When lifting gear company Rossendale Group was awarded a contract by GE Energy Products, it was in the belief that all it had to do was install an overhead crane. “The scope of Rossendale’s contract has grown several times over,” says GE’s site technical manager Rob Howe.
GE is building a combined cycle gas turbine (CCGT) power station in Baglan Bay, South Wales. To install the heavy power generating machinery and pipework into the main hall a pair of overhead cranes have been installed, one with an SWL of 125t, the other rated at 20t. Each spans 30.5m. These cranes will also see action later in the life of the power station, during repair and maintenance changeouts.
The bridge beams of the 125t crane are made from 2.5m deep by 1.5m wide box beams and are linked by four split end carriages. A pair of mobile cranes were hired to lift the overhead cranes over a four day period. The mobiles were an 800t-rated Demag AC 650 and a 500t Demag AC 1600, hired from Ainscough Group. Under the supervision of Rossendale’s contract manager John Roby, the crane was moved from the compound to the installation site and assembled on the ground as much as possible. The crab units were lifted once the beams were in position, 30m above the ground.
Installing the cranes was a major project in its own right for Rossendale. But before it got this far there was other work that had to be done.
GE had placed the contract for the cranes with an overseas manufacturer and the cranes arrived on site in packing cases in kit form – except for the bridge beams – in January this year. It was April, says Howe, before inventory checks took place. Howe was not satisfied with what he found. Among the problems was damage likely to have been sustained in transit.
“Extensive remedial work needed doing. We had a long list of change items. It was that bad,” Howe says.
“The festoon trolleyway, for instance, was very crooked. That had to be straightened out. The main structural members were sound but there was a lot of cosmetic work,” according to Howe.
To sort the problems out, GE turned to Rossendale, which was already contracted to assemble and install the cranes. “They did an excellent job in turning it around,” says Howe. “Our intention is to initiate a maintenance contract with them to make sure the crane gets us through the construction period.” Howe explains that the cranes are critically important during this period. “We anticipate most of the operating hours of their life will be during this time,” he says, “since once construction is complete, the cranes will only be used during periodic shut downs and emergencies.” Howe adds that there will be “an interesting lift” during construction. “We need to lift the top half of our gas exhaust diffuser which, along with the spreader beam, weighs 37t. The problem is that it is at the extreme west end of our turbine hall and cannot be reached by the 125t crane because the 20t crane sits to the west of the 125t one. Therefore we have asked Rossendale to design and build an eccentric lifting beam so that the two cranes can be run in tandem to lift the diffuser. We are also contracting with Commander Controls to provide matching remote controls for the two cranes that can work in ‘master-slave’ fashion to do this delicate lift.” In the end, all the remedial work – which took about two months – nearly doubled the value of Rossendale’s contract to more than £250,000 ($363,000). In fact, says Howe, the cost of the remedial work was about the same as the purchase price of the crane in the first place.
Howe admits that GE has to take its share of the blame for the over-runs and delays (which he is confident of making up further down the project). GE has a policy of global sourcing and has sourcing quality engineers that visit suppliers to check their competency. These engineers visited the factory of the crane manufacturer and found both the facility and the quality procedures to be perfectly adequate. What they failed to do, however, was visit the factory again to check the equipment before it left the factory.
“Lesson learned,” says Howe.
