The Australian Building Codes Board have released an update to the WMTS-040:2016 Waste pipe connection outlet and gratings, separate or integral specification. The update is now released as WMTS-040:2018.
The objective of this Technical Specification is to enable product certification in accordance with the requirements of the Plumbing Code of Australia (PCA). The objective of this revision is to specify what types of material are suitable for waste pipe connection outlets and gratings.
The WMTAC found that WMTS-040 had no materials specified, and as such was potentially open to individual interpretation.
The reason for the inclusion of a Materials section is the unfortunate confusion which allows unsuitable materials such as aluminium to be used as waste pipe connection outlets and gratings, either separate or integral.
Aluminium, although a durable, workable and generally reliable material is unsuited to particular applications because to its inherent susceptibility to corrosion when in a stagnant solution that is deprived of oxygen. Further, aluminium is tolerant to a range of pH values of between 4 & 8.5. Cementous products such as mortar, cement, concrete, tile glue, grout, bricks etc. can generate highly alkaline solutions of pH between 10 and 13. When this solution contacts the aluminium, particularly a crevice such as a corner, or scratch on the surface, corrosion can occur.
The WMTAC concludes that the use of aluminium should be restricted in its use under WMTS-040, particularly where exposed to wet environment, such as bathroom floors.
WaterMark Technical Specification WMTS-040: 2018 Waste pipe connection outlets and gratings, separate or integral was prepared by industry to supersede WaterMark Technical Specification WMTS-040:2016.