Flanges

A flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system. It also provides easy access for cleaning, inspection or modification. Flanges are usually welded or screwed. Flanged joints are made by bolting together two flanges with a gasket between them to provide a seal.

TYPES OF FLANGES

The most used flange types in Petro and chemical industry are:

  • Welding Neck Flange
  • Slip On Flange
  • Socket Weld Flange
  • Lap Joint Flange
  • Threaded Flange
  • Blind Flange

Most used flange types in Petro and chemical industry. All types except the Lap Joint flange are provided with a raised flange face.

SPECIAL FLANGES

Except the most used standard flanges, there are still a number of special flanges such as:

  • Orifice Flanges
  • Long Welding Neck Flanges
  • Weldoflange / Nipoflange
  • Expander Flange
  • Reducing Flange
  • Special flanges

A bolted flange connection is a complex combination of many factors (Flange, Bolts, Gaskets, Process, Temperature, Pressure, Medium). All these various elements are interrelated and depend upon one another to achieve a successful result.

The industry has recognized the critical nature of installation and assembly for several years. The standard provides a methodology for the training and assessment of technicians involved in the making and breaking of flange joints and can be viewed as being analogous to the training required for welders involved with pressure vessel work. Its publication demonstrates the importance placed upon the competent control of joint making process in ensuring leak-free performance from the flange. The gasket is but one of many reasons a bolted flange joint connection can leak.

Even when all the complex inter-related components of a bolted joint flange connection work in perfect harmony, the single most important factor leading to success or failure of that bolted flange connection will be attention given to proper installation and assembly procedures by the person installing the gasket. If done properly, the assembly will remain leak-free for the target life expectancy.