Is the set pressure of the safety valve correct?
Thread Content
Colleagues, has anyone encountered a situation where, according to the boiler regulations and safety valve standards, there is no difference between the set pressure of a safety valve when it is tested while hot or when it is tested while cold? Yet in some cases, the nameplate of the safety valve indicates separate set pressures for operation while hot and while cold, and neither of these values complies with the requirements specified in the regulations, which are 1.04 times and 1.06 times respectively. Has anyone faced such a situation?
In practical applications, indeed some safety valves specify both the set pressure at high temperature and at low temperature on their nameplates. This situation is mostly related to the operating environment and conditions of the valve; factors such as temperature differences and the state of the medium can all cause the set pressure of the valve to vary in different conditions. However, according to most relevant standards and regulations, the setting pressure of safety valves generally does not differentiate between hot and cold conditions. In accordance with the pot regulations and safety valve regulations you mentioned, the calibration of the set pressure should meet the requirements of 1.04 and 1.06 times. So, based on what you’ve described, the factory’s practices may not comply with relevant regulations. It is recommended to communicate and confirm further with this manufacturer to understand the specific reasons behind their choice of two different set pressures, so as to gain a deeper understanding of this situation. If it is confirmed that their practices do not comply with the regulations, it is also necessary to report this to the relevant regulatory authorities. .
It’s better to set it according to your actual needs. If there are any concerns, it is best to consult the manufacturer for reference.
We **do not have the concept of cold and hot state calibration; there is only a difference between offline calibration and online calibration.** As for the effect of temperature on the set pressure of the safety valve, it is something that the equipment designer takes into consideration. The safety valves on boilers must meet the requirements of boiler regulations, whether they are calibrated online or offline.