**What Is ANSI Flange Rating And Flange Class?**

Each pipe fitting retains a certain pressure holding ability that is determined by the type and thickness of the metal. A flange is one of the essential parts of a pipe that connects to industrial valves, tools, and other spools of piping and carries the pressure created in the piping system during the operation.

The term “flange pressure rating” refers to a particular classification that specifies the ultimate temperature at which a given flange can withstand a given amount of pressure. The utmost pressure a flange can resist with growing temperature up to a limit for a certain temperature span is indicated by the flange pressure rating or class.

The American National Standards Institute, also known as ANSI, is a nonprofit, independent association that assists in regulating the standards for a variety of goods, services, operations, and personnel. One can be sure to get the appropriate flange given the material and the maximum pressure and temperature to which it will be subjected by looking at the ANSI rating.

Seven flange pressure ratings are delivered by the ASME or ANSI B16.5 standard, which are: 150, 300, 400, 600, 900, 1500, and 2500. Additionally referred to as the flange class, they are identified by the class and observed by any of the dimensionless integers. The terms “pound rating” and “pressure class rating” are also used to describe them.

Here are some vital features of flange classes are:

- If the flange rating is high, the more pressure and temperature flanged valve can resist.
- In comparison to flanges with less grades, those with higher values are thicker, heavier, and stronger.
- Because flange dimensions fluctuate as pressure rating classes change, a flange from one pressure class might not match with a flange from an elevated or lower class.
- The number of bolts grows along with the pressure rating, boosting the bolt area. By improving the bolt’s capacity to carry force and moment, the gain in bolt area decreases the potential for flange leakage.

**What To Know About ANSI Flange Pressure Rating Chart**

Flanges, valves, and fittings are governed by a variety of standards, but ANSI pressure ratings are arguably the most widely used set of guidelines. There are seven distinct ANSI flange pressure ratings. The flange will be smaller, lighter, and less robust if the flange rating is less.

140 pounds psi is the most that a class-150 carbon steel flange can resist when exposed to 600 degrees Fahrenheit. A class-300 flange with identical other specifications can sustain 570 psi. With the exact substance and bore size, a class-2500 flange can sustain up to 4730 psi, which is 34 times more pressure compared to a 150-class flange.

ANSI flanges are utilized for all applications other than oil drilling and well heading. For flanges up to 24 inches in diameter, ANSI B16.5 is utilized, and for flanges larger than 24 inches, ANSI B16.47 is employed.

**Pressure Rating Designation Of Flanges**

The results of the ANSI pressure rating chart are displayed in Class, Lb, or Pound. The designation of the pressure-temperature rating of flanges is class, which is followed by an arbitrary number. There are seven different sorts of flange rating designations, each denoted by a “#”:

- 150#
- 300#
- 400#
- 600#
- 900#
- 1500#
- 2500#

The pound system is represented by the symbol “#,” which is also symbolized by “Lb.” Numerous designations, including 150 Lb, 150 Lbs, 150#, and Class 150, are used to identify flanges and these all signify the same thing. However, there is just one signal that is accurate, which is “Pressure class.”

All of these signs just represent the idea of a flange’s pressure or temperature capability for valves and are interchangeable. This pressure or temperature performance is crucial since it aids in the selection of the best flange for the circumstances.

**A Brief Guide To ANSI Flange Pressure Rating Chart**

Check out the details of **the ANSI flange pressure ratings chart** about class 1 flanges.

**Class 150**

- If the temperature for Class 1 150# flange is < 100 degrees Fahrenheit, the maximum pressure for flanges is 285 psi.
- If the temperature for Class 1 150# flange is 200 degrees Fahrenheit, the maximum pressure for flanges is 260 psi.
- If the temperature for Class 1 150# flange is 300 degrees Fahrenheit, the maximum pressure for flanges is 230 psi.
- If the temperature for Class 1 150# flange is 400 degrees Fahrenheit, the maximum pressure for flanges is 200 psi.
- If the temperature for Class 1 150# flange is 500 degrees Fahrenheit, the maximum pressure for flanges is 170 psi.
- If the temperature for Class 1 150# flange is 600 degrees Fahrenheit, the maximum pressure for flanges is 140 psi.
- If the temperature for Class 1 150# flange is 700 degrees Fahrenheit, the maximum pressure for flanges is 110 psi.
- If the temperature for Class 1 150# flange is 800 degrees Fahrenheit, the maximum pressure for flanges is 80 psi.
- If the temperature for Class 1 150# flange is 900 degrees Fahrenheit, the maximum pressure for flanges is 50 psi.
- If the temperature for Class 1 150# flange is 1000 degrees Fahrenheit, the maximum pressure for flanges is 20 psi.

**Class 300**

- If the temperature for Class 1 300# flange is < 100 degrees Fahrenheit, the maximum pressure for flanges is 740 psi.
- If the temperature for Class 1 300# flange is 200 degrees Fahrenheit, the maximum pressure for flanges is 680 psi.
- If the temperature for Class 1 300# flange is 300 degrees Fahrenheit, the maximum pressure for flanges is 655 psi.
- If the temperature for Class 1 300# flange is 400 degrees Fahrenheit, the maximum pressure for flanges is 635 psi.
- If the temperature for Class 1 300# flange is 500 degrees Fahrenheit, the maximum pressure for flanges is 605 psi.
- If the temperature for Class 1 300# flange is 600 degrees Fahrenheit, the maximum pressure for flanges is 570 psi.
- If the temperature for Class 1 300# flange is 700 degrees Fahrenheit, the maximum pressure for flanges is 530 psi.
- If the temperature for Class 1 300# flange is 800 degrees Fahrenheit, the maximum pressure for flanges is 410 psi.
- If the temperature for Class 1 300# flange is 900 degrees Fahrenheit, the maximum pressure for flanges is 230 psi.
- If the temperature for Class 1 300# flange is 1000 degrees Fahrenheit, the maximum pressure for flanges is 85 psi.

**Class 400**

- If the temperature for Class 1 400# flange is < 100 degrees Fahrenheit, the maximum pressure for flanges is 985 psi.
- If the temperature for Class 1 400# flange is 200 degrees Fahrenheit, the maximum pressure for flanges is 905 psi.
- If the temperature for Class 1 400# flange is 300 degrees Fahrenheit, the maximum pressure for flanges is 870 psi.
- If the temperature for Class 1 400# flange is 400 degrees Fahrenheit, the maximum pressure for flanges is 845 psi.
- If the temperature for Class 1 400# flange is 500 degrees Fahrenheit, the maximum pressure for flanges is 805 psi.
- If the temperature for Class 1 400# flange is 600 degrees Fahrenheit, the maximum pressure for flanges is 755 psi.
- If the temperature for Class 1 400# flange is 700 degrees Fahrenheit, the maximum pressure for flanges is 710 psi.
- If the temperature for Class 1 400# flange is 800 degrees Fahrenheit, the maximum pressure for flanges is 550 psi.
- If the temperature for Class 1 400# flange is 900 degrees Fahrenheit, the maximum pressure for flanges is 305 psi.
- If the temperature for Class 1 400# flange is 1000 degrees Fahrenheit, the maximum pressure for flanges is 115 psi.

**Class 600**

- If the temperature for Class 1 600# flange is < 100 degrees Fahrenheit, the maximum pressure for flanges is 1480 psi.
- If the temperature for Class 1 600# flange is 200 degrees Fahrenheit, the maximum pressure for flanges is 1360 psi.
- If the temperature for Class 1 600# flange is 300 degrees Fahrenheit, the maximum pressure for flanges is 1310 psi.
- If the temperature for Class 1 600# flange is 400 degrees Fahrenheit, the maximum pressure for flanges is 1265 psi.
- If the temperature for Class 1 600# flange is 500 degrees Fahrenheit, the maximum pressure for flanges is 1205 psi.
- If the temperature for Class 1 600# flange is 600 degrees Fahrenheit, the maximum pressure for flanges is 1135 psi.
- If the temperature for Class 1 600# flange is 700 degrees Fahrenheit, the maximum pressure for flanges is 1060 psi.
- If the temperature for Class 1 600# flange is 800 degrees Fahrenheit, the maximum pressure for flanges is 825 psi.
- If the temperature for Class 1 600# flange is 900 degrees Fahrenheit, the maximum pressure for flanges is 460 psi.
- If the temperature for Class 1 600# flange is 1000 degrees Fahrenheit, the maximum pressure for flanges is 170 psi.

**Class 900**

- If the temperature for Class 1 900# flange is < 100 degrees Fahrenheit, the maximum pressure for flanges is 2220 psi.
- If the temperature for Class 1 900# flange is 200 degrees Fahrenheit, the maximum pressure for flanges is 2035 psi.
- If the temperature for Class 1 900# flange is 300 degrees Fahrenheit, the maximum pressure for flanges is 1965 psi.
- If the temperature for Class 1 900# flange is 400 degrees Fahrenheit, the maximum pressure for flanges is 1900 psi.
- If the temperature for Class 1 900# flange is 500 degrees Fahrenheit, the maximum pressure for flanges is 1810 psi.
- If the temperature for Class 1 900# flange is 600 degrees Fahrenheit, the maximum pressure for flanges is 1705 psi.
- If the temperature for Class 1 900# flange is 700 degrees Fahrenheit, the maximum pressure for flanges is 1590 psi.
- If the temperature for Class 1 900# flange is 800 degrees Fahrenheit, the maximum pressure for flanges is 1235 psi.
- If the temperature for Class 1 900# flange is 900 degrees Fahrenheit, the maximum pressure for flanges is 690 psi.
- If the temperature for Class 1 900# flange is 1000 degrees Fahrenheit, the maximum pressure for flanges is 255 psi.

**Class 1500**

- If the temperature for Class 1 1500# flange is < 100 degrees Fahrenheit, the maximum pressure for flanges is 3705 psi.
- If the temperature for Class 1 1500# flange is 200 degrees Fahrenheit, the maximum pressure for flanges is 3395 psi.
- If the temperature for Class 1 1500# flange is 300 degrees Fahrenheit, the maximum pressure for flanges is 3270 psi.
- If the temperature for Class 1 1500# flange is 400 degrees Fahrenheit, the maximum pressure for flanges is 3170 psi.
- If the temperature for Class 1 1500# flange is 500 degrees Fahrenheit, the maximum pressure for flanges is 3015 psi.
- If the temperature for Class 1 1500# flange is 600 degrees Fahrenheit, the maximum pressure for flanges is 2840 psi.
- If the temperature for Class 1 1500# flange is 700 degrees Fahrenheit, the maximum pressure for flanges is 2655 psi.
- If the temperature for Class 1 1500# flange is 800 degrees Fahrenheit, the maximum pressure for flanges is 2055 psi.
- If the temperature for Class 1 1500# flange is 900 degrees Fahrenheit, the maximum pressure for flanges is 1150 psi.
- If the temperature for Class 1 1500# flange is 1000 degrees Fahrenheit, the maximum pressure for flanges is 430 psi.

**Class 2500**

- If the temperature for Class 1 2500# flange is < 100 degrees Fahrenheit, the maximum pressure for flanges is 6170 psi.
- If the temperature for Class 1 2500# flange is 200 degrees Fahrenheit, the maximum pressure for flanges is 5655 psi.
- If the temperature for Class 1 2500# flange is 300 degrees Fahrenheit, the maximum pressure for flanges is 5450 psi.
- If the temperature for Class 1 2500# flange is 400 degrees Fahrenheit, the maximum pressure for flanges is 5280 psi.
- If the temperature for Class 1 2500# flange is 500 degrees Fahrenheit, the maximum pressure for flanges is 5025 psi.
- If the temperature for Class 1 2500# flange is 600 degrees Fahrenheit, the maximum pressure for flanges is 4730 psi.
- If the temperature for Class 1 2500# flange is 700 degrees Fahrenheit, the maximum pressure for flanges is 4425 psi.
- If the temperature for Class 1 2500# flange is 800 degrees Fahrenheit, the maximum pressure for flanges is 3430 psi.
- If the temperature for Class 1 2500# flange is 900 degrees Fahrenheit, the maximum pressure for flanges is 1915 psi.
- If the temperature for Class 1 2500# flange is 1000 degrees Fahrenheit, the maximum pressure for flanges is 715 psi.

**What Is The Effect Of Flange Pressure Rating On Flange Size**

A method of grouping different pressure-temperature established ratings of flanges as per the flange material is known as flange pressure rating. There are a few aesthetic characteristics that distinguish a lower-class flange from a higher-class flange:

- A flange with a comparatively higher grade is thicker and has greater pressure and temperature resistance.
- The flange’s outside diameter will grow as the flange pressure rating does.
- In accordance with the flange pressure rating, the bolt circle diameter will rise.
- With higher flange classes comes larger bolt holes and more bolts to install.
- Higher flange ratings also result in wider flange faces.

**Conclusion**

At some particular temperature requirements, a flange with an elevated rating or class is more powerful than a flange with less rating or class. If they are constructed of the same material and have a higher grade, flanges can tolerate more pressure and heat. At the exact rating and flange class, a flange manufactured of a distinct material will have a varied holding capability for pressure and temperature.

Flanged valves play an important role in every industrial application, hope this article could help you find the best valve for your application. If you need high quality flanged valves, feel free to contact Dombor, flanged butterfly valve or ball valves are all available.