【 Weak current College 】 air sampling smoke detection system of application-large space--Power By 【 China power house network 】

Common large open space, including the gymnasium, museums, exhibition centers, storage facilities, the airport terminal, railway station and the large hotels, shopping centers, office buildings etc. The space is big, the roof high, covers an area of wide, is the difficulty in fire detection. Moreover, this kind of place, personnel are crowded, property value, if there is fire, very prone to injuries and property damage. So there is a strong need for high-performance, State-of-the-art fire detection method.
Traditional smoke detection system sensitivity is not high enough, unless you are very fierce fire, resulting in a lot of smoke and heat, otherwise it is not in such a big open space efficient detection of smoke. In addition, because of the smoke rise in air will make it freely in large open space, traditional smoke detectors of addressability is meaningless. Air sampling smoke detection technologies for such establishments of brought hope for fire detection. 1. for large open space, smoke detection system design experience those problems? First, you need to solve the problem with smoke tiered moyamoya smoke stratification refers to reach a balance, the ceiling was below the level of the mushrooms, but failed to reach the ceiling installed smoke detectors. This is a big space is a common phenomenon. Whereas the provisions of the national standard in China, dot detector installation height of not more than 12 metres, the barrier-type detector installation height not exceeding 20 meters. In this way, these traditional probe will not be able to use such site installation. But the amendment to the fire alarm system construction and acceptance (GB50166-200X), the high sensitivity of air sampling smoke detector can be installed in any of the 16 meters above the sea level. Because air sampling smoke detection system is through the distribution network for active sampling, the sampling points can be placed in the most effective smoke detection position, which is the only way the smoke, but not necessarily on the ceiling, thus avoiding the smoke stratification on fire detection. This type of construction and the environment more installed ventilation equipment, and air conditioning systems run into another fire detection of constraints. According to the requirements of ventilation system of control, as well as on its installation height (height from floor) of the design requirements, smoke and fire detection systems-related design need to consider several factors. Secondly, it is necessary to overcome the effects of smoke diluted because the mixing of the air conditioning system, big open spaces smoke will flow process is highly diluted. Therefore, in such an environment, select high sensitivity and ability to multi-sampling of a smoke detector is crucial. Even in this kind of environment frequently used barrier-type detector or video detector, relatively speaking it is not sensitive. It must wait until the fire reaches a more serious level to detect the presence of fire. Dot detector is in the area of a single point for smoke detection, if smoke concentration here is not large enough, the detector does not beep. And air sampling smoke detection system are based on sampling of accumulation to improve sensitivity, detection of the fire, it passed the tube sampling points online air sampling, sampling of installation on the ceiling, which breaking through the fog layer or dilution of smoke particles can also be captured, each sampling point detector to provide the total amount for detection of smoke, providing very early fire detection. In the sampling point placed in the place where the altitude at the same time, you can also set the sampling point placed in the premises of cooling and heating and ventilation system back into style gate, a smoke with air flow in a outlet at the back was detected. Third, far from the surface of high-altitude on smoke detection system for maintenance can be difficult to install in high ceiling traditional smoke detectors for maintenance, you need to set special equipment and staff, the high cost and risk. Barrier-type detector because maintenance is required for adjustment, the same need very high costs. We can put air sampling smoke detectors and their sampling probe points placed in accessible location so that the small number of cases requiring maintenance easy access equipment. Fourth, how to avoid false positives a big open space often use infrared correlation type of smoke detector. Unfortunately, advertising, products, goods, etc., will block the radiation, causing a false positive or failure. And air sampling smoke detection system is difficult to produce false positives. Fifthly, how to maintain the building's appearance for sports centres, museums and other places, traditional point-and-smoke detector will damage the building's appearance. We can use covert sampling network installation mode, so that the building was not aware of the presence of smoke detection system. Sixth, how to do it on the fire of orderly response to air sampling smoke detection system to 0.005%-20% obs/m smoke concentration range offers 4-level alarm, may correspond to different levels of response, for example, "warning" (the first level alarm) State is used only to bring together local staff survey exception conditions, as soon as fumes continued to increase, you will reach the "operation" (second-level alarm) thresholds, this will start the smoke control program, start by evacuation system alarm and pagers or SMS to more staff issued an alert signal. "Fire 1" (third-level alarm) description of the fire is imminent or has burst into flames, at this stage, the building was evacuated in the personnel, the fire alarm controller "region" is activated, the alarm signal is transmitted to local fire supervision departments. Once smoke concentration sufficient proof that the fire started, it will stimulate the "fire alarm threshold 2", the fire extinguishing system will start. Second, air sampling smoke detection system in the Olympic Games Stadium of the Olympic Games in 2000, one of the important symbols of closed multifunctional Stadium – Sydney SuperDome Super Stadium. Huge Bowl Stadium height 39 metres, divided into five levels, its area is equal to eight football fields, is the southern hemisphere's largest indoor Entertainment Centre and stadium can accommodate 21000 spectators. Venue versatility means that the SuperDome and pre-function space rock concerts, indoor windsurfing movement and formal banquets and other events. It also created a large ballroom and a Sports Hall, and other entertainment. These form theDifferences and requirements in 8 minutes evacuating personnel of new standards, you need to open the dew of staircases and limited export, by various fire detection and fire prevention measures. In addition, due to be diluted because detecting large open-air places of smoke is very difficult. As the smoke rising from the ground of fire, stratification, the smoke is very difficult to reach the ceiling. Traditional fire and life safety and security measures has been to regulations and standards-based. Australia building code made in 1997, the performance-based design and write into the Guide. It considered building technologies and on fire characteristics and in-depth knowledge of human behavior. On this basis, the fire protection and security in Sydney Holmes directors and experts Dr. MarianneFoley designed a special system solutions to meet a series of fire control system performance requirements. The venue of the competition area of the site exceeds 4, 300m2, Bowl game volume more than 350, 000m3, which far exceeded is considered to meet the regulations stipulated in the area and volume. Existing specifications, this kind of competition venues should be equipped with spray equipment. Installed in the roof height of spray equipment cannot control the ground of fire. Use a spray device makes smoke cooling, so that it lost buoyancy, it will give workers evacuated at risk. In the SuperDome Super Stadium in performance-based design of fire scenarios, use the Australia VisionFire & Security company production of VESDA air sampling smoke detection system. Implements:
1) larger open areas; 2) in the calculation of the fuel load and burning time, reduces the probability of fire, thus improving the cost-effectiveness of construction; 3) more of the available space (reduces the width of the aisle and export); 4) removed the spray system; 5) improved the evacuation of people with disabilities for emergency response; 6) improves the environment for sustainable development. VESDA detection system is the world's leading air sampling smoke detection system, it can detect trace amounts of the initial fire smoke particles, the SuperDome Super Stadium provides effective protection. Conclusion: for large open space, air sampling smoke detection system is the ideal detection system, which provides very early warning, as personnel evacuation and fire disposition provides sufficient time, effectively avoid panic caused by the loss of life and to protect high-value property is not lost.