International Project
housed in a NEMA 4X polyurethane-coated cast aluminium housing with stainless steel hardware . Warning labels are installed for safety reasons .
The ducting on the roof is insulated and cladded ( jacketed ). A weather station is installed to measure ambient temperature and humidity and is connected to the BMS .
Condensate drains that are exposed to the weather elements are typically insulated , jacketed and heat traced to prevent freezing in cold months . Identification labels serve to indicate the heat trace .
Rooftop units are typicaly placed on top of roof curbs . Observe the outside air intake louver and the insulated condensate drains ( jacketed and heat traced to prevent freezing in cold months ).
A metal screen wall encloses the mechanical area on the roof . Note that the screen is not solid but perforated to allow airflow through it . Also observe the screen is raised 2 feet ( 609mm ) from the roof to allow additional airflow .
units . The perforated screen wall and opening below of screen wall improves airflow .
The annual winter climate can drop below freezing temperatures and therefore special care must be taken to prevent freezing of water pipes that are installed outside . Condensate pipes are typically insulated and equipped with electrical heat tracing systems . Nickel-copper bus wires embedded in parallel in a self-regulating polymer core that varies its power output to respond to temperature all along its length , allowing the heating cable to be cut to length in the field .
Heating cables can be overlapped without overheating or burnouts . The heat tracing system is controlled by standalone controller and connected to an ambient-sensing thermostat
It is fairly standard to install a unitary heating unit in each fire escape staircase to maintain a temperate space during winter months to prevent sprinklers from freezing .
Aluminium fixed pattern 3 cone stamped quare ceiling diffusers are used distribute the supply airflow in the corridors ,
toilets , receptions , and clinic spaces . Slot diffusers are used around the perimeter zones in some rooms like the exercise area . As with any other project numerous balancing devices were installed to balance and commissioning the air system allowing the HVAC system to run efficiently and effectively .
Passages connect the main reception to the various clinic rooms . Aluminium fixed pattern 3 cone stamped quare ceiling diffusers are used for supply air .
www . hvacronline . co . za RACA Journal I February 2022 49