This appraisal is for a range of HYMAX unrestrained mechanical couplings and flanged adapters in sizes DN 80 to DN 600 complying with AS/NZS 4998:2009 Bolted unrestrained mechanical coupling for waterworks purposes.

HYMAX couplings are unrestrained mechanical couplings designed to suit a wide range of pipe outside diameters and are intended for jointing spigot ends of pipes, other than PE, in water and sewerage applications, in either above or below ground situations.

The coupling range includes long and short barrel couplings, reducing couplings and flanged adapters.

The innovative design features of the couplings include:

  • top operated fasteners to affect activation of the sealing mechanism, one on each end for sizes up to DN 300 and 2 on each end for sizes above DN 300.
  • two-layer detachable gaskets and gaskets with a flip feature that allows a wider pipe outside diameter range (reach) to be accommodated, when compared to traditional couplings.

gaskets with dual mechanical and hydraulic operation.


Product categoryUnrestrained mechanical couplings
PA NumberPA 1701 Issue 2
Report holderKrausz Industries Ltd
StandardAS/NZS 4998:2009 Bolted unrestrained mechanical coupling for waterworks purposes.
Publication date
Expiry date

Download appraisal

Title Format Download
PA 1701 Issue 2 - Krausz - Hymax Unrestrained Mechanical Coupling-Final.pdf PDF