What measures should be taken to prevent ignition of combustible gas leakage sources in the event of a fire in the system pipe gallery?
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Accidents similar to the following system pipe gallery fires have been encountered more than once: At 14:3 pm on April 7, 2008, a flash explosion occurred during the replacement of the steam pipe network drain valve in the oil product workshop system pipe gallery of a branch of Sinopec, causing a fire. Four construction workers of the contractor were severely burned, more than 10 meters of pipe racks were damaged, and 10 pipelines burst. The direct cause of the accident was a flash explosion and fire caused by leakage of flammable gas when construction workers were using gas welding and cutting. Some pipes burst during the fire and combustible materials leaked, causing the fire to expand. Because the modified or newly added pipelines are close to the transportation pipelines, the pipeline corridors are arranged in layers, and many process devices are involved, leakage point inspections are generally only required by the contractor, and are basically not carried out effectively. Because construction sites are generally located high in pipe corridors, combustible gas detection lacks credibility and is difficult to implement, and is generally blank. In this case, fire and explosion are inevitable results when encountering a leak point. Ask for advice: Who should conduct the inspection of leak points? (Pipelines are managed by different units) Is it necessary to conduct combustible gas testing on the pipe gallery system? What fire safety measures should be taken?
Let me first answer part of it based on my experience. The inspection of leak points on the pipe gallery can be done by the operator.； If you have a unified management department for the pipe gallery, you can also ask them to do it! In short, gas detection must be done!
From your description, it sounds like the unit is too hot. . . . I can't stand it anymore! ! If there is a fire in the system pipe gallery, it must also pass the explosion test before starting the fire. It is also necessary to check whether there are leaks in the surrounding area and handle it as high-altitude operations. But I have a question: To cause such a large-scale explosion, it is definitely not just a slight leak in the system pipeline, but also such a large leak. The construction and monitoring personnel should have discovered it long ago, so it is impossible for this situation to be the final analysis result.: When the construction workers were cutting the pipeline, they cut the wrong pipeline! ! Moreover, the pipeline was still transporting materials, which eventually caused a large-scale fire and explosion. ! I don’t know if my analysis is correct, so when constructing old pipelines, technicians must confirm on site! !
The inspection of leakage points should be carried out by the fire party. It is necessary to conduct combustible gas detection in the pipe gallery system. The detection must be carried out before the fire occurs, and the time cannot exceed 30 minutes. For other fire safety measures, please refer to "HG23011-1999 Safety Regulations for Fire Operations in Factory Areas" and "SY/T5858-2004 Safety Regulations for Fire Operations in the Petroleum Industry"
(1) What can be removed must be removed, such as using a crane or something. Clean, replace, and inspect the pipelines before moving them to a fixed fire area before starting a fire. (2) If it really cannot be dismantled, the pipe rack system must be tested for combustible gas. Many combustible gases cannot be seen, touched, or smelled. How can we know that there is combustible gas around us without measuring with instruments? For safety reasons, clean up the surrounding combustibles, equip with a sufficient amount of fire extinguishing equipment, suspend the transportation of various pipes on the pipe gallery, and add blind plates at both ends of the pipes (because you cannot ensure that the pipes suddenly perforate and leak when there is a fire, and the probability of leakage during transportation will be much greater). In addition, we should also consider from a process perspective whether there is the possibility of pipelines crossing each other. Even water pipes may have the possibility of combustible gas.
I agree with the comment above. If there is a fire, the pipeline should be steam cleaned or washed with water first, and blind plates should be added at both ends of the pipeline! Atmospheric gas detection must be done, and measures must be taken to prevent sparks from flying at high altitudes. Necessary manholes, floor drains, and trenches must be covered around the fire point!
I think the investigation of leakage points should be carried out by the relevant departments of the company, because only the people in the company are most familiar with the specific conditions of the work site and pipelines, so that the leakage points can be clearly identified. If the construction unit is asked to conduct an inspection, they have no understanding of the on-site conditions and how to ensure that the inspection results are correct. In addition, explosion testing must be done before hot work to ensure fire safety. As for fire safety measures, first of all, the pipelines that need to be ignited must be purged clean, and then blind plates must be added at both ends to cut off contact with the outside world to prevent oil and gas from flowing into each other and causing fire and explosion. Secondly, relevant personnel must confirm the hot pipeline, otherwise cutting the wrong pipeline in operation will inevitably cause an accident. Thirdly, it is necessary to clean up flammable materials on site and block nearby manholes, open ditches, etc. to prevent sparks from splashing and causing fires and explosions. In addition, it is necessary to protect other pipelines in the pipe gallery to prevent accidents from cutting off other running pipelines due to improper operations during the fire process.
There are dedicated personnel to investigate leakage in the process pipe network, and make preparations before starting a fire. Fire work must strictly comply with* * , companies, industries and other related professional requirements. As for fire safety measures, first of all, the pipelines that need to be ignited must be purged clean, and then blind plates must be added at both ends to cut off contact with the outside world to prevent oil and gas from flowing into each other and causing fire and explosion. Secondly, relevant personnel must confirm the hot pipeline, otherwise cutting the wrong pipeline in operation will inevitably cause an accident. Thirdly, it is necessary to clean up flammable materials on site and block nearby manholes, open ditches, etc. to prevent sparks from splashing and causing fires and explosions. In addition, it is necessary to protect other pipelines in the pipe gallery to prevent accidents from cutting off other running pipelines due to improper operations during the fire process. 1) What can be removed must be removed, such as using a crane or something. Clean, replace, and inspect the pipelines before moving them to a fixed fire area before starting a fire. (2) If it really cannot be dismantled, the pipe rack system must be tested for combustible gas. For other fire safety measures, please refer to "HG23011-1999 Safety Regulations for Fire Operations in Factory Areas" and "SY/T5858-2004 Safety Regulations for Fire Operations in the Petroleum Industry"
Later I learned a little about the accident analysis: There is a light oil flange leakage in another layer of pipe rack below the working layer. Because it is far away from the working point and may be affected by the wind direction during sampling, it cannot be analyzed. As the wind direction changes during the operation, the oil and gas spread to the ignition point, causing a flash explosion.
Generally speaking, if the company's internal pipe gallery is managed internally by the company, and the public pipe gallery belongs to a third party, we only rent the pipe gallery. In theory, the management is mainly based on third-party management, supplemented by user management.； We are like this: Daily inspections are the responsibility of the management party, and unscheduled inspections are the responsibility of the user. ； If it involves hot lifting operations in the pipe gallery, we need to declare to the management party to apply for a work ticket, and they will cooperate with other users. Relevant operations can only be carried out after approval. And during the entire operation process, the management party needs to manage the site.