After cleaning the process pipelines and equipment, the personnel in the jurisdiction need to compile the energy isolation plan and isolation blind plate diagram according to the content and work scope of the operation area.
The energy isolation plan mainly includes work content and scope, approval process, first isolation point, second isolation point, first and second isolation point approval and change approval management.
The first isolation point is mainly to close or open the valve on the process pipeline according to requirements and empty the residual chemical materials in the process pipeline and equipment;
At the same time, the power switch of the electrical equipment is physically disconnected in the control cabinet of the motor control center to ensure that the electrical energy is completely removed. The primary isolation point is to prepare for the installation of secondary isolation point devices.
The secondary isolation point is a necessary and sufficient supplement to the primary isolation point.
For high risk of chemical process piping, equipment disconnected operation, hot work, into a limited space or involved in serious danger of chemicals (including flammable, explosive, toxic, reactivity, high pressure or high temperature and other chemicals) related to the maintenance work, in principle, must want to have a second isolation protection, such as installing a blind plate as a separation point, just rely on the valve and electrical switch for energy isolation is not reliable.
Failure, such as internal leakage of valve and short circuit of electrical switch, will cause the sudden release of residual energy in the process system or the sudden rotation of transmission equipment, which will cause injury to personnel in the operation area, damage to equipment and fire, explosion and other unsafe accidents caused by chemical leakage.
In addition, for the energy isolation points, the principle of proximity of the isolation points to the operating area is required, so as to ensure the safety of pipelines and equipment in the operating area to the maximum extent, and prevent the residual chemicals in the lengthy process pipelines from affecting the operation safety.
According to the content and scope of maintenance or project work as well as the process status, the personnel in the production area will evaluate the energy isolation residual status and isolation method in the operation area, including the process diagram of the operation area, valve switching status, electrical equipment power failure status and so on.
About the blind flange
Blind plate is a kind of isolation device, which physically blocks the pipeline connected with flange through nuts and bolts, and can completely cover the pipe aperture of the opening, so as to ensure that chemicals cannot flow into the pipeline and into the operation area needed for isolation.
Because the blind plate is used in the process pipeline, sometimes it needs to bear the corresponding pressure, temperature and corrosion of the process pipeline, so the thickness of the blind plate must meet the corresponding pressure requirements, and the material must meet the anti-corrosion requirements.