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Comprehensive wiring alarm fire communication system three links
China's national standards require that fire alarm systems and fire-fighting fire-fighting linkage control systems and fire-fighting communication systems must be set up in important locations and key locations in intelligent buildings or intelligent communities. The automatic fire alarm system and the fire communication system have an extremely close relationship with the integrated wiring system, but they have their own independent characteristics and requirements. The two parties must cooperate and coordinate with each other.
Overview of Automatic Fire Alarm System
The overview of the fire alarm system described here is the most basic content. Automatic fire alarm system is an application system with multiple technical functions of detection, alarm, and fire control. It involves multiple disciplines and multiple professions. To this end, it must have some understanding of it, especially the part related to the integrated wiring system. Helps with design.
The fire automatic alarm system is mainly composed of fire detection alarms and fire alarm control devices and control lines between them. Therefore, it is a huge system that is organically combined with various components, devices, and devices. They work together to undertake the important task of disaster prevention and alarm. The detection of fire due to fire alarm is more important in the automatic fire alarm system, and is related to the integrated wiring system. This section briefly describes the current situation of fire detection alarms.
1) Relationship between automatic fire alarm system and other systems
In order to ensure that the state's property is not lost and people's lives are safe. It is required that in intelligent buildings and intelligent communities, especially the critical departments and important sites, facilities must be set up and equipped with effective and effective disaster prevention and fire extinguishing facilities that can timely detect fires, quickly and automatically alarm, and link and control various functions.
To this end, it is necessary to set up an automatic fire alarm system, a fire-fighting linkage control system, and a fire communication system, taking into account the scale of construction, use objects, and coverage of intelligent buildings and intelligent communities. Therefore, there are differences in the scale and specific content of the above three systems, but the fire communication system is an indispensable part.
2) Types, Lines, and Connections of Fire Detection Alarms
Fire detection alarm is called fire detector or fire alarm for short. It is commonly known as probe. It is an important part of automatic fire alarm system. It is distributed throughout important parts of the entire intelligent building and is the sensory organ of automatic fire alarm system. "Closely monitor and detect the surrounding environment wherever it is located.
It cooperates with the fire alarm control equipment to cooperate with each other, and the fire automatic alarm control equipment is the "body" and "brain" of the fire automatic alarm system, and is also the core of the system. They are complementary and inseparable combined with each other. .
1 Fire detection alarm wire system and connection
The fire detection and alarm subsystem in the fire automatic alarm system and the fire-fighting linkage control system is the most important part, and its cable distribution is the most extensive, because the fire detection alarm installation position is distributed to various parts inside the intelligent building, and Corresponds to the level of the object of protection.
2 Types of fire detection alarms
At present, the types and types of fire detection alarms produced at home and abroad are extremely varied. Therefore, its classification methods are diverse and not yet unified. They are classified according to their technical performance and application requirements, and they differ from each other, for example, according to fire detection. Alarm detectors trigger different parameters of the fire classification, there are smoke-type, temperature-sensitive, sensitive, flammable gas detection, composite and other million-and other;
According to their structural shape classification, can be divided into two types of point type and line type; according to their use of environmental classification, can be divided into land-use type, marine type, cold-resistant type, acid-resistant type. Alkali-resistant and explosion-proof. Each of the above types can be subdivided into different types. Domestically, parameters classified by fire are commonly used. Therefore, the number of cables (ie, wire system) and connection method of the fire detection and alarm subsystem is extremely important, and it is also related to the distribution and utilization of cables of the integrated wiring system.
The wire system of the fire detection and alarm device mainly refers to the number of wires of the transmission signal line between the fire detection alarm device and the control device, and is mainly divided into two systems: multi-wire system and bus system. Because of the different connection methods derived from the wire system, there are mainly two bus systems, four bus systems, multiple wire systems (n+4), and two bus systems and ring network combined connection methods.
In addition, there are chain and other connections million. The above network structure, line system and connection method have their own characteristics and are related to each other. Therefore, under normal circumstances, based on factors such as the size of the detection and alarm area within the intelligent building, the distribution status and equipment of the fire detection alarm, etc., the corresponding network structure, line system and connection type are selected comprehensively.
Bus system: an independent address circuit to determine the specific location of the fire, and the alarm control device uses serial communication to access each detector. This type of wire system and the connection of thousands of wires have been significantly reduced in number and installation and construction are simple, so they are widely used today. However, the disadvantage is that once the bus circuit has a short-circuit fault, the entire circuit fails, fails to work properly, and may even damage some detectors or control devices.
Multi-wire system: Multi-wire system is the link method of early detection and alarm system. It is characterized by a live detection alarm (or a group of several fire alarms) forming a loop that is linked to a fire control device. When any of the detectors in the loop finds a fire, the loop where the detector is located on the control device cannot determine its exact location (ie, the ignition point), so each detector must be connected with a single wire to connect. A multi-line system was formed. The multi-wire system is "n+4 wire system, n is the number of detectors, and 4 is the common line. They are the power line (V, ± 24V), ground (G), signal line (S) and self-diagnosis line respectively. (T) In addition, each detector has a gate line (ST).
Only when a gate line is at an active level, the signal transmitted on the signal line is the status information of the probe site. The advantage of this connection is that the circuit of the detector is relatively simple. Observing the information is more intuitive, it is easy to determine the specific location of the fire; the disadvantage is that the number of wires is large, the diameter of the piping is relatively thick, the construction of the threading is difficult, and the line failure is also numerous. Therefore, this kind of wire system and connection method in China has been gradually reduced. Therefore, in order to ensure the normal operation of the entire system and to avoid accidents and reduce the maximum loss, short-circuit isolation measures must be taken in the system, such as the installation of short-circuit isolator.
The 4 buses are: P line gives the detector's power, coding, and siting signals; T line gives the self-test signal. In order to determine the accessibility of the detection site or the transmission signal line; the control device acquires the information of the detection site from the S line; the G line is the public ground line. The four lines P, T, S, and G are all connected in parallel. Because the bus system adopts the code location technology, the control device can accurately determine the specific location of the detected fire, simplify the installation and debugging, and greatly increase the reliability of the system operation. The two-bus system has fewer lines than the four-bus system, but the technology is more complicated. The difficulty has increased. In the two-bus system, the P line is used for various functions such as power supply, site selection, self-check, and access to information. The G line is a public ground line.
At present, this wire system and connection method are used more often. Its network structure has a tree type and a ring type. The tree type, which is the most commonly used method in most systems at present; the ring type, for the control device, becomes the access to four lines. In addition, there is a chain connection type, its P line is connected in series with each fire detection alarm. For each detection alarm, there are 3 wires to access. For the control equipment, only 2 wires are connected.
From the various connection methods described above, it can be seen that in addition to the network forming a ring type, which provides relatively safe and reliable conditions for ensuring normal operation, other bus systems have the disadvantage of poor bus safety and reliability, so when designing We must weigh the pros and cons and make a comprehensive determination.
The three of them complement each other as a whole so as to give full play to their overall timely warning and fire fighting functions. Therefore, the fire communication system should be an infrastructure in intelligent buildings and intelligent communities, and it must be valued and set aside.