How Flange Rating Works?

How Flange Rating Works?

Consider the following implications in terms of pressure rating:

At 600 degrees Fahrenheit, the class 150 flange can only tolerate 140 psi (as per the rating chart below)

The class 300 flange, which is larger and stronger but has the same hole size, can bear 570 pressure at 600 degrees Fahrenheit.

Finally, a class 2500 flange of the same size can withstand 34 times the pressure of a class 150 flange with a rating of 4730 psi at 600 °F!

To get the right rating table for your flange, scroll down (this depends on the material of the flange, as flanges with different material grades have different pressure ratings)

Find out what the pipe system’s maximum operating temperature is (i.e. select one line in the table)

Based on the expected maximum pressure at that temperature, choose a rating (i.e. select one column in that line)

You have now received the necessary rating!

We have provided the ASME B16.34 pressure rating charts for the most popular flange materials to assist you (carbon, alloy, stainless).

The terms “pressure rating,” “class,” “#,” “Lb,” and “Lbs” all refer to the management of pressure and temperature by a flange (and other equipment like valves, fittings, etc).

Let’s take an example to demonstrate:

If two flanges have the same bore size, say 6 inches, are constructed of the same material, say A105, but have various pressure ratings, say class 150 and class 300, the class 150 flange will be smaller, lighter, and less robust (class 300). The picture shows what is below:

How the Flange Rating System Works

The idea of flange rating is usually difficult for people new to the pipe sector to understand. Let’s define a flange and discuss what it does in the plumbing industry before we get into the specifics.

What exactly is a flange and how does it work?

A pipe fitting called a flange is used to connect pipes, pumps, valves, and other piping parts to construct a pipeline system. The flange is a crucial component of the plumbing system because it makes cleaning, inspecting, and modifying pipes easier. Weld neck flanges, slip-on flanges, socket weld flanges, lap joint flanges, threaded flanges, blind flanges, orifice flanges, reducing flanges, and numerous other types of flanges are available.

What is the flange rating and how does it work?

The pressures and temperatures that flanges used in the oil, gas, and petrochemical industries must be able to withstand. Both the rating and the flange size are significant. In order to ensure that a flange can resist the pressures of operation at all temperatures, it should have the appropriate rating.

The maximum pressure that a flange can withstand at high or rising temperatures depends on its class. Flanges with a higher flange rating or flange class are naturally thought of as being stronger since they are able to withstand more pressure at higher temperatures.

Flanged fittings and pipe flanges must adhere to ASME B16.5, the industry standard for flanges. There are included flanges with sizes between 12″ NPS and 24″ NPS.

As a result, as the temperature increases, so does the maximum permitted pressure. The illustration below makes the idea of flange rating simple to understand.

A Class 300 flange can resist more pressure than a Class 150 flange because it is made of more metal and can do so. On the other hand, a flange’s ability to withstand pressure is affected by a number of factors.

Because it is comprised of more metal and can withstand greater pressure, a Class 300 flange can withstand more pressure than a Class 150 flange. On the other hand, a flange’s capacity for pressure is influenced by a variety of variables.