Fittings

We have been known as a specialist for fittings for decades and supply our quality products to a wide range of industries that primarily process steel threaded pipes for industrial applications. The focus is on DVGW-certified malleable cast iron threaded fittings in accordance with EN 10242, which are marketed under the brand name HS Fittings. The range is supplemented by steel fittings (pipe double nipples) in accordance with EN 10241. We are one of the market-leading suppliers in both product segments. Stainless steel threaded fittings in grade V4A round off the overall range and are used to connect stainless steel pipes. We have a core range of pipe bends and flanges for the alternative joining technique of “welding” carbon steel pipes. In building services, pre-pressing pipes with press fittings as connectors is now the predominant joining technique for heating and sanitary installations.

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Subcategories

Fittings and not fittings

Until the invention of malleable cast iron, fittings were always forged. The process for manufacturing fittings using malleable cast iron was not developed until 1864. Initially, the fittings were mainly used for gas pipes, but they were also used early on for water and steam pipes. Plastic as a material for fittings was not ready for the market until the mid-1950s. In 1955, PVC fittings were presented for the first time at a trade fair. The word fitting is borrowed from English and means fitting, connecting piece or molded piece. Fittings are available in stainless steel, malleable cast iron, brass, gunmetal, copper and plastic. Fittings made of plastic, brass, gunmetal or white malleable cast iron are used for screw connections.

The malleable cast iron

The white malleable cast iron is annealed in an oxidizing gas atmosphere. This burns carbon from compounds in the edge areas of the casting. The diffusion of the carbon atoms creates a purely ferritic (ferrum = iron) structure in the edge areas. The cast iron material is forged within certain limits. This becomes very clear from the English and American translation of malleable cast iron. Malleable cast iron is called malleable cast iron in these languages: Malleable Cast Iron, which means forgeable cast iron.

Steel fittings

Pipe bend

Malleable cast iron

Flange

Stainless steel

Pressfitting stainless steel and carbon steel

Press fitting, copper

The fitting for pipes

Straight fittings in pipeline construction are very popular for connecting straight and curved pipe sections to each other. Pipe fittings, valves or cleaning openings, thermometers or pressure gauges are easier to install. At the beginning of the 1980s, the examination for apprentice welders still required the manufacture of 90 degree fittings from copper pipe, but today the time saved by buying ready-made fittings clearly outweighs this. Manually produced fittings require manual skill and a good knowledge of the material and temperature. The copper pipe to be bent is filled with sand and heated to such an extent that a true-to-shape bend can be achieved. The pipe is then sawn and widened at the ends.

The function of fittings

Fittings in a wide range of materials and dimensions are available for complex and widely branched piping systems.
Short or long sockets, double nipples and couplings are used for straight connections
For a change of direction angles or bends
For a diameter change Reducing pieces
T-pieces (3 arms) or crossings (4 arms) are used for branches
Flanges or nipples are suitable for connecting built-in parts
Different fittings must be used to connect different materials in order to prevent corrosion damage.
Example: Brass or gunmetal fittings are usually used to connect steel and copper pipes

Product innovations

Fittings

AquaGas V

Fittings

Flexi-Press

Downloads

Catalogs

Flyer

AQUAGAS

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Flexi-Press

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Price lists

Stainless steel threaded fittings

To the price lists

Press fittings

To the price lists

Steel fittings

To the price lists

Pipe bends & flanges

To the price lists

The Standard

The shape and dimensions of pipe fittings are regulated by standards.

DIN = German Institute for Standardization
EN = European standard
ANSI = American National Standards Institute

The diameters of the flow openings are specified as nominal diameters (the inner diameter of the pipe).

For gas and water installations, the pipes and fittings should bear the DVGW letter sequence. This abbreviation stands for the German Technical and Scientific Association for Gas and Water (DVGW), which is the recognized standard setter for the gas and water industry.

The connection techniques

In earlier times, pipes were joined together by screwing, welding or soldering. This was very time-consuming and required not only a good eye when soldering or welding, but also sometimes a mirror to be able to see the weld or soldered seam at all. Today’s techniques, such as plugging, clamping, pressing and gluing, are not only faster, but can also be carried out in areas where there is a risk of fire.

Copper solder fittings

The copper solder fittings offered for capillary soldering are subject to DIN EN 1254 and can be found, if still present, on every finned radiator in old buildings.

Push-in fittings

The push-fit connections are used for wastewater pipes made of ceramic, concrete and HT and KG pipes. The abbreviation KG pipe stands for sewer base pipe. They are orange-brown in contrast to the gray HT pipe (high-temperature pipe). The HT pipe can withstand temperatures of up to 95 degrees. There is usually a rubber sealing ring in the groove. Greasing the rubber helps enormously when fitting together.

Press fittings

Today, professional heating and plumbing companies work almost exclusively with press fittings. Special pressing tongs or electric pressing machines are used to press copper, steel or multi-layer composite pipes in a single operation. The advantage is the time saving, the disadvantage is that the fittings are relatively expensive.

Fittings with M and V contour

For pressing metal pipes, the press fittings have a visible bead at the sleeve ends, into which an O-ring is inserted from the inside for sealing. After using the radial press, the original circular cross-section is transformed into a hexagonal shape. The durability and quality of the O-ring is crucial for the service life of the entire system. This is why there are different sealing rings for heating, cooling and drinking water systems than for solar systems, gas installations, the transportation of hydrocarbons and pressure lines. In fittings with an M contour, the bead is located at the outer end of the fitting. During pressing, the bead is compressed on all sides. This pressing process causes the inserted O-ring to deform and to fit snugly against the inserted pipe. To ensure a tensile and torsion-resistant connection between the fitting and pipe, the socket is pressed in at several points around the bead. On fittings with a V-contour, the bead for holding the O-ring is located in front of the end of the fitting. The socket is stamped all the way around in several places in front of and behind the bead using the pressing tool. The pipe pressed in this way is then also resistant to rotation and tension.

Press fittings for PE (polyethylene) and multilayer composite pipes

In order to prevent severe deformation during the pressing process, press fittings for plastic pipes are fitted with support sleeves so that they can be pressed radially.

Threaded fittings

All major companies in Germany have their threaded fittings manufactured in Asia. Pipe nipples, weld-on nipples or blind plugs are imported from the Far East due to the low manufacturing costs. Threaded fittings made of stainless steel are manufactured using the investment casting process. The threaded fittings for the European market comply with the ISO7-1 standard. This means that the thread dimensions comply with the international ISO7/1 standard. DIN EN 10226-3 applies to the new gauge system in accordance with ISO7/1. This pipe thread is designed for a thread-sealing connection.

Weld fittings

Weld fittings with a polished surface are installed in the food industry in particular in order to comply with hygiene guidelines. These fittings are also standardized and are formed from either seamless or welded stainless steel pipes.

The maximum achievable pressure values of pressfitting systems

The rules for carrying out pressure tests are specified by the DVGW. The press connections can withstand loads of up to 16 bar as standard. The prerequisite for this is a well-maintained pressing tool, perfectly lubricated and free of metallic residues and dirt. The pressure resistance tests are preferably carried out with water, as other liquids, such as oil, could have an influence on the O-ring. Some laboratories wanted to know even more precisely and also measured the burst pressure values (the pressure value at which the correctly crimped fitting detaches from the pipe) for various pipe diameters under the strictest safety controls.

Stainless steel press fitting

Pipe diameter Burst pressure

12 mm 200 bar
15 mm 170 bar
18 mm 130 bar
22 mm 170 bar
108 mm 50 bar

The measured values show that for all standard applications of a pressfitting system, the guaranteed maximum pressure of 16 bar offers maximum safety and, in the event of a disaster, would have to increase many times over before the pipe system bursts. For heating and sanitary systems in particular, the pressfitting system is a real asset in terms of the time factor and is almost without alternative in times of rising labor costs.