Storing water at 75°C requires careful consideration of insulation, connections and long-term maintenance. At a biogas plant in Cape Town, SBS Tanks adapted two modular steel tanks to accommodate the demands of high-temperature water storage. Material testing, specialised insulation supports and modifications to the roof and nozzle connections helped address the practical challenges of insulating the installation.
At 75°C, the tank design needed to account for more than the stored water and structural requirements. The insulation had to withstand compression, remain securely positioned and help limit heat loss.
Several other details required attention:
Addressing these requirements called for a considered approach to material selection, insulation support and the detailing of the complete tank assembly.
Insulation materials underwent compression strength testing at the Durban University of Technology to assess their suitability for the installation.
The team also investigated gasket and sealant specifications. Supplier compatibility charts, operating-temperature data, research papers and material specifications for standard hot-water storage containers informed the material assessment.
Steel nozzle fittings presented another consideration because they could provide paths for heat loss through the insulated tank assembly.
High-temperature thermoplastic spacer flanges were introduced at the nozzle penetrations to address this issue. The external pipework was insulated separately to help limit heat loss beyond the tank body.
During installation planning, neutral-cure silicone was found to be unsuitable for reliably securing the modular insulation panels, given its strength and drying time.
The approach was adapted by introducing purpose-designed brackets to mechanically secure the panels to the tank body. This provided a more practical means of keeping the insulation in position during installation.
The roof presented two key challenges: keeping moisture away from the insulation and maintaining clearance around the overflow pipes.
SBS Tanks designed a pillow arrangement for the roof insulation panels to seal the roof area and help keep the insulation dry. The arrangement also created an additional insulating layer through trapped air.
Additional roof support beams held the insulation in position and helped prevent it from obstructing the overflow pipes.
Sealing the roof also raised an important maintenance consideration. Access was needed for liner installation and future work inside the tank.
An access hatch was incorporated into the design to provide entry while retaining the intended benefits of the insulated roof arrangement.
Commissioning proceeded successfully. By the end of the reporting period, no performance data or complaints had been shared by the end user.
No additional insulation had been requested. However, without measured thermal performance results, this could not independently confirm whether the installation achieved its intended temperature requirements.
The project demonstrated how insulation, nozzle connections, roof detailing and maintenance access can influence the design of a high-temperature tank installation. Addressing these considerations together helped SBS Tanks adapt its modular tank configuration to the project’s operating requirements.
The project highlighted five practical considerations for future high-temperature tank installations.
High-temperature water storage requires consideration of the complete tank assembly, not just the tank body. Material selection, connection details, insulation supports, roof protection and maintenance access all influence the installation approach.
At a biogas plant in Cape Town, SBS Tanks applied engineering-led design and practical adaptations to address these requirements for two modular steel tanks intended to store water at 75°C.
The project highlights the value of resolving installation challenges during the design process, where material choices and construction details can be assessed together.
SBS Tanks was involved in an installation of two ST09-07 modular steel tanks at a biogas plant in Cape Town. With a gross capacity of 217 kL and an effective capacity of 192 kL, the tanks were designed to store water at 75°C. The installation required compression testing of insulation materials, high-temperature thermoplastic spacer flanges, mechanical insulation brackets, roof supports and maintenance access. Commissioning proceeded successfully, but measured thermal performance data was not available for independent verification.
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