Large-scale event stages and lighting systems are usually temporary facilities that consume large amounts of electricity. Many electrical wires are distributed in audiences and stage performance areas, intersecting with personnel, scenery, and combustible decorations, which increase the electrical fire hazard of large-scale event venues. Therefore, the electrical fire safety of lighting systems in large-scale event venues has become an important part of the fire-fighting supervision of large-scale events.

1. Features of lighting installations and technical measures for fire safety
(1) Fire safety issues of basic light sources
The basic light source is mainly concentrated in the stage performance area. According to the different positions and uses of the lighting, it can be divided into surface light, side light, top light, sky row light, ground row light and mobile light, etc., generally equipped with spotlights, floodlights, Return light and follow light, etc., with power ranging from 0.5 kW to 2 kW. Since these lighting devices have a high temperature when they are lit, and they are close to the stage curtain, scenery, sky curtain, side curtain and other decorations, they are the focus of fire prevention. Pay attention to the design and installation of basic light sources. The following points:
     1. The lamp should be installed on a non-combustible base, and the distance from the combustible textiles such as curtains should be greater than 0.5 meters, and the distance between the front of the lamp should be greater than 1.5 meters. It is necessary to fully estimate that the spacing is affected by factors such as curtain lifting, opening and closing, movement of lamps and swing caused by natural airflow, and thermal insulation measures should be taken if the safe spacing cannot be met. If the big screen is close to the column light, a fixed metal bracket or net cover should be set to block the big screen from getting close to the lamp.
     2. When there are people or flammable materials under the lamps, lead wire protective nets or baffles made of non-combustible materials should be installed on the front of the lamps and the heat dissipation holes to reduce the hazards caused by glass fragments and hot filament splashing caused by the burst of the lamp.
　　3. For buildings such as old theaters and theaters where the surface light bridge is a wooden structure, because the surface light bridge space is very narrow and the relative temperature is high, it is difficult to detect problems. There must be no combustible materials around the lighting equipment in such parts.
　　 4. It is necessary to avoid hanging flags, launching ribbons, flying balloons, and setting up other moving objects in the air in the lighting installation area to prevent direct contact with high-temperature lamps, entanglement, collision and fire.
　　 5. For the construction and hoisting of temporary light stands, prior approval should be obtained from the construction commissioning department for the load capacity and installation method of the load-bearing components. The towering floor lamp holder should have measures to prevent the center of gravity of the lamp holder from falling to the side where the lamp is installed and the side of the standing operator.
　　 6. Outdoor large-scale event venues must fully estimate the safety factor of the lighting system under severe weather conditions and specific preventive measures. Outdoors, water-proof distribution boxes, connectors, lamps, etc. should generally be used, and other rain-proof measures shall not affect the heat dissipation of electrical equipment.

(2) Fire safety issues of artistic effect lights
　　 Computer lights, neon lights, laser lights, optical fiber lighting, plastic rainbow lights, and various mechanical rotating lights are commonly used in artistic effect lights. When designing these lamps, the artistic effect and fire safety should be combined, and special attention should be paid to the safety of neon lights. The neon tube, which is commonly used in large-scale activities, has a working voltage of up to 5000 volts, which is very easy to produce electric sparks and arcs, which is a great fire hazard. Therefore, the handle and bottom plate of the neon lamp should be made of non-combustible materials or the combustible materials should be treated with fire and flame retardant technology; when the neon lamp transformer and tube are installed in the parts that may be touched by personnel, protective measures should be provided. Neon lights hanging outdoors should be protected from short circuits caused by shaking and collisions. There is a forced air-cooling device inside the computer lamp, and the air outlet cannot be covered, and to prevent the fan from malfunctioning. The laser light is cooled by circulating water, and the water pipe must be installed reliably to avoid interruption of the water source. In the layout of artistic effect lights, it is also necessary to consider not affecting fire safety evacuation and not occupying fire passages.

(3) Fire safety issues of auxiliary equipment

　　 Auxiliary equipment is a device that cooperates with lighting effects, usually fog machines, snow machines and bubble machines. The fog machine is a large amount of carbon dioxide gas produced by heating the dry ice. After spraying it out, it forms a dense fog along the ground. It is a high-power electric heating device and has a fire hazard. The power terminal of the device is poorly connected, the live terminal is exposed, and the electrical Moisture short circuit is a more common problem. The smoke generated by the hood does not settle on the ground but spreads everywhere, which will cause the fire detector to alarm and the linkage of firefighting equipment, and sometimes make people on the scene mistakenly believe that it is the smoke produced by the fire, causing unnecessary panic, but the hood , Bubble machine itself generally has no fire hazard.
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(4) Common fire hazards in light power lines
　　 The commonly used domestic bakelite connector materials are of poor quality, low craftsmanship, easy to loose connections, large contact resistance and overheating. The long-term heating of the connector accelerates the aging of the insulating material, which can easily cause a short circuit. Due to the heavy wire load of the lighting system, the heat itself is high, and sometimes bundles of temporary wires are bundled or stacked together, the laying method is improper, and the heat dissipation conditions are poor, which further increases the temperature of the wires. The denser the wire and the greater the current, the higher the heat generation. Temporary electrical wiring of the lighting system, during the stage and props lifting, telescoping, and rotating, crossing roads, stacking heavy objects, and using steel folding chairs, etc., such as improper installation of electrical wires, they are easily impacted and worn. , Squeezing and other mechanical external forces, resulting in damage to the electrical insulation protection layer or the charged body hitting the shell, causing a short circuit. Some installation and construction units do not follow the standard operation and try to save trouble by simply winding multiple power wires on the electrical wiring terminals or using unmatched wiring terminals. The connections are poorly connected, and the joints are overheated when a large current passes, and combustible materials are ignited. Or electrical insulation layer.
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2. Fire audit and inspection method of lighting system
(1) Determine the feasibility of the lighting system plan
　To understand the main content of large-scale events, venue arrangements, building fire-fighting facilities, power supply and distribution, and electricity consumption of the event venues, and to inquire about the historical practices and problems of large-scale events held in the venue. Secondly, review the lighting system layout diagram, power supply system diagram, electrical equipment list and related technical issues. After the plan is discussed and revised, a formal lighting system design and construction drawing is produced.
(2) On-site inspection of lighting system
The inspection can be divided into two stages: the first is the inspection during the installation and commissioning stage, which mainly checks whether the installation layout, type selection, appearance quality, and protective measures of the electrical circuit of the lighting system and the lighting device are reasonable, and the Test the power usage. The second is the inspection during the trial operation phase of the system, that is, the inspection at the rehearsal and rehearsal phases of large-scale events. After all the lighting systems are put into use, the safety status of the system under long-term continuous operation is confirmed and the hidden danger of electrical fires is eliminated.
(3) Strengthen the electrical testing of the premises before large-scale events
The normal operation of electrical circuits, equipment, appliances, etc. in large-scale event venues will directly affect the fire safety of the venue. A little carelessness will easily lead to fire hazards such as electrical high temperature, line aging, open circuit, short circuit, overload, and equipment ignition. , Improper control will lead to serious fires. Therefore, strengthening electrical inspections before holding large-scale event venues can promptly discover electrical equipment, improper installation and use of wiring, and seize the operation of electrical wiring equipment, abnormal quality conditions, and power supply and distribution ratings. The voltage, current, and the matching of electrical equipment and appliances are used to eliminate fire hazards in time.