The world’s largest offshore wind farm is under construction in the North Sea, 23km off the coast of England. Scheduled for completion in 2012, the Greater Gabbard wind farm’s 140 turbines will generate 500MW of electricity for the people of London. Use of Dyneema® ultra-high molecular weight polyethylene (UHMWPE) fiber is helping ensure that the construction project moves ahead as efficiently and safely as possible.
To provide peak performance in 35m seas, the turbines are mounted on top of 65m, 650t steel ‘mono piles’ that are transferred by barges from the Verbrugge Zeeland Terminal in Vlissingen, Netherlands to the construction site.
For lifting the long and heavy mono piles, the operating company’s safety department wanted an alternative to steel-wire and chain lifting slings that would have better ergonomics and be safer to use. The new slings would need to be as strong as (or stronger than) those made from traditional materials, but lighter and easier to handle, and so less likely to cause operator injury to hand, arm, shoulder, and back. Additional safety concerns over steel wire rope slings, such as the tendency for wire strands to snap over time and create ‘fishhooks’, prompted the search for a safer solution.
ULTRALIFT™ round slings made with Dyneema provided all the answers.
They are made by Technotex, located in Coevorden, Netherlands. They have quickly won the full approval of the terminal operator.
According to Mattheo Rozemond, responsible for handling the Greater Gabbard mono piles at Verbrugge Zeeland Terminal, “Initial skepticism among our employees has turned into admiration. The new slings help our team optimize safety and provide damage-free cargo handling.”
Costs associated with corrective maintenance have been virtually eliminated.
ULTRALIFT slings are just as strong as slings made with steel wire, but are seven times lighter, yielding considerable operational efficiencies. For example four operatives handle each sling, instead of eight for traditional steel wire rope slings. Auxiliary equipment such as forklift trucks, previously required to move the steel slings, has gone too. Easier sling handling is quickly converted into much higher productivity. The unloading time of a full shipload of mono piles has been reduced by one full day, with a saving in barge rental fee of over €60,000.
Rozemond summarises: “Using these new slings, we save costs in manpower, auxiliary equipment and rental fees. And we create more capacity for dealing with unforeseen circumstances. Furthermore, after intensively using the new slings to unload 56 mono piles, the slings show no signs of damage.”
Technotex ULTRALIFT round slings comprise a load-bearing core made covered with a heavy duty sleeve – both with Dyneema fiber. The abrasion- and cut-resistant sleeves protect the load-bearing core and prolong its useful life. Slings are CE-marked according to the European Machinery Directive 98/37/EG. The slings supplied to Verbrugge Zeeland Terminal have an effective work length of 15m and weigh only 230kg each.
In brief: slings made with Dyneema are as strong as steel wire rope slings of equal cross section, but are much lighter, they are easier to use, they present less risk of injury to operatives, they are extremely durable and highly resistant to chemicals and abrasion; they offer enhanced cost-effectiveness and operational flexibility.