Projects
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3 basement . These both discharge above the basement level and operate together with various push fans that are spread across the area to assist in smoke flow towards the intake points .
In the basement ventilation VMG also implemented the positioning of CO₂ and CO sensors across the different levels to monitor the levels of carbon dioxide and monoxide . Having a lot of vehicle traffic through these areas , it can then be determined to either increase the fan speed of the ventilation or reduce it to save on electrical use .
Another notable design element of this project was the fire pressurisation system . There are four pressurisation zones in the building – the main stairwell , the fireman ’ s lift , the normal passenger lift and the goods lift . Each of these , due to regulations and the height of the building , required an emergency pressurisation system that operates together with the fire detection systems . These zones were designed based on simulation to achieve a 50 Pascal pressure differential .
Another control feature VMG implemented was electricity management , accommodated when a power shift occurs between power supplies . The generator switches off and goes through a restart . Every time this happens , the supply is not capable of managing a full load immediately – there is approximately a three minute time period for the generator to be able to start up and reach full capacity . Through the central controller again , all of the AC units are limited not to auto-restart until the generator is at full capacity again , whereafter a signal is sent allowing the AC systems to continue normal functionality .
CHALLENGES Changing a building ’ s design midway through ongoing construction was one of the more significant challenges in this project . The design
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1 . The top two luxury offices are fited with various ducted cassette units . 2 . The top floor boardroom with fresh air and hideaway units . 3 . The condenser units installed on the roof plant area . 4 . One of the sets of CO and CO₂ sensors installed in the basement levels . 5 . Each hotel room and space throughout the building has their own controls .
6 . Various actuators are installed throughout the top two floors that automatically open selected windows and doors on any smoke activation signal .
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RACA Journal I February 2021 www . hvacronline . co . za