Which is more malleable iron or zinc

The name of the "fitting"(Fittings) stands for Fitting piece, Fitting, Connector and Accessory in the Pipe assembly technology. Each Piping system (Steel pipe, copper, stainless steel, plastic, multi-layer composite pipe) standardized fittings (Thread, solder, press, push-in, cutting ring fitting) or dimensions specified by the manufacturer. The fittings can be made of steel, malleable cast iron, copper, brass, gunmetal, stainless steel and plastic.
The Dimensions are from the Manufacturer documents refer to. About the specified dimensions is the so-called "z-measure method" (isometric illustration[Room scheme]) for the Prefabrication of Line parts possible.
The fittings will used For
· Straight connections of pipelines (sleeves, screw connections, couplings)
· Diameter change (Reductions)
· Change of direction (Pipe bends)
· Junctions (T-pieces [3 outlets])
· Crossings (4 outputs)
· Links to Components (Nipple)
· Connections of various pipe materials

Thread fitting - malleable cast iron
The Company Georg Fischer GmbH has 140 years of experience in efficient, precise pipeline assembly and is the developer the z-measure methodwho have a simple Prefabrication of Pipeline installations enables.
Even nowadays are still Threaded fittings used. The threads for pipes, fittings, fittings and other pipeline components are internationally and nationally standardized. The Size information the Fittings (e.g. R 1/2) behaves in parallel with the Nominal size specifications the Tube (e.g. DN 15). In contrast to the "newfangled" fittings in the Plastic- and Composite pipe installation have the threaded fittings no cross-sectional constrictions and thereby low resistance.
Both Thread types one differentiates between
  •  Connection thread: These pipe threads seal the thread in accordance with ISO 7-1 or prEN 10226-1 (those in the respective national edition, DIN 2999, BS 21)
  • Fastening thread: These threads do not seal in the thread according to ISO 228-1
This results in the difference, that this Pipe thread to ISO 7-1sealed in the thread mainly through metallic pressing (conical / cylindrical) of the completely form-fitting threaded surfaces in the sealing area, whereby through sealant (Hemp / Fermit, Teflon tape) improves the sealing effect and the cavities become airtight and watertight.
The Pipe thread to ISO 228-1 is a pure mechanical fastening thread. The seal, of the parts to be connected with it, takes place via Soft seals (Flat, pinch seals) or over metallic mating surfaces.


Source: GOK regulator and armatures company mbH & Co. KG

The material the Malleable cast iron fittings is a Iron-carbon alloywhich combines the properties of cast iron (castability) and steel (strength and toughness properties). The chemical composition of the melt achieves excellent castability and is therefore particularly suitable for the production of complex shapes and for the production of parts with very small wall thicknesses.
There Malleable cast iron is hard, brittle and not workable in the cast state, the structure can only be used after a subsequent heat treatment. A Long-term annealing treatment (Annealing) ensures very good machinability and very good toughness properties with at the same time sufficiently high strength. A distinction is made between two types of malleable cast iron
  •  Black malleable cast iron will be in a inert atmosphere (Inert gas or vacuum) annealed and has a uniform structure with a higher carbon content
  •  White malleable cast iron will be in a oxidizing atmosphere annealed and the carbon content of the edge zone is greatly reduced and the structure is decarburized, which is decisive for better galvanization or an alloying of the zinc layer, ensures higher strength with the same expansion and, through additional heat treatment, leads to conditional weldability and solderability.

To the Corrosion protection the malleable cast iron fittings galvanized. Whereby either the Hot-dip galvanizing or the galvanizing is applied. The Hot dip process becomes prefers used because doing a good Surface alloy with an even Layer thicknesses (at least 500 g / m2 or 70 µm). In the galvanic zinc plating only one is formed Top layer (maximum 25 µm) and no alloying with the material, which in practice is the Chipping at Expansion operations can lead. Therefore should galvanized fittings and galvanized pipesNot in Heating, solar and Hot water pipes to be built in.

Threaded pipe connection

Solder fitting
The Capillary soldering fittings (Soft soldering and brazing) are made from deoxidized Copper Cu-DHP (formerly: SF-Cu) CW024A (min. 99.90% Cu and 0.015-0.040% P [phosphor]) for molded parts, copper alloy (Brass Cu-Zn39Pb2, Cu-Zn40Pb2) and GunmetalCC499K (CuSn5Zn5Pb2-C) for Threaded parts and Castings manufactured and thus meet the requirements of DIN EN 1254-1. You can in Heating, solar, Cool-, Drinking water- and Compressed air systems can be used. The fittings should always be in front the processing from the Original packaging can be taken so that the occupancy of the Interior surfaces the Capillary soldering fittings With Carbon- and Lubricant residues the conditions to DVGW worksheet GW 8 (Capillary soldering fittings made of copper pipes [max. 0.5 mg / dm2]) correspond.


Solder fitting
Source: Viega GmbH & Co. KG

The Capillary soldering fittings will be in the DIN EN 1254 Parts 1 - 5 - Copper and Copper Alloys - Fittings - are listed and are for processing with Copper pipes suitable according to DIN EN 1057. All fittings must be legible and permanent at least with the Manufacturer's mark and, if it is practically possible, with the Nominal diameter, the number and the part of this standard. The soldering fittings and accessories are available in the dimensions 6, 8, 10, 12, 15, 18, 22, 28, 35, 42, 54, 76.1, 88.9 and 108 mm.


z dimensions solder fitting (Example)
Source: SANHA GmbH & Co. KG

About the z dimension (Construction dimension) specified by the manufacturers, the fittings can also be used for the Prefabrication (z-measure method) can be used. With its help, the exact one can easily be calculated Pipe length between Fittings and or Fittings determined. The basis for determining and applying the z-dimension is the principle - uniform measurement - middle - middle = M

Solder fittings - z dimensions - Viega GmbH & Co. KG


Solder fittings - SANHA GmbH & Co. KG

Press fitting
Press fittings are molded parts that come with a Crimping pliers in Tubular steel, Stainless steel-, Copper pipe or Multi-layer composite pipe installations be pressed. The pressing is one Pipe connection technologythat has been around for approx. 50 years is known in practice. Compared to conventional fittings (threaded and soldered fittings), these fittings more expensive and have in some cases considerably higher flow resistance.

Areas of application:

  • Drinking water (cold and warm)
  • Heating up to 110 ° C
  • Cooling water pipes
  • Sprinkler systems
  • Rainwater
  • Solar systems
  • Gas systems
  • Inert gases
  • Fire extinguishing systems
  • Compressed air up to 16 bar, oil-free

But the advantagessuch as B. the Time saving in the Assembly, the commitmentat Put, with those of Heat not possible is (fire hazard) and the supposedly unnecessary manual skills have led to this technique used more and more (in Small systems up to approx. 80%). It can be particularly problematic for handyman then, if they are not suitable for the respective system Pressing toole to have. But these can be rented. It should be noted here that Work at Drinking water- and Gas pipes just licensed specialist companies allowed to work.

The Press fit connection is a frictional connectionwhich is secured against pulling apart by pressing. The seal between the pipe and the fitting is made by inserting or placing them in the grooves of the fitting socket or the fitting socket at the factory O-rings. A DVGW certification mark is required for drinking water, gas and liquid gas installers.

For Gas installation or Solar systems need press fittings with special sealing elements be provided. Press system for solar systems with O-ring both made of EPDM (temperature up to +120 ° C, Steam compatible) or especially for use in the solar sector green sign (Temperatures up to +180 ° C or. +200 ° C (according to the manufacturer), but Not With Steam compatible).

Sealing materials for solar systems

Pioneering achievement: 50 years of pressfitting
Raxofix multilayer composite pipe
Pipeline systems with press fittings for all applications

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FlowFit - plugging and pressing
Geberit will bring that in spring 2021 FlowFit installation system With novel fittings and Pipe components with protective caps for multilayer pipes on the market. The system is mainly intended for the Drinking water- and Heating installation can be used, but is also used for Cool- and Service water, For Compressed air and Gases.suitable. The FlowFit system is for Heating installation to 80 ° C, for the Drinking water installation to 70 ° C and for one operating pressure up to 10 bar (1 MPa) approved.


Flow behavior in the FlowFit fitting

Hand crimping pliers and FlowFit fittings

FlowFit fittings

Combination - FlowFit with PushFit connector
Source: Geberit Vertriebs GmbH

FlowFit installation system

To install  +   To plan

Through the hydraulic optimization of fitting and pipe geometry reduced pressure losses achieved, which leads to smaller pipe diameters with lower pipe contents and discharge times. In addition, the fittings do not have any Dead water zones. The system is for the currentless hand press just two press jaws For eight dimensions (d16 to d75 mm) necessary. The fitting does not have to be completely enclosed, as is the case with other pressing techniques, the tool is attached to the Lateral crimping only on the side of the pipe. This enables better work in confined spaces.

Special properties of the system
The system does not require calibration or deburring of the pipe.
With the hand crimping pliers, crimping that is independent of current is possible so that the tool is always available.
The fitting has viewing windows that provide information about the insertion depth. If the pressing process is successful, the pressing indicator is released so that unpressed connections can be quickly and clearly seen during a subsequent check.
The tool and the indicator fit together like a lock and key. The risk of incorrect crimping due to incorrect positioning is thus almost eliminated.
The color coding makes the assignment very easy> blue pressing indicator blue tool, orange pressing indicator orange tool, mix-ups are almost impossible.
The lateral pressing point can be rotated in 45 steps and can be optimally aligned with the processor. This makes it possible to work safely and effortlessly even in difficult-to-access locations.
After the pressing process, the pressing indicator is released so that it is always easy to check which connections have already been pressed. Even with poor visibility, it can be clearly seen whether the pressing indicator is still present or whether the area has already been pressed.

Geberit FlowFit stands for a future-proof Take-back concept available, which collects the accumulated recyclable materials and the Recycling cycle feeds again.

Section - fitting with legend


Tectite® push-fit fitting made of brass for copper pipe
Source: Seppelfricke Armaturen GmbH

Push fitting

Become more and more common Connector systems offered. Some can be removed again later. In practice, non-detachable connections are preferred by specialist companies. Actually, only unsolvable systems can be tolerated.
The pictured Zewo plug-in technology is based on a metallic press ring (holding sleeve), which is located inside the plug-in fittings. This press ring is made of a special steel which, through a special heat treatment, achieves an enormous pressing force. When the pipe is pushed into the push-fit fitting, a lock pops out and the press ring presses the pipe onto the support body of the fitting with absolute certainty. The press ring perfectly absorbs the dimensional changes that may arise in the pipe.

The absolutely dense, non-detachable connection guarantees a high level of security. The connections are absolutely secure against tensile movements, but also against temperature changes and pressure loads.
They often have a disadvantageous effect very small cross-sections in the fittings has a negative effect on the flow.
Also the system "PushFit"from Geberit meets these requirements.

Cutting ring fitting (screw connection)
Ring fitting (crossing fitting)


Source: Lima ring fitting

In practice they are increasing Ring fittings (Crossing fittings) used. These fittings are there for everyone Pipe materials (Steel, carbon steel, copper, plastic and multilayer composite pipe) and all common ones Pipe connection techniques (Welding, soldering, pressing, plugging). Unfortunately, this makes them go craftsmanship for making overbows lost.
With this one fitting the crossing pipe is pushed through a hollow body with an inlet and outlet each.The water flows in a ring around the crossing pipe, which does not significantly increase the existing construction height.

Ring fitting