In search of a perfect pressure vessel: deep dive beneath the surface

Managing a pressure vessel's lifecycle is a decades-long battle of attrition against internal and external pressures, temperature changes, and corrosion. Scheduled inspections are needed to ensure safety without disrupting operations, and evolving regulations add further demands. Sustainability is another priority, involving low-carbon materials, resource conservation, and end-of-life recycling. Thus, price and cost are two different things also for pressure vessels. Ultimately, material selection is a long-term investment in safety, profit, and sustainability.

"Over the years, we've seen that sustainability and cost-effectiveness are not opposing or mutually exclusive. Rather, they are interdependent and reinforce each other,"

emphasizes Claes Tigerstrand, Application Development Manager at Outokumpu.

Combine cost-efficiency and responsibility with Outokumpu

As an innovative solution partner in pressure vessels, Outokumpu supports forward-thinking customers in lowering their carbon footprint and increasing profit. Properly selected high-strength duplex stainless steel can cut even half of the pressure vessel's total costs after a few decades. The direct benefits are, for example, decreased material consumption and costs by using thinner gauges without coatings, more efficient logistics, faster manufacturing and implementation, less maintenance with extended inspection intervals, and thus, secure and reliable industrial processes with minimized downtime.

"Our approach enables building greener production infrastructures and meeting upcoming regulatory requirements, such as the Green Claims Directive," says Tigerstrand.

The question is, how are such benefits measured?

The journey towards a perfect pressure vessel is built on analysis, testing, and reliable partnership

First, long-term financial and environmental impacts must be considered to discover the optimal pressure vessel material. "The tools of the trade are Life Cycle Cost (LCC) analysis and Life Cycle Assessment (LCA). "Combined, they enable pressure vessel design that optimizes total costs with environmental responsibility," explains Tigerstrand.

Life Cycle Cost (LCC) analysis provides a comprehensive view of all product costs throughout the pressure vessel's lifespan, including initial production and acquisition, operations and maintenance, and any costs related to repairs or upgrades during the product's use. LCC also accounts for end-of-life expenses, such as disposal or recycling.

In turn, Life Cycle Assessment (LCA) is a method for quantifying the environmental impact of pressure vessels, focusing primarily on CO₂ emissions. The assessment begins with resource extraction, measuring the emissions generated from mining and refining raw materials. In the production phase, emissions are calculated from manufacturing processes, transportation of materials, and energy consumption. During the use phase, LCA accounts for emissions related to the product's operation, maintenance, and energy needs over its functional life.

Furthermore, disposal and recycling are considered as the product reaches the end of its life, including emissions from waste treatment, decomposition, incineration, and recycling. By capturing emissions across each phase, LCA helps identify areas where environmental impact can be minimized, supporting efforts toward more sustainable product design and development.

When partnering with Outokumpu, the customer makes the final selection based on the analysis and field testing. Following the purchase, Outokumpu maintains a close relationship with the customer, ensuring timely deliveries and further technical support, covering aspects related to fabrication. After a long and reliable service life, the stainless steel can be returned to Outokumpu, where it is recycled, completing a closed-loop cycle and reinforcing commitment to sustainability.

Did you know:

• Outokumpu is the world's first stainless steel producer to offer customers a product-specific carbon footprint certificate.
• While the industry's European average carbon footprint is 2.8 kg CO₂ per kg of stainless steel, Outokumpu achieves a significantly lower 1.8 kg CO₂ per kg (Circle Green, potentially 50% further reduction).
• In Europe, the recycled content of stainless steel is at an estimated average of 85%, with Outokumpu stainless steel reaching up to 95%.
• If all stainless steel were made like Outokumpu Circle Green®, the global carbon footprint would be cut by 364 million tons yearly.
• Outokumpu's flagship product line, Circle Green stainless steel, has a closed-loop recyclability, meaning the material can be 100% recycled an infinite number of times—supporting the sustainability of the manufacturing process and the whole lifecycle of a pressure vessel. With a carbon footprint down to a fraction of the global average, the material surpasses any existing solution in sustainability.

Streamline your design work with Outokumpu's pressure vessel calculator

While pressure vessels are always designed for a specific application, the regulative codes, such as ASME and PED, are the blueprints for safety and performance. The ASME is an American code but is often used globally, while the PED is mainly used in the EU. Both these guidelines aim to ensure the safe operation of pressure vessels but follow different regulatory frameworks and standards tailored to their respective regions. Often, an engineer working in the international field must use both.

In practice, following the codes and comparing the materials can get tricky. Thus, Outokumpu provides engineers with an online calculator, which helps estimate the required plate thickness and relative material consumption for the cylindrical shell of a vessel and compares the selected alloys' effects on plate thickness and relative material consumption according to the design rules given in EN 13445, ASME Section VIII Div.1 and Div.2.

"Our online pressure vessel calculator is a handy tool for estimating the weight reduction potential duplex can offer your project, up to 50%," encourages Tigerstrand.