Drainage flanges must be durable and must be able to be reliably joined to the drainage system plumbing.

They must also be cost effective and easy to install.

To achieve this they are best made of UPVC* because:

  • UPVC is the approved material for Australian and New Zealand Drainage Systems to AS3600.
  • UPVC is the only cost effective plastic suitable for drainage pipes and fittings that can be reliably glued with good durability to join pipes and fitting.
  • UPVC flanges bond correctly to UPVC pipes without the risks of bonding dissimilar materials such as bonding PVC to ABS. Standard PVC solvent cement is neither recommended nor suitable for this application.
  • With UPVC to UPVC, normal plumbing priming glues are suitable.
  • Plumbers invariably have PVC glue in their kit, but quite likely do not have the special glue required for PVC to ABS joints, and in the real world will mostly use what they have, resulting in potential expensive failures at a later date if they glue ABS to PVC with PVC type solvent cement.
  • PVC is inert to the chemicals often found in wet areas such as cleaning agents. Unlike other non-PVC flanges it is not subject to chemical attack causing environmental stress cracking and failure. For comparison, please see the chemicals resistance chart comparing PVC to ABS attached.
  • Buildings and pipes do move due to things like soil subsidence, intrusion of tree roots and different rates of thermal expansion. This generates stress in the joints which results in solvent stress cracks if the systems are not fully compatible with the UPVC pipes.
  • Stress generated from unsupported pipes hanging from flanges also results in solvent stress cracks if the flange systems are not fully compatible with the UPVC pipes.

These factors combined with the initial chemical attack of glues on non UPVC flanges can result in failure of the flange causing water leakage and damage to surrounding surfaces.

Do not install the cheapest flange now only to pay for potential expensive maintenance problems later.


* UPVC vs. PVC.

UPVC is the same resin as PVC, but specifically has no chemicals added to plasticise it or to make it flexible.

Comparison of Chemical Attacks on PVC and ABS