Why do some pipeline systems require two safety valves
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Is it for the reason of emissions? Then why not design one that is larger? What’s the advantage of designing two safety valves?
The safety valve on the boiler drum is designed as such a valve at lower temperatures, pressures, and with reduced gas generation. However, once the gas generation rate exceeds a certain level, it is required by boiler regulations to be equipped with two safety valves, although their setting pressures differ. Furthermore, due to the continuous production nature of petrochemical enterprises, the safety valves for pipelines and equipment may need to ensure continuous operation for over 3 years during each major overhaul. However, per regulations, the safety valves also need to be inspected and checked once a day; therefore, two safety valves are designed so that they can be rotated for inspection and checking at regular intervals, ensuring continuous production.
The largest valves according to American standards are currently 8 inches in size, but 20-inch valves are now available as well. Large diameters can indeed meet the displacement requirements, but the weight is too high; as long as the pipes can withstand that weight, it’s fine
Only some sections are equipped with two safety valves; most have just one
Usually, one valve is in use and another is on standby; when one safety valve needs to undergo annual inspection, the other one is used to ensure the safety of the system
Dual valves – no need for shutdown for maintenance
Most of them have one, with only a few locations having two; are those areas where there are two more people present due to a higher level of risk?
It can also be said that way； There are also those that the client requested the design institute to add; all of them are acceptable ； Some other companies carry out major overhauls every 2 years or more in order to meet certain requirements
It facilitates annual disassembly, inspection, and verification. . .