Safety Instrumented System trip time
Thread Content
Are there any specific standard requirements regarding the timing at which the safety instrument system should be shut down? The field equipment has been out of service for a long time; it involves a 2-out-of-3 pressure monitoring system that needs to be disabled; otherwise, it will trigger an interlock shutdown. How should a work order be prepared for this SIS interlock shutdown? Can it be removed permanently?
In general, there are no specific standards or specifications governing the time required for the deactivation of safety instrumented systems. However, the removal of safety instrumented systems should generally follow these principles: 1. Minimize the removal time: Try to shorten the time required to remove the safety instrumented systems in order to reduce potential risks. 2. Maintain other safety measures during removal: While removing the safety instrumented system, other safety measures such as interlock systems and alarm systems should remain in effect to ensure the safety of equipment and personnel. Regarding how to prepare work orders for SIS interlock removal, the specific procedures can be established based on the actual conditions and regulations at the site. Generally, a work order should include the following: 1. Work order number and date; 2. Reasons and purposes for disabling the safety instrumented system; 3. Description of the specific equipment to be disabled and its location; 4. Time of disactivation and estimated time for restoration; 5. Other safety measures to be implemented during the disactivation period; 6. Signatures and approvals from relevant responsible persons. Whether it is possible to disable the safety instrumented system for an extended period depends on the specific circumstances and requirements. However, generally speaking, permanently disabling the Safety Instrumented System is not a desirable practice, as it may increase the risks to equipment and personnel. If it is necessary to shut down the safety instrumented system for an extended period, it is recommended to consult with relevant departments or professionals for further assessment to ensure that risks can be effectively controlled. .
According to the latest criteria for identifying major hazards, having the interlock system disabled for more than a month constitutes a major hazard. To avoid such situations, it is recommended not to keep the interlock system disabled for extended periods; if it cannot be put back into use in the short term, the logic of the interlock system can be optimized.