What is the difference between a flange and a fitting?

A fitting is any component used to connect, redirect, branch, or terminate piping, including elbows, tees, reducers, caps, and couplings. A flange is a specific type of connection component that bolts two pipe ends together with a gasketed joint. Flanges are typically classified separately from butt-weld and socket-weld fittings because of their bolted, serviceable design that allows the connection to be opened and closed without cutting the pipe.

What are the main types of flanges?

The seven primary flange types are weld neck, slip-on, blind, socket weld, threaded, lap joint, and reducing flanges. Weld neck flanges handle high-pressure and high-temperature service and are the most widely used type in critical applications. Slip-on flanges are common in low-pressure systems where ease of installation matters. Blind flanges close off the end of a piping run. Socket weld and threaded flanges are typical on smaller bore lines. Lap joint flanges pair with stub ends for systems that need frequent disassembly.

What pressure classes do flanges come in?

ANSI/ASME B16.5 flanges are produced in pressure classes 150, 300, 400, 600, 900, 1500, and 2500. The class number reflects the pressure-temperature rating, not a direct PSI value. API 6A flanges for wellhead service are rated 2,000 PSI through 20,000 PSI. AWWA C207 waterworks flanges are produced in Class B, D, E, and F. Selecting the correct class depends on operating pressure, temperature, and the standard the system is designed to.

What materials are flanges made from?

Common flange materials include carbon steel (ASTM A105), low-temperature carbon steel (ASTM A350 LF2), stainless steel (ASTM A182 F304/F316), chrome-moly alloys (ASTM A182 F11, F22, F91), duplex and super duplex (F51, F53, F55), and nickel alloys such as Inconel, Monel, and Hastelloy. Material selection depends on operating pressure, temperature, and the corrosivity of the service media.

How are flanges sized?

Flanges are specified by nominal pipe size (NPS), pressure class, type, material, and face style. A typical callout reads 6 inch, Class 300, weld neck, ASTM A105, raised face. Bolt circle, bolt count, outside diameter, and flange thickness are all governed by the applicable standard, whether ANSI B16.5, B16.47 Series A or B, API 6A, or AWWA C207.

Pipe Flanges | ANSI, API & AWWA Flanges Since 1986

Most Popular Flange Styles

A Flange is a key component in piping systems and pressure vessels, providing a secure way to connect pipes, valves, or equipment. A Flange, by definition, secures, strengthens, or attaches. For us, Flanges create strong, leak-proof joints.

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Providing ASME Code & Non-Code Industrial Flanges

About Us

First Flange Web Site 1997

First Online Catalog 2001

Shipped to every continent in the world 2005

Texas Flange has served the petrochemical, process, and waterworks industries for over 3 decades.

We provide ANSI, API, and AWWA pipe flanges in carbon steel, stainless steel, alloys, and chrome steel. Styles we offer include weld neck, slip on, blind, threaded, socket weld, lap joint, orifice flanges, ring, and custom flanges in sizes from 1/2″ to 203″.

Pressure classes we offer include 75, 125, 150, 175, 250, 300, 350, 400, 600, 900, 1500, 2500, 5K, 10K, 15K, 20K. High Yield – Low Temp.

In memory of our founder, Gerald “Jerry” Fuller May 2nd, 1942 – December 25th, 2012

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Industries We Serve

Petrochemical

As a trusted ANSI flange supplier for petrochemical facilities, we provide Flanges that resist aggressive chemicals and process conditions. Whether for high-temperature reactors, pressure vessels, or chemical transport systems, our products ensure safety and performance in critical applications.

Oilfield Industries

Oilfield flange supplier providing API-rated flanges for upstream, midstream, and downstream operations across Texas and the Gulf Coast.

Waterworks

AWWA flange supplier for municipal water treatment and distribution systems

Resources

Our Resources and Drawings

0.5-150-blind-ff-Flange

SIZE-0.5 | CLASS-150 | TYPE-BLIND | FACE-FF | SPEC-B16.5

0.5-150-blind-rf-Flange

SIZE-0.5 | CLASS-150 | TYPE-BLIND | FACE-RF | SPEC-B16.5

0.5-150-eb-ff-std-Conn-Flange

SIZE-0.5 | CLASS-150 | TYPE-EB | FACE-FF | SPEC-STANDARD-CONNECTION

0.5-150-eb-rf-std-conn-Flange

SIZE-0.5 | CLASS-150 | TYPE-EB | FACE-RF | SPEC-STANDARD-CONNECTION

0.5-150-fb-rf-Studout-Flange

SIZE-0.5 | CLASS-150 | TYPE-STUD OUT | FACE-RF | SPEC-STUDDING-OUTLET

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Frequently Asked Questions

What is a Flange used for?

A flange is essential for connecting pipes, valves, pumps, and other equipment in piping systems. It ensures a secure, leak-proof joint and facilitates assembly, disassembly, and maintenance of the system.

What is a Flanged fitting?

What are the 3 most common Flange types?

What is the most commonly used Flange?