Episode 23: Positive locking for trucks

Securing the cargo with positive locking methods is the best, simplest and safest solution in most cases. In practice, however, there is often a lack of clarity as to which boundary conditions have to be met for this to actually work.

Episode 23: Positive locking for trucks

EN-12642 has been around since 2007 with the unwieldy title: "Load securing on road vehicles - Superstructures on commercial vehicles - Minimum requirements; German version EN 12642:2016".

Most of them use the common short title "EN-12642 Code XL". During the development of the standards, the superstructures were divided into two groups. The so-called standard superstructure Codel L with maximum strengths of the superstructure and the reinforced superstructure Code XL with minimum strengths.

The specifications refer to the end wall, the side walls and the rear portal. Testing of the floor load is not included because this is already covered by EN-283. The standard gives body manufacturers a great deal of freedom, as long as the tested strengths are within the specifications.

The strength of the end wall must be checked over the entire width and up to three quarters of the height. In order to secure positively, this area must be taken into account. Particular attention must be paid to the loading width.

For the shipper, there are also three important control aspects, namely

- the labeling requirement specified in the standard,
- the proof of each structure with a certificate and
- the requirement of the manufacturers that the superstructures must be tested once a year.

This type of spacer acts on the end wall like a can opener.

In the event of emergency braking, the end wall would simply be pushed through.

The loader must therefore ensure that the end wall is loaded at least across its entire width.

1. The shipper should check whether the driver has the Code XL certificate with him and read it to determine what special features should be
observed.

Then an eye check is required to ensure that the body strength is not affected by damage. The last thing to check is the evidence for the annual inspection.

Vehicles with damage as shown in the picture on the right should not be loaded under any circumstances.

2. Such marking would not replace the certificate, but would be sufficient as Code XL proof for the time being. According to the newer marking regulation, the load-bearing capacity of the end wall must even be specified at different heights.

3. The last thing to check is the proof for the annual inspection. They could look like this or similar, but the paper form would also be fine.

4. The manufacturer specifies that the coefficient of sliding friction should be at least μD=0.30. This condition can be achieved if the driver sweeps the loading area properly with a broom.

Broom clean, that's the magic word. In load securing, many screws can be turned, but the "friction screw" moves a lot. The loader must therefore demonstrably ensure that the loading area has been swept before loading.

Form-fit loading in the direction of travel means that the load units are lined up without gaps, starting at the end wall. The important thing here is that the forces from the individual load units are transmitted continuously to the end wall.

Unstable, overbuilt or underbuilt cargo units do not. Example of this:

Such a load will move into any free gap. The load unit securing is completely inadequate.

Overbuilt pallets transfer forces via the product to the end wall or other load units. The case of damage is pre-programmed.

Whether the superstructure strength can actually secure the load via form fit depends crucially on the type of cargo units and how they are secured. It is grossly negligent to talk of a tight fit for a load unit of this type, because the end wall will inevitably be damaged.

Form-fit loading to the side means that, according to the manufacturer's specifications, the loading width must be at least 2.40 m. The internal width of today's standard bodies is between 2.40 m and 2.50 m, depending on the design and body type. The specification of 2.40 m can be traced back to the Euro dimension.

This means that two europallets can be placed crosswise or three lengthwise in a loading row. Of course, the same requirements are placed on the load units again: they must be dimensionally stable and stable against tipping, so that the centrifugal forces are transmitted without gaps during cornering or evasive movements.

The sum of the permissible gaps results from the maximum inside width of the superstructure, minus 2.40 m. A common measurement is 8 cm as the gap sum.
Form-fit loading to the rear means that the distance to the rear portal must not exceed 15 cm. If the distance is greater, it must either be
filled or the load must be secured to the rear. To fill the gap, there are several solutions. The most common solution is the use of Euro pallets.

If the pallets are stowed upright, care must be taken to ensure that they do not fall out when the rear door is opened.

So it is better to position the pallets before the last row of loaders.

The following excerpt can be found in most certificates:

This means that if the requirements I have described above are not met, the manufacturer cannot guarantee that the body can withstand the securing forces. The responsible shipper is therefore required to demonstrably ensure that the necessary measures/checks are carried out.

If not, he has to apply according to §22 StVO "Load", using the methods according to "VDI-2700 "Load securing on road vehicles", (the recognized rules of technology). He must also provide evidence in the case of how the load securing looked at the time when the truck left the area of responsibility of the loader.

Unfortunately, practice shows that there is often a lot of luck involved.