Massive backup water system for Nando’s factory

By Dineo Phoshoko

Nando’s head office and factory in Midrand have a fully integrated 240 000ℓ backup water system that ensures ongoing production in the event of a water cut.

The restaurant chain’s head office in Midrand also has a factory where Nando’s sauces are produced. The area experiences regular water cuts due to maintenance or water shedding at times, which affects production at the sauce factory. As a result, Nando’s loses out on revenue, since production of the sauces is not possible without water.

IMG 1250 Nando’s reception and offices.
Image credit: Burgess and Partners

The factory initially had an 80 000ℓ backup water system that was made up of eight 10 000ℓ JoJo tanks. It had a temporary quick connection with a small pump in a bypass. The factory needs massive amounts of water for its production cycle, but the backup water system of Nando’s was not ideal, as it did not meet the factory’s water requirements and it was not a fully integrated system. The system had tanks with a suction (the booster pump) and then a supply, with both coming off valves that needed to be manually turned on and off depending on whether municipal or backup water was being used. The water remained in the tanks and required crossover every two days to get fresh water. 

Nando’s approached Burgess and Partners Plumbing Services for a sustainable backup water system that would also use the eight JoJo tanks in the initial system. Calculations were done, and it was determined that the factory required a 240 000ℓ backup system. The system would ensure ongoing production for at least one day, in the event of a water cut.

With this information, Burgess designed a system that incorporated four 40 000ℓ Roto tanks, which amounted to 160 000ℓ. When combined with the initial eight 10 000ℓ tanks, this system would provide the factory with the required 240 000ℓ of backup water supply.

ASSEMBLING THE NEW BACKUP WATER SYSTEM

To get the system up and running, a dedicated team from Nando’s and Burgess collaborated on the project. The team started by cutting into the existing municipal supply that goes straight into the factory and diverted the pipework with new galvanised pipework. The surrounding area had to be excavated and connected to all the tanks.

Nando’s had designated an area close to the factory for all 12 tanks to be installed. A concrete slab was built to support the weight of all 12 tanks combined. Together, the tanks weighed approximately 240 tonnes. As such, a lot of concrete was used to build a reliable slab.

Once the concrete was dry and the tanks ready, two booster pumps from HMS pumps were installed. All the tanks were connected with pipework and fittings to suit, which go through to the booster pumps. The booster pumps’ function is to pump the water back into the factory.

The entire backup system operates on electricity. However, if there is no electricity, there is an option to bypass the system through the bypass line. Bypassing simply means isolating the two lines and opening the line that would make bypass successful.

The eight 10 000ℓ JoJo tanks, booster pumps, and air relief valves. 
Image credit: Burgess and PartnersA 50mm pipe galvanises connections onto the existing water supply to the factory. 
Image credit: Burgess and PartnersThe 50mm galvanised water supply and return to and from the new backup water plant. 
Image credit: Burgess and PartnersCOVER OPTION.jpgWater reticulation for the machinery in the factory. 
Image credit: Burgess and Partners

GETTING AROUND THE CHALLENGES

All projects have challenges along the way and this project was no different. 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.

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.

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 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.

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.

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.

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 with water. This ensures that the pump only uses the electricity required to pump the amount of water needed for the factory. In so doing, excessive usage of electricity is avoided.

Successful execution

This massive project had to be completed within a tight deadline. With the dedicated team who worked on the project, it took only four weeks to complete. The project was handed over to a happy Nando’s in August 2017.

Booster pumps installed on a mild steel assembly with a canopy for protection. 
Image credit: Burgess and PartnersBooster pumps, air relief valves, non-return valves, strainers, and isolation valves. 
Image credit: Burgess and PartnersSuction 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. 
Image credit: Burgess and PartnersNando’s reception and offices. 
Image credit: Burgess and PartnersThis photo shows the height difference between the 40 000ℓ and 10 000ℓ tanks. 
Image credit: Burgess and PartnersThe size of a huge boulder that had to be removed can be seen to the left of this photo. 
Image credit: Burgess and Partners


The Burgess and Partners team who worked on the project:

  • Warren Burger (business development manager): Designed, specified, quoted, and managed the project
  • Darryl Brainen (director): Developed the blueprint/drawings and oversaw the project
  • Raymond Brown (contracts manager): Site supervisor responsibilities
  • Simpiwe Shongwe (plumber)
  • Bhekani Nzimande (plumber).

LIST OF SUPPLIERS

 House of Plumbing  Raw materials
 Plumblink  Raw materials
 Astore Africa  Pipework, fittings, and raw materials
 HMS Pumps  Pump supplier
 TW Electro  Electrical
 Pronto Ready Mix  Concrete for slab
 MM Builders  Building of slab
 JoJo Tanks  JoJo tanks (10 000ℓ)
 Roto Tanks  Roto tanks (40 000ℓ)

MATERIALS USED IN THE PROJECT:

  • 4 × 40 000ℓ Roto tanks. Height: 4 850mm. Diameter: 3 300mm
  • 8 × 10 000ℓ JoJo tanks. Height: 3 150mm. Diameter: 2 200mm
  • 2 × Dual 1.1kW 380/3/50 horizontal stainless steel booster pumps
  • 32 × 50 suctions manifold
  • 32 × 50 discharge manifold
  • Isolating and non-return valves
  • Dual 1.1kW 4 500V DOL starter panel, including flip flop relay, main isolator switch, indicator lights, manual pump selector switch, overload, and current protection, all mounted in a weatherproof steel enclosure and base mounted
  • Intermediate pre-wiring between pumps and panel
  • All mounted on a fabricated mild steel base assembly
  • Float level control
  • Fabricated mild steel pump protection canopy.

Click below to read the February 2018 issue of Plumbing Africa

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