What are the applications of the very early air sampling system in the data center?

With the development of computer technology and microelectronics technology, the requirements of communication equipment system integration are higher and higher. The high system integration makes the equipment contained in many machine rooms in the past be concentrated into a cabinet. In this way, the constant temperature and humidity of ventilation and machine room environment in the machine is essential, and the adoption of ventilation and air conditioning equipment in the machine can reduce the temperature and avoid the occurrence of excessive temperature The function of fire is to dilute the fire smoke. In this way, the thermal buoyancy of the smoke generated by the initial fire becomes smaller and it is difficult to reach the ceiling, which greatly delays the response alarm time of the ordinary passive point type smoke fire detector. Even because the smoke is seriously diluted or hard to spread to the detector, it has no use and can not be detected. Therefore, the smoke can not be detected Cause fire accident.

Communication room is the heart of information network. Because of the high price of communication equipment, once a fire occurs, it will not only cause serious economic losses, but also cause equipment paralysis, which will make the communication and data loss of the government, companies, banks, businesses, factories and individuals interrupted. The loss can not be estimated, and more importantly, the social benefits are irreparable. For example, if there is a fire in IDC room of communication, it will seriously affect the network and communication, and will cause great loss and social impact to users. Therefore, early fire alarm in communication room will win sufficient time to find and deal with the fire and avoid fire disaster, which is of vital importance.

In order to increase the flame retardancy of the plastic insulation layer of wires and cables of the equipment room, additives such as halides and phosphates are added. These additives slow down the spread of the fire, but produce excessive smoke. The randomness of the smoke conduction may cause the misoperation of the circuit, and the smoke on the components may also cause the wear of the moving parts. In addition, in addition to heat and smoke, corrosive gas and toxic gas are also released during the fire. Phenolic gas is produced during the combustion of most plastics, and a large amount of hydrogen chloride gas is released during the combustion of PVC insulation. It combines with water molecules to form hydrochloric acid. Hydrochloric acid is a strong corrosive agent that corrodes the terminals of electronic components and circuit boards, which will endanger the normal operation of the equipment 。 This loss can be avoided by early warning before the formation of smoke. In order to improve the alarm, it needs high detection sensitivity, and it also needs to be able to alarm when the smoke is relatively weak. The ordinary point type smoke detector has to wait passively for the smoke to gather enough concentration to alarm, which limits its use in such an environment as the computer room.

The potential fire hazard of communication room is mainly caused by the over-voltage or over-current of cables and wires. The practice shows that when the ordinary smoke detector gives an alarm, the wires and cables have been burnt out and can not be used again. In this way, even if the ordinary smoke detection system reports an alarm, it will not help. The lines and cables have been burned. It is necessary to give an early alarm. It is required that the cables and wires just overheat and emit a burnt smell, but the visible smoke has not been generated yet. Then the early alarm can avoid damage to the equipment and cables. Fire hazards can be found and avoided. In addition, the data storage and personnel evacuation of the computer room also need enough time to deal with, so early alarm becomes an essential requirement for fire prevention of the computer room environment.

The requirements of communication building for fire alarm system are summarized as follows:

1. The automatic fire alarm system shall be suitable for working in the environment with strong air flow, and the general air change rate shall be 20-40 times / hour or higher.

2. in order to find out the fire as early as possible and have enough time for manual processing and firefighting, the automatic fire alarm system should give an early warning at the early stage of the fire.

3. In order to prevent false alarm, the automatic fire alarm system shall be suitable for working in the environment with electromagnetic interference, and shall not produce false alarm due to dust and humidity.

4. The operation of the equipment in the machine room shall not be interrupted, and the automatic fire alarm system shall reduce the maintenance times to a low level, so it is not advisable to have trouble in maintenance.

5. Try to avoid the spraying of fire extinguishing agent, and the automatic fire alarm system should give an early alarm, so as to have enough time to deal with the fire and avoid the formation of a fire.

6. The smoke and gas generated by the fire in the machine room are highly corrosive. The automatic fire alarm system will alarm at the beginning of the fire to prevent the smoke from polluting the equipment, which requires a high sensitivity and a consistent and sensitive response to the smoke generated by the combustion of various materials.

7. The automatic fire alarm system must be high reliability, high stability, high sensitivity and easy to maintain to reduce its operation cost.

8. Especially for the unattended or scattered computer rooms, it should have the networking function, realize the remote centralized monitoring, unified management, and convenient expansion and upgrading.

Experiments and experience show that most fires can be divided into four stages: no visible smoke stage in the initial stage, there is very weak smoke invisible to the naked eye, the initial stage of fire development is very slow, can last for several hours, and is not easy to be found by people. However, ordinary smoke detectors have not yet responded at this stage. If the fire detection system can detect and alarm the fire as early as possible at this stage, it will win a precious opportunity to control the development of the fire. In the visible smoke burning stage, the obvious presence of smoke can be seen, which is also the working stage of ion and photoelectric smoke detectors. This stage is only a few minutes away from the appearance of open fire In the stage of flame combustion, the heat accumulated by smoldering leads to flame combustion of materials; in the stage of intense combustion, the ambient temperature rises tens to hundreds of degrees, which is the action temperature zone of temperature detector and water spray. Because the traditional detectors usually give out alarm when the fire develops to the later three stages (smoke, open fire, high heat), and these three stages are relatively short, about a few seconds to more than ten minutes, so it is too late to find a fire.

The ordinary smoke detector works in the second stage (visible smoke or thick smoke). From the experiment, when it sends out the alarm, it is full of smoke in the protected area. Although the alarm is reported, the staff in the computer room do not have enough time to deal with it. They miss the opportunity to put out the fire in the embryonic stage. Even if the fire-fighting equipment is started, it has caused different degrees of property and personnel In addition, communication equipment is not allowed to pause and interrupt, so early alarm is very important.

In recent years, the early smoke detection and alarm system of air sampling mode used in many computer rooms of domestic telecommunication system has solved the problem of automatic alarm in the early stage of fire.

In the initial stage of fire development, communication rooms often emit tiny smoke particles due to over-voltage and over-current of some equipment or cables. People can not see it, but can smell the peculiar smell in the smoke. This shows that there is smoke in the air, but the concentration of smoke is lower than the visual threshold of human eyes, and certainly lower than the alarm threshold of ordinary alarm detector. Even if there's a lot of smoke,