There are more than 650 fires caused by electric welding and cutting in winter! These safety measures should be taken well

Did you know that electric welding and cutting pose a fire hazard?

The reporter analyzed and sorted out the fire data of the past five years and found that on average, there are 658 fires caused by electric welding and cutting every winter, most of which are caused by igniting combustibles stored at or near the welding and cutting sites. At about 10:00 on June 10, 2021, a fire broke out at a construction site in Pubei County, Qinzhou, Guangxi. Firefighters rushed to the scene to put out the fire. Fortunately, no casualties were caused.

The reporter retrieved the video from a public place. At 10:12, there was a small black dot on the foam board under the scaffolding. In just 6 seconds, the small black dot became the size of an egg, accompanied by open flames, and soon formed a burning area the size of a palm.

The fire grew bigger and bigger. After 40 seconds, the fire quickly spread to half of the foam board, producing a lot of black smoke. At 10:01:17, the fire engulfed the entire foam board and quickly spread to the surrounding area. At 10:02:02, the entire foam board stack was ignited, and the fire was in a fierce burning state. At this time, someone discovered the fire. Faced with the raging fire, they did not take any fire-fighting measures, but just let the fire burn wantonly. Afterwards, the fire department investigated and found that the cause of the fire was that when the welder was welding on the roof, the welding slag fell and ignited the foam board stack downstairs.

Fires caused by electric welding slag are not uncommon.

At about 7:00 on April 1, 2021, a fire at a fiber products factory in Jinhua, Zhejiang was also caused by welding slag. From the video in public places, we can see that a man was doing welding. At 7:22:58, the man seemed to realize something, and then stopped welding and turned to pick up a bucket to pour water under the welding operation. However, when he bent down and looked down, he found that the fire was beyond his imagination, so he quickly ran out and pushed the fire extinguisher. At 7:23:28, in just 30 seconds, the fire spread rapidly and burned fiercely. The man who was still fiddling with the fire extinguisher nozzle was called away by the woman who escaped from the fire. Obviously, he did not know how to operate the fire extinguisher.

Just as they left the fire scene, a large amount of dripping matter produced by the combustion fell from the upper floors. The high temperature generated by the combustion melted the woven bags 3 meters away. Subsequently, the large amount of dripping matter ignited the woven bags, causing large-scale combustion, and eventually the fire engulfed the entire factory building.

In addition, sparks from cutting machines can easily cause fires. At 16:00 on April 24, 2021, a fire broke out in a plastic waste pile at a scrap car recycling and dismantling station in Songyuan, Jilin. The cause of the fire was that workers used plasma cutting machines to cut scrap cars, which caused sparks to ignite nearby combustibles. The plastic waste pile and scrapped vehicles were burned, and the fire area was about 200 square meters.

Fires caused by cutting have also occurred in Pujiang County, Jinhua, Zhejiang. On January 11, 2020, a fire broke out in a leather goods factory in Pujiang County, Jinhua, Zhejiang. From the video in public places, we can see that at 11:03:17 in the morning, workers began cutting operations, and a large number of sparks from cutting poured down. In just 36 seconds, the polyurethane foam board downstairs was ignited. After the workers downstairs found out, they quickly rushed to the fire point to deal with it. However, the fire soon formed a fierce burning situation. Although the workers came to get buckets of water and fire extinguishers to put out the fire, they could not stop the fire from spreading and expanding, eventually causing about 3,200 square meters of the factory to catch fire.

It is common that combustible materials are not cleaned up at welding and cutting work sites

If the welding slag and sparks from cutting operations come into contact with combustibles, they will cause fires in a very short time. So, what safety precautions should be taken before welding and cutting operations at construction sites and interior decoration sites?

When the reporter accompanied the fire supervisors to inspect Nankai and Binhai in Tianjin, he found that many workers at the construction sites did not clean up the flammable materials around or below the work points when performing welding operations. At some construction sites, there were no personnel on site to supervise the welding operations.

During an inspection, fire supervisors discovered that several fire extinguishers at a construction site had become inoperable.

Sun Jinhao, fire supervisor of Tianjin Nankai District Fire Rescue Brigade: The pressure is now in the red zone, which means it is under pressure. The fire extinguisher needs to be replaced in time. The pressure pointer of the fire extinguisher must point to the green zone to be used normally.

Fire supervisors reminded that before welding, it is necessary to clear the combustibles around or below, equip with appropriate fire-fighting equipment, and assign special personnel to supervise. Fire supervisors require the person in charge of the construction site to promptly rectify the fire safety hazards found, and to carry out open flame operations such as welding and cutting in accordance with regulations.

Fire safety test: welding bead temperature reaches up to 1372℃

How high is the temperature of the molten beads produced by our common electric welding operations? Can it really ignite cardboard boxes and foam boards?

The reporter conducted a small experiment with these questions at the Tianjin Fire Research Institute of the Ministry of Emergency Management.

In order to measure the temperature of the molten beads generated by electric welding operations, the test personnel took safety precautions and placed the temperature sensing probe of the temperature measuring instrument at the point where the molten beads were splashing at the welding operation point. The temperature of the large amount of molten beads pouring down rose exponentially from 16°C and soon exceeded 1000°C. The highest temperature reached 1372°C, which was much higher than the ignition point of cartons, polyurethane foam boards and various items.

Afterwards, the experimenters placed the polyurethane foam board under the welding operation point, and the welder operated the welding machine to start welding. A large amount of welding molten beads fell on the polyurethane foam board. In less than 2 minutes, a flame appeared on the polyurethane foam board. After the welder stopped welding, the board continued to burn and produced a large amount of black smoke, and soon burned out.

Then, the test personnel took a cardboard box and placed it under the welding operation point. After the welding operation started, a large amount of high-temperature electric welding beads poured directly on the cardboard box, just like a fire point directly igniting the cardboard box. In less than 3 minutes of the test, the cardboard box was ignited and soon formed a fierce combustion state. The test proved that the temperature of the molten beads produced by the welding operation was extremely high and it was very easy to ignite the surrounding combustibles.

Editor-in-charge: Zhao Yuqi

Source: CCTV News Client