UKTSiP. Safe operation of automatic fire extinguishing systems
Powder modules, which are the executive devices of many fire extinguishing systems, in most manufacturers have basically the same startup nodes:
- the starting current of 0.1 A. (100 mA.) is the guaranteed starting current;
- maximum starting current up to 1.0 A;
- safe starting circuit testing current 0.02 A. (20 mA);
- time of the impulse to trigger the trigger node: 1.0 millisecond is enough.
Modules with starting currents of 0.4 and 0.7 A. and others are also available.
In the regulatory documents, the requirements for the parameters for the launch units of modules of automatic fire extinguishing systems are not reflected.
And here there are problems: the safe current of the check of the start circuit is very small and at a current of more than 0.02 A. the start node can trigger. The pulse width for starting the module is very small – 1.0 millisecond is enough.
The start loop is relatively long, and the starting circuits of the modules are connected directly to this loop. During a thunderstorm or under the influence of other negative factors, electromagnetic interference occurs to this plume and, consequently, to the starting circuits of the modules.
From electromagnetic interference sometimes there is an unauthorized launch of one or two modules, with up to 30 modules connected in the loop. This indicates that the current in the start loop sometimes reaches 0.1 – 0.15 A.
The fire control devices (hereinafter referred to as PPC) control the start loop, but do not control the starting circuits of the modules, since the modules in the automatic fire suppression systems are connected in parallel. When the modules are connected in parallel, the total resistance will tend to a small value, therefore, the current will increase, so it is necessary to calculate and set the limiting resistances.
The maximum starting current of the modules is 1.0 A. Even the PUU, to which one module is connected, monitors the start circuit of the module in one direction, at start-up, the starting voltage passes in a different direction, whereby through an additional diode and this direction of the starting circuit is not controlled.
According to paragraph 12.4.1.b of the code of regulations 5.13130.2009 (fire protection systems, fire alarm and automatic fire extinguishing systems, design rules and regulations), control equipment for gas and powder fire extinguishing systems should provide automatic monitoring of connecting lines for control of starting devices and start-up circuits devices to the breakage.
After analyzing the many shortcomings of the starting circuits of modules and PPU, our specialists came to the conclusion that for reliable and safe operation of automatic fire extinguishing systems of a modular type, it is necessary to do the following:
- start-up circuits of the modules are galvanically isolated from the start-up loop;
- Increase the safety check current in the start loop;
- the modules must be started only from the DC voltage output by the FPU;
- increase the voltage pulse time for the signal to start the modules;
- to force the control unit to control the starting circuit of all modules connected to it.
To solve these problems, our company has developed and manufactures a circuit monitoring and start-up device (hereinafter referred to as CCTS & P) PTKL.425400.015.TU.
In a properly installed automatic fire extinguishing system, UKC & P is included in the start loop of the PPU, which monitors the loop. Neither diodes nor resistors in the starting circuits of the modules are installed, even if they are provided in the scheme of switching on the PPU, only the terminal devices are installed in the last DCC & C.
Specifications UKTSiP:
- one fire suppression module is connected;
- the supply voltage is constant from 12 to 24 V;
- signal “START” for UKCiP from PPU: a constant voltage of 8.0 to 26 volts, duration of not less than 0.1 seconds. and current from 0.2 A;
- UKCiP gives to the starting circuit of the module 10 to 20 V. DC voltage, depending on the supply voltage UKCiP, duration from 5.0 ms. and current up to 1.0 A;
- monitors the starting circuit of the module, the supply voltage UKC & P, light indication and signal transmission to the control panel.
What gives the application of CC & C in automatic fire extinguishing systems:
- the module start-up circuits are galvanically isolated with the start-up loop through the CC & C scheme; electromagnetic pick-ups on the module starting circuit will not be dangerous;
- safe test current in the start loop 0.15 A;
- Signal “START” from PPU to UKTSiP a constant voltage from 8.0 to 26 V, duration from 0.1 seconds and current from 0.2 A;
- no need to calculate and install in the start-up circuits of the modules limiting resistors and diodes;
- the control of the status of the module start circuit, the supply voltage UKC & P, the light indication and the signal transmission to the control panel are monitored;
- Any module with a starting current of up to 1.0 A can be used;
- the voltage in the start-up and power-supply loop of the MC & A can be from 12 to 24 V, with which they can be independent;
- UKTSiP can be used with different PPU.