May I ask whether PN2.5 refers to a pressure of 2.5 kilograms or 2.5 MPa?
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Is PN2.5 referring to a pressure of 2.5 kilograms or 2.5 MPa? From online searches, some say it’s 2.5 MPa; however, for PN25, it’s said to refer to a pressure of 25 kilograms.
This is a matter of the different naming conventions for pressure ratings in the old version versus the new version. In the old version, the nominal pressure was denoted as PN2.5MPa (note the MPa), which is equivalent to the nominal pressure PN25 in the new version (the actual unit is bar, without MPa); both refer to a nominal pressure rating of 2.5MPa. So, PN2.5 here refers to a nominal pressure of 2.5 bar, which is equivalent to 0.25 MPa, or 2.5 kilograms.
For PN2.5MPa, the “MPa” indicates that it’s 2.5MPa. If it’s just PN2.5 with nothing following, then it’s 0.25MPa. PN25 also means 2.5MPa
It is usually 2.5 kilograms. However, many designs these days are also not standardized. I’ve seen many that were wrong from the start. Each time, I ask a few more questions about the pipe pressure, or the pressure range for pipes and equipment, as a reference. Because many designs and installations themselves also lack proper labeling. It all involves analyzing based on experience. If they insist it’s 25 kilograms, don’t argue; just follow the requirement. Currently in the market, many who used to do this also give inaccurate descriptions. Just look at the reference pressure for the connected equipment and pipes. It’s fine to ask more questions, because you never know what level of expertise the designer or the person you hired for the installation possesses.
In the new standard, the unit is bar. For older drawings, it’s advisable to re-evaluate based on the pressure class series and actual conditions.
If it is PN2.5MPa, then it corresponds to the current PN25 standard, which is 2.5MPa (25bar). If it is PN2.5, then it is 0.25Mpa (2.5bar)