The European Standard EN 12999 defines a loader crane as a powered crane composing of a column that slews around a base with a boom system attached on the top of the column. The crane is usually fitted on a vehicle (including trailer), and is designed for loading and unloading the vehicle.

While loader cranes make it easier, quicker, and safer to load and unload a vehicle than doing it by hand, hazards may result for the driver of the vehicle – who is also the crane operator – and for other people. These hazards occur when:

* driving the vehicle,

* accessing raised control stations, and

* operating the crane.

Driving the vehicle: There are two primary risk issues when driving the vehicle – the security of the stabilisers, and the crane itself.

EN 12999 (section 5.4.3) stipulates that two separate locking devices shall be fitted for each stabiliser to prevent uncontrolled movements of the stabilisers. At least one of these shall be automatically operated.

The reason for this requirement was a serious accident in France. The French government intervened at CEN, the European standards organisation in Brussels. The CEN consultant contacted CEN’s product working group “Loader cranes” (WGP8) in January 1999, and urged them to put into EN 12999 a requirement for two separate locking devices. This was just at the last meeting before formal vote to approve the new standard. From a safety point of view, this was a good and sufficient technical solution.

During a meeting of WGP8 in Berlin in May 2005, our English colleagues told us that several accidents would still happen in England every year because of uncontrolled movement of stabilisers during transport. But nobody could say if the accidents happened with manually operated or with hydraulically operated stabiliser extensions; or if the accidents happened with old loader cranes, not yet fitted with two separate locking devices; or if the crane driver failed to correctly secure the stabilisers with these two devices before driving the vehicle.

I would like to make this quite clear – if a loader crane is fitted with locking devices for securing each stabiliser (regardless of whether it is with one or with two separate devices), the crane operator must use them as written down in the operator’s manual. The full responsibility for this action will always be with the crane driver. Possible accidents will mostly affect civilians, and not him.

To secure the stabilisers is one part of ´securing of loads´ that a lorry driver has to do several times every day. It must be familiar to him; it must become second nature to him.

Section 5.6.1.3 of EN 12999 states that when the boom system of a loader crane has to be parked on the load platform or on the top of the load during transport, a height warning device shall be provided.

The BGF regularly has to examine accidents that could have been prevented by a height warning device. Typically, when passing under a low bridge, the boom hits the bridge and crane and load are ripped off the vehicle.

Who has the responsibility to eliminate this hazard – the manufacturer, the installer, or the owner? The European Machinery Directive sets out a hierarchy of risk. The manufacturer must eliminate or reduce risks as far as possible. Next, it must adopt necessary protection measures in relation to risks that cannot be eliminated. Finally, it must inform users of residual risks. (See section 1.2.2b, annex 1 of the Machinery Directive)

The risk of hitting a bridge cannot be eliminated, but it can be reduced by installing a height warning device. So whose responsibility is this?

It is the duty of the manufacturer if he designs and constructs the loader crane in such a way that the boom system has to be parked on the load platform.

It is the duty of the installer if the manufacturer delivered a loader crane without a height warning device, but if he, as installer, fits a clamshell bucket, for example, instead of a hook at the end of the boom system. As defined by Machinery Directive, the installer is the manufacturer who completes the loader crane with the vehicle to a running machine. Additionally, the installer has to add information about the height warning device to the operator’s manual, because he has added an indicating device and changed the intended use of the crane.

If the installer delivers a loader crane without height warning, but the owner wants to park the boom system on the load platform or on the load for any reason, then it is the duty of the owner to fit a height warning device. However, he is forbidden to do so because the operator’s manual says: This is a service condition, for which the crane shall not be used. Therefore, the owner should go to the installer and tell him to install a height warning. He may not think to do this, but he will after one of his drivers totally destroys his crane and damages a bridge.

In my opinion, it is very important, that the manufacturer and the installer can prove – for example, by the bill of sale, and the crane documentation – what special features the owner requested, and what special features were installed at the time of handover. This will be particularly important after an accident, especially if someone was killed because there was no height warning.

There can be no excuses since the risks of an “overheight” crane hitting a bridge have been well known for years.

(By “overheight crane”, I mean a crane on which boom system has been parked on the platform and therefore the admitted height of the vehicle with the loader crane has been exceeded.)

Accessing raised control stations: Many loader cranes are equipped with a raised control station, such as a high seat or platform. The operator has to climb up the vehicle to use the crane, and then back down again.

Section 5.10.8 of EN 12999 states that the installer shall provide suitable access to any control station on the crane from the ground. In my opinion, the word “suitable” seems to be a problem.

Stumbling, slipping, and falling are typical accidents on building sites. The BGF specialises in insuring health and safety at work in the road transport business. One in three accidents we have to pay out for involve such falls from vehicle. Stumbling, slipping, and falling during access to raised control stations of loader cranes are very common accidents for us. And the reasons for these accidents are:

* unsuitable access

* inadequate lighting

* access is not used.

The responsibility for a suitable access lies with the installer. Do all installers know what EN 12999 requires for safe steps and ladders? I am not sure that they do. I think that maybe some manufacturers should ensure that their installers are more familiar with the standard.

Climbing a ladder in darkness is not easy. I am not sure I know the absolute solution to this problem. EN 12999 has no specific requirement for lighting. The installers are simply required to design and fix ergonomic access to the loader cranes. EN 12999 gives the installers solutions, which they must regard as only a minimum requirement.

The decisive point is still the so called ´simultaneous three-point support´ of each access: two hands and one foot or two feet and one hand. When I look at all the steps, platforms and ladders mounted on loader cranes, they often seem to me to be the last thing fitted, almost as an afterthought, while the new owner is already sitting in the cab waiting to drive away.

Of course, the responsibility to use the access supplied is up to the crane operator. We know a lot of accidents happen because of jumping or climbing over the wheel or the wheel hub instead of using the fitted access. It is hardly possible for owners to monitor operators on site. The only solution is continual education and training.

Operating cranes: How to operate a crane is not up to the Machinery Directive or EN 12999, but each European country may regulate the safe use of a loader crane in its country. On the other hand, the level of the safety requirements written down in Machinery Directive and EN 12999 has a great impact on the use of loader cranes. This means that the level of safety requirements has a great influence on the type and frequency of accidents.

When operating a loader crane there is one very important requirement for safety at work: stability. Section 5.10.3 of EN 12999 says that the stability of a loader crane installed on a vehicle shall be such that the working unit does not overturn under foreseen operating conditions.

For the operator, stability depends mainly on:

* operating within the load chart

* correct deployment of stabilisers (fully extracted)”

* firm ground

* vehicle being horizontal or within the permissible slope.

The incorrect deployment of stabilisers has caused two fatal accidents in Germany in the past three years as well as numerous other accidents that also caused extensive damage to vehicles and loads.

How many more are there all over the world?

Here are some of the things that operators tell us:

“There was no room at the building site to fully pull out the stabilisers.”

“I am experienced, I know my crane. It was just a misjudgement.”

“I had to work only on one side of the vehicle with my loader crane. Just before finishing crane work, the foreman asked me to slew round and pick up a small load at the other side of the vehicle.”

“I was in hurry.”

“I did not expect it.” (i.e. “I don’t know the basics of crane physics”).

“I have had no training – this is only my second day working with this loader crane.”

This is what the manufacturers tell us:

“The crane driver has to operate the machine as we tell him in the owner’s manual.”

“The responsibility to train the crane driver is up to the owner.”

Manufacturers and installers study the market every day, but do they study accidents? In Germany they have to do so by law and, if there is a problem, they have to analyse it, and may eventually have to change the design of their machine.

Safety inspectors like me always hold the view: Let us put as much safety as acceptable in the machine because human beings are the weakest link in the whole system. And this is also the target of the hierarchy of risk set out in the Machinery Directive (section 1.2.2 annex 1).

Both the crane operators killed In Germany recently would probably be still alive today if their crane had been fitted with a device that prevented the crane being operated over a range where stabilisers are not correctly deployed.

From a safety point of view, incorrect deployment of stabilisers is a totally foreseeable misuse of loader cranes. The risk of overturning is not new – we all know it. If this risk is not just any risk, but a risk which has written names on gravestones, we as technicians and safety inspectors cannot leave it as it is. The key phrase is ‘stabiliser interlocks’. In draft of amendment 2 of EN 12999 we have gone a first small step towards it. I believe, stabiliser interlocks will come and will be a standard equipment of nearly every loader crane in future.

This article is based on a presentation made by Ulrich Birkenstock at the Crane Safety & Management Conference in Amsterdam in June 2005. For details of the 2006 conference, which takes place in London on June 22 and 23, visit www.wilmingtonconferences.com/cranes2006