PROJECT
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Niel Bosman, technical engineer at Stiebel Eltron
Southern Africa, explains that the choice of system is
largely a function of the size of the development. “The
fewer the number of units, the higher the price would
be per unit/tenant in the case of a centralised heat
pump system because of its fixed costs. A centralised
heat pump system consists of the heat pump itself,
storage capacity, ring main system, lagging of pipes,
the plant room itself – whereas with a decentralised
instantaneous hot water system all you need is the cold
water connection with the water heater connected to
the DB directly.
Eamonn Ryan
The selection of a hot water system depends broadly
on two factors: the number of units in a development,
and what the water is to be used for. The number of
units is similarly affected by occupancy levels: heat
pumps are most efficient when used to their maximum.
If it is the sort of development where people are away
for long times, then the heat pump will not achieve its
full potential. In that case, an on-demand system is
more effective.
The bathroom in a typical unit.
is not yet common in South Africa, and so the design
has emphasised more congregating spaces so that each
floor feels like a unique community. For instance, the
basement has been renovated to provide a mix of retail
and accommodation, with a creche. We have used every
inch of space,” says Katz. PA
“An instantaneous water system definitely works better
than an integrated system, where the need is for a
simple configuration of shower, basin and sink.
“With regards to the installation, the instantaneous
water heaters will be done according to SANS 10254.
Their installation is much simpler than a geyser, as they
do not have any storage capacity. So, no drip tray, TP
valve or vacuum breakers required. As for SANS 10400
XA, the instant water heater is quite new to the market
and was not included/considered when the standard
was written,” says Bosman.
“There is huge demand for housing in CBDs, which
is fuelling the trend to adapt and reuse existing
buildings – a form of recycling reflecting an urge
towards sustainability to reuse rather than demolish.
It’s an ethical solution,” explains Katz of Gregory Katz
Architecture, the architect on the project.
“There are a number of challenges to adaptation, but
also advantages. In this case, a good starting point
was the fact that the structure had an H shape, which
was conducive to good natural lighting, but the building
also had the ribbon-window design of the 1950s and
1960s, where there was no break between windows.
This made it tricky for fire control purposes to separate
the structure into individual units, but also enabled us
to be more creative in finding a solution.” That solution
was to intersperse clear glass with Georgian wire
glass, thereby creating an interesting façade set at a
45-degree angle so as to create a bay window feel.
“The idea of the community feel is that residents ‘take
ownership’ of the building. High density urban living
February 2020 Volume 25 I Number 12
Professional team
• Gregory Katz
Architecture
Contractor
• Pro Plumbing
List of suppliers:
• Geberit – piping
The architect’s perspective
• Nightwell Properties
• Gyproc – Rhinolite
Niel Bosman, technical engineer at Stiebel Eltron
Southern Africa.
• Triumph Taps, Solo
Sanitary Ware,
Triumph Showers
– mixers, taps and
sanware
• Stiebel Eltron –
water heaters
“Thus, the use of a rational design is required by
the professional in charge of the energy efficiency
of the building. Due to the lack of storage capacity
and the short pipe runs, the energy efficiency/power
consumption of the instantaneous water heater is a lot
better than that of a geyser or in this case, even a split
heat pump system,” he adds.
Developer
Greg Katz, architect at Gregory Katz Architecture.
www.plumbingafrica.co.za