Roben Manufacturing engineers and fabricates welded steel storage tanks to API 650 for atmospheric service and API 620 for low-pressure service. From shell-course thickness and bottom-plate layout to roof design and nozzle schedules, every tank is calculated to the governing API standard and the site's product, seismic, and wind conditions.
Storage tanks are deceptively simple in appearance but unforgiving in the field: an undersized shell course, a poorly designed roof-to-shell junction, or an overlooked seismic load can compromise an asset that is expected to last decades. Our engineering group treats tank design with the same rigor as pressure vessel design, supported by code-based calculations and complete documentation.
Welded Storage Tanks Engineered to API Standards
API 650 governs welded tanks for the storage of petroleum, chemicals, water, and other liquids at atmospheric pressure. Our engineers size shell courses using the one-foot or variable-design-point methods, lay out the bottom and annular plates, design the roof, and detail nozzles, manways, and appurtenances to suit your process and access requirements.
When the stored product develops internal pressure above atmospheric — for example, certain volatile liquids or blanketed tanks — API 620 applies. API 620 extends the design rules to low-pressure service, and our team selects the correct standard and design basis for the actual operating envelope rather than defaulting to one approach.
Seismic and wind loads are central to safe tank design. We perform the load calculations the standard requires, sizing anchorage, checking shell stability, and verifying the roof and shell against overturning and buckling. Where a jurisdiction or owner specification imposes additional requirements, those are incorporated into the design basis from the outset.
Material selection follows the service. Carbon steel is common, but corrosive products, low temperatures, or product-purity requirements may call for stainless steel, clad construction, or special linings. Each tank ships with the calculations, material documentation, and weld records needed for commissioning and future inspection.
Why Choose Roben Manufacturing
- API 650 and API 620 capability. We design both atmospheric and low-pressure welded tanks and choose the correct standard for your actual operating conditions.
- Complete load analysis. Seismic, wind, and overturning calculations are performed so the tank and its anchorage are safe for the installed location.
- Large-diameter fabrication. Our plate rolling and head-forming capacity lets us produce large shells and components without subcontracting critical work.
- Material flexibility. Carbon steel, stainless steel, and clad constructions are available to match the stored product and environment.
- Documentation built for the field. Calculations, material reports, and weld records ship with every tank for fast commissioning and clean future inspections.
Key Features & Capabilities
- API 650 atmospheric welded tank design
- API 620 low-pressure welded tank design
- Shell-course sizing by one-foot and variable-design-point methods
- Bottom, annular-plate, and roof design
- Seismic and wind load calculations with anchorage design
- Nozzle, manway, and appurtenance detailing
- Material selection for corrosive and low-temperature service
- Plate rolling up to 144 inches and large-diameter shell fabrication
- Welding to qualified procedures with NDE
- Hydrostatic testing and inspection documentation
Applications & Industries Served
- Crude, intermediate, and product storage in petrochemical facilities
- Bulk chemical and solvent storage
- Process water and fire-water storage
- Blanketed tanks for volatile or oxygen-sensitive products
- Food-grade liquid storage requiring sanitary construction
- Power generation auxiliary fluid storage
Codes, Standards & Quality Assurance
Roben Manufacturing fabricates under a controlled quality system and holds the ASME U Certificate of Authorization, with registration through the National Board of Boiler and Pressure Vessel Inspectors. Every applicable project is supported by material test reports, qualified welding procedures, nondestructive examination records, and complete documentation.
Relevant standards and resources include: API Standards; ASME Boiler and Pressure Vessel Certification.
Frequently Asked Questions
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