West Welding carried out a large-scale district heat accumulator project for Vaasan Voima, enhancing the city’s heating reliability. The project included the accumulator’s design, manufacturing, surface treatment, as well as transportation and installation.
Comprehensive Pressure Equipment Delivery with Expertise
Pressure equipment deliveries are complex projects where coordinating different aspects is critical for schedule and quality. By providing design, manufacturing, surface treatment, transportation, and installation through a single provider, we ensure all project phases are planned and executed seamlessly. This simplifies project management, which is especially important for large and demanding pressure equipment. A comprehensive delivery allows the customer to have a worry-free project experience.
“The project was a success from the client’s point of view. We acquired the pressure vessel on a “turnkey solution basis”, and the project was completed on schedule as planned. It’s great that this kind of expertise is available in our region.” Markus Nabb, Operations Manager, Vaasan Voima Oy.
Careful Pressure Equipment Design Required for Large District Heat Accumulator
The district heat accumulator is 33 meters long and weighs approximately 125 tons when empty, and nearly 1,000 tons in operation. Such size and weight required precise logistics and special transportation from West Welding’s workshop in Teuva to Vaasa. During the design phase, strength calculations, detailed manufacturing and installation drawings, and 3D modeling were completed. Transportation and installation logistics were carefully planned in advance. The close collaboration between design and manufacturing enables rapid response to customer needs and any required modifications.
Surface treatment as part of the district heat accumulator manufacturing
Thanks to long-term experience, the manufacturing of the district heat accumulator was straightforward from a welding-technical point of view. The material used was P355GH, which has good pressure resistance and sufficient strenght. The pressure vessel shell was mostly welded using submerged arc welding (SAW), while external and internal components were primarily welded with flux-cored arc welding (FCAW). With a volume of 840 m³, the tank operates at a pressure of 4.5 bar. In addition to the pressure shell, the manufacturing included the prefabrication of supports, diffuser plates, manholes, and pipelines. Manufacturing complies with international standards (EN 13445 and PED 2014/68/EU) and includes third-party approval and NDT inspections to ensure quality.
After manufacturing, the district heat accumulator underwent surface treatment, starting with sandblasting to meet cleanliness requirements and to remove dirt, grease, or rust. The accumulator was primed with workshop primer to enhance durability against UV radiation, weather conditions, and mechanical stress. It was insulated with 200 mm wool to prevent unnecessary heat loss. Cladding completed the insulation, protecting it from weather conditions.
Transportation and Installation Included in the Delivery of District Heat Accumulator
The District heat accumulator was transported from West Welding’s workshop in Teuva to Vaasa, starting at 8 PM to minimize disruption to other traffic. Due to its size, the transport was a special transport, which requires precise logistigs planning. Installation was carefully planned due to limited space. It was lifted into place using two cranes. The main crane was equipped with counterweights due to the tank’s heavy weight. After installation, the lifting points and transport cradle areas were insulated and cladded.
“Due to the tight space, extra counterweights were required, which also demanded precise planning from Havator. The installation went even better than expected, and the tank was lifted a day earlier than planned because of the next day’s wind forecast,” Tomi Ketola, Technical Specialist, West Welding Oy.
