Principle of short - term energy isolation during inspection and maintenance
During the inspection and maintenance of process pipeline system, an energy isolation plan should be formulated for the upstream and downstream valves directly connected with the maintenance pipeline.
During the inspection and maintenance of pressure vessels, an energy isolation scheme should be formulated for the inlet and outlet valves of pressure vessels and the valves directly connected to and upstream with pressure;
During the inspection and maintenance of the vent and sewage systems, an energy isolation scheme shall be formulated for the vent and sewage valves directly connected with the operation pipe section with upper and lower pressure. The combination of the above energy isolation methods can be considered in the case of too many blowout, sewage system and upstream connection pipelines.
When the inspection and maintenance of the process system equipment lasts for more than one day, an energy isolation plan should be formulated for the upstream and downstream pressure valves of the system and equipment under maintenance. It is required that the energy isolation should be maintained during the operation until the repair and maintenance work is completed.
The energy isolation plan for the above situation shall be formulated in accordance with "5.1.3 Selection of isolation method" to determine the priority of selecting isolation method;
Personal locks are required to perform the locking function when implementing short-term energy isolation during inspection and maintenance.
Principle of medium and long term energy isolation in production and operation
For the process equipment that has hidden trouble and is out of service, it is necessary to use a blind plate to blind and die the upstream and downstream pressure valves of the equipment, or to realize energy isolation by closing the cut-off valve and locking it, so as to avoid damage of the equipment due to misoperation and other reasons;
For the system and equipment that are not put into operation downstream, the upstream pressure valve should be killed by blind plate, or the energy isolation should be implemented by closing the valve and locking;
According to the needs of production operation, the defunct process (metering comparison process) can be closed, and the energy isolation valve can be locked;
In the process of production operation, it is necessary to use department locks to perform locking function when long-term energy isolation is needed.