PROJECT
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All photos by © Plumbing Africa Rory Macnamara
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Gas boilers . |
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Hot water circulating pumps with temperature gauges . |
Hot water production and reticulation . Hot water is produced using two 105kW natural gas boilers / two 11 000 litre low pressure hot water storage tanks which are heated by the gas boilers and store the water . Furthermore , two hot water circulation pumps are used to circulate water from the hot water storage tanks to the gas boilers at a flow of 5litres per second , thus 2,5litres per second per gas boiler . Water temperature is controlled at 65 degrees in the tanks .
Two heat exchangers in parallel are coupled to the hot water tank storage tanks in a closed circuit . Suitable water treatment and a rust inhibitor system is to be supplied for the closed circuit . Incoming water from the building main water supply pump set is heated by the heat exchanger before being supplied to the building . The pumps , one duty and one on standby , circulate water from the HWS tanks to the exchangers and back to the tanks . The pumps are variable speed drive ( VSD ) and are controlled by the hot water supply temperature to the building .
Two Grundfos hot water circulating pumps in duty and standby are used to circulate hot water throughout the building , ensuring constant hot water . Thermostatic balancing valves were installed on the hot water return pipes before connecting to the main hot water return ring main .
A shut off valve , PRV and NRV was installed in the closed hot water system near the tanks for
the filling of the hot water tanks from municipal supply . The PRV is set at 200kPa when filling the tank and the shut off valve is closed after filling .
All hot water pipes were insulated with Armalfex insulation and cladded with galvanised sheet metal in plant rooms .
Hot & Cold-water reticulation for apartments . Each apartment is fed from hot and cold Mepla pipes water pipe risers to each floor from the ring main on Parking level 7 . Each riser feeds all the apartments vertically aligned . From the risers each apartment is fed with hot and cold water by means of a manifold .
A service cupboard is allocated for the pressure reducing and metering stations on the outside of the apartment close to the kitchen . Inside the service cupboard are : a valve , strainer , water meter , PRV and valve for the hot and cold-water pipes . The service cupboards also hold the water and gas metering stations .
Hot water supply and return pipes are copper and hung from soffit of parking level 7 . Cold water pipes are galvanised steel .
Hydrant and hose reel installation A 30m hose reel was installed within an area of 500 square metres . Such hose reels complied with SANS 543 and installed according to SANS 10105-1 and SANS 10400 -W .
May 2022 Volume 28 I Number 3 www . plumbingafrica . co . za