Source: Article by Plant, Equipment & Hire Magazine (August 2009) Anti-collision technologies that can be retrofitted to existing cranes have been introduced and are popular worldwide. Philippa McAlister probes the merits of this technology. Tower cranes are the most visible piece of equipment on construction sites, and it is critical that they are installed, maintained and operated by competent personnel. Failure can and has lead to major incidents in the past and in response the construction industry is looking at various measures to improve the safety of the sector in order to reduce the risks that end up causing accidents. One of these technologies that is relatively new to South Africa is an anti-collision device that can be retrofitted to a tower crane. Complexity Complicates The complexity of buildings has increased dramatically over the years, which has resulted in construction methods that involve bringing cranes closer together. Consequently, this has created extended zones of interference between cranes, the direct consequence of which is the appearance of a new risk – the collision of the cables of high cranes and the jibs or counter-jibs of lower cranes. At the same time, a demand for efficient tools in order to restrict the movement of loads over sensitive areas has arisen. In order to eliminate the collision risk without penalising a site’s productivity and to provide crane operators with efficient and helpful tools, such as working area limitation (zoning), several companies have been involved in the development of anti-collision systems. One such company is SMIE, a French company that developed and marketed the first anti-collision system in 1985. Readers will recall that Bombela installed this system on tower cranes at three Gautrain sites. Liebherr supplied Bombela with all of the tower cranes and worked closely with SMIE. One of SMIE’s devices is the AC243 anti-collision system, which is intended to assist the crane operator in preventing the collision of two or more interfering cranes. It allows the operator to detect and anticipate the risk of the moving elements of his crane and those of the adjoining ones running into each other. When a collision risk arises, the system immediately takes over and stops the dangerous movement, as well as providing the means to prohibit sailing over protected zones. The AC243 is adaptable to all types of cranes, and according to SMIE, it can, therefore, treat sites with any combination of cranes simultaneously. SMIE also claims that the system is easy to install, especially since its connecting cables are all equipped with industrial connectors. The display unit not only keeps the crane operator posted about their environment relative to anti-collision functions, but also provides other precious information, such as the trolley position on the jib and the slewing angle. “Our primary concern,†tells SMIE, “is to ensure safety without decreasing work site output.†Typical risk situations include: 1.The hoist rope of a high crane being hit by the jib of a low crane. The load is jolted and the banksman is thrown off balance. 2.The load hitting the jib of a low crane and spilling part of the load, which could fall on workers below. 3.A badly slung load dropping on a public area. 4.A hoist rope accessing a dangerous area, such as a high voltage line. 5.The jib of a crane hitting the mast of an interfering crane, or another obstacle. Getting The Basics Right First However, is this technology suitable for South Africa? “It is suitable for everywhere in the world,†says Quentin van Breda, CEO of SA French. “However, I think South Africa still needs to get the basics right.†According to Van Breda, South Africa tends to ‘under crane’ jobs because of its so called ‘cheaper labour’. “So, where we use one crane in South Africa, they would probably use three cranes for the same job in Europe. That automatically reduces the problem and the need for anti-collision technology.†Van Breda says that this technology works in a similar way to a three-phase traffic light. “If the light is red then you can’t go and you can only turn left if the left arrow is green. But, on a site, this technology is a little more complicated because it will stop a crane dead in its tracks. Now, if you add a device called anti-collision technology, you can stop the crane from hoisting, slewing and travelling backwards and forwards, so for each function there is a left and right. “Everyone is stretched already just trying to ensure that the crane operates like it was designed to and then you get called out to site because the crane won’t hoist. And, of course, it won’t hoist because it is in a collision zone,†tells Van Breda. “You would have to make training mandatory so that everyone understands up front how the system works, including all of the foremen, so that everyone on site has an understanding of how the technology works. Until or unless it is brought into legislation, the general consensus is that people in the industry would rather focus on improving what they have. Van Breda cites Europe as an example in which any crane that exceeds 50 m has to have a personal hoist in order to transport the operator into the cab. “But, there is absolutely no talk of that ever being applied here,†imparts Van Breda. This issue has never been seen as important and one hears idle banter around a site about keeping crane operators fit, which is fine if you are not the one that has to climb to 90 m at least four times a day. “I think there are far more practical issues that need addressing first that would really make the lives of operators and the safety of cranes much better, without getting terribly sophisticated,†stresses Van Breda. First Things First One area that Van Breda mentioned where there is a distinct lack of resources is in terms of inspectors. There are not enough inspectors to go around to building sites to check whether operators are in fact qualified to be doing what they are doing. “My concern has been, and continues to be, that safety is not what it should be,†says Van Breda. Another issue is the strategic placement of cranes and the fact that often there is no consideration of the direction in which a crane is placed. A simple adjustment can make a huge difference to operators, especially in a situation where they have the sun in their eyes all day. The question of a crane register being kept for the entire lifespan of a crane is also an issue of concern for many in the industry, and Van Breda is particularly vocal about his concerns. “Instead of a mandatory register for the period a crane is used on a particular project and the register being scrapped once the job has been completed, every crane should have a ‘bible’, just like the service record and log book for a car,†imparts Van Breda. The remuneration of crane operators also differs when compared with Europe. In Europe operators are frequently one of the most highly paid on a site, which is certainly not the case in South Africa. “I honestly feel we should be focusing on the basics first,†stresses Van Breda First World Standards Safety falls under the umbrella of the Department of Labour, so when the department introduced legislation with regards to companies having to be registered as lifting machinery entities, this included the registration of the people that you had in your company who erected, commissioned and handed over cranes. The registration was then ‘subcontracted’ to the Engineering Council of South Africa, with the result that very few were registered as they applied the correct criteria. However, according to Van Breda, it was soon realised that the entire industry would be ‘strangled’, so to speak. “I think it is a double-edged sword,†says Van Breda, “because if you look at it practically we cannot necessarily apply first world standards to an emerging market, because we are in a state of change and it is just not practical.†Perhaps we need to apply the existing legislation without introducing any more. Van Breda draws an analogy of going to a restaurant and telling the owners that they have a wonderful menu, but you would prefer it to be three pages longer. “We already have extremely good legislation,†imparts Van Breda, “we just have to make it work.†In terms of the standard of operators, Van Breda is of the opinion that all of the instrumentation in the world should not substitute the quality of an operator. And, if one was to compare the aviation industry with the construction industry, despite most aircraft using ‘fly-by-wire’ technology today, there would be a public outcry if pilots were done away with. Although health and safety is essential in all areas of construction, and while this technology can certainly assist with the avoidance of collisions, it should by no means substitute a first-rate crane operator and the importance of undertaking detailed planning and risk assessments, ensuring robust and thorough examinations and maintenance regimes are in place and undertaking more site inspections.
