28 PROJECT
the hot water design, piping installation, how quickly the
boilers heat up and how rapidly they cool, and the water
coming out the tap – LEED confirms the design matches the
energy and water efficiency requirements of the client.”
Challenges with design
Campbell explains that LEED was chosen over other
international green systems for a number of reasons, but
primarily because LEED audits, does physical checks on
everything and follows through on its system before issuing
its rating. “They have a process which verifies each facility
as it is complete that it conforms to their requirements,
thereby giving the client reassurance – because otherwise
this building is a big project to track.”
The Grundfos pumps are on back-up generator power, so that the building will always
have water.
The extent of ground water was a challenge relative to
the site, says Colin, though that primarily affected the
civil engineers “who sorted that out” says Griffiths. These
were not especially challenging, they say, but simply the
parameters of the design. Bulk earthworks for the project
started in August 2017. The development was scheduled
for completion in the first quarter of 2020. Deloitte began
operating from its new South African base from April 2020.
The real challenge was the tight time frames demanded
by the client, due to financial constraints and the need to
start getting a return on investment in the form of rent. The
entire construction phase has been achieved in virtually a
single year.
The wet services engineers worked closely with the
architects as to the specifications of the wet services
system, which the architect then made provision for in the
drawings. “We give them the parameters of what we need
in terms of space and head room and they then try work
around that.”
Although there is also a combination of rainwater harvesting and borehole water, the heart
of the plumbing systems at the Deloitte building is water supplied from the municipal
mains.
irrigation with 100% harvested rain/sub-soil drainage
water. Notwithstanding the extent of the property, Campbell
explains that the pump is relatively small as the irrigation
works on a circuit system and irrigates by the hydroponic
drip system.
With the addition of a special flow limitation system the
faucets by Hansgrohe/Duravit reduce water consumption
by up to 60%. The Duravit urinal flush systems have flush
actuator plates set at only one litre a flush. These flow
capacities are dictated by the LEED rating system. Campbell
says that on some jobs, the design provides for many more
hand driers in toilet blocks to encourage greater hygiene.
The rainwater harvesting system was design by DG
Consulting Engineers.
Gayle Griffiths, Wat-Sol Design Technology, design and
quality control manager, says that the primary objective
governing the design was conformance to the LEED water
efficiency requirements. “It governed the entire design as it
what the client (Atterbury and Attacq) wanted. It governed
The installation of the heat pumps in the main plant room
in the first and second basements, supplying the kitchens
was undertaken by Jazzman Plumbing, (with TekniHeat
units – large boilers and heat pumps), and SA Heat Pumps
(two smaller boilers and heat pump) on the roof to supply
the sixth floor only. Griffiths says, “We would generally install
heat pumps in any case due to the requirements of SANS
10400-XA energy efficiency regulations, but LEED does not
permit anything but alternative energy sources. Heat pumps
were selected primarily because of the space limitations –
as there is not enough roof space for solar panels. The heat
pumps – there are three heat pump plants – are located
on two different basements and a third on the roof, in the
case of the basements, they occupy a couple of parking
bays against the wall with sufficient ventilation. All three are
directly in line (above or below) with the building’s kitchens
so as to limit the pipe run (even though the pipes are well
cladded). The heat pumps were set to a certain temperature
to meet LEED’s energy efficiency requirements.
“It is all very tight – you have to fight for this space,”
says Dowie. “We used the Valsir piping system with the
joints welded. It also has a Sensus water meter (specially
stipulated in the specs) which constantly monitors
the water flow so the owners can measure the water
consumption throughout the building. “Given the cost of
water, it’s good practice.”
www.plumbingafrica.co.za @plumbingonline @plumbingonline @PlumbingAfricaOnline August 2020 Volume 26 I Number 06