Post by techworks on Aug 22, 2018 13:09:15 GMT 12
GD06 is a great technical resource for on-site designers, but the extremely prescriptive methodology requiring comprehensive documentation of the design, risk management and commissioning is imposing a huge additional time input and responsibility on designers that is significantly increasing design costs.
e.g GD06 Section F now require the following documentation:
-management plan
-pre commissioning test
-cold commissioning
-hot commissioning
-commissioning report
Some of these tasks are undertaken by the contractor as part of the construction (though often not documented), and some aspects of the commissioning and testing are "observed" by the designer which are usually documented.
On a commercial system with a construction cost is $100k+, this level of documentation is justified and necessary and easily included within the design fees for such work. However on domestic systems with a construction cost in the region of $15-25k a typical design fee is expected to be in the region of <10%.
Even a basic septic tank system now requires as a minimum some form of dosed loading and LPED trenches, which requires specific hydraulic design and consideration of site specific constraints, so the design time (and cost) has increased and is often in excess of 10%. The additional time to prepare all the documentation now required is in the often equivalent to the design input so effectively doubling the time (and cost) for designs on domestic systems.
Just completing the check appendix C1.6 Design Report checklist is probably another 1 hrs work!
GD06 does not appear to make any allowance for the scale of the work, or risk to the environment, in setting requirements for the level of detail required for these additional reporting requirements.