Spherical tanks are industrial equipment with a spherical geometry, used for storing LPG, ammonia, and similar products under pressure. Specially designed scaffolding systems are required to provide safe access to different areas of these tanks during maintenance, inspection, painting, coating, and repair activities.
Spherical tank scaffolding is an industrial scaffolding system installed to create safe working areas on the internal or external surfaces of the tank. Because of the spherical form, the distance between the tank surface and the scaffold varies at the lower, middle, and upper sections. Scaffold layout must therefore be approached differently from conventional façade scaffolding applications.
In this article, we discuss what spherical tank scaffolding is, which activities it supports, the technical conditions that must be considered during installation, and how the appropriate scaffolding system should be selected.
What Is Spherical Tank Scaffolding?
Spherical tank scaffolding is a temporary scaffolding system installed to provide maintenance teams with safe access and working platforms at different elevations around spherical storage tanks.
When preparing the scaffold layout, the tank diameter and height must be considered together with the supporting legs, pipelines, valves, ladders, existing platforms, and the surfaces where work will be performed. Since the circumference of the spherical form changes at each level, the platforms must be positioned at an appropriate working distance from the tank surface.
When work is to be carried out inside the tank, the system must also be planned according to manhole dimensions and confined-space conditions. For external applications, circumferential access, platform continuity, and scaffold stability become the primary considerations.
What Is Spherical Tank Scaffolding Used For?
Spherical tank scaffolding enables inspection, maintenance, and surface-treatment activities to be carried out safely and systematically in different areas of the tank.
Its main applications include:
- Inspecting weld seams and connection points
- Examining corrosion, cracks, and surface deformation
- Performing wall-thickness measurements and non-destructive testing
- Carrying out abrasive blasting and surface-preparation activities
- Applying primer, paint, and protective coatings
- Performing insulation and cladding work
- Carrying out local repairs and component replacement
- Creating simultaneous working areas at different elevations
Continuous working platforms around the tank are particularly important during painting and abrasive-blasting operations. Allowing work teams to reach the surface from an appropriate distance helps the application proceed in a more controlled and uniform manner.
Where Is Spherical Tank Scaffolding Used?
Spherical tank scaffolding is used in industrial facilities where pressurized products are stored in spherical tanks.
The main application areas include:
- Refineries
- Petrochemical plants
- LPG storage and filling facilities
- Chemical storage areas
- Energy facilities
- Industrial production plants
- Terminals and tank-storage areas
On external tank surfaces, scaffolding is most commonly installed for inspection, painting, abrasive blasting, coating renewal, and corrosion-control activities. Inside the tank, scaffolding may be required for cleaning, technical inspection, weld examination, and repair work.
For internal applications, installation work must not begin until confined-space requirements have been fulfilled, including safely taking the tank out of service, gas freeing, atmospheric testing, ventilation, and adequate lighting.
What Technical Factors Should Be Considered During Spherical Tank Scaffold Installation?
The most important factor in planning spherical tank scaffolding is the curved geometry of the tank. The tank circumference increases around the middle section and decreases toward the lower and upper sections. Scaffold platforms must therefore be arranged to match the tank surface at each working level.
The following factors should be evaluated before installation:
- Tank diameter, height, and surface geometry
- Required working elevations
- Distance between the tank surface and the platform
- Tank legs and supporting structures
- Pipelines, valves, ladders, and existing platforms
- Ground-bearing capacity and load transfer from the scaffold
- Loads generated by personnel, equipment, and application materials
- Safe access and material-handling routes
- Anchoring and stability arrangement
- Assembly and dismantling programme
Unauthorized drilling, welding, or fixing to the tank shell must not be carried out. The method used to ensure scaffold stability must be determined in accordance with site conditions and the approved installation plan.
When the scaffold is to be enclosed with sheeting or protective covers during painting or abrasive-blasting activities, additional wind loads must also be included in the structural assessment. It should be considered that the wind load acting on the scaffold increases as the enclosed surface area becomes larger.
What Should Be Considered in Internal and External Spherical Tank Scaffolding Applications?
The main purpose of external spherical tank scaffolding is to create safe platforms that provide access to different elevations around the tank. Platform widths and the working distance from the surface should be determined according to the nature of the activity, such as inspection, painting, abrasive blasting, or insulation.
For internal spherical tank scaffolding, manhole dimensions and material transfer become more important. Scaffold components must be suitable for transport through restricted openings, delivered in accordance with the assembly sequence, and stored in a controlled manner inside the tank.
Before internal installation:
- The tank must be confirmed as safely out of service.
- The required energy isolations must be completed.
- Gas measurements must be carried out.
- Adequate ventilation and lighting must be provided.
- Safe entry and exit routes must be identified.
- An emergency and rescue plan must be prepared.
Internal and external scaffolding systems may be installed during the same maintenance period. However, working areas, material movements, and access routes must be organized so that the teams do not interfere with one another.
Which Scaffolding System Should Be Used for Spherical Tank Applications?
For spherical tank applications, modular scaffolding systems that can adapt to changing surface geometry and allow connections in multiple directions should be preferred.
Ringlock scaffolding systems provide significant advantages by allowing platforms to be created at different elevations, enabling stepped layouts that follow the curved form of the tank, and offering flexible solutions around existing plant components.
When selecting the appropriate system, personnel access should not be the only consideration. Loads from abrasive-blasting hoses, painting equipment, measuring devices, hand tools, and application materials must also be included in the scaffold plan.
Spherical Tank Scaffolding Solutions by Mod Industrial Services
Mod Industrial Services provides scaffolding solutions for spherical tank maintenance, inspection, painting, and overhaul activities carried out in refineries, petrochemical plants, energy facilities, and industrial storage sites.
The tank dimensions, working elevations, surface geometry, existing plant components, and scope of work are evaluated to prepare a project-specific scaffold layout, material plan, and installation organization.
From site survey and engineering assessment to installation, pre-use inspection, and dismantling, we plan the entire process to ensure that maintenance teams can reach the tank surface safely and from an appropriate working distance.
Frequently Asked Questions (FAQ)
Why does spherical tank scaffolding require project-specific planning?
The surface geometry of a spherical tank changes at the lower, middle, and upper elevations. The distance between the platforms and the tank surface, the supporting-system layout, and the working levels must therefore be evaluated separately for each elevation. Tank legs, pipelines, and existing equipment also directly affect the scaffold layout.
Can external spherical tank scaffolding be used for painting and abrasive-blasting work?
Yes. External spherical tank scaffolding can be planned to provide suitable working platforms for surface preparation, abrasive blasting, priming, and painting applications. When the scaffold is enclosed, wind loads and the effect of the enclosure system on the scaffold must also be assessed.
Can internal and external spherical tank scaffolding be installed at the same time?
Internal and external scaffolding systems can be installed during the same maintenance or shutdown period. However, material-handling routes, manhole access, platform elevations, and the work programme must be coordinated in advance to prevent interference between teams.