API 650 statment
API 650 statment
(OP)
In API 650 standard , item 5.2.1 C) , the design internal pressure shall not exceed 18 kpa , and since atmospheric pressure is 100 kpa so does this statement means that internal pressure shall not exceed 118 kpa ? also the external pressure shall not be less than 100.25 kpa ?





RE: API 650 statment
RE: API 650 statment
RE: API 650 statment
This is mainly because API 650 is intended for tanks to be at an internal pressure of "approximately atmospheric pressure" see 1.1.1
Appendix F states that if the pressure is less than 1kPa (4 inches of water), then it is classed as "atmospheric" Design pressure higher than that up to 18 kPa needs Appendix F to be applied.
It is clear that the internal design pressure is gauge pressure, i.e. the differential pressure between the internal pressure and local atmospheric pressure. I use the term local to indicate the atmospheric pressure at the location where the tank is as "atmospheric" pressure varies with altitude. You cannot use a design pressure of 118 kPa absolute as if you then build your tank at say 3000m above sea level then your internal pressure will be a lot more than 18 kPa (guage).
Is that clearer?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: API 650 statment