The upgrading and maintenance of industrial sites over time often requires the execution of works to elevated structures that would historically require significant scaffolding systems
As part of the ConocoPhillips Teesside Operations in the UK, SYNTEX were tasked to perform the reduction in height of a 75m Boiler stack down to 43m by removing the top 2no and installing a new reducing cone section.
The removed sections weighed approximately 24tonnes each and required installation of temporary access systems and the installation of new lifting points to facilitate the works.
Temporary access platforms were installed using a proprietary tensioned banding system at each of the stack flanges to provide a stable platform for bolting works. Temporary suspended access platforms (cradles) were also used for access to other locations both internally and externally.
To facilitate the lifting activities a set of purpose designed trunnions were welded to each of the boiler stack sections to be lifted. The installation and welding works were carried out from the installed temporary access platforms and from the suspended access platforms with support from a temporary winch system avoiding the need for crane support during the preparation phase.
Once the new reducing cone sections were installed to the now reduced height stacks external cladding and insulation was installed to the flanged joints ensuring that the stack cladding systems remain weather tight. The temporary access systems were then removed and the stack successfully returned to service.