Welded Tank Configurations
Since 2000, Paso Robles Tank has set the standard in carbon steel welded tank engineering, fabrication, construction, maintenance, modification, and repair. We also specialize in the relocation of above-ground storage tanks (ASTs) and specialty vessels. From our experience serving water and wastewater, petroleum refineries, and the ever-growing energy sector, we provide our customers a wide variety of tank options.
Tank Configurations We Build
- Cone Roof and Bottom Tanks. Cone bottom tanks, inductor tanks, and specialty rinse tanks all have conical bottoms, a shape that lets the tank drain completely when it is emptied. A cone roof adds a fixed, sloped top that sheds water and suits atmospheric storage across a wide range of products.
- Open Top Floating Roof Tanks. An external floating roof tank is typically used to store petroleum products such as crude oil or condensate. It is built with an open-topped cylindrical steel shell and a roof that floats on the surface of the stored liquid, which reduces vapor space and evaporative loss.
- Internal Floating Roof Tanks. These pair a fixed outer roof with a second roof that floats on the liquid inside. The fixed roof keeps out weather while the internal deck rides on the product to limit vapor space, which makes the design a good fit for volatile fuels and solvents where evaporation and emissions matter.
- Dome Roof Tanks. A dome roof is a self-supporting, rounded top shaped like a shallow spherical cap. The curved geometry carries load and sheds rain and snow efficiently, which makes it a strong choice for larger diameter tanks that need a clear span without internal roof supports.
- Umbrella Roof Tanks. An umbrella roof is a self-supporting fixed roof that curves smoothly from a high center down to the shell, much like an open umbrella. The consistent slope sheds water well and gives small to mid-size tanks a clean, structurally efficient top.
- Knuckle Roof Tanks. A knuckle roof adds a curved radius, the knuckle, at the joint where the roof meets the shell instead of a sharp angle. That rounded transition spreads stress more evenly and strengthens the roof-to-shell connection on tanks that see pressure or heavier roof loads.
- Sloped / Dished Bottom Tanks. Sloped and dished bottoms are shaped to move liquid and solids toward a low point for complete drainage and easier cleaning. A sloped bottom grades toward a drain or sump, while a dished bottom uses a gentle concave profile that also adds structural strength.
- Thermal Energy Storage Tanks. These large welded tanks store chilled water produced during off-peak hours and hold it in thermally stratified layers. Facilities draw on that stored cooling when demand and energy costs peak, which lowers operating costs and eases load on the grid.
- Molten-Salt Energy Storage Tanks. Molten-salt tanks store heat by holding salt at high temperature, most often for concentrated solar power and large-scale thermal storage. They call for high-temperature materials, careful insulation, and precise fabrication so the tank holds molten salt safely through repeated heating and cooling.
- Digesters and Clarifiers. Digesters and clarifiers are core to water and wastewater treatment. Digesters break down organic solids so they can be processed and, in anaerobic designs, capture biogas, while clarifiers let suspended solids settle out so cleaner water can move on to the next stage.
No matter how demanding the project, Paso Robles Tank has the in-house engineering, fabrication, and field crews to deliver tanks built to meet or exceed the governing standard, whether AWWA D100, API 650, or API 653, with certified welding, code-compliant coatings, and documented QA/QC at every stage. For a project to succeed, owners and operators need a partner they can rely on to control costs and hold quality to a measurable standard, upholding Paso Robles Tank’s motto:
SAFETY + QUALITY = PRODUCTION
Our Experience With Steel Welded Tanks
Paso Robles Tank designs, fabricates, and field-erects welded steel tanks built to AWWA D100 and API 650 standards, and that work has earned repeated recognition from STI/SPFA. The Holly Drive Steel Tank Reservoirs in Upland, California took the STI/SPFA 2023 Tank of the Year award, and the Dalton Reservoir Replacement in Livermore earned the 2020 Tank of the Year. On the industrial side, our API 650 Thick Juice Storage Tank in Twin Falls, Idaho received a 2019 Tank of the Year Product Award for an API 650 atmospheric tank.
Our track record runs deep across California water systems and beyond, including the Jamestown Reservoir Replacement Project, honored as the STI/SPFA 2018 Tank of the Year. Because engineering, fabrication, coatings, and field erection are all handled in-house, we control quality from the first drawing to the final weld, delivering tanks built for long-lasting performance.

