The welded connection

PP-RCT pipe system

PP-RCT (Polypropylene-Random Crystalline Temperature) is a material classification used to describe the second generation class of PP-R materials (Type 4). It sets a milestone in the advancement of PP pressure piping systems

High impact resistance even at temperatures below freezing, the secure connection technology without added materials ensures that after connection, the pipe and fitting form a permanently sealed unit made of one single continuous material. 

Optionally, the system is also available pre-insulated – this enables fast, standard-compliant and cost-saving concealed installation.


Link to the products for the product line KELEN PP-RCT

Drinking water, sanitary and utility water piping for hot and cold water.  

PP-RCT (Polypropylene Random Crystallinity Temperature) is the material designation for the second generation of PP-R raw materials (type 4). It marks a milestone in the development of PP pressure pipe systems. ÖNORM EN ISO 15874, for hot and cold water piping systems made of polypropylene, was supplemented in 2013 by the classification for PP-RCT.

The KELEN pipe system has many advantages: ideal for hot and cold water in old and new buildings

  • KELEN PP-RCT/PN16 and PN20 diameter range d20 –110 mm for hot and cold water 
  • KELEN PP-RCT/PN10 diameter range d20–160 mm for cold water
  • Inside and outside corrosion resistant
  • No crystallisation points for limescale 
  • Safe connection technology without additional materials
  • Safe in terms of food safety, hygienically flawless
  • Low pressure losses due to smooth surfaces 
  • Low noise 
  • Temperature and pressure resistant
  • Low thermal conductivity
  • Cost-saving during installation
  • Guarantee insurance – also for consequential damage 
  • Secure long-term service life
  • Factory-insulated flush-mounted conduit parts

Pipes and pipe fittings are completely identical in the raw material type.

Field of application:PN20 - SDR series 6 
Class 1 – 60°C/10 bar 
Class 2 – 70°C/10 bar
PN16 - SDR series 7.4 
Class 1 – 60°C/10 bar 
Class 2 – 70°C/10 bar
PN10 – SDR series 11
Cold water – 20°C/10 bar
Dimension range:KE02 PN10: d20, 25, 32, 40, 50, 63, 75, 90, 110, 125, 160
KE08 PN16: d20, 25, 32, 40, 50, 63, 75, 90, 110
KE00 PN20: d20, 25, 32, 40, 50, 63, 75, 90, 110
KE06 PN20: d20, 25, 32, 40, 50, 63, 75, 90
Dim. LX - System:d20, 25, 32
Insulation:Insulating thicknesses: 4, 9 and 13 mm
Factory pre-insulated pipes in coil and straight length products made of cross-linked, closed-cell PE foam with special profile of dimpled and air chamber elements, extruded, viscoelastic protective film, tear-resistant mesh fabric and SENSO positioning in the UP area
Factory-pre-insulated fittings in material-identical design Thermal conductivity: 0.039 W/mK at 40°C 
Tests:ÖNORM EN ISO 15874 Teil 1-5 
ÖVGW Reg.Nr. W 1.254 
ÖNORM B 5014/1 
ÖNORM B 5019 
Colour:Grey with 3 coloured longitudinal stripes which accord to the pressure level
Special parts:KE06 KELIT ALU composite pipe PN20


  • Polyfusion welding (socket welding) using material-identical PP-RCT fittings with moulded welding sleeves d20–110 mm
  • Material-identical LX-insulated PP-R fittings with 4, 9 and 13 mm insulation d20–32 mm
  • Butt welding using material-identical POB fittings in d160 mm
  • Metal transitions with internal or external thread made of stress-free annealed, dezincification-resistant brass, pore-free and metallised d20–75 mm
  • Electric welding process by means of push-on electric welding socket d20–160 mm
  • Detachable Dutch connections d20–90 mm
  • Detachable flange connections d20–110 mm