Connections and Flange Types on Piping & Fabrication

We continue with Connections and Flange Types on Piping & Fabrication here, and this chapter will make us know what is Flange and what kind of types that Flange have, and this is the explanation on from Piping and Fabrication.

Proprietary Bolted Connections. 

There are various proprietary bolted pipe joining systems produced that are not formally addressed by any standard. Under the various piping codes, pressure-retaining components not covered by standards specifically cited as acceptable for use under the ‘‘Code’’ may be used provided their design is proved by analysis or proof testing or a combination of both.

Flange Types
Flanges differ in method of attachment to the pipe, i.e., whether they are screwed, welded, or lapped. Contact surface facings may be plain, serrated, grooved for ring joints, seal-welded, or ground and lapped for metal-to-metal contact. Some common types of joints and facings are shown in Fig. A2.18. In Section VIII, Unfired Pressure Vessels, of the ASME Boiler and Pressure Vessel Code, three types of circular flanges are defined, and these are designated as loose-type (Fig. A2.17), integral-type (Fig. A2.16), and optional-type flanges. Under the code, the welds and other details of construction shall satisfy the dimensional requirements stated therein.

Loose-Type Flanges. 

This (slip-on) type covers those designs in which the flange has no direct connection to the nozzle neck or the vessel or pipe wall and those designs where the method of attachment is not considered to give the mechanical strength equivalent of integral attachment.

FIGURE A2.16 Typical integral flange (welding neck flange)

FIGURE A2.17 Typical loose flanges (threaded and slip-on)

Integral-Type Flanges. 

This type covers designs in which the flange is cast or forged integrally with the nozzle neck or the vessel or pipe wall, butt-welded thereto, or attached by other forms of arc or gas welding of such a nature that the flange and nozzle neck or vessel or pipe wall is considered to be the equivalent of an integral structure. In welded construction, the nozzle neck or the vessel or pipe wall is considered to act as a hub.