When you’re transporting loads, you want to ensure your product arrives at its destination in the same state it left your warehouse. Strapping is one of the most effective ways to bundle products to ensure this. Based on the product you are securing, or the industry you are working in, you need to weigh up your options on the best product for your needs.
The team from Melbpack packaging shares with us some key considerations you need to take into account when it comes to safely packaging and strapping loads for transport.
Steel strapping has been around for the longest time. It’s known for its high tensile strength and is versatile because it’s available in a range of grades and widths and thicknesses. Think this is right for your needs? It’s appropriate for circumstances where you want strength, without stretch. The only situation it’s not suitable for is when the product needs to be secured in either hot or sharp. If the load is heavy and stable, needs to be transported long distances, and needs to be loaded and unloaded multiple times on its journey, steel strapping is the way to go.
Steel strapping has no give, so if you require elongation, plastic strapping is a better alternative. When plastic strapping materials are placed under tension, they elongate
and recover a portion of the elongation as stress is relieved. So, the straps contract when the package shrinks. Different plastic strappings will have different capacities to elongate and recover. You’ll need to choose the strapping material based on how much elongation recovery you need, the tension that can be pulled without damaging the strapped items, and how much creep is allowed.
Plastic strapping (often referred to collectively as poly strapping) can be just as strong as steel strapping. Here are some simple guidelines to help make the best choice:
- FOR HIGHER INITIAL TENSION Recovery on polyester strapping elongation is 70%. It offers well retained tension on rigid loads. The recovery properties of this material mean it can absorb impact, with strap breakage not becoming an issue. It will keep the necessary tension for the length of time needed. It is glossy and smooth.
- WHEN LOW RETAINED TENSION IS NEEDED Recovery on polypropylene strapping elongation is between 20 and 40% (based on the initial tension). This material is more sensitive to temperature. It is economical, however, and suitable for light to medium uses in bundling and for pallets. It offers high elongation but is less effective if your product is under constant stress. It is rigid and can be used in the place of steel strapping. It feels more like plastic, has a matte finish, and is often embossed.
Let’s look at tension. How does this work? Tension refers to any form of pulling or pushing needed to tighten a strap. Tension can lessen over time. Polyester less so than polypropylene. The tensile strength of strapping is measured in pounds. What you are measuring is the amount of force required to break a strap.
Some other terms you will need to be familiar with when working with strapping include:
- Core size. This is the diameter and depth of a coil of each strap. This is important because it must be the same as the strapping dispenser or machine that is being used with the strapping.
- One measures the physical thickness of a strap in fractions of an inch/width. Again the physical width of the strap must correspond with the tools you are using.
- This refers to the amount of stretch in the strap when tension is applied. When it returns to its former state when tension is removed, it is referred to as ‘elongation recovery’. We refer to the ‘working range’ when assessing how far the strap can be elongated before it wants to recover. It can go beyond a certain point where it can no longer recover. You need to find the point at which it performs well, without overreaching this crucial sweet spot.
Strapping can be used in both horizontal or vertical bands. It’s recommended that edge protectors are used in addition to strapping. This helps spread the tension of the strap on the load at corners. This can limit the risk of damage caused by tension. Rail cars, trailers, or skids also make use of strapping used in loops.
How is strapping traditionally used? It often depends on the industry it is being used for. For example, newspapers, lumber, or concrete blocks are often bundled together when being moved around or shipped. When pallets, skids, or crates need to be attached to items, strapping is useful too. It can be used to reinforce boxes, wooden boxes, or containers and attach items to trailers too. Bricks, packaged glass, and other items in the construction industries often use strapping to secure the loads. In the agricultural sector and the textile industry, they are used to hold bales. A common use is for closing corrugated boxes and shipping containers.
For more information and packaging equipment supplies check out Melbpack, you can visit the website here.