Lower weight and simpler to use – the new, latest design of scaffolding manufactured from high strength steel by Haki is around 25 percent lighter than earlier systems. Due to its low weight, the new high strength steel scaffolding will also be able to replace many of the aluminium scaffolding systems now available on the market.
Haki – which is a specialist company in scaffolding systems – launched an in-house programme aimed at reducing the weight of the company’s steel scaffolding systems. The target was to reduce the weight by about 20–25 percent, and this target has now been reached. The driving force behind the development was to meet the need for durable and lightweight scaffolding systems for maintenance work on oil drilling platforms in the North Sea. Low weight is crucial for scaffolding intended for oil drilling platforms, due to their limited storage and load-carrying capacities. Aluminium scaffolding, which is sufficiently light but very expensive to produce, currently dominates in the offshore industry. “The most important benefit of the new lightweight system is that it is better for the users,” says Bengt Olsson. A quick calculation shows that the daily load that a scaffolding erector must handle is reduced by more than 400 kilos when the new high strength steel system is used. This machine that is at the heart of Haki production system, and a well-kept secret. However, it is more sensitive to damage from impact and is also less resistant to fatigue than steel scaffolding. This reduces the feeling of security for those working on scaffolding, which is often suspended from the platform, with icecold open water immediately below.
“The new lightweight scaffolding systems we developed had to meet many demands,” recalls Bengt Olsson, Managing Director of Haki AB. “In the early days of the project, we tested various materials, but we soon realised that the future lay in high strength steels, particularly since the availability of high strength steel tube has improved radically in recent years.”
In addition to changing to high strength steel for the scaffolding, the design has also been modified, which contributes further to the reduction in weight and includes the clips between the standards (the vertical tubes of the scaffolding). The previous clips were heavy and had welded supports to carry the load applied from above. The new standards are manufactured from high strength steel tube with a minimum yield strength of 400 Nm/mm2 and have folded joints. Due to the high strength of the material, the tube walls are thinner, having been reduced from 3.2 mm to 2.7 mm, which is the minimum it can be. Pressing is carried out in one operation, with one end shrunk and folded to replace the previous welded support. The scaffolding components are produced in a special machine developed in-house by Haki.
“This machine is at the heart of our production system, and just how we go about shrinking the hard steel is our well-kept secret,” continues Bengt Olsson. A very close fit in the joints and other parts is of major importance to ensure sturdiness and safety. The Haki scaffolding system can be erected to a height of 200 metres and must therefore be very strong to withstand the stresses imposed.
Another component that has been developed is the location of the clips on the standards onto which the ledgers (horizontal tubes of the scaffolding) are hooked. A symmetrical design has been produced, which makes it easier to erect the scaffolding.
Other major components of the system – the horizontal transverse tubes (putlogs) and longitudinal tubes (ledgers) supporting the decking are also manufactured from high strength steel with a minimum yield strength of up to 600 N/mm2.
“We intend to go much further in reducing the weight of our products,” declares Ulf Oskarsson, who is responsible for technology and production at Haki.
Text: Roger Blomqvist News Magazine No 1 2005