Acceptance specification for electrical fire alarm systems

Because the "High-rise Civil Building Design Fire Code" is an architectural design specification, not an electrical fire alarm system product inspection standard, it is not an electrical fire alarm system design, construction acceptance specification, therefore, the provisions are relatively coarse, resulting in the current electrical fire alarm system design , construction, inspection is not clearly marked, is bound to affect the smooth construction and operation of electrical fire alarm systems engineering, electrical fire alarm system affect its normal functioning.

1.1 According to the national standard "Installation and operation of electrical fire monitoring action protection device" GB13955-2005, regarding the classification protection provisions, when installing the electrical fire monitoring fire monitoring device, the reasonable distribution design of the fire prevention area in the building should be made to determine the appropriate The protection range, the scheduled electrical fire monitoring action value and the action time, and should meet the operational characteristics requirements of the hierarchical protection, and reduce the power failure range caused by the failure of the power supply. Therefore, the design should first have a clear understanding of the relevant parameters of the control distribution system, study the relevant drawings related to the control of the distribution line, and investigate the distribution of the building electrical to determine the distribution equipment (distribution box, disk) The position of the cabinet, the electrical fire monitoring detector is assigned to the corresponding power distribution equipment, according to the actual situation, such as: setting current, estimation of normal leakage current, determining the number of electrical fire monitoring detectors. In order to avoid repeated settings, the allocation principle is as follows: According to the building power load and the specific conditions of the line, it is determined to adopt the two-level or three-level protection mode; generally all the two-stage switches must be equipped with electrical fire monitoring detectors; Installation should be based on actual conditions of the load and the actual use of the building, fire hazard, etc. After determining the installation position of the electrical fire monitoring detector, it should be designed and wired in the bus mode. The bus system is a four-core cable, and an independent system bus should be formed. The four-core bus is converted into an RS232 serial port by the bus-based transmitter data, and the terminal An electrical fire alarm system consisting of a console (leakage alarm system host). The bus transmitter and terminal console (leakage alarm system host) should be installed in the fire center or duty room.

1.2 Important load: including fire, security, emergency power supply, channel lighting circuit and important places that are not allowed to be powered off. According to GB139554.6, alarm type electrical fire monitoring detector should be installed, which has the signals of collecting leakage current and over current. When the set value is exceeded, only the sound and light alarm signal is issued, but the power is not cut off, and the collected signal is transmitted to the control center through the bus mode, and the manual power-off mode can be set, which ensures the safety of the power and ensures the safety. The uninterrupted power supply.

1.3 The design must pay attention to the principle of hierarchical protection and avoiding large-scale power outages.

In order to prevent electrical fires, GB13955-2005 emphasizes the use of hierarchical protection. The electrical fire monitoring and protection devices on the power supply or branch lines should be coordinated with the operational characteristics of the electrical fire monitoring and protection devices at the end to achieve hierarchical protection with action selectivity. To avoid large-scale power outages. Under normal circumstances, the low-sensitivity delay-type electrical fire monitoring and protection device should be used on the power incoming line or the branch main circuit. At the end, the leakage current IΔn≤30mA and the rated operation time Tn<0.1s are mainly used to prevent personal electric shock protection and complement the electrical fire alarm system.

One or several electrical fire monitoring detectors may be installed at the total entrance of each floor of the building, but the electrical fire monitoring detectors with appropriate parameters shall be selected and selected according to the normal leakage current. The electrical fire monitoring at the general incoming line is set at 200 to 500 mA.