A Guide to Pipe Fittings

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Industrial Piping System

Pipe fittings are components used to join pipe sections together with other fluid control products like valves and pumps to create pipelines. The common connotation for the term fittings is associated with the ones used for metal and plastic pipes which carry fluids. There are other forms of pipe fittings that can be used to connect pipes for handrails and other architectural elements, where providing a leak-proof connection is not a requirement. Pipe fittings may be welded or threaded, mechanically joined, or chemically adhered, to name the most common mechanisms, depending on the material of the pipe.

There is some inconsistency in terminology surrounding the terms pipe, tube, and tubing. Therefore, the term pipe fittings will sometimes be mentioned in the context of tubing as well as pipe. While similar in shape to tube fittings, Europress pipe fittings are seldom joined by methods such as soldering. Some methods overlap, such as the use of compression fittings, but where these are commonplace for connecting tubes or tubing, their use in pipe connections is rarer. It suffices to say that while there are general distinctions, the common usage of terms can differ from supplier-to-supplier, although they represent the same items.

In Australia, we can provide stainless steel pipe fittings, manufacturers, and suppliers. We specialise in large-scale stainless steel pipe fittings that have been fabricated. The torodial seat for the O-ring, as well as the strict tolerances in fitting design and manufacture, are at the heart of our one-of-a-kind press fitting system.
Strong joints and a precise fit are the result of precision pressing tools and strong press fitting components.

In this article, the concentration will be on discussing typical fittings and connection methods associated with rigid pipe and piping, with a limited presentation of the fittings that are associated with flexible tubes, tubing, or hose.

To learn more about the varieties of pipe, consult our related guide to pipe and piping.

Pipe Fittings Explained: Fitting Materials and Manufacturing Processes

Cast and malleable iron

Fittings for cast iron pipe fall under hubless and bell-and-spigot styles. Hubless designs rely on elastomeric couplers that are secured to the outer diameters of the pipe or fitting by clamps, usually a stainless steel band clamp that compresses the elastomeric material and forms a seal. These hubless or no hub designs are sometimes referred to as rubber pipe couplings or rubber plumbing couplings and are especially popular for transitioning from one material to another—from copper to cast iron, for instance. Bell-and-spigot, or sometimes, hub-and-spigot, fittings are joined today primarily with elastomeric gaskets that fit inside the bell and accommodate the insertion of the plain pipe end or fitting. Older systems before the 1950s were caulked using a combination of molten lead and a fibrous material such as oakum. Cast iron pipe is sometimes joined with bolted flanges, or in some cases, mechanical compression connections. Flanged joints employed in underground applications can subject the pipe to settlement stresses unless the pipe is adequately supported.

While there are both malleable iron pipe fittings and ductile iron pipe fittings available, the improved mechanical properties and lower cost of ductile iron is causing a shift towards greater use of that material.

Stainless Steel pipe

Fittings for steel (aka, “black pipe”) and galvanized pipe as found in residential and commercial plumbing work are generally cast and referred to as “malleable iron fittings.” They can be galvanized. Although standards list threaded fittings up to fairly large diameters, these generally are not used today as the threading of large-diameter pipe is considered needlessly difficult.

Steel and steel alloys

Aluminium compressed air pipe are often extruded or drawn over a mandrel from welded or seamless pipe. In smaller sizes they are often threaded to match threads on the ends of pipe. As sizes and pressures increase, they are often welded in place by either butt-weld or socket-weld methods. Socket-weld fittings, usually forged, are restricted to smaller pipe diameters (up to NPS 4, but usually NPS 2 or smaller) and are available in 3000, 6000, and 9000 class pressure ratings, corresponding to Schedule 40, 80, and 160 pipe. Socket fittings are welded into place with fillet welds, which makes them weaker than butt- welded fittings, but still preferable to threaded fittings for high-end work. The need for an expansion gap in the fitting precludes their use in high-pressure food applications.

Europress pipe Fitting

Europeans are particularly fond of press fittings with either a V or M profile (or contour) in stainless steel, carbon steel, or copper. Several manufacturers, including Viega, Geberit, Swiss Fittings, and ISOTUBI, distribute patented systems of press fittings. When compared to other types of connection, press fittings have the advantages of being quicker to install and being more secure. When using the appropriate equipment, pressing a stainless steel fitting can be done in less than 5 seconds. The majority of the pressing of fittings to pipes or other fittings is done with electrically powered press equipment, however manually driven press equipment is also available for certain applications. Additionally, most of the major brands include a plastic slip on the end of the press fittings, which allows for easy identification of whether or not a press fitting has been properly inserted and secured. Furthermore, no welding is required for the installation; press fittings with appropriate and region-specific certification may be used for gas lines, if they are available. Press fittings made of stainless steel and carbon steel can withstand pressures of up to 16 bars.

Durability, quickness, neatness, and safety are some of the advantages of this technology. In order to be utilised with copper tubing, some crimped fittings are designed to not require the addition of flux or filler metal. Even if the tube is moist, the connection can be accomplished. Crimped fittings, while suited for drinking-water pipes and other hot-and-cold systems (including central heating), are significantly more expensive than sweated fittings, which are more affordable.

EFFICIENCY

You will be astounded by the rapidity with which the Europress press-fit technology operates. Installation of the tube and fittings can be completed by a competent tradesperson without the use of qualified welders.

Consistency

Every connection is consistent throughout the installation, providing good connection quality and eliminating the need to worry about revising installations due to inconsistency.

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