11 days into the new NCC2019, I am starting to see consultant's specification to reference it for compliance requirements, however we just need to look at the designs and system descriptions … nothing seemed to have changed! It would seemed to me business as usual. Business as usual is not enough with the new NCC2019.
I am both happy and sad at the same time; happy that the NCC2019 is finally addressing energy efficiency and efficacy quite adequately as it should have, but sad for the profession, to the extent we need the NCC2019 to specifically point out the exact metrics.
Let's decipher NCC2019 a little. Here are some examples why I believe the NCC2019 is not going far enough.
The clause (c)(i) below on page 368 stated the average pressure drop in the index run must not exceed 1Pa/m, we have been using 0.8Pa/m for more than 10 year in our designs following best practice guidelines by ASHRAE.
With reference to (vii) page 369 on attenuators. I would agree with attenuators pressure drop must not exceed 40Pa if and only if we really need them. In 2018, I recommended to remove the attenuators specified by the base building consultant design for kitchen exhaust system. There were no noticeable noise perceived attributing by the exhaust fan after the removal. In the early 2010, I challenged the acoustic report that recommended attenuators for every air handling units, we ended up with no attenuators, but six metres of internal lining before and after the air handling units.
We need engineers to be engineers. It's our social and moral responsibility to mitigate heating or cooling loads as much as we possibly can. Finally predicted mean vote (PMV) made it into the NCC.
To help you understand better what PMV is all about
What interests me the most is Part J5.2(a)(viii) Air-conditioning system control. We do not need precise temperature control for human comfort! We are now required to widen the control dead band to no less than 2°C
What does all this means, heat mass cooling or better know as evaporative cooling will be as effective as vapour compression cooling for our indoor climatic comfort.