What is the difference between an automatic fire monitor and an automatic tracking and positioning jet fire extinguishing system?
Automatic tracking and positioning jet extinguishing devices can be classified into jet-type automatic jet extinguishing devices and spray-type automatic jet extinguishing devices according to the jetting method. Among them, jet-type automatic jet extinguishing devices with a rated flow rate greater than 16L/s are called automatic fire monitor extinguishing devices.
Therefore, automatic fire monitor extinguishing devices are the same as jet-type automatic jet extinguishing devices with a rated flow rate greater than 16L/s. They belong to the same product category and have the same product standards and inspection standards.
How do you determine the design flow rate of automatic fire monitors and automatic tracking and positioning jet extinguishing devices, as well as the flow rate of each jet extinguishing device?
Automatic fire monitor extinguishing systems and jet-type automatic spray extinguishing systems are the same type of product, with identical product and inspection standards, and should conform to the same design standards.
Regarding the determination of the flow rate for fire monitor extinguishing systems, it is recommended to refer to Chapter 4.3 of the *Design Code for Fixed Fire Monitor Extinguishing Systems* (GB50338-2003): The water consumption for civil buildings should not be less than 40 L/s, and for industrial buildings, it should not be less than 60 L/s. Taking civil buildings as an example, indoor fire monitors should be able to simultaneously deliver water jets from two monitors to any part of the protected area, and each spray extinguishing system should have a flow rate of not less than 20 L/s.
Please note that 40 L/s and 60 L/s are only minimum design flow rate requirements. As stated in Clause 4.3.4 of the *Design Code for Fixed Fire Monitor Extinguishing Systems*, the design flow rate for automatic tracking and positioning jet extinguishing systems should be determined according to the *Design Code for Automatic Sprinkler Extinguishing Systems*, with the higher value taking precedence. For example, if the calculated flow rate of an exhibition hall is 50L/s, then a jet fire extinguishing device with a flow rate of 25L/s should be selected, and the water jets from both water cannons should reach any part of the protected area simultaneously.
Can an automatic tracking and positioning jet fire extinguishing system replace an automatic sprinkler system?
Automatic tracking and positioning jet fire extinguishing systems rely on fire detection, tracking, positioning, and automatic control systems. They have high installation and commissioning requirements and strict operation and maintenance requirements, and should only be used in locations where it is difficult to install automatic sprinkler systems, primarily referring to locations exceeding the protection height of closed-loop automatic sprinkler systems.
The "Code for Fire Protection Design of Buildings" 8.3.5 explicitly states that automatic tracking and positioning jet fire extinguishing systems are suitable for densely populated places such as exhibition halls and auditoriums where it is difficult to install automatic sprinkler systems, as well as tall spaces such as Class C production workshops and warehouses.
Does an automatic tracking and positioning jet fire extinguishing system require an elevated fire water tank and pressure stabilization facilities?
Automatic tracking and positioning jet fire extinguishing systems employing temporary high-pressure water supply systems can be equipped with only an elevated fire water tank or only a pressure-stabilizing pump. The elevated fire water tank can be shared with other systems.
Under normal circumstances, elevated fire water tanks and pressure-stabilizing pumps are insufficient to guarantee the initial fire extinguishing needs of the system. If the water supply does not reach the rated design flow rate and pressure, the jet may not even reach the ignition point, rendering it meaningless. Therefore, automatic tracking and positioning jet fire extinguishing systems only need to ensure that the system piping is completely filled with water; they do not need to meet the static water pressure requirements at the most unfavorable point of the water extinguishing facility.
Note: Unless limited by ambient temperature (e.g., in locations where the ambient temperature is below 4℃ or above 70℃), the piping of automatic tracking and positioning jet fire extinguishing systems should be in a fully filled, wet state. This reduces the system's start-up water filling time and allows for monitoring of the piping condition (valve malfunction, leakage, etc.).
Main components
The automatic tracking and positioning jet fire extinguishing system mainly includes a detection, positioning and control section, a fire extinguishing section, and a fire-fighting liquid supply section.
Fire extinguishing and fire-fighting fluid supply components:
The automatic tracking and positioning jet fire extinguishing system mainly includes:
1. Fire water tank;
2. Fire pump;
3. Pump connection;
4. Elevated fire water tank;
5. Signal valve;
6. Flow indicator;
7. Inspection valve (signal valve or control valve with locking device);
8. Solenoid valve (or electric valve);
9. Jet device (or fire monitor);
10. End-of-line test device; etc.
Detection and Positioning Control Section
The detection and positioning control section of the automatic tracking and positioning jet fire extinguishing device mainly includes a primary detection component (starting component), a secondary detection component (positioning component), a field camera, a field manual control box, and a control host.
1. The primary detection component detects initial fires and comes in various types, including infrared, ultraviolet, and image detection. The primary detection component can be pre-installed on the nozzle or installed separately (this varies between manufacturers).
2. The secondary detection component automatically tracks and positions the fire. The secondary detection component and drive motor are pre-installed on the nozzle and include both horizontal and vertical detection parts. Through horizontal and vertical scanning, it locates the fire and extinguishes it with jet fire. The secondary detection component often uses infrared scanning.
3. The field camera is usually pre-installed on the nozzle and its main function is to acquire images from the scene and transmit them to the control host in the control center.
4. The field manual control box is used for manual control of the jet device and is usually installed at the bottom of the jet device.
5. The control host is located in the fire control center and is the core of the control system. It can remotely and manually control the jet device through the images from the on-site camera.
