BigBen Construction (Pty) Ltd are leading South African contractors passionate about the green credentials of their builds: here managing director Colin Ridley tells TABJ about their recent Little Moorings project
TABJ: Can you tell us a bit about the ‘green aspects’ of the ‘Little Moorings in Century City’ project?
Colin Ridley: Little Moorings is a 42 unit, sectional title development situated in Century City alongside one of the main canal tributaries. The main “green aspect” of the building is that water is centrally heated via a heat-pump system situated on the roof. A heat pump has an efficiency for the heating of water of between 3 and 3.5. This means that for every one kilowatt of electricity input an output of heat is between 3 and 3.5kw. In comparison a standard geyser will produce at most one kilowatt of heating for every kilowatt of electrical input. Further to this the water-heating system at Little Moorings is split into two separate heat pump systems. In the event of requiring maintenance or a mechanical fault the building can still be supplied with hot water off one of the systems for a period of time. By centrally heating water for all units there is also an economy of scale that is taken advantage of due to the diversification factor in water usage. To reduce the aforementioned statement into hard numbers the following comparative calculation displays the electrical saving: the average geyser has a 2.5kw element which would result in a design load of 105kw for 42 units; the central system has two 7kw heat pumps with a design load of 14kw. The saving displayed here being self-explanatory.
Each dwelling has a water meter in it that is connected to a central “data box with sender unit” and the managing agents are able to read water consumption of each unit from their office. Each owner/tenant is thus charged for hot water (being the amount of water plus the cost of heating) which makes this a more equitable system noting that most bodies-corporate split the water bill via the PQ ratio rather than actual consumption per dwelling. In addition to the central water heating, all Little Moorings units are fitted with gas hobs, noting that in a standard residential unit the electrical hob is probably the second most energy-hungry appliance after the geyser. The accommodation of gas hobs was done in consultation with the local fire department to ensure that all local municipal regulations were complied with as well as slight kitchen design alterations to accommodate the gas bottles. Lastly all internal light fittings as well as walkway light fittings are low-energy compact fluorescent lights and the downlighters to the main lift core areas are all LED fittings. The basement parking lights are on a combination of daylight switches and movement sensors so that in the event of there being no-one in the basement at night the lights switch off and will only be activated on movement. When all the above factors are taken into account and electrical calculations are done the energy savings incurred with the above sets a new standard for residential sectional title developments. When these energy savings are converted into a monetary value it is very exciting to see how efficient a building can be in energy usage.
Little Moorings was also the first development in Century City to be connected to the Century City Connect main fibre optic highway that runs through the development. This gives each dwelling exceptionally fast fibre-optic internet connection as well as carrying the full DSTV service and telephony services. In addition there are a host of “free to air” additional TV channels which operate free after the purchase of a minimal cost decoder.
TABJ: What would you say the split in the business is between commercial and residential builds for your company?
CR: The split in builds between residential and commercial for BigBen Construction varies from year to year. Fortunately the two markets follow different economic cycles (although in extreme market conditions they may often share similar peaks or troughs) and if a construction company is adept and comfortable with both types of construction, which BigBen Construction is, it is easier to keep a more consistent flow of work which is critical in our industry to retain the skills acquired and developed in previous projects.
TABJ: What do you see as expansion areas for your business?
CR: We were fortunate to be working in conjunction with Rabie Property Group at Little Moorings who work in close conjunction with their contractors in the development of green building principles as well as the inclusion of high tech “data and communication” provisions to their buildings . We are in addition progressing with Rabie Property Group on the construction of Quayside, a 63 unit sectional title development, which is being developed off all the same main principles of Little Moorings in terms of central water heating, gas hobs, vertical transportation by means of lifts, Optic fibre connectivity etc. The Quayside development will be the highest building Bigben have done to date with the structure topping out at six stories high (excl basement). Quayside, we expect will be the first of many future higher rise structures for BigBen Construction, this being a natural progression in construction complexity that was initially embarked upon six years ago when our business commenced growing from single residential construction into small commercial and sectional title structures.