Amending EN 13000 - rated capacity limiters for mobile cranes
By Euan Youdale18 November 2009
One of the most interesting and important debates at the World Crane and Transport Summit in October centred on an amendment to the European EN 13000 mobile crane standard regarding rated capacity limiters. EUAN YOUDALE reports.
European Machinery Directive is law. To fulfil that law a range of standards is referred to - one of them, for mobile cranes, is EN 13000, first published in 2004. Since then an amendment, relating to the rated capacity limiter, coming into effect in June 2010, has caused controversy among crane users on both sides of the Atlantic.
It is the chapter regarding the rated capacity limiter that has generated particularly strong opposition from the USA. The amendment calls for the elimination of the standard override key and for reduction of operating speed down to 15% when in an override situation.
In hydraulically controlled cranes it is not possible to reduce the speed at each movement separately. So the pump output will be reduced to 25% when the crane is in an override situation.
As soon as the 2009 amendment is set into force, all cranes sold in European Union countries must incorporate these changes. Presenting the views of crane users in the USA is a task force set up by the Specialized Carriers and Rigging Association (SC&RA).
It argues that this law would bring critical decision making out of the hands of the operator and stifle the international used crane market.
These issues were brought to a head at the World Crane and Transport Summit in October, when members of the Specialized Carriers& Rigging Association (SC&RA), the European Association of Heavy Haulage, Transport and Mobile Cranes (ESTA),Crane Industry Council of Australia (CICA) and the Federation Europeenne de la Manutention (FEM), which represents the European manufacturers of mobile cranes, met to discuss the situation with a view to creating a potentially groundbreaking set of proposals.
To take a few steps back, the health and safety officials in Germany, France and Norway, who felt that the chapter regarding the rated capacity limiter was not fulfilling the requirements of the Machinery Directive, raised the Safeguard Clause. This chapter was given back to the European working group WGP 1 to find a compromise.
The result was the EN 13000 prA1 2009 amendment to the harmonised standard EN 13000: 2004. The amendment is now part of a unique acceptance procedure (UAP) closing on 18 November 2009. It may be delayed three months longer than originally planned, due to misleading translations of the amendment that led to misinterpretations in some EU countries.
During the World Crane and Transport Summit, Hans-Dieter Willim, FEM member and general manager of the design department at mobile crane manufacturer Liebherr-Werk Ehingen in Germany, outlined the plans for the rated capacity limiter's (RCL) bridging device as per the amendment:
The crane may be equipped with a set up button in the operator's cab. This button may be required for rigging and de-rigging or getting out of deadlock situations when the crane is working. A bypass device outside the operator's cab may be also required for emergency operation, as is a data logger to record all relevant information for incident analysis.
After the amendment of EN 13000 is set into force in 2010, all cranes put into the European market must fulfil the new requirements. Hans-Dieter Willim explains, "This is valid not only for new cranes but also for used cranes. For example, a used crane, originally brought into the American market then brought back into the European Union after three or four years has to fulfil the newest standards."
Speaking at the World Crane and Transport Summit, Robert Weiss, chairman of the SC&RA EN 13000 Task Force and vice president of Cranes Inc, said the US crane industry, including users and manufacturers, wholeheartedly opposed the EN 13000 amendment.
"To understand the reasons why, you must first understand our views concerning RCLs and similar technologies. In the US, devices such as RCLs, boom angle indicators and anti-two blocks are considered operational aids, which are there simply to facilitate operation of a crane - not control it. In fact, they are not even considered to be safety devices by regulatory and standard-writing authorities."
According to Weiss, the American National Standards Institute (ANSI) states that the use of operational aids shall not replace the requirement of an operator to know the load and capacity chart, and even goes on to note that verified weights and measured radii shall take precedence over indicator readings.
The Occupational Safety & Health Administration (OSHA) in the USA further divides operational aids into two categories, with Category I operational aids being more important than Category II. Not only does OSHA consider an RCL to be a Category II device, it does not even require that a crane be equipped with one. All OSHA mandates is a scale to help the operator know the weight.
"Furthermore, it is SC&RA's position that a reduction in speed to 15% when in override actually creates a hazardous condition by hindering an operator's ability to get out of an emergency situation in the quickest way possible," says Weiss.
"That being said," adds Weiss, "SC&RA agrees with its European colleagues that something must be done to make it more difficult to abuse the override key. While SC&RA does not agree with the approach taken in the EN 13000 amendment, they are committed to working with the worldwide crane organisations to develop an acceptable solution whereby the key can only be used on a limited basis and for its intended purpose - emergency operation."
Another important aspect of the EN 13000 section is the lockable bridging device, No. 3 (see diagram), outside the operator's cab. The device is for bridging a defective RCL or for getting out of emergency situations.
For example, explains Willim, if an angle indicator is defective, then you must be able to bring the crane back to a safe position. Or, in an emergency situation, where a load has been miscalculated and transferred to the crane (e.g. a girder which is attached to the crane hook is flame cut from the bearing structure), there must be the opportunity to bring the load safely to the ground. However, as soon as you bridge the RCL, for load moment increasing movements, the crane speed is again reduced to 15%.
The location of this bridging device on the crane was discussed during a meeting with some of the European Health & Safety officials in Manchester, UK, on 16 October.
"The positioning of the override key was discussed, as well, and a position outside of the cabin with a key in a locked cabinet or a key switch was seen as appropriate. Most European manufacturers will locate it at the rear of the crane operator's cab on the outside," Willim explains.
The most recent meeting, at the World Crane and Transport Summit on 21 October, continued efforts to develop and propose a potentially workable solution to the issues raised by the new requirements of the amendment. Willim described the set of proposals:
Firstly, there should be an additional, third function of the set up button No. 1 (see diagram) in the cab. For example, if a safety-related sensor fails, this is automatically detected by the crane control system, allowing the bridging to continue at full speed. "For example, if an angle indicator has gone and you know the exact radius and the load, then, in America you can continue work as long as you know the loading status of the crane exactly. In Europe the rated capacity limiter is mandatory, therefore, it will be only be allowed to bring the crane back into the transport position."
Secondly, the bridging device must be in the operator's cab in direct reach of the operator to mitigate a sudden emergency situation without any restrictions. All movements must be possible at full speed, but only for one operation. After that the operator must reset the switch before lifting another load.
"There was a very long discussion about how to safely reset the switch. There were a lot of solutions, but in the end we came to the solution that there must be a lockable switch outside the cab to reset."
The operator is not allowed to continue work when switch number 3 is not in the reset position. The key, number 4, must be in the possession of a site manager or appointed person. As well as the appointed person supplying a report of the emergency procedure, the data logger also records all information if switch number 3 or 1 is used.
These proposals will now be discussed with the European health and safety officials who initiated the amendment. If they agree to the proposals, they can be part of the next revision of EN 13000.