- Category: PROJECTS
- Published on 30 January 2017
- Hits: 192
By Ilana Koegelenberg
The new, modern Netcare Christiaan Barnard Memorial Hospital in Cape Town doesn’t just boast the latest technology in health care, but also an impressive wet services installation to match.
On 5 December 2016, Netcare Christiaan Barnard Memorial Hospital entered an exciting new phase in its long history, when it relocated from the premises it had been occupying in the city centre since 1983, to brand new premises on the foreshore, adjacent to the Cape Town International Conference Centre.
The 16-storey, purpose-designed hospital is set to become a landmark in the City of Cape Town. Its new location is easily accessible from all major freeways into the city.
This new Netcare hospital offers a full range of medical disciplines — many of them highly specialised — to local, national and international patients. It incorporates, among others, 11 theatres and two cardiac catheterisation laboratories, with 61 of its 248 beds being intensive care and high-care beds for adults, children and neonates.
The new hospital building has been designed to international safety standards and incorporates sophisticated, ‘green’ principles and technology to ensure ongoing sustainability. Considerable emphasis has been placed on the inclusion of design elements to optimise infection prevention, and control and enhance patient wellbeing and their hospital experience.
Netcare Christiaan Barnard Memorial Hospital is a living tribute to its namesake, Professor Christiaan Barnard, who performed the world’s first heart transplant in 1967. His legacy of clinical excellence and innovation in South African medicine and that of other pioneers of important medical advances in South Africa are celebrated by means of exhibits at the lift lobbies.
Construction of the hospital’s shell began in 2013, whereas construction of the internal Netcare fit-out commenced in March 2015. All work was completed in time for the 5 December opening.
The client, Netcare, needed a water and drainage system that was efficient, compact and sterile, explains Reza Davids of Ekcon who handled the wet services design aspect of the project. The hospital required a drainage system that drains quickly with little or no chance of blockages. Water must be of adequate pressure and temperature (hot water), both for equipment and sterile purposes.
“As it’s a state-of-the-art hospital, it required many services to be incorporated into a small ceiling area, including HVAC, medical gas, water, drainage, fire protection sprinklers, electrical cables, and a pneumatic tube to transport medication,” explains Davids. “Finding the space to route our piping was very challenging.” Thus the water system had to be designed in such a way that the water ring main stayed within 3–4m of the sanitary fixtures to minimise the length between the sanitary fixtures and the water ring main. This was to reduce the amount of stagnant water in the pipe and subsequently reduce the chance of bacteria being discharged.
Davids walked us through the wet services design of the hospital.
The sewer system consists of vertical sewer stacks running from the roof of the building all the way down to the basement. There are areas where the stacks had to be re-routed to a different position on one floor to fit in with the architecture and routed back on the next floor, which made things quite challenging considering the amount of space and other services around.
All the stacks are collected on the soffit of the basement via collector pipes, which are then routed into a sewer manhole on the outside of the building. Ekcon, with the help of Modern Plumbing Works Cape as wet services contractor, also installed a backup sewer system that consists of a sewer sump in Basement -2 (where the oncology bunker will be located). This system comprises an upsized sewer pump that will kick in when there is a blockage in the council’s main sewer line in the road. This will pump the sewerage back into the sewer manhole on the outside of the building at a higher pressure, preventing the sewerage from building up and rising up through the sanitary fixtures on ground floor. As the hospital is a clinical area, such a rise up of sewerage would be completely unacceptable.
During construction, there were two cases of the council sewerage system causing blockages and as such, the sewage system was designed in this new manner to prevent this from happening once the hospital became operational.
The subsoil drainage system drains the water from the soil around the foundation of the building. This reticulates all around the pile footings, which then gravitates to two storm water sumps in Basement -2, where it will be pumped up to Basement -1 to the storm water outlet pipe.
The water system consists of a domestic water feed from council, which then reticulates up the building in a shaft and supplies water to the main domestic water tank on the roof. This tank, which has a volume of 400 000ℓ (400m3), can supply the building for up to two days in the case of an emergency.
The water discharged from the water tank reticulates down a shaft and supplies each floor (which consists of two water ring mains supplying either side of the floor).
The hot water plant, which was designed by Spoormaker & Partners, consists of a chiller with a heat exchanger, with backup heat pumps in case the chiller fails. The domestic water tank supplies the hot water plant with cold water and the hot water produced is reticulated down a shaft to all floors. The team also installed a backup booster pump on the council main feed in the event that the council’s water pressure drops. If this happens, the pump’s pressure sensor will sense the drop in pressure and the pump will be activated, pumping the water up to the water tank on the roof of the building, which then supplies the hot water plant and all floors.
A grey water tank is located on Level 8 and it collects water from the hospital’s autoclaves and renal dialysis plant room. This water then gravitates to the first and ground floors to be used to flush toilets and urinals, helping the hospital to save water.
As mentioned, the one element that was particularly challenging was fitting the drainage pipes in the extremely limited ceiling space and routing the piping around the HVAC ducts. “These ducts are quite large and because we have sprinkler pipes just below them, it was very difficult for us to co-ordinate around them,” explains Davids. “To solve this we required intensive co-ordination sessions with all design consultants, and all services had to accommodate one another.” Additional drainage stacks were added where a compromise couldn’t be made.
- The hospital required a drainage system that drains quickly with little or no chance of blockages.
- The hospital’s wet services design boasts various sustainable/‘green’ features, including the re-use of sterilised autoclave and renal care water.
Geberit HDPE was used for the sewer piping. “Because we had such a confined ceiling space, we required a pipe that would be customisable in regard to its fittings,” explains Davids. PVC piping has fixed fittings and therefore there were many instances where the size and the angle would have compromised the planned drainage route. With HDPE, the fittings are welded together, so the fitting and piping can be cut to the required size and angle, thus giving much more options with regard to routing the piping in confined spaces. The other advantage is that the piping is welded together, which means that there should be little to no leaks over a long period.
Geberit Mepla was used for the water piping as it is much more cost effective than copper piping and requires little to no maintenance. The pipes are also bendable, thus requiring less fittings to achieve the same result. There is also a cost saving on labour as the piping is crimped together rather than welded.
So what is the impact of the wet services system on electrical usage?
The installation has four pumps that require electricity, and the power consumption is as follows:
• 2 × subsoil sump pumps: Flow measurements taken on site indicate an inflow into each sump of approximately 15m³/hr. This may vary seasonally and over time. An estimated 19.68kWh of energy is required (assuming a pump efficiency of 0.6) for a 24-hour period per sump.
• Sewer pump sump: The sewer pump sump is provided for the future Netcare bunker areas, with a few toilets, wash hand basins and sinks, as well as some floor drains provided for the draining of the fire riser pipes. It is expected that very little water will be pumped from this sump — an estimated average daily volume of 2 000ℓ. An estimated 0.1kWh of energy is required (assuming a pump efficiency of 0.6) for a 24-hour period per sump.
• Cold-water distribution pumps: Water from the council mains is fed by gravity pressure up to the roof level to the main domestic storage tanks. From the main tanks, the water will be pumped into the building so that a minimum pressure at the top level of 3 bar is achieved. The domestic pumps will be regulated by a variable speed drive.
The total estimated daily water demand for the building is 120 000ℓ. An estimated 12.24kWh of energy is required (assuming an efficiency of 0.8) per day.
The hospital’s wet services design boasts various sustainable/‘green’ features, including the re-use of sterilised autoclave and renal care water.
Both the autoclaves, as well as the renal care service, produce sterilised wastewater that can be recycled, especially for flushing in water closets and urinals. It is anticipated that the autoclaves will produce approximately 3.6m³ of wastewater per day.
From the renal care/dialysis, it is anticipated that approximately 5m³/day of wastewater will be generated.
This water will be collected in a 4 000ℓ tank provided on parking Level 8 from where a separate gravity water system supplies the water closets and urinals on the first and ground floors. A total of 35 water closets and two urinals have been provided at these levels. It is very difficult to predict the precise water consumption. An average of four flushes per hour for a total period of eight hours per day amounts to a total daily water consumption of 9m³ per day, which is in excess of the total of 8.6m³ of wastewater available per day.
The estimated saving in water consumption is approximately 267 000ℓ/month.
List of professionals
|Owner||Hamilton Naki Square|
|Developer (superstructure)||Hamilton Naki Square|
|Developer (hospital internal construction)||Netcare 911|
|Architect (superstructure)||Fabian Architects|
|Architects (hospital internal construction)||BSM Architects and BVA Architects|
|Project manager (superstructure)||SIP|
|Project managers (hospital internal construction)||Mbatha Walters and Simpson Projects|
|Quantity surveyors||Mbatha Walters and Simpson Quantity Surveyors|
|Consulting engineers||Electrical||Rawlins Wales Cape|
|Mechanical||Spoormaker & Partners|
|Civil and structural||Ekcon|
|Wet services||Modern Plumbing Works Cape|
|Drainage piping||Geberit HDPE|
Images: Netcare / Johann Lourens