaurants, commercial complexes, industrial and mining enterprises, key fire protection units, as well as the oil and chemical, cultural and educational, healthcare, financial, and telecommunications sectors.
System Features
- The monitoring equipment can receive residual current and temperature information from multiple detectors. When an alarm is triggered, it emits both audio and visual alarm signals. Simultaneously, the red "ALARM" indicator light on the device illuminates, the display indicates the location and type of the alarm, records the alarm time, and the audio-visual alarm persists until the "RESET" button on the device or the "RESET" key on the touch screen remotely resets the detector. The audio alarm signal can also be manually silenced using the "Mute" key on the touch screen.
- When the monitored loop alarms, the control output relay closes to control the protected circuit or other equipment. Once the alarm is cleared, the control output relay releases.
- Communication Fault Alarm: In the event of a communication failure between monitoring equipment and any connected detector, or if the detector itself fails, the corresponding detector on the monitoring screen will display a fault alert, and the yellow "Fault" indicator light on the device will illuminate along with an alarm sound. Power Supply Fault Alarm: Should the main power supply or backup power supply fail, the monitoring equipment will emit an audible and visual alarm signal, display fault information, and allow access to a specific interface for detailed information and to silence the alarm sound.
- In the event of residual current, overtemperature alarms, communication, or power supply failures, the alarm location, fault information, and alarm time are stored in the database. Similarly, records are kept when alarms are lifted and faults are resolved. Historical data offers various convenient and quick search methods.
In summary, for high-rise buildings, it is crucial to ensure effective electrical fire monitoring. This requires design and construction units to combine the specific circumstances of the building, strengthen the equipment and installation of related devices and circuits based on the working principle of the electrical fire monitoring system, continuously improve system functionality, enhance electrical fire monitoring and control capabilities, ensure the safe use of high-rise buildings, and promote the stable development of the construction industry.
[Reference]
Li Yang. An Overview of Architectural Electrical Fire Monitoring Systems[J]. Private Science and Technology, 2010(10): 305+40.
Xu Xisheng. A Discussion on the Design of Electrical Fire Monitoring Systems for High-Rise Buildings[J]. Machinery and Electrical Information, 2011(15): 160-161
Xiao Guangming. An Analysis of Electrical Fire Monitoring Systems for High-Rise Buildings[J]. Public Engineering Design, 2018
Ankoray Emergency Lighting and Evacuation Guidance System / Fire Door Monitoring System / Fire Equipment Power Supply Monitoring System / ElectricalFire Gas Monitoring System Selection Handbook. 2022.05 Edition
