Under what conditions can a stop valve be installed between an overpressure relief device and a pressure vessel?
Thread Content
It is generally not advisable to install a globe valve between the overpressure relief device and the pressure vessel. To enable online calibration of safety valves, a burst disc can be installed between the safety valve and the pressure vessel. The installation of a stop valve between the safety valve and the pressure vessel must meet the following conditions: 1. Approval from the person in charge of management at the using unit is required ； 2. Establish reliable preventive measures ； 3. Ensure that the stop valve is fully open, locked, or sealed with lead during the operation of the pressure vessel ； 4. The diameter and structure of the stop valve must not hinder the discharge of the safety valve ；
I have a question: in the petrochemical industry, maintenance is carried out every three or even four years, so how do they manage to calibrate their safety valves on an annual basis? Is online verification used for all of them?
When parking operation is not possible, a stop valve needs to be installed
Isn’t it necessary to install it? How do I replace or verify it?
This post was last edited by wanlirn on 2021-4-13 at 14:43. What the original poster summarized are also the management requirements for manufacturers in the petrochemical and oil industries； But in practice, if the safety valve fails to activate due to issues with the shut-off valve, it is still your manager’s responsibility; in other words, those four clauses are not exemption provisions ； There have been precedents for this in the industry; the safety supervision agency doesn’t care about such things ； It’s not allowed to use stop valves ； For example, even if the safety valve passes its annual inspection, it still fails to activate, which is considered an accident. If something happens to the safety interlock door, it’s considered a safety liability accident; there’s a big difference between the two