Design Reporting Provisions in AS/NZS 1547:2012 On-site domestic wastewater management

 The provisions within AS/NZS 1547:2012 (AS/NZS 1547) dealing with design reporting cover a vast range of topic areas scattered throughout the Standard, some of them overlapping. The question arises, what is an appropriate structure and content for a design report conforming to the provisions of AS/NZS 1547?

 Incorporating content dealing with every aspect of the design process considered in the Standard would seem to be a complex undertaking, and could indeed be unnecessary for many small scale projects. Hence, a decision needs to be made by the designer as to the level of detail necessary to ensure design adequacy, and to confirm the recommended system covers all relevant design elements in presenting an outcome appropriate to the site, soil, environmental conditions, design and operational risks, and the client’s expectations.

 Those provisions dealing with “designer” and “design reporting” in the Standard have been extracted into Table B of the document “Design Reporting Provisions – AS/NZS 1547:2012 On-site wastewater management” which can be accessed from the pages sidebar to this blog post. Table B is preceded by Table A which sets out suggested topic and sub-topic headings for a typical design report, and links these to the relevant provisions in the Standard by reference to Table B.

 Overall there are five sections in the suggested report content, these being supported by five appendices.

  1. Introduction
  2. Site and soil evaluation
  3. System design
  4. Installation and commissioning requirements
  5. Operation and maintenance requirements
  •  Appendix A: SSE report
  • Appendix B: Design calculations
  • Appendix C: Risk management summary
  • Appendix D: Loading Certificate
  • Appendix E: Site plans and construction details

 The host of provisions re content of a design report as detailed in the Standard would appear to require very detailed and complex reports. However, what the Standard does is set out a comprehensive set of factors which need to be addressed in any design, but without providing guidance on how those factors are to be reported on. The challenge is to identify those factors which are important within a specific design.

The best approach for a designer may be to compile a checklist of items essential to covering all aspects of design, and then to use this for specific design projects to confirm which are relevant to the particular site and design brief. Table B provides the essential items for compiling such a checklist. Individual designers can thus draw up checklist appropriate to their area of on-site wastewater management practice and ensure that all relevant provisions in AS/NZS 1547 are not overlooked.

It has to be borne in mind that design reports have to be thorough, clear, concise and economical. Over reporting increases costs to the client and diminishes competitive edge where several consultants may be quoting for a project. However, although a design report which conforms to the provisions of the Standard may, on the face of it, be more costly than a non-conforming report, the AS/NZS 1547 compliant consultant should be able to emphasise that any extra cost provides quality and value in terms of a sustainable design solution.