Consulting engineering and project implementation firm Hatch has been instrumental in the shop detailing of six boiler ducts at Eskom’s Medupi and Kusile power stations, in the Lephalale and Delmas areas.Engineering, contracting and construction services company Murray & Roberts approached Hatch to assist with the shop detailing of the boiler ducts, which included the creation of 3D models, 2D fabrication and erection drawings of ducting for twelve boilers using Tekla Structures software. Hatch Structural Practice and Project Delivery Group, Detailing section leader, Hendrik van Graan, says that each boiler duct stretches a full 103 m up in the air and weighs up to 1 480 t per unit. The plate work varies between 5 and 6 mm depending on hot or cold air flow. Van Graan says that Hatch had to supply the fabrication workshop and site with intensive, high-quality drawings and daily communications on progress, safety and accuracy. This required that the team members perform well in a fast-tracked environment with a significant amount of pressure. The number of drawings per unit was as follows: 8 755 single part drawings, 3 623 assembly drawings and 40 general arrangement drawings; a total of 12 058 drawings per unit. “Owing to the nature of this project, there was a substantial amount of tasks that occurred simultaneously, such as interface complexities with other detailing companies, and mechanical and structural miss matches. Due to the complex nature of the interfaces, we needed to be able to think on our feet and provide innovative solutions to problems of varying complexity. The work often involved multi-disciplinary approaches to problem solving,” explains Van Graan.
One of the complexities that Hatch managed to overcome through innovative work was the modification of the duct structures previously detailed by others. The ducts needed to be modified for the correct interfacing as per the calculation sheets done by Hitachi in Germany. Van Graan says that most of the other detailing companies withdrew from this project due to the schedule and complexity.Included in the innovative work items completed by Hatch was the modeling of major round duct structures as well. Van Graan states that work accuracy was one of Hatch’s most important aspects on the project: “Owing to the fast changing nature of the construction environment, it was essential that every individual on the team, do his or her part to ensure that the detailing sequence experience as little delay as possible. Accuracy was very important in ensuring that the solution was engineered correctly. Mistakes can easily be made in such a fast track programme, but the team members performed exceptionally well, with the project coming in on time and on budget.” Hatch is one of the only consulting engineering firms in South Africa with an in-house detailing division. These capabilities are spread across the globe and can be accessed through Hatch’s offices in Montreal, Canada; Johannesburg, South Africa; Delhi, India; and Shanghai, China.