In the plumbing game not all pipes align or match

Got two pieces of poly pipe you need to join and they aren’t the same diameter?  The simple solution is PLASSON poly pipe reducing fittings.

PLASSON compression reducing fittings can easily join two different-diameter metric HDPE pipe. Our Reducing Sets also help you modify existing fittings to connect pipe of different sizes and, using PLASSON adaptor kits, you can also connect pipes of different materials.

Compression reducer fittings match common pipe sizes and are usually PN16 rated.

‍PLASSON reducing fittings are suitable for water and other similar fluids with pressures up to 16 bar, however, this varies with the ambient temperature and temperature of the pipe contents.

A compression reducing tee fitting is used to tee off a metric HDPE pipe and add a smaller size outlet. Compression reducing tees are often used to supply water or other fluids off a main pipeline because the smaller off-take provides less flow than the original pipeline.

PLASSON reducing sets are available in the 110mm to 20mm range. They can be inserted into will existing PLASSON metric compression fittings to reduce the size of the outlet whilst maintaining pressure ratings and eliminating leak risk.

  • Increase flexibility of existing fittings – convert tees or elbows to another size
  • Reduction without threads – eliminate leak risk and maintain pressure rating
  • Utilises the PLASSON Captive O-Ring system – no movement and high compression
  • Poly-to-Copper adaptor kits available


Compression reducers are suitable for outdoor use and are resistant to etching by numerous chemical substances and are UV stabllised.

These fittings are compatible with PELD, PEHD, PE40, PE80 and PE100 pipes, and may also be known as compression reducing joiners, compression reducing couplings, compression reducing couplers or compression reducing pipe joiners.