Example 1: The welder arbitrarily turns on the power of the welder and is shocked. (1) The accident passes through a welder in a factory to the temporary construction site. When the welder is wired, the rubber of each wire of the cable is removed. They are connected to the open-air power grid line. Because the wrong zero line is on the fire line, when he adjusts the welding current and touches the shell by hand, he is killed by electric shock.
(2) Analysis of the main reasons Because the welder is not familiar with the relevant electrical safety knowledge, the neutral wire and the fire wire are misconnected, resulting in the welding machine casing being charged, resulting in an electric shock death.
(3) Main preventive measures:
Welding equipment wiring must be carried out by an electrician, and the welder must not carry out it.
Example 2: When you want to change the welding rod, the hand touches the welding jaw and is shocked. (1) The accident passes through a shipyard. A young female electric welder is welding in the cabin. Because of the high temperature in the cabin and poor ventilation, the body sweats a lot of work clothes and leather gloves. Drenched. When the electrode was replaced, the electrode of the welding jaw was touched, and the electrode fell on the neck and failed to get rid of it, causing an electric shock. After the accident, the patient died after being rescued.
(2) Main reason analysis 1 The no-load voltage of the welding machine is higher than the safety voltage.
2 The temperature inside the cabin is high, the welder sweats a lot, the body resistance is reduced, and the risk of electric shock increases.
3 After the electric shock, it was not discovered in time. The duration of the current passing through the human body was longer, which caused serious damage to the vital organs such as the heart and lungs, and the rescue was ineffective.
(3) Main preventive measures 1 When welding in the cabin, ventilation means should be provided to convect the air.
2 Guardians should be set up when working in the cabin, pay attention to the welder's dynamics at any time, and when the danger signs are met, immediately pull the brakes for rescue.
Example 3: The terminal block is burned, and the outer casing of the welder is charged, causing an accident. (1) When a welder A and B of a factory spot weld the iron shell, it is found that the lead coil of the welder has been broken, and the electrician only finds a section of the soft wire. Replace it yourself. When B changed the line, I found that the wire terminal block bolts were loose, and the wrench was tightened (when A was not in the scene), and then the test was carried out a few times to leave the scene. After returning to A, I did not understand the situation and started spot welding. Just yelled and fell to the ground. Worker C immediately pulled the brakes but died because the rescue was not timely.
(2) Main reason analysis 1 The coil is in contact with the outer casing of the welder due to burning of the terminal block, thus causing a short circuit.
2 The welder housing is not grounded.
(3) Main preventive measures 1 Equipment maintenance should be carried out by an electrician.
2 Welding equipment should be protected from grounding.
Example 4: The welder is welded in the container, and the fire is replaced by oxygen. (1) The accident passes through the welding machine of a pesticide factory and enters the welding baffle in the breeding pot with a diameter of 1m and a height of 2m. The smoke exhausting device is not installed, and the flue gas in the pot is blown with oxygen. To make the smoke disappear. When the welder re-entered the welding operation in the pot, he only heard the "bang" sound. The welder burned 88% of the area, the third degree burned 60%, and died after 7 days of rescue.
(2) Analysis of the main reasons 1 The use of oxygen as a source of ventilation is a serious violation of regulations;
2 There is no ventilation device for welding into the container.
(3) Main preventive measures 1 Ventilation should be provided for welding into the container.
2 The ventilation source should be compressed air.
Example 5: The pressure reducer of the oxygen cylinder is burned and burned. (1) The accident passes through a welding torch of a construction team. When welding, the torch is leaked. The welder's palm is burned and foamed by the torch seedlings at the adjusting wheel. The oyster sauce also continues to weld. During the welding process, tempering occurs again. The oxygen hose is exploded. The pressure reducer is on fire and burned. When the oxygen cylinder valve is closed, the upper half of the oxygen cylinder is hot and very dangerous.
(2) Main reason analysis 1 The leaking torch is prone to tempering.
2 When adjusting the oxygen pressure, the oxygen cylinder valve and the pressure reducer are greased and tempered, causing intense combustion under the strong oxidation of compressed pure oxygen.
(3) Main preventive measures 1 Check whether the welding torch is good before gas welding, and find that the air leakage is strictly prohibited. Continue to apply welding after repair.
2 Do not use greased gloves to open the oxygen cylinder valve and pressure reducer.
Example 6: The fire site does not meet the requirements, and the fire is ignited. (1) The accident occurred after a shipyard welder Gu Mou applied for fire to the resident firefighters. The firefighters did not go to the scene to approve the fire. After Gu Mou cut the wire, the oil on the bottom of the ship splashed with sparks, igniting a raging fire. The presence of water and fire extinguishers failed to save, resulting in five deaths and one serious injury and three minor injuries.
(2) Analysis of the main reasons 1 Firefighters dereliction of duty, blind approval.
2 There is oil under the moving parts.
3 On-site personnel lack of knowledge about fire fighting.
(3) Main preventive measures 1 After the firefighter receives the application for the fire report, it is necessary to go deep into the site to check and confirm the safety before issuing the fire certificate.
2 To remove oil stains below the moving parts.
3 to strengthen the safety knowledge of employees.
Example 7: Unlicensed violations, brewing a catastrophic fire at the end of the century
(1) After the accident
Christmas night on the evening of December 25, 2000. Located in the old city of Luoyang, the Dongdu Commercial Building is in front of the building and is brightly lit. Taiwanese businessmen recently rented the first floor and the first floor of Dongdu Commercial Building to open the Luoyang branch of Zhengzhou Dennis Department Store. They plan to open their business on the 26th. They are busy and continue to renovate the store. A dance hall on the 4th floor of the top floor of the commercial building is being held. Christmas party.
However, just as everyone is immersed in the joy of Christmas, a few small electric welding sparks downstairs will be burned in the basement of the renovation. The fire and smoke will follow the stairs and push the top dance hall, which will become the extra large at the end of this century. The disaster took 309 people's lives.
(2) Analysis of the main reasons 1 The direct cause of the fire was that the four welders employed by Dennis did not receive safety technical training and carried out illegal operations without the operation permit of special operators.
2 No precautions were taken. The brutal construction caused the flaming slag to splash down and ignited the flammable items such as wooden furniture and sofas in the underground two-storey furniture store.
3 In the panic, the water dragon was watered down from the fire, and several people did not report to the scene. The timing of fire fighting and evacuation was delayed, causing 309 people to be poisoned and suffocated to death.
(3) Main preventive measures 1 Welders should be certified to work; pay attention to fire prevention during the welding process.
2 Proper protective measures should be taken at the welding site.
3 A full-time security officer should be set up to monitor the fire.
4 The flammable products should be kept away from the working site by 10 m. If it is not possible, a practical isolation method should be adopted.
5 There are a number of fire-fighting equipment, such as sand boxes and foam fire extinguishers.
6 Immediately after the accident, the police should call for time to minimize the fire damage.
7 to strengthen the employee's professional ethics education.
Example 8: Fire in the spray booth
When the welder welds a workpiece in the spray booth, the spark is splashed onto the wood board with a thick paint film nearby. The workers at the scene were all panicked, some took fire and some used compressed air to blow the fire, causing the fire to expand. After the fire brigade rescued for half an hour, the fire was extinguished. Although it did not hurt people, it caused a lot of property damage.
(2) Analysis of main reasons 1 Before the welding in the fire-extinguishing area, the fire-fighting operation was carried out without authorization, and the operation rules were violated.
2 Perform hot work without removing the paint film from the room and taking any fire prevention measures.
3 improper fire-fighting methods, wrongly blowing fire with compressed air, not only can not extinguish the fire, but promoted the fire, causing the consequences of the expansion of the accident.
(3) Main preventive measures 1 Do not allow open fire in the spray booth. If welding is required, a hot fire approval system should be implemented.
2 Remove all combustibles.
3 Sand, foam or carbon dioxide fire extinguishing equipment should be provided in the paint room.
Example 9: Desorption tank is used as the grounding pole of the welding machine to cause an accident. (1) The accident passes through the welder of a certain factory, and the newly installed desorption tank is used as the grounding pole (there are two tons of activated carbon in the tank). During the electric welding, the localized heating at the wire connection ignited the activated carbon in the tank, and as a result, more than two tons of activated carbon were burned out.
(2) Analysis of the main cause The ignition due to the resistance heat generated by the welding current and the local heating of the activated carbon generated by the spark generated during the arc ignition causes ignition.
(3) The main preventive measures are strictly prohibited to use metal materials as a conductor of the welding circuit.
Example 10: Misuse of oxygen instead of compressed air, causing an explosion (1) Accident After a welder in a hardware store repairs the compressor and condenser in the store, during the final air pressure test, the welder replaces it with oxygen because there is no compressed air. When the pressure is applied to 0.98 MPa, the compressor leaks, and the welder immediately fills the weld. At the moment of arc ignition, the compressor immediately exploded, the store was blown up, the welder was killed on the spot, and many people were injured.
(2) Analysis of the main reasons 1 The store hall cannot be used as a welding place.
2 All hole covers should be opened before welding, and must be repaired without pressure.
3 Oxygen is a combustion-supporting substance and cannot replace compressed air.
(3) Main preventive measures 1 The welding hall should not be used as a welding place. If it is urgently required to be welded, practical protective measures should be taken, that is, there are no flammable materials and corresponding fire-fighting equipment within 10m of the fire point.
2 Pressure relief should be applied during repair welding.
3 It is strictly forbidden to use oxygen instead of compressed air for test pressure.
Example 11: The loading and unloading work violates the regulations, causing the oxygen bottle to explode. (1) The accident is transported back to the newly filled oxygen by a unit. The loader is convenient for the figure. The oxygen bottle is taken from the car and the first gas bottle just falls. The second cylinder followed just above it, immediately causing the explosion of two cylinders, causing one death and one injury.
(2) The main reason is that the two cylinders collide with each other, and the compressed gas is violently vibrated when the oxygen cylinder collides, causing the pressure to rise, so that the pressure generated somewhere in the cylinder exceeds the strength limit of the bottle wall, which causes the cylinder to explode.
(3) Main preventive measures 1 When carrying the oxygen cylinder, avoid collision and severe vibration, and wear a safety helmet and a shock-proof ring.
2 Do not roll when loading or unloading oxygen.
Example 12: Welding repair acid tank explosion (1) Accidents After a unit of a tank of sulfuric acid, the bottom of the tank is leaking acid. When repairing the welding, the bottom of the tank is facing upwards, and the manhole is placed on the ground. When the welder starts to arc, the acid tank That is, an explosion occurred, the welder was burned on the spot, and one of the workers was killed.
(2) Analysis of main reasons After sampling analysis, the tank material is not acid-resistant steel. Under the action of dilute sulfuric acid, the iron and acid in the tank material can react as follows:
Fe + H2SO4=FeSO4 + H2↑
It can be seen from the above formula that the acid tank is filled with a mixed gas of hydrogen and air, and the content of hydrogen in the air exceeds the explosion limit range, so that it is apparent that the mixed gas in the electric spark ignition tank is exploded.
(3) Main preventive measures 1 Before welding the acid and alkali tanks, you must first understand the inside of the tank, then clean it with (ç¡·) water, and wait until the liquid or gas in it is drained, and the weldment is not sealed. .
2 Tanks containing dilute sulfuric acid, made of acid-resistant steel or lead-plated steel.
Example 13: Welding repair diesel engine explosion
(1) The accident passes through a diesel engine loaded in a car of a tractor factory. The oil pipe is damaged near the oil valve and needs to be repaired. After the operator put the diesel in the cabinet, it was not cleaned. Only the access hole cover was opened for welding repair, and immediately exploded, killing 3 people on the scene.
(2) Analysis of main reasons 1 After the diesel oil in the oil tank is discharged, there is still oil film remaining on the inner surface of the cabinet wall, and the oil and gas are volatilized into the cabinet, forming an explosive mixed gas with the incoming air, which is detonated by the high temperature of welding.
2 welders blindly weld, resulting in an accident.
(3) Main preventive measures 1 Diesel cabinets must be replaced before welding and meet the cleaning qualification standards before they can be repaired.
2 When welding, all the covers and valves of the oil tank should be opened and compressed air should be passed.
Example 14: Explosion of alcohol barrel leaking by weld repair (1) Accident After a leaking alcohol barrel was sent to the machine repair group by a pharmaceutical workshop of a factory, the welder was welded shortly, the alcohol barrel exploded, and the flying bucket lid cracked The head died on the spot.
(2) Main reason analysis Alcohol barrels are not cleaned before welding. Alcohol remains in the barrel. Alcohol is volatile and forms an explosive mixture with air in a closed container. It ignites and explodes during gas welding.
(3) Main preventive measures 1 Containers containing alcohol must be cleaned with water before welding and open with a lid for welding.
2 Before the welder, it is necessary to find out what kind of flammable and explosive materials and cleaning conditions have been installed in the container, and do not blindly match the fire.
Example 15: The welder caused the arc to cause the explosion of the cabin. (1) The accident was carried out by two oilers in a shipyard spraying the last paint in a closed cabin. When leaving the cabin, leave the manhole cover half-closed and leave. There are also no signs of danger around the hatch (if the cabin is painted, the fire cannot be close, etc.).
At about 3 pm, an armored riveter was installed on the small machine seat, and the working position was close to the cockpit. When the shovel found that there was no electronic squirt gun, the welder asked the welder to help him. The welder picked up the welding tongs and ignited the arc on the stern hatch, followed by a loud bang and the cockpit exploded. Eight people were killed and six were injured on the spot.
(2) Main reason analysis 1 The flammable gas of benzene in the paint mixed with air to reach the explosion limit. In addition, the weather is hot, which further exacerbates the flammable gas concentration of benzene, so it immediately explodes in case of fire.
After the 2 cabins were painted, no warning signs and guardians were provided.
3 No ventilation measures were taken in the cabin after painting.
(3) Main preventive measures 1 There should be warning signs and guardians around the cabin.
Compressed air should be passed in the 2 cabin to reduce the concentration of flammable gas.
3 When the welder starts the arc, pay attention to the surrounding environment (ie, flammable and explosive materials).
Example 16: Explosion of welding fill-in petrol barrels (1) Accidents After a cracked empty petrol tank of a factory car team needs to be repaired, the welder class proposed that no direct measures for welding are dangerous, but the car team said that the empty barrel: it is dry , no danger. As a result, no safety measures were taken; even if the fuel filler cap was not opened, the welding was performed. The situation at the scene was that a welder smashed on the ground and another worker held the petrol can. At the beginning of the welding, the gasoline barrel exploded, the ends of the barrels flew out, the barrel was blown into an iron plate, and the gas welder who was operating was killed.
(2) The main reason is that the explosion limit of motor gasoline is 0.89% to 5.16%, and the lower explosion limit is very low. Therefore, although the empty barrel is dry, as long as the micropores on the inner surface of the oil drum adsorb a small amount of residual oil, or the residual oil in the coil and even the gasoline vapor volatilized and diffused, it is easy to reach and exceed the lower explosion limit. The welding flame or arc will explode, and the open hole cover will not open, and the explosion will be more powerful.
(3) Main preventive measures 1 It is strictly forbidden to weld and cut fuel containers and pipes that have not been safely treated.
2 It is strictly forbidden to weld and seal the sealed container without opening holes.
3 Welding repair of fuel containers shall be subject to relevant safety organization measures as required.
Example 17: Gas-cutting petrol barrels and explosions (1) After a certain accident, a certain unit used a car to pull an empty barrel filled with gasoline. Without any formalities, directly find the gas welder, and ask to cut the empty oil drum from the middle. At that time, A required to be cleaned before cutting. The two soldiers pulled the barrel away.
After 1 hour, the two soldiers pulled the oil drum back again, and said to A: "Use 2 pounds of alkali and hot water to wash it twice, and wash it twice with water." A will make the oil barrel big and small. The hole covers are all open; placed on the ground, standing at the bottom of the barrel for cutting. Just after cutting through a small hole, the oil drum exploded. The bottom of the barrel was blasted, and the legs of A were broken into comminuted fractures. The bottom of the barrel flew nearly 5m, and the barrel moved nearly 1.5m.
(2) Analysis of main reasons 1 The cleaning of the petrol drum is not complete. There is still residual gasoline and its vapor in the barrel. The cutting flame ignites the gasoline in the barrel and explodes.
2 After the oil drum was cleaned, it was not analyzed by gas and blindly cut; it caused an accident.
(3) Main preventive measures 1 Before welding and cutting the fuel-filled container, it must be strictly cleaned, replaced, etc., and must be subjected to gas analysis and testing before it can be repaired or cut.
Example 18: Falling in the ascending operation (1) Accident After a certain winter, a certain university student who had just graduated from the school for less than half a year was internship in the workshop. He did not wear a standard fall protection seat belt and repaired the equipment at a height of 2 to 3 floors. As a result, accidentally, one foot fell from the sky, just below his working position is a hot pool, there is no protective measures on the pool, the college students plunged into the hot pool, hot water poured into his neck, the result was Hot water burns and burns (dead on the road in the hospital).
(2) Main reason analysis 1 No seat belts were worn at high altitudes.
2 There are no protective measures on the hot pool.
(3) Main preventive measures 1 Wear a standard fall protection seat belt.
2 Set a protective cover or iron mesh on the hot pool.
Example 19: Falling in high-altitude welding operation (1) After the accident, the deputy section chief of the unit's infrastructure department did not use the seat belt, and did not take other safety measures, then climbed the roof truss and replaced the welder's steel workshop roof frame angle steel and steel bar support. After working for 1 hour, the auxiliary worker C went down to take the angle steel. Because there was no assistant, A left hand supported the steel bars to be welded, and the right hand held the welding tongs and closed eyes.
A first fixes one end, then the left hand puts the steel rod that is only one end fixed to the other end. A just closed his eyes, the steel bars held by his left hand were not firmly fixed, and he could not support the weight of the human body. Suddenly, the nails fell off the 12.4m roof truss with the steel bars and died immediately.
(2) Analysis of the main reasons 1 The deputy section chief of the Infrastructure Department is not a professional welder.
2 There is no guardian at the time of the accident.
3 Ascending operators do not use seat belts and no other safety facilities.
(3) Main preventive measures 1 Non-professional welders cannot engage in welding and cutting operations.
2 Guardian should be set up for the ascending operation.
3 Ascending work must use standard fall protection belts and safety nets such as safety nets.
Example 20: When the depth of the slag pool is deep, it is burned by molten steel. (1) When a welder in a welding workshop of a factory stands at the depth of the slag pool on the side of the module, the molten steel of the molten pool suddenly flows out, and the left and right insteps are burned and hospitalized.
(2) Analysis of the main reasons 1 When the welder tests the depth of the slag pool, it is sloppy, and the illegal operation is the main cause of the accident.
2 Poor lighting on site is the direct cause of the accident.
3 The lack of regular safety education and safety inspections in the workshops and section leaders is also the main cause of accidents.
(3) Main preventive measures 1 Strengthen the safety education and operation technical training for employees.
2 Strengthen the inspection and rectification of hidden dangers and improve the working conditions of employees.
3 Implement a sound responsibility system to stop illegal operations and illegal command.
Example 21: Mechanical damage during resistance welding
(1) The accident was led by a worker in a tool workshop of a factory using a butt welder. When the master puts the weldment on the electrode clamp and finds the correct position, the oral commander approxes the tail of the workpiece. When the upper arm of the pneumatic clamp is depressed, the right index finger of the right hand that has not been extracted by the apprentice is squeezed between the tail of the workpiece and the horn, causing the end of the index finger to rupture and open fracture.
(2) Analysis of the main reasons 1 In the coordination work between the two people, the master did not remind the apprentices of the work when starting the electrode clamp, and did not get the appointee.
2 When the worker is working on the pad, the way of holding the horn is not correct. Do not use the finger to hold the horn up and down.
(3) Main preventive measures 1 The two people should cooperate closely, agree on the way of oral communication in advance, and then act on the equipment after receiving the signal.
2 Special tools should be made to hold the horn to prevent fingers from getting into the jaws.
3 Improve the process performance of the welder fixture so that it can deflect the angle and move in the up, down and horizontal directions.
4 Strengthen safety technology learning and improve safety production skills.
Example 22: Ion arc welding health hazard accident (1) Accident After two welders in a factory in a plasma welding operation, one welder suddenly had nosebleeds, and another welder was recently uncomfortable. After examination by doctors, it was found that the white blood cells in the blood of the two welders were greatly reduced, which was below the health standard.
It turns out that the two welders have been engaged in plasma welding for 6 months, the work site is narrow, and there is no smoking and vacuuming device. Two welders have long felt mental fatigue, chest tightness, cough, and headache. But I don't know the cause.
(2) Main reason analysis 1 Plasma arc welding process is accompanied by a large amount of vaporized metal vapor, ozone, nitrogen oxides, and the like. These fumes and dust have a serious impact on the respiratory tract, lungs, etc. of the operator.
The air in the above work place is not smooth, and the smoke suction device is not used to increase the concentration of harmful gases and smoke in the air. Workers have long been operating in this environment and suffered cumulative damage.
2 Workers lack understanding of the dangers and protection of this new process and do not use appropriate personal protective equipment.
(3) Main preventive measures 1 When adopting this process, the technical process department of the enterprise shall formulate technical measures for labor hygiene at the same time.
2 The safety and production departments of the enterprise shall arrange appropriate places for the implementation of this process, configure smoking and dust suction devices, reduce the concentration of harmful gases and soot, and make them meet the national labor health standards.
3 operators should pay attention to the use of personal protective equipment.
Example 23: The oxygen hose is washed off, and the plumber's eyeball is cracked and blinded. (1) The accident passes through a factory gas welder A and plumber B to carry out overhaul work on the upper and lower pipes. B. Open the oxygen valve on the pressure reducer, the oxygen suddenly impacts, and the oxygen hose connected to the air outlet of the pressure reducer is flushed, just hitting the left eye of B, and the eyeball is broken and blind.
(2) Main reason analysis The oxygen pressure in the bottle is high, and the opening valve is too large, so that the oxygen is violently impacted.
2 The connection between the oxygen hose and the pressure reducer is not tight.
3 Plumber B does not understand the safety operation knowledge of gas welding, open the valve too fierce, and stand in the direction of oxygen outlet, which is an illegal operation, resulting in an accident.
(3) Main preventive measures 1 Non-gas welders shall not operate gas welding equipment and tools.
2 Open the oxygen valve not too strong or too large; the operator should stand on the side of the gas outlet direction.
3 The oxygen hose on the air outlet of the pressure reducer should be tightly fastened.
(2) Analysis of the main reasons Because the welder is not familiar with the relevant electrical safety knowledge, the neutral wire and the fire wire are misconnected, resulting in the welding machine casing being charged, resulting in an electric shock death.
(3) Main preventive measures:
Welding equipment wiring must be carried out by an electrician, and the welder must not carry out it.
Example 2: When you want to change the welding rod, the hand touches the welding jaw and is shocked. (1) The accident passes through a shipyard. A young female electric welder is welding in the cabin. Because of the high temperature in the cabin and poor ventilation, the body sweats a lot of work clothes and leather gloves. Drenched. When the electrode was replaced, the electrode of the welding jaw was touched, and the electrode fell on the neck and failed to get rid of it, causing an electric shock. After the accident, the patient died after being rescued.
(2) Main reason analysis 1 The no-load voltage of the welding machine is higher than the safety voltage.
2 The temperature inside the cabin is high, the welder sweats a lot, the body resistance is reduced, and the risk of electric shock increases.
3 After the electric shock, it was not discovered in time. The duration of the current passing through the human body was longer, which caused serious damage to the vital organs such as the heart and lungs, and the rescue was ineffective.
(3) Main preventive measures 1 When welding in the cabin, ventilation means should be provided to convect the air.
2 Guardians should be set up when working in the cabin, pay attention to the welder's dynamics at any time, and when the danger signs are met, immediately pull the brakes for rescue.
Example 3: The terminal block is burned, and the outer casing of the welder is charged, causing an accident. (1) When a welder A and B of a factory spot weld the iron shell, it is found that the lead coil of the welder has been broken, and the electrician only finds a section of the soft wire. Replace it yourself. When B changed the line, I found that the wire terminal block bolts were loose, and the wrench was tightened (when A was not in the scene), and then the test was carried out a few times to leave the scene. After returning to A, I did not understand the situation and started spot welding. Just yelled and fell to the ground. Worker C immediately pulled the brakes but died because the rescue was not timely.
(2) Main reason analysis 1 The coil is in contact with the outer casing of the welder due to burning of the terminal block, thus causing a short circuit.
2 The welder housing is not grounded.
(3) Main preventive measures 1 Equipment maintenance should be carried out by an electrician.
2 Welding equipment should be protected from grounding.
Example 4: The welder is welded in the container, and the fire is replaced by oxygen. (1) The accident passes through the welding machine of a pesticide factory and enters the welding baffle in the breeding pot with a diameter of 1m and a height of 2m. The smoke exhausting device is not installed, and the flue gas in the pot is blown with oxygen. To make the smoke disappear. When the welder re-entered the welding operation in the pot, he only heard the "bang" sound. The welder burned 88% of the area, the third degree burned 60%, and died after 7 days of rescue.
(2) Analysis of the main reasons 1 The use of oxygen as a source of ventilation is a serious violation of regulations;
2 There is no ventilation device for welding into the container.
(3) Main preventive measures 1 Ventilation should be provided for welding into the container.
2 The ventilation source should be compressed air.
Example 5: The pressure reducer of the oxygen cylinder is burned and burned. (1) The accident passes through a welding torch of a construction team. When welding, the torch is leaked. The welder's palm is burned and foamed by the torch seedlings at the adjusting wheel. The oyster sauce also continues to weld. During the welding process, tempering occurs again. The oxygen hose is exploded. The pressure reducer is on fire and burned. When the oxygen cylinder valve is closed, the upper half of the oxygen cylinder is hot and very dangerous.
(2) Main reason analysis 1 The leaking torch is prone to tempering.
2 When adjusting the oxygen pressure, the oxygen cylinder valve and the pressure reducer are greased and tempered, causing intense combustion under the strong oxidation of compressed pure oxygen.
(3) Main preventive measures 1 Check whether the welding torch is good before gas welding, and find that the air leakage is strictly prohibited. Continue to apply welding after repair.
2 Do not use greased gloves to open the oxygen cylinder valve and pressure reducer.
Example 6: The fire site does not meet the requirements, and the fire is ignited. (1) The accident occurred after a shipyard welder Gu Mou applied for fire to the resident firefighters. The firefighters did not go to the scene to approve the fire. After Gu Mou cut the wire, the oil on the bottom of the ship splashed with sparks, igniting a raging fire. The presence of water and fire extinguishers failed to save, resulting in five deaths and one serious injury and three minor injuries.
(2) Analysis of the main reasons 1 Firefighters dereliction of duty, blind approval.
2 There is oil under the moving parts.
3 On-site personnel lack of knowledge about fire fighting.
(3) Main preventive measures 1 After the firefighter receives the application for the fire report, it is necessary to go deep into the site to check and confirm the safety before issuing the fire certificate.
2 To remove oil stains below the moving parts.
3 to strengthen the safety knowledge of employees.
Example 7: Unlicensed violations, brewing a catastrophic fire at the end of the century
(1) After the accident
Christmas night on the evening of December 25, 2000. Located in the old city of Luoyang, the Dongdu Commercial Building is in front of the building and is brightly lit. Taiwanese businessmen recently rented the first floor and the first floor of Dongdu Commercial Building to open the Luoyang branch of Zhengzhou Dennis Department Store. They plan to open their business on the 26th. They are busy and continue to renovate the store. A dance hall on the 4th floor of the top floor of the commercial building is being held. Christmas party.
However, just as everyone is immersed in the joy of Christmas, a few small electric welding sparks downstairs will be burned in the basement of the renovation. The fire and smoke will follow the stairs and push the top dance hall, which will become the extra large at the end of this century. The disaster took 309 people's lives.
(2) Analysis of the main reasons 1 The direct cause of the fire was that the four welders employed by Dennis did not receive safety technical training and carried out illegal operations without the operation permit of special operators.
2 No precautions were taken. The brutal construction caused the flaming slag to splash down and ignited the flammable items such as wooden furniture and sofas in the underground two-storey furniture store.
3 In the panic, the water dragon was watered down from the fire, and several people did not report to the scene. The timing of fire fighting and evacuation was delayed, causing 309 people to be poisoned and suffocated to death.
(3) Main preventive measures 1 Welders should be certified to work; pay attention to fire prevention during the welding process.
2 Proper protective measures should be taken at the welding site.
3 A full-time security officer should be set up to monitor the fire.
4 The flammable products should be kept away from the working site by 10 m. If it is not possible, a practical isolation method should be adopted.
5 There are a number of fire-fighting equipment, such as sand boxes and foam fire extinguishers.
6 Immediately after the accident, the police should call for time to minimize the fire damage.
7 to strengthen the employee's professional ethics education.
Example 8: Fire in the spray booth
When the welder welds a workpiece in the spray booth, the spark is splashed onto the wood board with a thick paint film nearby. The workers at the scene were all panicked, some took fire and some used compressed air to blow the fire, causing the fire to expand. After the fire brigade rescued for half an hour, the fire was extinguished. Although it did not hurt people, it caused a lot of property damage.
(2) Analysis of main reasons 1 Before the welding in the fire-extinguishing area, the fire-fighting operation was carried out without authorization, and the operation rules were violated.
2 Perform hot work without removing the paint film from the room and taking any fire prevention measures.
3 improper fire-fighting methods, wrongly blowing fire with compressed air, not only can not extinguish the fire, but promoted the fire, causing the consequences of the expansion of the accident.
(3) Main preventive measures 1 Do not allow open fire in the spray booth. If welding is required, a hot fire approval system should be implemented.
2 Remove all combustibles.
3 Sand, foam or carbon dioxide fire extinguishing equipment should be provided in the paint room.
Example 9: Desorption tank is used as the grounding pole of the welding machine to cause an accident. (1) The accident passes through the welder of a certain factory, and the newly installed desorption tank is used as the grounding pole (there are two tons of activated carbon in the tank). During the electric welding, the localized heating at the wire connection ignited the activated carbon in the tank, and as a result, more than two tons of activated carbon were burned out.
(2) Analysis of the main cause The ignition due to the resistance heat generated by the welding current and the local heating of the activated carbon generated by the spark generated during the arc ignition causes ignition.
(3) The main preventive measures are strictly prohibited to use metal materials as a conductor of the welding circuit.
Example 10: Misuse of oxygen instead of compressed air, causing an explosion (1) Accident After a welder in a hardware store repairs the compressor and condenser in the store, during the final air pressure test, the welder replaces it with oxygen because there is no compressed air. When the pressure is applied to 0.98 MPa, the compressor leaks, and the welder immediately fills the weld. At the moment of arc ignition, the compressor immediately exploded, the store was blown up, the welder was killed on the spot, and many people were injured.
(2) Analysis of the main reasons 1 The store hall cannot be used as a welding place.
2 All hole covers should be opened before welding, and must be repaired without pressure.
3 Oxygen is a combustion-supporting substance and cannot replace compressed air.
(3) Main preventive measures 1 The welding hall should not be used as a welding place. If it is urgently required to be welded, practical protective measures should be taken, that is, there are no flammable materials and corresponding fire-fighting equipment within 10m of the fire point.
2 Pressure relief should be applied during repair welding.
3 It is strictly forbidden to use oxygen instead of compressed air for test pressure.
Example 11: The loading and unloading work violates the regulations, causing the oxygen bottle to explode. (1) The accident is transported back to the newly filled oxygen by a unit. The loader is convenient for the figure. The oxygen bottle is taken from the car and the first gas bottle just falls. The second cylinder followed just above it, immediately causing the explosion of two cylinders, causing one death and one injury.
(2) The main reason is that the two cylinders collide with each other, and the compressed gas is violently vibrated when the oxygen cylinder collides, causing the pressure to rise, so that the pressure generated somewhere in the cylinder exceeds the strength limit of the bottle wall, which causes the cylinder to explode.
(3) Main preventive measures 1 When carrying the oxygen cylinder, avoid collision and severe vibration, and wear a safety helmet and a shock-proof ring.
2 Do not roll when loading or unloading oxygen.
Example 12: Welding repair acid tank explosion (1) Accidents After a unit of a tank of sulfuric acid, the bottom of the tank is leaking acid. When repairing the welding, the bottom of the tank is facing upwards, and the manhole is placed on the ground. When the welder starts to arc, the acid tank That is, an explosion occurred, the welder was burned on the spot, and one of the workers was killed.
(2) Analysis of main reasons After sampling analysis, the tank material is not acid-resistant steel. Under the action of dilute sulfuric acid, the iron and acid in the tank material can react as follows:
Fe + H2SO4=FeSO4 + H2↑
It can be seen from the above formula that the acid tank is filled with a mixed gas of hydrogen and air, and the content of hydrogen in the air exceeds the explosion limit range, so that it is apparent that the mixed gas in the electric spark ignition tank is exploded.
(3) Main preventive measures 1 Before welding the acid and alkali tanks, you must first understand the inside of the tank, then clean it with (ç¡·) water, and wait until the liquid or gas in it is drained, and the weldment is not sealed. .
2 Tanks containing dilute sulfuric acid, made of acid-resistant steel or lead-plated steel.
Example 13: Welding repair diesel engine explosion
(1) The accident passes through a diesel engine loaded in a car of a tractor factory. The oil pipe is damaged near the oil valve and needs to be repaired. After the operator put the diesel in the cabinet, it was not cleaned. Only the access hole cover was opened for welding repair, and immediately exploded, killing 3 people on the scene.
(2) Analysis of main reasons 1 After the diesel oil in the oil tank is discharged, there is still oil film remaining on the inner surface of the cabinet wall, and the oil and gas are volatilized into the cabinet, forming an explosive mixed gas with the incoming air, which is detonated by the high temperature of welding.
2 welders blindly weld, resulting in an accident.
(3) Main preventive measures 1 Diesel cabinets must be replaced before welding and meet the cleaning qualification standards before they can be repaired.
2 When welding, all the covers and valves of the oil tank should be opened and compressed air should be passed.
Example 14: Explosion of alcohol barrel leaking by weld repair (1) Accident After a leaking alcohol barrel was sent to the machine repair group by a pharmaceutical workshop of a factory, the welder was welded shortly, the alcohol barrel exploded, and the flying bucket lid cracked The head died on the spot.
(2) Main reason analysis Alcohol barrels are not cleaned before welding. Alcohol remains in the barrel. Alcohol is volatile and forms an explosive mixture with air in a closed container. It ignites and explodes during gas welding.
(3) Main preventive measures 1 Containers containing alcohol must be cleaned with water before welding and open with a lid for welding.
2 Before the welder, it is necessary to find out what kind of flammable and explosive materials and cleaning conditions have been installed in the container, and do not blindly match the fire.
Example 15: The welder caused the arc to cause the explosion of the cabin. (1) The accident was carried out by two oilers in a shipyard spraying the last paint in a closed cabin. When leaving the cabin, leave the manhole cover half-closed and leave. There are also no signs of danger around the hatch (if the cabin is painted, the fire cannot be close, etc.).
At about 3 pm, an armored riveter was installed on the small machine seat, and the working position was close to the cockpit. When the shovel found that there was no electronic squirt gun, the welder asked the welder to help him. The welder picked up the welding tongs and ignited the arc on the stern hatch, followed by a loud bang and the cockpit exploded. Eight people were killed and six were injured on the spot.
(2) Main reason analysis 1 The flammable gas of benzene in the paint mixed with air to reach the explosion limit. In addition, the weather is hot, which further exacerbates the flammable gas concentration of benzene, so it immediately explodes in case of fire.
After the 2 cabins were painted, no warning signs and guardians were provided.
3 No ventilation measures were taken in the cabin after painting.
(3) Main preventive measures 1 There should be warning signs and guardians around the cabin.
Compressed air should be passed in the 2 cabin to reduce the concentration of flammable gas.
3 When the welder starts the arc, pay attention to the surrounding environment (ie, flammable and explosive materials).
Example 16: Explosion of welding fill-in petrol barrels (1) Accidents After a cracked empty petrol tank of a factory car team needs to be repaired, the welder class proposed that no direct measures for welding are dangerous, but the car team said that the empty barrel: it is dry , no danger. As a result, no safety measures were taken; even if the fuel filler cap was not opened, the welding was performed. The situation at the scene was that a welder smashed on the ground and another worker held the petrol can. At the beginning of the welding, the gasoline barrel exploded, the ends of the barrels flew out, the barrel was blown into an iron plate, and the gas welder who was operating was killed.
(2) The main reason is that the explosion limit of motor gasoline is 0.89% to 5.16%, and the lower explosion limit is very low. Therefore, although the empty barrel is dry, as long as the micropores on the inner surface of the oil drum adsorb a small amount of residual oil, or the residual oil in the coil and even the gasoline vapor volatilized and diffused, it is easy to reach and exceed the lower explosion limit. The welding flame or arc will explode, and the open hole cover will not open, and the explosion will be more powerful.
(3) Main preventive measures 1 It is strictly forbidden to weld and cut fuel containers and pipes that have not been safely treated.
2 It is strictly forbidden to weld and seal the sealed container without opening holes.
3 Welding repair of fuel containers shall be subject to relevant safety organization measures as required.
Example 17: Gas-cutting petrol barrels and explosions (1) After a certain accident, a certain unit used a car to pull an empty barrel filled with gasoline. Without any formalities, directly find the gas welder, and ask to cut the empty oil drum from the middle. At that time, A required to be cleaned before cutting. The two soldiers pulled the barrel away.
After 1 hour, the two soldiers pulled the oil drum back again, and said to A: "Use 2 pounds of alkali and hot water to wash it twice, and wash it twice with water." A will make the oil barrel big and small. The hole covers are all open; placed on the ground, standing at the bottom of the barrel for cutting. Just after cutting through a small hole, the oil drum exploded. The bottom of the barrel was blasted, and the legs of A were broken into comminuted fractures. The bottom of the barrel flew nearly 5m, and the barrel moved nearly 1.5m.
(2) Analysis of main reasons 1 The cleaning of the petrol drum is not complete. There is still residual gasoline and its vapor in the barrel. The cutting flame ignites the gasoline in the barrel and explodes.
2 After the oil drum was cleaned, it was not analyzed by gas and blindly cut; it caused an accident.
(3) Main preventive measures 1 Before welding and cutting the fuel-filled container, it must be strictly cleaned, replaced, etc., and must be subjected to gas analysis and testing before it can be repaired or cut.
2 Repair welding or cutting empty oil drums should open the hole cover, place the oil drum on the ground, the operator should stand on the side of the barrel, avoid the oil drum cover operation, in case of explosion, the oil drum end cover ( Here the intensity is weak) blasts and hurts people.
Example 18: Falling in the ascending operation (1) Accident After a certain winter, a certain university student who had just graduated from the school for less than half a year was internship in the workshop. He did not wear a standard fall protection seat belt and repaired the equipment at a height of 2 to 3 floors. As a result, accidentally, one foot fell from the sky, just below his working position is a hot pool, there is no protective measures on the pool, the college students plunged into the hot pool, hot water poured into his neck, the result was Hot water burns and burns (dead on the road in the hospital).
(2) Main reason analysis 1 No seat belts were worn at high altitudes.
2 There are no protective measures on the hot pool.
(3) Main preventive measures 1 Wear a standard fall protection seat belt.
2 Set a protective cover or iron mesh on the hot pool.
Example 19: Falling in high-altitude welding operation (1) After the accident, the deputy section chief of the unit's infrastructure department did not use the seat belt, and did not take other safety measures, then climbed the roof truss and replaced the welder's steel workshop roof frame angle steel and steel bar support. After working for 1 hour, the auxiliary worker C went down to take the angle steel. Because there was no assistant, A left hand supported the steel bars to be welded, and the right hand held the welding tongs and closed eyes.
A first fixes one end, then the left hand puts the steel rod that is only one end fixed to the other end. A just closed his eyes, the steel bars held by his left hand were not firmly fixed, and he could not support the weight of the human body. Suddenly, the nails fell off the 12.4m roof truss with the steel bars and died immediately.
(2) Analysis of the main reasons 1 The deputy section chief of the Infrastructure Department is not a professional welder.
2 There is no guardian at the time of the accident.
3 Ascending operators do not use seat belts and no other safety facilities.
(3) Main preventive measures 1 Non-professional welders cannot engage in welding and cutting operations.
2 Guardian should be set up for the ascending operation.
3 Ascending work must use standard fall protection belts and safety nets such as safety nets.
Example 20: When the depth of the slag pool is deep, it is burned by molten steel. (1) When a welder in a welding workshop of a factory stands at the depth of the slag pool on the side of the module, the molten steel of the molten pool suddenly flows out, and the left and right insteps are burned and hospitalized.
(2) Analysis of the main reasons 1 When the welder tests the depth of the slag pool, it is sloppy, and the illegal operation is the main cause of the accident.
2 Poor lighting on site is the direct cause of the accident.
3 The lack of regular safety education and safety inspections in the workshops and section leaders is also the main cause of accidents.
(3) Main preventive measures 1 Strengthen the safety education and operation technical training for employees.
2 Strengthen the inspection and rectification of hidden dangers and improve the working conditions of employees.
3 Implement a sound responsibility system to stop illegal operations and illegal command.
Example 21: Mechanical damage during resistance welding
(1) The accident was led by a worker in a tool workshop of a factory using a butt welder. When the master puts the weldment on the electrode clamp and finds the correct position, the oral commander approxes the tail of the workpiece. When the upper arm of the pneumatic clamp is depressed, the right index finger of the right hand that has not been extracted by the apprentice is squeezed between the tail of the workpiece and the horn, causing the end of the index finger to rupture and open fracture.
(2) Analysis of the main reasons 1 In the coordination work between the two people, the master did not remind the apprentices of the work when starting the electrode clamp, and did not get the appointee.
2 When the worker is working on the pad, the way of holding the horn is not correct. Do not use the finger to hold the horn up and down.
(3) Main preventive measures 1 The two people should cooperate closely, agree on the way of oral communication in advance, and then act on the equipment after receiving the signal.
2 Special tools should be made to hold the horn to prevent fingers from getting into the jaws.
3 Improve the process performance of the welder fixture so that it can deflect the angle and move in the up, down and horizontal directions.
4 Strengthen safety technology learning and improve safety production skills.
Example 22: Ion arc welding health hazard accident (1) Accident After two welders in a factory in a plasma welding operation, one welder suddenly had nosebleeds, and another welder was recently uncomfortable. After examination by doctors, it was found that the white blood cells in the blood of the two welders were greatly reduced, which was below the health standard.
It turns out that the two welders have been engaged in plasma welding for 6 months, the work site is narrow, and there is no smoking and vacuuming device. Two welders have long felt mental fatigue, chest tightness, cough, and headache. But I don't know the cause.
(2) Main reason analysis 1 Plasma arc welding process is accompanied by a large amount of vaporized metal vapor, ozone, nitrogen oxides, and the like. These fumes and dust have a serious impact on the respiratory tract, lungs, etc. of the operator.
The air in the above work place is not smooth, and the smoke suction device is not used to increase the concentration of harmful gases and smoke in the air. Workers have long been operating in this environment and suffered cumulative damage.
2 Workers lack understanding of the dangers and protection of this new process and do not use appropriate personal protective equipment.
(3) Main preventive measures 1 When adopting this process, the technical process department of the enterprise shall formulate technical measures for labor hygiene at the same time.
2 The safety and production departments of the enterprise shall arrange appropriate places for the implementation of this process, configure smoking and dust suction devices, reduce the concentration of harmful gases and soot, and make them meet the national labor health standards.
3 operators should pay attention to the use of personal protective equipment.
Example 23: The oxygen hose is washed off, and the plumber's eyeball is cracked and blinded. (1) The accident passes through a factory gas welder A and plumber B to carry out overhaul work on the upper and lower pipes. B. Open the oxygen valve on the pressure reducer, the oxygen suddenly impacts, and the oxygen hose connected to the air outlet of the pressure reducer is flushed, just hitting the left eye of B, and the eyeball is broken and blind.
(2) Main reason analysis The oxygen pressure in the bottle is high, and the opening valve is too large, so that the oxygen is violently impacted.
2 The connection between the oxygen hose and the pressure reducer is not tight.
3 Plumber B does not understand the safety operation knowledge of gas welding, open the valve too fierce, and stand in the direction of oxygen outlet, which is an illegal operation, resulting in an accident.
(3) Main preventive measures 1 Non-gas welders shall not operate gas welding equipment and tools.
2 Open the oxygen valve not too strong or too large; the operator should stand on the side of the gas outlet direction.
3 The oxygen hose on the air outlet of the pressure reducer should be tightly fastened.
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