The functionality and effectiveness of load securing depends to a large extent on the securing equipment used. Unfortunately, this often leaves a lot to be desired. The causes are mainly to be found in the following areas:
- Incorrect equipment of the means of transportation
- Insufficient equipment
- Incorrect application
- Ignorance of the mode of action
There are two modes of action for locking devices, namely force-fit and form-fit.
The fact that the introduction of the Code XL standard means that much better vehicles are available leads some drivers and shippers to believe that they no longer need to do anything. The Code XL standard is only fully applicable when the vehicle is fully loaded. In other words, the load must fit snugly against the bulkhead, the load width must not be less than 2.40 m across the entire loading area and the distance to the rear portal must be less than 15 cm.
However, this is the case with very few transports. In most cases, the strength of the rear portal according to Code XL cannot be used because the load is more than 15 cm away from it. The truck is more likely to be too heavy before it is fully loaded.
A key factor is the fact that means of transportation are offered without safety equipment. The buyer has to purchase them additionally and the costs of systemic security devices that match the means of transportation are often saved. As a result of this necessity, safety equipment is later purchased or taken over from other vehicles.
Point 1: wrong equipment
This can be seen, for example, from the fact that a box van has a combination anchor rail on both sides, which is designed for form-fit securing devices, but clamping rods are actually used. This means that the securing force is far below what is possible.
A typical picture for incorrect equipment. A refrigerated box body in which the load is secured with clamping rods. Regardless of which load is stowed, the requirement for securing 0.5 g to the rear cannot be met in this way. The truck is designed for full loads, but not for partial loads on the return journey.
Point 2: insufficient equipment
The size of the load securing forces required depends on the permissible total weight. The Code XL standard requires that the rear portal must hold 30% of the payload. This can serve as a guide for the amount of securing equipment. Example: If a semi-trailer (technical payload 27,000 kg) is loaded with 20,000 kg and the load is more than 15 cm away from the front wall, a securing force of 6,000 daN would be required at the rear.
If commercially available clamping boards (intermediate wall fasteners) with a securing force of 400daN are used, 15 would be required. The majority of trucks are equipped with 2-3 units. If the truck were to be equipped with steel insertion slats or combination anchor rails and locking beams with 4,000 to 4,500daN each were used, two would be required.
Point 3: incorrect application
Clamping boards and clamping rods are designed in such a way that they must be loaded along their entire length. It is not uncommon for the truck to be loaded in such a way that there is a single pallet in the last loading row. The securing device is then positioned behind it.
The picture on the right shows the best method for damaging clipboards. Irrespective of this, the securing force is not sufficient for the entire load. In the best case, this would be 2x400daN. Incorrect use reduces this value considerably.
Even as-new clamping boards have a maximum securing force of 400daN if they are loaded across their entire width.
In this loading situation, an attempt is made to secure a load weighing approx. 17 tons to the rear with three belts. Two of these (yellow) result in a head lashing with a reduced effect and one (red) represents a tie-down lashing.
Assuming that the friction on the loading surface is ฮผ=0.3, a securing force of approx. 3,400daN would be required.
With the correct pre-tensioning force, the tie-down lashing would bend the frame of the IBC. The blue belt would damage the insertion slats by pulling them inwards. The head flashing with the gray belt could slip off the edge when riding and the belt would be loose. Overall, everything is uncertain. It would also be better overall to stow the individual IBC in the loading row in front of it in order to have a complete loading row at the end.
Point 4: Ignorance of the mode of action
Securing devices with the word “clamps” in their name always act on friction, i.e. they are friction-locked. Those containing the word “lock” have a form-fitting effect. Unfortunately, the technical condition often leaves a lot to be desired.
This adjustment screw is used to adjust the locking mechanism, which ultimately generates the securing force, to the thickness of the insertion bar in order to achieve the highest possible clamping force/friction force.
However, if the hinge pin is replaced by a wooden dowel, everything is ineffective.
Compensating for the excessively thin insertion plate with an old license plate shows a lack of knowledge about the mechanism of action. The adjustment screw is intended for precisely this case.
Welding a tubular bar to the defective clamping devices of a clamping board is a lot of work. Nothing is for nothing, it can still serve as a bad example. Nothing has been done to the two jaws where the actual clamping effect is generated. The question of the securing force is useless because the inspection authorities will judge this part to be ineffective.
Clamping an anti-slip mat into the mechanism is a good approach, but can only be a temporary emergency solution because the securing force is not known. The counterpart is missing on the other side.
Both the driver and the responsible shipper believe that they are safe when in fact they are not.
Clamping beams work on the same principle, but are not as sensitive to point loading.
The securing force for flat loads is between 800 and 1,000daN.
Clamping rods are also based on the friction principle. When the second pole was clamped, the first one fell over because the roof lifted. When the driver inserted the third one, the first two fell over. All three poles only hold enough to prevent them from falling over on their own. They do not have a load-securing effect.
In general, the securing force of clamping rods is a maximum of 150daN for flat loads. This means that they are actually only suitable for vans, but not for vehicles over 12 tons GVW.
Barrier bar systems are much more effective. However, they are typical for the manufacturer and are not interchangeable in parts.
The manufacturer specifies a blocking force BC of up to 4,100daN per beam for this locking beam system.
This extract from the Code XL certificate of a SchmitzCargobull semi-trailer shows the boundary conditions under which the locking beams achieve their maximum effect.
Very often these boundary conditions are not met. For example, the coefficient of friction of ฮผ=0.3 is not given if the loading area has not been swept clean.
An improved version of this system achieves 4,500daN per beam. This also allows a load to be secured to the front if it cannot be positioned against the bulkhead due to the load distribution.
In summary, it can be said:
- The equipment of a vehicle must be designed at the time of procurement in such a way that even heavy loads can be secured if they do not completely fill the load compartment or cannot be positioned against the bulkhead due to the load distribution.
- Calculated over the lifetime of the means of transport, the investment in systemic safety equipment is always worthwhile.
- These systems make it much easier for both the driver and the responsible loader to secure the load properly.
- The right safety equipment helps to increase safety during road transportation and thus protect all road users, which can be any of us, from dangerous situations.
Yours, Sigurd Ehringer
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