What does PN 500 DN 13 mean?

PN 500 DN 13 refers to a specific standard for pipes and fittings. "PN" stands for "Pressure Nominal," indicating the maximum allowable pressure in bars that the pipe can handle, which in this case is 500 bars. "DN" stands for "Diameter Nominal," which indicates the nominal diameter of the pipe, with DN 13 corresponding to a nominal diameter of 13 millimeters. Together, these terms specify the pressure rating and size of a piping component.