When you encounter PN16 on a valve specification sheet or product listing on Alibaba.com, you're looking at one of the most common pressure ratings in industrial valve applications. But what does this number really tell you - and more importantly, what does it not tell you?
PN stands for Pressure Nominal, a European standard widely adopted globally in metric-system countries. The number following PN indicates the maximum allowable working pressure (MAWP) in bar at a reference temperature of 20°C (68°F) [1].
So PN16 = 16 bar at 20°C, which translates to approximately 232 psi or 1.6 MPa. This is the pressure the valve can safely withstand during continuous operation under normal temperature conditions.
However, here's where many buyers and even some suppliers make costly mistakes: the PN rating is only valid at the reference temperature. As operating temperature increases, the valve's pressure-bearing capacity decreases significantly due to material strength reduction [3].
This is not a minor detail - it's a critical safety consideration that separates professional valve suppliers from amateur traders. A PN16 valve that performs perfectly at 20°C may only handle 11-12 bar at 100°C, depending on the body material.
Many engineers assume that if a valve is rated PN16, it's safe for any system running below 16 bar—but that's a costly mistake. Temperature derating is mandatory for safe operation [3].
