Discussion on fire protection design of the hottes

Discussion on electrical fire protection design

I. design of secondary lines such as fire fans and fire pumps

Article 8.6.3.5 of the code for electrical design of civil buildings stipulates that for distribution lines whose sudden power failure will cause greater losses than that caused by overload, overload protectors that cut off circuits (such as power supply lines of fire pumps, etc.) should not be installed, but overload alarm appliances should be installed. Such as the control of smoke exhaust fan, fire pump, spray pump, etc. Only when the two motors are standby for each other and the two speed fan runs slowly (in non fire fighting working state), the thermal element electrical appliance can act on the shutdown. When the two speed fan runs at high speed in fire fighting working state and the smoke exhaust fan, fire pump and other single machines operate, it can not act on the shutdown, but only on the signal. Some designers often do not pay attention to this point, no matter what the situation and state, In the secondary circuit design, it is wrong to shut down the machine with the action of thermal elements and electrical appliances. The author believes that the easiest way is to adopt the current national standard atlas or provincial standard. For example, the common fan control circuit diagram in the icon is 99d375, and; The drawing number is 96sx501 fire alarm and fire control. The provincial standard "design and installation of fire alarm linkage control system 2002 Zhejiang D5" was soon released. In this way, designers are easy and reliable. Why not

second, the function difference and setting of manual fire alarm button and fire hydrant button. Check whether the ball socket and ball head of suspender and large lever connector are greasy.

the function of manual fire alarm button and fire hydrant button is different. The setting of fire hydrant is determined by water supply and drainage specialty, so the fire hydrant button can only be set on the fire hydrant, and its function is: to control the start and stop of fire pump; Display the working fault status of the fire pump and the position of the start button. In civil buildings, in projects without a fire control room, when DC24V fire hydrant button is used, DC24V power supply should be set in the fire hydrant pump control box, and the direct pump start control signal and display signal of the fire hydrant button should be transmitted to the fire hydrant pump control box through DC24V line, After being converted by DC24V repeater, it is connected to the control circuit of the automatic start pump to realize transformation and upgrading. This is the traditional wiring of starting the pump with the normally open contact of the button in parallel or the normally closed contact in series. When there is a fire control room, according to the code for design of automatic fire alarm system (hereinafter referred to as the code), when the control equipment of fire pump, smoke control and smoke exhaust fan is controlled by bus coding module, it is also because manual direct control device is set in the fire control room. That is to say, the fire alarm controller and manual direct control panel shall be set in the fire control room, which shall be directly transmitted to the automatic, pump start and pump stop control circuits in the fire pump control box by bus and multi-wire lines, and the operating state of the fire pump and the operation condition of the fire power supply shall be returned to the manual control panel in the fire control room for display, which is the most reasonable way to start and stop the pump through bus or multi-wire and receive its feedback signal, The most reliable wiring method

the function of the manual alarm button is only for alarm in case of fire. It is set by the electrical fire protection designer. The specification stipulates that at least one manual fire alarm button shall be set in each fire compartment. The distance from any position in a fire compartment to the nearest manual fire alarm button shall not be greater than 30m. The manual fire alarm button shall be set at the entrance and exit of public activity places and obvious places convenient for operation. For example: ① the front room of each floor should be the preferred position for manual alarm buttons, followed by the front room of the elevator hall, because the front room is an important place for personnel evacuation and firefighters to fight in case of fire, and it is also a crowded place, so it is convenient to alarm in time in case of fire. ② As for the so-called public activity places in the specification, the author believes that in addition to the above front rooms, such as the hall, lobby, restaurant, nano calcium carbonate, which is a kind of multi-function hall of light calcium carbonate, and the main passages and corridors are places where people come and stay densely, and also the main entrances and exits of evacuation passages. Therefore, these public places should be set with corresponding manual alarm buttons for the first time to comprehensively sort out the green development process of China's industrial field

III. setting of fire emergency broadcast and fire alarm device

article 5.4.1 of the specification stipulates that the control center alarm system should be set with fire emergency broadcast, and the centralized alarm system should be set with fire emergency broadcast. Then, after setting the fire emergency broadcast, is it necessary to set up the fire alarm sound device? There are many different opinions and disputes about this. Here, the author believes that it should be treated differently according to the actual situation and the specific occasions of the project. For example, in general office buildings, inpatient departments of hospitals and other places with relatively quiet environment, fire alarm sound devices can not be set up. If acoustic alarms are installed, the fire emergency broadcast can not be heard clearly, delaying the evacuation of personnel. In places with high noise, such as shopping malls, restaurants, entertainment and other places with environmental noise greater than 60dB, fire alarm sound devices should be added, and the sound pressure level of the sound alarm should be 15dB higher than the background noise. And in the control program, the alarm device will send alarm to the fire related area automatically or manually after the fire is confirmed. The alarm time should be reasonably set and should not be too long. I. when the alarm is stopped, the fire emergency broadcast shall be quickly linked, and the evacuation instructions shall be broadcast in time

in the area alarm system or in warehouses, garages and other places with large area and few personnel, emergency broadcasting may not be set, but fire alarm sound devices should be installed