The piping engineering literature commonly uses the words “DN” and “PN.” These are crucial terms in the design of pipe systems. We shall talk about the significance of DN and PN in this article.
What is DN in Pipes?
The term “DN” stands for Diameter Nominal (DN). The metric unit system’s term for pipe size is a dimensionless number. The International Standards Organization, or ISO, is the organization that created the DN pipe size designator. Standard pipe sizes are indicated by the letters DN followed by a number. For instance, DN50 denotes a 2′′ NPS pipe, while DN80 denotes a 3′′ NPS pipe.
NPS vs. DN
Another designation for dimensionless pipe sizes is NPS or nominal pipe size. NPS followed by a number indicates a certain pipe size. NPS 2 denotes a pipe, for instance, with an outer diameter of 2.375 inches. For NPS 12 and smaller pipes, the pipe’s outside diameter is greater than its NPS designator. However, the pipe OD in inches for NPS 14 and bigger pipes is the same as the NPS designator. This indicates that the OD of an NPS 24 pipe is 24 inches.
Therefore, the main difference between DN and NPS is that the former denotes an approximate pipe diameter in mm, whilst the latter denotes an inch-based pipe dimension. The DN number is derived for pipes greater than NPS 3.5 by multiplying the NPS size designation number by 25. For instance, DN 100 and NPS 4 are equivalents.
What is the PN Rating Number?
The pressure-temperature rating technique used for flange classification is typically used to categorize pipes. An equivalent designation for pressure rating is the PN number system. Pression Nominal, or “PN,” is the French name for pressure nominal. The term “PN” is followed by a designating number to identify the PN number. PN 10 and PN 50, for instance. The approximate pressure rating in bars is indicated by the value that comes after the term PN. Be aware that the PN rating does not establish a correlation between various PN numbers.
The imaginary pressure that a pipe or tube can withstand is essentially represented by PN. The reference PN number value is used to design the piping components. The most common uses of the PN rating number are for HDPE, PVC, and PE pipes made of plastic. The European standards BS, DIN, EN, ISO, and so forth frequently use PN. For the same pipe DN, a different PN rating indicates a different pipe thickness.
What does PN in HDPE pipe mean?
The maximum pressure that a polyethylene pipe can bear without breaking at a given temperature range is indicated by the PN acronym for pressure nominal. For instance, PN 16 pipe designates a pipe that can bear 16 bars of pressure without breaking. In a similar vein, PN 20 pipe designates a pipe that can resist a pressure of 20 bar at its highest intended temperature.
The PN rating pressure for PE/HDPE pipes typically refers to the pressure capabilities at a temperature of 20°C. For HDPE/PE pipes, the Pipe Diameter, Thickness, and Weight chart typically include PN values. The thickness of the pipe grows as the PN number rises.
