African Fusion November 2020

Complex repair at Babcock

Babcock prevails under pressure

safe working environment to enable the safe removal of the damaged sections of pipework; source and supply the replace- ment components on the piping system; and install them. As part of removing the existing ‘as- damaged’ piping system, various tech- niques using load-bearing scaffolding and ratchet type restraints were employed to remove the residual spring as a result of the rupture and prevent further displacement. Naidoo explains that even though this was a replacement, the complexity of adhering to the latest standards and the introductionof design smarts, suchas cold- pull andadditional pipe supports, rendered most of the existing design information irrelevant. He explains that cold-pull is a process whereby the piping system is pre- stressed in its cold state such that it is less stressed in its hot state, which maximises design life. As part of the design process, Babcock performed pressure containment calcula- tions, performing stress analysis to size the

Keagan Naidoo, piping engineering manager at Babcock Ntuthuko Engineering, describes a complex repair project at a power station following a steam pipe rupture.

F ollowing a rupture on the main steam-piping system on one of the units at an older major power station, Babcock’s Ntuthuko Engineering division, along with two other major boiler companies, was part of a competitive bid- ding process todevelopaproposal in a very short period of time to repair the piping system as quickly as possible to the strict- est of international standards. Babcockwas successful in its tender and was awarded the work to undertake the design, procurement and supply, fabrica- tion, manufacture, and construction of the complete main-steam and high-pressure bypass system for the power unit. Keagan Naidoo, piping engineering manager at Babcock Ntuthuko Engineer- ing, explains that a complex project of this nature taking into account the engi-

neering scope, manufacturing, logistics and the scope of construction involved, usually takes 18 to 24 months to execute. However, Babcock successfully completed the project in just seven months, working under pressure to restore the additional power capacity. In order to assess the extent of the dam- age, Babcock used a combination of visual inspection and 3D scanning technology to scan the piping system and associated structures. Using specialised software, Babcockwas able to digitise the real-world architecture by capturing existing plant conditions and complex geometry, result- ing in a digital copy, which identified that large sections of pipework and structures had been displaced during the rupture. Babcock was tasked with designing the replacement system, whilst establishing a

Babcock undertook the design, procurement and supply, fabrication, manufacture, and construction of the complete main-steam and high-pressure bypass system for the power unit.

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November 2020

AFRICAN FUSION