PROJECT
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The biggest challenge was the height difference between
the Roto tanks and the JoJo tanks. The height difference
(head of a tank) between a 10 000ℓ and a 40 000ℓ tank
is significant, which results in a couple of thousand litres
of water sitting above the height of the existing tanks. To
overcome this challenge, a separate water supply with
the ball valve in the 40 000ℓ tanks was needed, as well
as a separate one in the 10 000ℓ tanks. In addition, non-
return valves were required to prevent the head of the
water pushing into the tanks.
With all tanks being connected at the bottom, the 40 000ℓ
tanks have an extra head. This means that if one tank is
filled, all the other tanks will also be filled. This way, the
water would fill up to the same level in all the tanks.
Accommodating the potential risk of the tanks
overflowing was a challenge during the project. The
tanks would overflow if the ball valve remained open and
continued to fill other tanks. This issue was addressed
with a non-return valve being installed just before the
10 000ℓ tanks.
2
it ideally suited for the tanks. The finished level on the
embankment is about three metres off the ground floor
area level. Not only was it high, but it was also steep. To
get the eight 10 000ℓ tanks up to the designated area,
they had to be manually lifted with the trucks. The bigger
40 000ℓ tanks had to be driven up to the designated area.
The area where the factory is situated and the
designated area for the tanks had several rocks, which
needed to be removed. Google Earth Professional
identified areas where the rock could be avoided —
determining the best place to build the concrete slab.
2.
Booster pumps, air relief
valves, non-return valves,
strainers, and isolation
valves.
Suction lines connecting
the tanks together and
flexible hose to allow
for tank expansion and
contraction, with lever
valves to individually
isolate the tanks if
needs be.
BENEFITS OF THE SYSTEM
The main advantage of the system is that the staff
at the factory will have uninterrupted water supply,
which will keep production going even if water cuts are
experienced. If there are any water cuts, employees at
the factory will not be affected because they have the
backup water system to rely on. This then creates a
comfortable and convenient working environment.
Another challenge experienced was the space
constraints on the designated area, which made it
impossible to install numerous 10 000ℓ and 20 000ℓ
tanks. For this reason, Nando’s had to settle on the
compact 40 000ℓ tanks. The system was strategically designed in such a
way that the pumps are set to work at the required
operating pressure. Based on the usage of the water,
the required distance that needed to be pumped,
operating pressure, and demand, the system
determined the most suitable pump.
Transporting all the tanks to the designated area turned
out to be a major challenge. The area was selected
because of minimal activity in terms of traffic, which made Another impressive feature of this system is that the
pumps’ specifications have been designed within a
specific range of kilowatts required to supply the factory
www.plumbingafrica.co.za
1.
Continued on page 45 >>
February 2018 Volume 23 I Number 12