In many Fire Among cases, Electric Occupy a certain proportion of the fire equipment. In the conditions allow, the power is the most basic common ground fire. However, in exceptional circumstances, the impact caused by power failure, the loss is enormous. For example: running a range of high-pressure fire power, if power failure, could directly affect tens of thousands, hundreds of thousands or even hundreds of thousands of people’s normal work and life order; factories, mines and other production power unit, once off power, it could seriously affect the production, resulting in greater economic losses. In actual combat, waiting for electricity, fire fighting is likely to lose the best opportune time, bungled fighters.
Then, in the charged case, the commonly used Extinguishing agent (Water, foam) to the number of kilovolts to the following routine fighting equipment fire live? Water (foam) gun (cannon) from the nozzle to a charged body how much was safe? How to carry out fire fighting? And so on, has been the concern of front-line combatants. To clarify these issues need to clarify: the harm to human body leakage current, leakage current commonly used fire extinguishing agent and the relationship between the three charged issue of fire precautions.
1, leakage current on the human body against
Harm the human body according to current theoretical data, the current at 1 mA, the human body feel electric; at 5 mA, the body will be pain; at 10 mA, the body will feel unbearable pain; 20 milliamperes severe contraction of human muscles will lose freedom of action; to 25 mA, the human body very dangerous; within 100 milliamperes will make people to death. Electrical department for the work of current through the body more than 5 mA, while Fire Required by the body not more than 1 mA leakage current, we can guarantee the safety of personnel fighting.
Two commonly used fire extinguishing agent and the relationship between the leakage current
Order to fire fighting equipment charged a scientific basis for fire brigade, and Yinchuan in Ningxia Power Supply Bureau, in the absence of both subdue, insulated gloves, insulated tools, insulated boots and conditions, jointly conducted live fire tests. According to its regional water quality characteristics have on the water (water), the Yellow River water, lake water, ordinary protein foam (foam liquid mixture, foam) to the resistivity (unit: Europe? Cm) test (Table 1), have adopted commonly used 16 and 19 mm Water gun , PQ4, PQ8 foam gun, respectively, in 10 meters, 15 meters of 110 kV and 220 kV voltage of the electrified water and foam jet, measured the water (foam) gun parts leakage current (unit: mA) 32 data (Table 2). Live fire fighting equipment should be chosen resistivity greater extinguishing agent. As can be seen from Table 1, use foam to fight the fire extinguishing agent is superior to other water. Bubbles the better, the greater the resistance, leakage current smaller. On the contrary, the leakage current increases.
Can be seen from Table 2, the voltage at 220 kV, gun nozzle 10 meters away from live equipment, using water, the maximum leakage current of 0.102 mA, the body does not feel. This means that DC gun (foam gun), not ground, not all subdue, insulated gloves, insulated boots of the case, you can directly on the voltage of 220 kV under conventional charged body, direct fire.
Three live fire precautions (A) of the gun nozzle and between the charged body to maintain a safe distance. The safe distance shall be not less than 10 meters. This is also in line with “electrical safety regulations” to prevent wounding step voltage of not less than 4 m indoor range, outdoor requirement of not less than 8 meters. Fighting a fire of not less than 10 meters is safe.
(B) charged with the DC gun fire, we should consider the water column on both sides of the gunmen and enrich the live equipment, and ensure that a safe distance. “Electrical safety regulations,” provides: The following should be kept 110 kV 1.5 m 220 kV should be kept 3 meters. Complicated because the scene for safety should be doubled, namely: to keep the following 3 meters of 110 kV, 220 kV to maintain 6 meters.
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