WSAA is pleased to announce a new product and information guidance note titled WSA TN 13 Hydraulic performance of manufactured maintenance structure bases is now available for comment.

Technical Note:  DR WSA TN 13

Title: Hydraulic performance of manufactured maintenance structure bases

Public Comment period Closures: 3.00 PM AEDT 31 October 2022


WSAA is currently reviewing WSA 137 and will be carrying amendments to correct clause numbering errors and is all investigating the provision for a new adhesive glue for PE to PVC-U connection, provided this adhesive glue can demonstrate compliance with the durability requirements.

With the release of WSA 137 Version 3.1 we included in the scope provision for a spherical base for MC and MS’s and included a note for MH with alternative base designs (i.e. without formed channel) indicating that they may be considered subject to a hydraulic assessment of the flow properties.

A literature search conducted by WSAA and our appointed Consultant failed to identify any existing published test method for conducting a hydraulic assessment of the various flow conditions through a spherical MH base design. So we decided to develop our own. It is intended to incorporate the requirements in the final draft of Technical Note 13 into a new Appendix in WSA 137  titled Hydraulic Assessment of the Flow Properties.

The attached DR WSA TN 013 specifies the hydraulic test plan requirements for assessing the suitability of spherical and other alternative bases for manufactured maintenance structures, i.e., MS, MC and MHs, for installation on reticulation sewers.  A reticulation sewer is generally DN150 to DN300.

Although there is no industry standard, comparable to WSA 137, for maintenance structures manufactured from materials other than PVC-U, PP or PE, such as GRP or concrete, the hydraulic and test plan requirements developed in this report would be equally applicable to all such manufactured maintenance structures.

WSAA is seeking support for this initiative and input into its development. 

Comments are welcome by manufacturers, supplies, designers, installers and asset owners, using the comments form and emailing by 3.00 PM AEDT 31 October 2022. A copy of the DR WSA TN 013 is attached, along with a comments form.

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4 Aug 2022

Carl Radford

Carl Radford

Program Manager Asset Creation