The heating, ventilation and air-conditioning (HVAC) contract for the new 25 000-m3 Protea Gardens shopping centre currently under construction on the Old Potchefstroom road, on the outskirts of Soweto, has been awarded to WSP Consulting Engineers. Hoping to benefit from the current retail boom, Protea Gardens will be the biggest shopping mall in Soweto when it opens its doors in April.

“It has been designed along the architectural lines of a smaller local shopping centre that will serve the needs of the residents of Soweto and surrounding communities,” explains project director Graeme Page. He says that ARC Architects designed a mall of the highest quality, with impressive, yet functional, finishes. “Naturally, our HVAC system must fit in with the architects’ design and be as unobtrusive as possible,” he adds.

WSP Consulting Engineers has been contracted to do the air-conditioning, the fire design and the rational firework.

“Each of the main shops will have their own air-conditioning systems because they can account for individual factors like heat load, running hours and people densities,” elaborates Page. “The smaller shops will be divided into various zones, where large-package units will be installed to do zoned control for effective air sharing. “Operating and maintenance costing will therefore be calculated on a proportional-area basis.” The mall area itself will not be air-conditioned, but will rely on overflow air from the shops to maintain suitable conditions. “This method of supplying air to the mall is cost-effective in that the mall does not have to be provided with its own air-conditioning system,” Page maintains. WSP Consulting Engineers chose to use simple hide-away split DX units for all of the lineshops, with the mini-majors having their own packaged equipment. This system was selected to ensure that each tenant contributes directly to its own running costs and can also choose whether or not to have air conditioning in the shop.

“The tenant coordinator on the project, Gavin Tagg, of Retail Network Services, has worked tirelessly to bring the right tenant mix into the centre,” says Page.

The anchor tenant will be a 2 500-m3 Shoprite outlet, with the rest of the centre comprising several mini-major tenants, including big retail and clothing stores, restaurants and banks. Shoprite will have its own packaged air-conditioning equipment – an evaporative condenser-cooled plant, in accordance with its specification. WSP Consulting Engineers has installed similar equipment for most of the Shoprite stores in South and Southern Africa. “We have provided a system for the canopy extracts in the food shops, all of which are situated on the outside of the building,” says Page.

“Each tenant has its own extraction facility and can operate it as required, and sufficient make-up air is introduced for the larger canopies, where a large volume of air is being extracted from a shop.” In addition to the HVAC component of the mall, WSP Consulting Engineers worked closely with the Fire Department on the design of the smoke- and fire-extraction system, which is an integral component of the overall project. WSP Consulting Engineers’ Doug Blaine motivated a drenching-type system in the malls, which effectively cuts the shops off from the mall. This has saved the client a large sum of money and, together with a smoke-extraction system to the malls and main shops, has provided the client with an economical fire-protection system for the building. The architects had to ensure that the mall design would accommodate the drenching system and the accompanying smoke-extraction component.

Protea Gardens is one of several shopping centres that WSP is completing in this manner, and Page says that, in his view, this approach has been highly successful. His team is already hard at work on the next shopping centre to be completed along these lines – the nearby Jabulani shopping centre.

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