Project
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valves , a strainer , and flushing bypass at approximately 1 metre into the internal space .
The chilled and hot water system is a primary constant secondary variable system to allow for lower power consumption when the cooling and heating needs are in part load while utilising variable frequency drives on secondary pumps and multiple scroll compressors in the heat pump chillers .
A new dedicated outside air filtration unit is installed on the mechanical floor on level 15 to provide ducted filtered fresh air to the new offices and retail levels below . Two new ducts are installed in the existing riser shafts because a single duct would not have fitted into the existing riser shafts . Balancing dampers and fire dampers are installed on every tap-off to the floors they serve .
© RACA Journal | Benjamin Brits
1 and 2 : The toilet exhaust system .
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© RACA Journal | Benjamin Brits
The outside air unit on the 15th floor .
A new toilet exhaust system is also installed on levels one to nine to cater for the various gang toilets on every floor . The toilet exhaust system is a standalone system per floor , each consisting of two axial fans with sound attenuators and exhaust weather louvres .
The main reason for designing standalone exhaust systems on every floor in lieu of a central exhaust system is due to lack of space in the existing riser shafts . The existing riser shafts are taken up by the life safety systems like the new stair pressurisation systems , the outside air system , chilled and hot water pipes and other electrical , fire and plumbing systems .
A brand-new basement ventilation system is installed in compliance with the local and national building regulations . Large exhaust fans are strategically installed in two corners of the basements while outside air is pulled in from large vertical concrete shafts and louvres on the opposite side of the basement .
Multiple jet fans are utilised to force air flow from the air inlet point to the exhaust air point . This arrangement allows cross ventilation while minimising the need for long duct runs . Each basement had their own set of fans . Old stale air from the basement is exhausted vertically up into the atmosphere
© RACA Journal | Benjamin Brits © RACA Journal | Benjamin Brits © RACA Journal | Benjamin Brits
3 and 4 : The discharge position of the basement exhaust duct , showing how it was hidden by the architect on the ground floor .
on street level and their positioning was carefully coordinated with the architect to hide and obscure a view of the basement ventilation ducts . The basement ventilation system doubles up for smoke evacuation of the basements .
The basement exhaust fan .
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