Hot work on chemical pipeline supports
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I am a new safety officer at the factory. There are two pipes laid side by side on our company’s pipe rack: one for methanol and one for toluene. The methanol pipe needs to be rewelded (it has already been cleaned), while the toluene pipe adjacent to it cannot be cleaned. Is it possible to perform welding work there? Or what measures should be taken? Will the welding current affect uncleaned toluene pipes? Thank you
Strictly speaking, welding is permissible, but the following safety measures must be taken: 1. The methanol pipelines must be thoroughly cleaned (through internal inspections). 2. If there are flanges at both ends of the area where welding will take place on the methanol pipelines, they must be removed to allow for ventilation； 3. The methanol pipeline must be effectively disconnected from the production system or storage system. 4. Grounding must be provided on the methanol pipeline, and it should be done as close to the pipeline as possible. 5. The junction between the toluene pipeline and the methanol pipeline must be effectively isolated; asbestos gaskets can be used to cover the toluene pipeline. 5. Strengthen the monitoring of leaks in toluene pipelines to ensure there are no issues. Additionally, all solvent pipes in our company have been bonded and grounded.
With the methanol pipeline fully cleaned and purged, it is crucial that the welding wire not touch the toluene transport pipeline, and it must be ensured that there are no leaks in the toluene pipeline! Argon welding can be used for welding!
Reply to 3# changhw: Thank you, expert. I still have a question – when welding on a methanol pipeline, what distance is required from the welding point to ensure that no current will form a circuit in the toluene pipeline, so as to prevent any current or sparks from appearing in that pipeline? Sparks may form inside the toluene pipeline, as it cannot be guaranteed that the pipeline is completely filled! ）
Reply to 2# SJC1860: Thank you, expert. I still have a question – when welding on a methanol pipeline, what distance is required from the welding point to ensure that no current will form a circuit in the toluene pipeline, so as to prevent any current or sparks from appearing in that pipeline? Sparks may form inside the toluene pipeline, as it cannot be guaranteed that the pipeline is completely filled; there is definitely a small amount of air inside it! ）
1. The temporary wiring is made of well-insulated rubber wire, installed suspended or along the wall. During installation, the height above the ground indoors must be no less than 2.5 m, and outdoors it must be no less than 3.5 m. The distance between temporary wires and equipment, water pipes, hot water pipes, doors, and windows should be at least 0.3 m; at intersections with roads, this distance should be no less than 6 m. 2. The angle between the utility pole and the guy wire should be no less than 45°; in cases where environmental constraints apply, it should be no less than 30° ； 3. Grounding protection should be employed in three-phase three-wire supply systems whose neutral point is not directly grounded ； 4. In a three-phase four-wire power supply system with a grounded neutral point, neutral grounding protection should be employed; the transformer’s neutral point shall be grounded for operation, and repeated grounding should be provided every kilometer along the overhead branch lines and main lines as well as at the endpoints ； 5. Work is strictly prohibited in case of strong winds, heavy rain, lightning, or other similar conditions of level 6 or above. That’s all I can think of for now! Let others help fill in the details!
Reply to 6# changhw: Thank you, you’ve worked hard