Building Technology and Sustainability: Buildability, Energy Code and Green Rating
Building Technology and Sustainability asks whether the technical solution you recommend can actually be built in Hong Kong and whether it satisfies the territory's energy and green-building regime. Expect questions that pair a structural or construction choice with a statutory or sustainability consequence.
Structure, foundations and basements
- High-rise residential in Hong Kong is usually reinforced concrete shear wall and core; commercial towers are RC or structural steel frames with curtain wall.
- Foundation choice turns on geology and site constraints: large-diameter bored piles socketed into rock, driven H-piles where noise and vibration permits allow, or minipiles on tight sites. Basement excavation needs an engineered ELS scheme and often top-down construction to limit movement of neighbours.
- Curtain wall, cladding and glass walls need structural justification and performance testing; glass strength and falling-glass risk are treated seriously.
Statutory energy and green requirements
- Building (Energy Efficiency) Regulation (Cap. 123M) and the Building Energy Code 2018 impose OTTV on commercial buildings and RTTV on residential buildings.
- Buildings Energy Efficiency Ordinance (Cap. 610) requires energy audits and retro-commissioning for prescribed commercial buildings - existing buildings, not design-stage work.
- PNAP APP-152 governs GFA concessions for green and amenity features, subject to an overall cap of 10% of permitted GFA and to stated design criteria.
- BEAM Plus (HKGBC and BEAM Society), currently v2.0, is voluntary certification; adoption of Modular Integrated Construction attracts a GFA concession.
Worked example
A 20,000 m² office tower uses 150 kWh/m² per year, i.e. 3,000,000 kWh. A high-performance façade and efficient chillers cost HK$6 million more and cut consumption by 20% - 600,000 kWh a year. At HK$1.2 per kWh the saving is HK$720,000 a year, a simple payback of about 8.3 years, and roughly HK$10.8 million over a 15-year life before any tariff rise. The same measures improve the OTTV result and earn BEAM Plus energy credits, but check the OTTV calculation separately: a low electricity bill does not prove envelope compliance.
Traps that cost marks
- Using OTTV as a whole-building energy score; it measures envelope heat gain only.
- Treating BEAM Plus or LEED certification as satisfying the Buildings Ordinance or the Building Energy Code.
- Claiming GFA concessions beyond the 10% cap or without the required design criteria.
- Ignoring construction noise permits, waste charging and site access when the programme assumes easy delivery - MiC modules must physically reach the site.