inverted sustainability

The HKSAR Council for Sustainable Development (CSD) conducted a year long consultation exercise titled Building Design to Foster a Quality and Sustainable Built Environment. And now CSD has released the report [link].

One of the many issues raised in by the public was the coveted green features deal [BD Joint Practice Note 01],[BD Joint Practice Note PN2] essentially developers would be granted GFA concessions (READ more GFA) for providing gazetted green features. I don’t want to go into hideous detail on this decision, suffice to say that these “green” features included central facilities such as wider corridors, clubhouse, mail delivery room, etc. and also residential flat improvements such as balconies.

The consultation report noted the public views. However, for reasons best known to themselves, the CSD seems to believe its now expert, and includes a number of recommendations, including changes to the GFA concession arrangements.  If the Secretary for Development accepts implements the recommendations, some will impact the Hong Kong Green Building Rating System BEAM.

Green GFA

Don’t think for a moment that every CSD recommendation actually reflects the concept of sustainability, the report states:

The CSD recommends that the Government should reduce the level of GFA concessions for car parks in general and promote underground car parks where technically feasible through provisions of relatively higher level of GFA concession as compared with that for their above-ground counterparts.

Here CSD is promoting basement car-parking, compared to above ground parking, so the Life Cycle cost for basement parking must be superior right?  CSD have overlooked a few critical issues. Considering the construction work needed for top down excavation, and disposal of the created spoil.

Once created the basement car-park will require 24 hour 365 day mechanical ventilation systems and a higher level of illumination than an above-ground counterpart.  Also the actual construction area required to accommodate the same number of vehicles would require a larger footprint because:

1) Floor Area will sacrificed on every level for routing the necessary mechanical ventilation systems to grade level (consider the extra annual operating cost);
2) Floor Area will sacrificed accommodating the routing fire services =smoke control ventilation ducts back to to grade level;
3) basement car parking is inevitably below the water table, therefore requires a drainage system with drainage pumps to convey any waste water back up to grade level (consider the extra annual operating cost);

If you compare basement car parking with above-ground car parking, it doesn’t take a genesis to conclude that the latter is more energy efficient, and has a lower environmental impact.

Cap GFA Concession

The report noted there is no limit on the exempted area under the “green” features BD Joint Practice Note 1 and 2.  However, the CSD recommends limiting or capping the concession. It also suggests one way forward would be to provide a sliding scale for GFA concessions for buildings that achieve higher BEAM awards. The intention to encourage environmental best practice, the report states:

…….the Government may consider the feasibility of prescribing different levels of the overall cap corresponding to the overall environmental performance of the building by reference to certain benchmarks (e.g. BEAM Plus rating), i.e. the higher the rating, the higher the overall cap.

– John A. Herbert, consultant, Kelcroft E&M Limited