Architect and Builder July/August 2015 | Page 28

The brief from Investec Property was to create new P grade commercial offices in Sandton The smoke extract and fresh air extracts are coupled into one riser to minimise duct space required. Make-up air is provided by pumping air into the lift shaft which is then directed into each office area using the lift lobby ceiling as a plenum. Staircases are all pressurised on separate systems for the parking levels and the office levels due to the geometry of the building. Domestic Water installation Water is stored in the basement in booster tanks and pumped to the roof by means of a twin 26 pump system. The building has sufficient water storage for 24 hours of water which is housed within the sectional steel water tank, a total of 22,000 litres. The bathrooms located on each level within the central core of the building make use of Grohe concealed cisterns and urinal sensors as well as Hansgrohe brassware. Hot water in the building is generated through an air to water heat pump coupled to a 3,500 litre hot water storage tank. This is as per the Greenstar office portable water and sewage calculator for category 3 fittings, and allows all 85 Grayston