Pallet stability is essential for transport safety, both for the products being transported and for everyone involved in the distribution cycle. Beyond the importance of safety, an unstable unit load is also a cause of unnecessary costs and logistical inefficiencies.
For this reason, Safe Load Testing Technologies provides companies with the appropriate machines and tools to achieve load stability in palletized units, allowing them to analyze and study packaging systems through their own testing methods or following the test protocols of international associations.
What is pallet stability
Pallet stability is the ability of a palletized unit to remain intact and upright, i.e. stable, against forces experienced during the distribution cycle. These forces include acceleration, braking (deceleration) during transport, or forklift handling movements.
Achieving this load stability depends on the design of the correct palletizing system. Both the stretch wrapping machine and the amount and type of stretch film used play a crucial role in this design. In addition, the requirements of the product to be transported must always be taken into account.
For example, palletizing glass bottles should follow a different protocol than designing a system for transporting computers, depending on the fragility of the product. Then, through the appropriate testing methods, it is possible to test the designed system and validate it before it goes into the actual distribution cycle.
Pallet stability is important for producers for three reasons:
- Avoiding product shrinkage. An unstable pallet can cause crushing of products or cause falls when handled with forklifts. This leads to a loss of product and, consequently, a loss of money.
- Increased security. Unstable cargo endangers storage and transport operators. Thus, it is estimated that at least 25% of truck accidents are caused by the movement of unstable loads.
- Ensuring pallet stability translates into substantial savings for companies, not only by reducing shrinkage, but also in fines related to poor stowage and load stability.
Problems that compromise pallet stability
The problems to achieve load stability are related to the configuration of the goods on the pallet, the weight distribution or the choice of the packaging material used (stretch film or stretch hood). This last point is one of the most important to take into consideration, since the choice and use of the packaging material can cause several problems, among which are the following:
H3: Uneven edges in the shrink film roll / Bordes irregulares en el rollo de shrink film
Uneven edges on the shrink film (the material that surrounds the products transported on the pallet and shrinks to contain them) can cause problems during unwinding. This prevents the material from being wrapped straight and, therefore, makes the sealing necessary to protect the products impossible.
> Defective seals
Ueneven edges are just one of the reasons why shrink film sealing may not occur. This problem can also be caused by poor polymer material (which does not adjust when heat is applied) or poor sealing position during placement (which would require readjustment of the sealing machine).
> Shrink film blockage
In this case, the different layers of the film are stuck together, which does not allow its correct application. This situation may be caused by improper storage of the shrink film, where high temperatures may have occurred.
> Stretch wrap
Optimizing the wrap film fit is essential to achieve pallet stability: using too much film can damage the products, as can using less than the required amount.
Pallet stability: important aspects to consider
As mentioned above, it is not only the choice of packaging material that is important. There are other aspects to be taken into account to ensure that palletized unit loads remain stable during transportation and storage, such as:
> Pallet utilization
To avoid stability problems, the load should be placed along the entire surface of the pallet, as the unused space causes the products to shift.
Boomerang Horizontal Stability Tester installed at Samuel Grant pallet stability testing center.
> Pallet pattern
Stability is achieved by choosing the correct placement pattern on the pallet. Thus, if the pallets are not to be stacked on top of each other, an interlocking arrangement (like a brick wall) is recommended, which provides greater resistance to lateral movements.
If the pallets, on the other hand, are to be stacked on top of each other and no racking is to be used, then straight column stacking is recommended, which provides greater compressive strength. In any case, the placement pattern has to be studied in conjunction with the use of space on the pallet.
> Stack height
A greater height means more possibilities of movement due to dynamic forces and therefore a more complicated pallet stability. Therefore, it is essential to study the optimum stacking height of the palletizing system, bearing in mind that a safe height is considered to be one that allows the forklift operator to see over or to the sides of the pallet while driving.
Testing methods to achieve pallet stability
To ensure that the design of a palletizing system is safe, it must be subjected to various transport simulation tests before being put into the actual distribution cycle. Testing methods confirm that the method of wrapping, the amount of shrink film, the height chosen and the use and pattern of placement on the pallet are appropriate.
Ultimately, testing methods provide companies with information on how the palletized load will react to contingencies in the distribution cycle and verify that pallet stability has been achieved. In this context, there are two test methods directly related to load stability; Eumos 40509 and EN 12195.
EUMOS 40509: 2020
EUMOS 40509-2020 is a standard that describes a test method for analyzing load stiffness. For this purpose, dynamic horizontal forces or accelerations are applied to evaluate how the palletized unit reacts and to examine its stability.
This is a standard included in European legislation (Directive 2014/47/EU) that seeks to improve safety in road transport. To learn more, download our free ebook ‘40509: everything you need to know about the new 2020 version’
To carry out the EUMOS 40509: 2020 test method, Safe Load Testing Technologies has designed two simulation systems: the Horizontal Stability Tester system and the new Boomerang Horizontal Stability Tester.
EN 12195 proposes a standard for load securing devices on road vehicles. By applying the calculations proposed in the standard, road transport companies can design a suitable load securing system. For this purpose, the standard defines several coefficients and formulas to be used, as well as different reference tables for subsequent calculations.
Among the procedures described in this standard are blocking, lashing and various combinations of both methods, so that the load is secured to the surface of the vehicle. It is intended, in any case, for the design of stowage methods for vehicles with a total weight of more than 3,500 kg.
You might be interested in: ‘EN 12195: securing loads on road vehicles’
Later, it is possible to test the selected load securing system, for example, using the innTilt system. This tool allows companies to perform tilt tests to evaluate the stability of the load.
Testing solutions for pallet stability
> The innSlide family
Safe Load Testing Technologies has two solutions for horizontal stability testing.
- On the one hand, the Horizontal Stability Tester system is an advanced solution for simulating horizontal accelerations and decelerations of unit loads during transport.
This equipment is in line with major international standards such as EUMOS 40509 and U.S. FMCSA load safety requirements. Among its capabilities is the ability to adjust the stroke length according to the company’s needs.
- On the other hand, the Boomerang Stability Tester is the world’s most compact acceleration tester, its small size being the main difference with the Horizontal Stability Tester system.
This equipment is mainly oriented to meet standards such as EUMOS 40509 and the load safety requirements of the US FMCSA. Thus, it is an innovative patented test method that aims to obtain the same results as the Horizontal Stability Tester system in less than half a run.
Both systems are equipped as standard with the innVision ST system, which includes a high-speed camera and software to measure the load deformation of the unit. This system, after data capture, generates a results report useful for verifying pallet stability.
In addition, it is possible to install the most advanced system, innVision Pro, which incorporates a high-speed machine vision camera capable of measuring load deformation in real time and generating reports automatically.
You might be interested in: ‘Discover Dow’s success story and its new load stability center’
> Tilt Testing Tool
The Tilt Testing Tool simulation machine is specifically designed to perform the tilt test in order to evaluate the stability of the load. In this way, companies have access to a tool for quality control, validation and packaging optimization, since repeatability is guaranteed.
Available in 3 transportable models, with a maximum inclination angle of 30%, it is an electrical solution that allows the testing of loads up to 1,500 kg (3,306 lb).
Keep reading about ‘How to carry out a tilt test of your load properly?
Do you want to know more about how to improve the pallet stability of your loads? At Safe Load Testing Technologies we put our two decades of experience at the forefront of transport simulation and testing at the service of our customers, looking for solutions adapted to their needs. Contact us and let’s talk about how we can help you achieve stable, safe and economically efficient unit loads.