Class Ratings vs. PN Pressure Nominal

Attribute	Class Ratings	PN Pressure Nominal
Definition	Classification system used to indicate the pressure-temperature rating of a piping component	Pressure rating system used for piping components in Europe
Pressure Range	Class ratings typically range from 150 to 2500	PN ratings typically range from PN6 to PN100
Design Standard	ASME B16.5 for flanges, ASME B16.34 for valves	EN 1092 for flanges, EN 1759 for valves
Temperature Range	Class ratings are based on temperature range	PN ratings are based on pressure-temperature ratings

Introduction

When it comes to selecting the right materials for piping systems, it is essential to consider various factors such as pressure ratings. Two common methods used to classify the pressure handling capabilities of pipes are Class Ratings and PN Pressure Nominal. In this article, we will compare the attributes of these two systems to help you make an informed decision for your piping needs.

Class Ratings

Class Ratings are a system used to classify the pressure handling capabilities of pipes based on their design and construction. This system is commonly used in the United States and is denoted by a numerical value followed by the letters "Class." For example, Class 150, Class 300, and Class 600 are common Class Ratings used in piping systems. The Class Rating indicates the maximum pressure that a pipe can withstand at a specific temperature.

One of the key advantages of Class Ratings is their simplicity and ease of understanding. The numerical value of the Class Rating directly correlates to the pressure handling capabilities of the pipe, making it easy for engineers and designers to select the appropriate pipe for their application. Additionally, Class Ratings are widely recognized and standardized, making it easier to compare different pipes from various manufacturers.

However, one limitation of Class Ratings is that they do not provide information about the material composition of the pipe. This can be a drawback when selecting pipes for specific applications that require certain material properties. Additionally, Class Ratings may not be as widely used or recognized in certain regions outside of the United States, which can limit their applicability in a global context.

PN Pressure Nominal

PN Pressure Nominal is a system used to classify the pressure handling capabilities of pipes based on their nominal pressure rating. This system is commonly used in Europe and other parts of the world and is denoted by a numerical value followed by the letters "PN." For example, PN 6, PN 10, and PN 16 are common PN Pressure Nominal ratings used in piping systems. The PN rating indicates the maximum pressure that a pipe can withstand at a specific temperature.

One of the advantages of PN Pressure Nominal is that it provides information about the pressure handling capabilities of the pipe based on its nominal pressure rating. This can be useful for engineers and designers who need to select pipes based on specific pressure requirements. Additionally, PN Pressure Nominal is widely used and recognized in Europe and other regions, making it a valuable system for global applications.

However, one limitation of PN Pressure Nominal is that it may not be as easily understood by engineers and designers who are more familiar with Class Ratings. The numerical values of PN ratings do not directly correlate to pressure values in the same way as Class Ratings, which can make it more challenging to select the appropriate pipe for a given application. Additionally, the lack of standardization in PN ratings across different regions can make it difficult to compare pipes from various manufacturers.

Comparison

When comparing Class Ratings and PN Pressure Nominal, it is important to consider the specific needs of your piping system. Class Ratings offer a simple and standardized system for classifying pressure handling capabilities based on numerical values, making them easy to understand and compare. However, they may lack information about material composition and may not be as widely recognized outside of the United States.

On the other hand, PN Pressure Nominal provides information about pressure handling capabilities based on nominal pressure ratings, making it useful for engineers and designers who need to select pipes based on specific pressure requirements. However, PN ratings may not be as easily understood as Class Ratings and may lack standardization across different regions.

In conclusion, both Class Ratings and PN Pressure Nominal have their advantages and limitations. The choice between the two systems will depend on the specific requirements of your piping system and your familiarity with each system. It is important to consider factors such as material composition, standardization, and global applicability when selecting the appropriate system for your piping needs.