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Pipes and fitting joints must be lastingly impermeable to internal and external water pressures (5m head of water) when subjected to the interactions which may arise between them and their surroundings.

Angular Deflection

The tightness of the joint must be maintained when pipes are angularly deflected relative to one another according to the table below.


Angular deflection of pipe joints

DN Angular deflection
mm/m of effective length
100 to 200 80
250 to 500 30
600 to 800 20
DN > 800 10


Shear Strength

Tightness must be maintained when the joint is subjected to shear force of the specified load as per the previously mentioned standards, In any case shear strength ≥ 25 N/mm nominal size.

Joint Chemical Resistance

Joints are not influenced by chemicals and remain tight in the PH range 2 - 12.

Temperature Resistance

The efficiency of the joints is maintained at temperature ranging between 10° and 70°C.

Resistance to ageing

The compression pressure is of decisive importance for the "Steckmuffe" K joint. In order to achieve a permanent tightly sealing joint, it is essential that the initial sealing pressure is continuously maintained at a sufficiently high level. For this requirement, the following factors are made use of:

Drop in relaxation and an increase in creep deformation.

The relaxation in stress approaches a limit asymptotically so that finite relaxation is maintained.

Creep deformation also approaches a limit asymptotically, resulting in finite deformation.

The remaining relaxation and deformation are sufficient to maintain a fully effective seal.

Resistance to Root Penetration

"Steckmuffe" K joints are not susceptible to root penetration.