Regulatory overload29 July 2011
Regular overload testing will soon be extinct as changes in crane design make it costly and impractical. In Europe, regulations are changing across EU borders as manufacturers send out the message that regular overload tests have to go. The FEM is releasing a position paper that will help hirers kick the habit. Cristina Brooks reports
In the EU, national laws dating from the last century require overload testing — deliberately lifting test loads of more than the maximum rated capacity — to see if a crane works. Manufacturers still use overload tests in highly controlled environments for testing prototype and newly built cranes.
On the simple cranes of yesterday, regular overload tests showed hire firms whether there were bolts loose with a failure. The cranes of today have different designs. They are more complex and made of fine grain steel, so overloading them hides obvious stress failures, but creates cracks in booms.
Klaus Meissner is the director for product integrity at Terex. As FEM president, mobile cranes, Meissner is leading the front of crane manufactures, including Manitowoc and Liebherr, pushing to standardize maintenance across borders.
He explains that some states require overload testing on a crane each time it is reconfigured. This presents a serious challenge in multi-stage wind turbine construction. Regulations require testing to the point of fatiguing or ‘killing’ a new crane.
“If you just imagine a wind park being set up with 80 wind turbines,” Meissner says. “The mobile crane is configured for lifting tower sections at turbine number one, and it has to be overload tested according to national regulation.
“Then the crane is set to travel mode, travels to wind turbine number two and reconfigured for lifting and you have to overload test again, thus you perform overload tests each time for 80 towers, and then you go back to tower number one to install the nacelle in another configuration, followed by lifting the rotor blades with maybe a third configuration; it easily adds up to a big number of overload tests,” Meissner says A mobile crane’s lifetime of 30 years can be reduced to zero years by repeated overloading, especially as today’s mobile cranes are designed for performance and not endurance.
The introduction of fine grain steel created a mobile crane that can lift up to 30% more while remaining lightweight and roadable. In contrast, tower cranes and industrial cranes, in which the same areas are stressed by large loads over and over again, use a heavier kind of steel and have longer lifetimes.
“Mobile cranes are calculated for a limited number of maximum loads, as such each overload will reduce the lifetime of the crane,” says Meissner. For this reason, manufacturers have deliberately redesigned cranes to move the override key outside the cabin, showing that the crane is not for regular overloads.
The financial problem of prematurely wearing out a crane may be observed in insurance companies’ policies. Many insurers won’t insure a crane which is being regularly overload tested. “Insurance companies do not advocate the periodic overload testing of cranes, as this can be seen as being in part conflict with the general principles of insurance,” says Martin Banasik, Principal Engineer at Allianz Engineering Standards. “Insurers cover accidental unforeseen events or circumstances. However, overload testing deliberately imposes abnormal loading conditions on a crane beyond its normal operating limits.”
As generally insurers discourage the practice, it is occasionally only possible to obtain insurance if it is accompanied by audits and inspections.
Despite the industry’s signals that overloading is obsolete, states persist with four year testing requirements. Christian Vernazza is CEO of Mediaco in France, where overload testing is required every four years and also each time a crane is reconfigured.
“We as French companies are pushing to have a new regulation. For the time being, we are complaining to the French government so we can avoid all the testing in France which is contrary to the manufacturers’ recommendations,” says Vernazza.
However, in the UK, where once there were strict overload testing practices, overload practices are slowly changing. In the UK HSE (Health and Saftey Executive) repealed the Construction (Lifting Regulations) Operations 1961, required overload tests every four years. When LOLER was introduced in 1998, overload testing became optional.
Removal of overload testing in the UK has been led by industry. Hire companies at the CPA (Construction Plant-hire Association) have worked directly with HSE in the UK government to take steps towards ending overload testing this June by releasing a Technical Information Note (TIN) advising against it.
Tim Watson, the CPA's Technical Consultant, who edited the TIN, says, “The advice on overload testing in the TIN is endorsed by the HSE.”
While the TIN is not a law it will be taken by HSE as an unofficial standard banning regular overload testing. Watson clarifies: “I don’t think there will be a specific law against it because most UK legislation these days is goal setting, rather than prescriptive. The regulations set the goal of ensuring that the crane is safe.”
There is no offical ban on overload testing in the UK because there needs to be a recourse to it in case of a contingency, like when a crane part has been totally or partially replaced. Infrequent overload testing on a crane is only advised after a major repair or an overhaul of equipment.
The unenforced nature of the standard means that, while several major UK companies have gone cold turkey on overloading, other companies are unable to because their clients, unwary of developments in the industry, continue to demand it.
“It’s becoming less common, but the problem is mainly that clients of crane hire companies are still insisting on it. This is because they don’t understand the reasons for testing in the first place,“ says Watson.
“There tends to be a gap in people's knowledge of overload testing requirements, mostly clients who are insisting that cranes turn up on site with a four year testing certificate,” says Watson
“Crane hirer clients can include oil refineries and construction companies. Clients’ insistence on four yearly testing is particularly prevalent in the construction industry because the 1961 Construction (Lifting Operations) Regulations were originally aimed at construction.”
To spread the knowledge, the CPA introduced a Best Practice Guide in June 2010, called the Maintenance, Inspection and Thorough Examination of Mobile Cranes. It says overload testing can be replaced by ‘defined written scope’ inspections.
Defined written scope requires operators owning a crane that will be used more heavily, whether from overload testing after rebuilding or high cycle loading, to inspect it more frequently than the annual inspections required by law. Defined scope examinations include recording past and future use of a crane and shortening inspection periods for cranes which may be damaged by use or moisture.
As a justification for this testing, Watson cites an example of a mobile crane in Scotland that failed after regular high-cycle loading: “People sometimes use mobile cranes for loading and unloading ships. he problem there is that mobile cranes are intended for lifting a limited number of loads per day. Because ship loading is high cycle work you may use up the fatigue life of the crane in 2 or 3 years.
“The reason people do this is that mobile cranes are a lot cheaper to buy than a dedicated port crane, which is designed to do high cycle work, and is consequently more expensive,” Watson continues.
“If you’ve got a situation where a mobile crane is being used for high cycle work, you might well need to reduce the period between the thorough examinations quite significantly.
“Manufacturers are now putting a lot more information on looking for cracks in particular areas of cranes in their manuals and there is a general raising of awareness of the importance of crane specific information.”
Examination beats overloading
Meissner agrees with UK law on the requirement for a thorough examination. “I think a thorough inspection will give you more information than an overload test. Moreover any overload testing which is not followed by a thorough inspection of the highly loaded areas by detailed visual inspection and crack testing might bear the risk that cracks created during testing go undetected.”
Taking the written examination as an important requirement, the position paper will leverage the manufacturer’s authoritative view for changing government regulations.
Meissner says, “FEM will soon issue a position paper on overload testing to clarify that the manufacturers do not recommend overload testing except for repairs or major overhauls. In addition FEM members together with the other stakeholders of the mobile crane industry are working on the amendment of EN13000; when this process is over, there will be more information on content and intervals for inspection and thorough examination to be included in the manuals for mobile cranes.
The FEM is working with European Association for Heavy Haulage Transport and Mobile Cranes, (ESTA) to see how hire firms can better integrate new practices. European crane rental associations met in the Netherlands this month for ESTA’s bi-annual meeting in part to make plans for moving the issue forward.
Søren Jansen, general secretary of ESTA, ran the largest crane rental company in Scandinavia for ten years. He has also worked for crane manufacturers in Europe and the US. He presented a survey to the FEM that was critical to revealing the inconsistency in the industry and initiating the discussions.
“I made a survey in 11 European countries in December 2010 and I could see that each of the European countries did it differently. I passed this survey over to the crane manufacturers,” says Jansen.
Not only do regulations need to be changed, but the mentality in the industry that overloading proves something has got to change. It is partially created by overloading testing demos, which are common entertainment at crane shows and launches.
Jansen continues, “Overload testing is actually something that was introduced in the 1960s-70s. There’s really no good reason for doing it so long as you maintain the cranes according to the manufacturer’s manuals, because overload testing really proves nothing. The only thing you want to be sure of that the crane can lift according to its lifting capacity.
“It’s like having a car and you have a speed limit somewhere of 100 miles, then there is no reason for proving the car can run 120 mph,” Jansen says. “It’s something stupid. There has never been any reason to do an overload test. Today to do an overload testing is not impressive, it’s stupid.”
In the short term, the FEM position paper will aim to change regulations, and provide a jumping off point for trade associations like ESTA and safety organisations, as well as private hire firms, to lobby to governments to remove regular overload testing laws.
One of the long term results of the FEM position paper will be that manufacturers pump up manuals with more detailed descriptions of maintenance practices, such as defined written scope examination, that will help cranes last longer.