Home > About Us> Tech & Service

What is a Flange?

Measure the size of a flange

At some point, with all the possibilities of thread form, diameter, and pitch, you need to send it off to SK Grimes or another machinist.
Flange tolerance

You could buy the thread pitch gauges and comparator and thread micrometer (to measure minor diameter) to fully define the thread, but that still won’t help you to find a ring.

Flange Inspection
Following to be confirmed during inspection of flange

Permissible tolerances are given in B16.5 and B16.47 standard.

Flange inspection

Place one end of a tape measure on the inside of the flange. The diameter is used to determine what size pipe a flange can be used with, so you must find this information by using the inside of the flange as opposed to the outside.

Stretch your tape measure across the center of the circular shape of the flange until it touches the other side of the unit. Keep this end of the tape measure on the inside of the flange as well. Because the flange is circular in shape, the tape measure must stretch across the exact center of the flange to provide an accurate measurement.

How to Measure the Diameter of a Flange?

A flange is a circular piece of equipment used to connect two pipes together. Flanges can be made out of stainless steel, copper or any other type of metal. They typically match the metal of the pipes they connect. Flanges help seal the pipes together, preventing water from leaking when it passes from one pipe to another along the way from its origin to its destination.

Place one end of a tape measure on the inside of the flange. The diameter is used to determine what size pipe a flange can be used with, so you must find this information by using the inside of the flange as opposed to the outside.

Stretch your tape measure across the center of the circular shape of the flange until it touches the other side of the unit. Keep this end of the tape measure on the inside of the flange as well. Because the flange is circular in shape, the tape measure must stretch across the exact center of the flange to provide an accurate measurement.

Although the dimension of the flange diameter is just one measurement used when identifying your flange, it is an incredibly crucial one when lining this piece up to your system.

Getting started with measurement — the devil is in the details

There are three separate steps when discussing the measurement of the flange diameter. First, measuring the flange’s inside diameter, then across center of the flange and finally, the outside diameter.

Step 1 – Start by measuring inside the flange by simply measuring the center hole. This diameter lets you know what size pipe should be paired with the flange. If you have documentation that tells you the inside measurement of the flange and pipe, make sure you have the right documentation for the part. Papers can get mixed up easily, so it never hurts to take a quick measurement to verify independently.

Step 2 – Measure across the center of the flange. Make sure you find the exact center of the flange to get an accurate dimension. You’ll notice that the bolt holes around the flanges are distributed evenly. This will help guide you to the center.

Step 3 – Finally, measure around the outside diameter of the flange. If your system is squeezed into a tight space, a flange that is too thick may cause problems and some other pipes may need to be moved. Knowing the outside diameter will help you plan for this.

That’s really about all that needs to be done when measuring the diameter of a flange. However, it’s easy to acquire some false confidence and skip one or more of these steps. Be sure to watch the details, which will ensure a much better installation.

If you’re building a new system, this is an opportunity to buy the pipes and flanges specifically manufactured to fit together according to widely accepted standards. Obviously, this will eliminate chances for error. Beyond the measurement, keep in mind what type of fluid will be passing through the system, the temperature of both the fluid inside, the working conditions outside, and of course, the material used to create the flange.

Some pipe/flange materials will not play nice with the chemicals passing through. Make sure you understand the demands the system will create.

Standard we supply
ANSI
AWWA
ASME
DIN

Copyright © 2011 Sunny Steel Enterprise Ltd.  All Rights Reserved ICP No.:08010763
Sum Xu