How weather affects plastic strapping performance

Heat, cold, moisture and prolonged exposure to sunlight can all affect how strapping performs over time. The impact can vary depending on the type of strapping used, as well as how and where it is stored or transported.

Understanding how different weather conditions affect plastic strapping can help businesses choose the most suitable material for their application and maintain load stability throughout the year. In this guide, we’ll look at how temperature, moisture and UV exposure can influence strapping performance, and what businesses can do to protect their loads in challenging conditions.

Why weather matters for plastic strapping

Plastic strapping is designed to provide dependable load security, but it isn’t completely unaffected by the environment around it. Changes in temperature, moisture and exposure to sunlight can influence how strapping performs, particularly when loads are stored or transported for extended periods.

Some of the key environmental factors to consider include:

• Temperature fluctuations: Heat and cold can affect the flexibility, tension retention and overall performance of plastic strapping.
• Humidity and moisture: While plastic strapping itself is resistant to water, wet or damp conditions can affect the load, including its weight and the friction between products.
• UV exposure: Prolonged exposure to sunlight can gradually degrade plastic, potentially reducing tensile strength and affecting the strap’s performance.
• Long-term outdoor storage: Loads kept outside for weeks or months can face a combination of changing temperatures, moisture and UV exposure, making material selection particularly important.
• Load weight and conditions: The weight of the load is only part of the picture. Businesses should also consider where and how goods will be stored or transported when selecting the right strapping.

Taking these factors into account can help businesses choose a strapping solution that remains effective throughout storage and transport, whatever the season or conditions.

How heat affects plastic strapping

High temperatures can have a noticeable effect on plastic strapping, particularly when loads are stored or transported in hot environments for extended periods. As temperatures rise, plastic can expand, which may cause the tension in the strap to reduce over time. For some applications, this can increase the risk of load movement if the strapping no longer provides the same level of restraint.

The effects of heat can include:

• Plastic expansion: Higher temperatures can cause plastic strapping to expand, potentially affecting the tension applied to the load.
• Reduced strap tension: Over time, heat can contribute to tension loss, reducing the strap’s ability to keep products securely in place.
• Increased load movement: If tension drops significantly, products may shift during handling or transport, particularly where loads are already difficult to stabilise.
• Material softening: Higher temperatures can soften some plastic materials, which may affect their performance and tension retention.
• Hot containers and trailers: Temperatures inside shipping containers, trailers and other enclosed spaces can become considerably higher than the outside temperature during summer, so these conditions should be considered when selecting strapping.

For businesses regularly moving or storing goods in hot conditions, choosing a strapping material suited to the environment can help maintain load stability and reduce the risk of failures.

The impact of cold temperatures

Cold temperatures can affect plastic strapping in the opposite way to heat. As temperatures fall, some plastic materials become less flexible, which can make them more susceptible to cracking or breaking, particularly when the strap is under high tension.

This is especially important for polypropylene (PP) strapping, which can become more brittle in colder conditions. Key considerations include:

• Reduced flexibility: Lower temperatures can make plastic strapping stiffer and less able to flex around a load.
• Risk of brittle fractures: PP strapping is more susceptible to becoming brittle in cold environments, increasing the potential for cracking or breaking.
• Over-tensioning: Applying excessive tension to a strap that has become less flexible can increase the risk of it snapping.
• Cold storage and transport: Businesses using cold warehouses, refrigerated environments, or transporting goods during winter should consider how low temperatures may affect strapping performance.
• Material selection: PET strapping generally performs better than polypropylene in colder environments, making it a suitable option where loads are exposed to low temperatures during storage or transit.

Choosing a strapping material that is suited to the operating temperature can help maintain reliable load security and reduce the risk of strap failure during cold-weather handling and transport.

Moisture and humidity

Although plastic strapping doesn’t absorb water in the same way as some other packaging materials, moisture can still have an impact on overall load stability. In many cases, it is the load and the conditions around it, rather than the strapping itself, that are most affected.

Wet and heavier loads

When pallets or products become wet, they can become significantly heavier. This can place additional demands on the strapping and other load-securing methods. Businesses transporting goods in wet conditions should consider how moisture could change the weight and stability of the load.

Reduced friction between products

Moisture can also reduce the friction between products or between the load and its packaging. This can make surfaces more slippery and increase the potential for products to shift during handling or transport. Even where strap tension remains consistent, reduced friction can make maintaining overall load stability more challenging.

Ice and condensation

Cold weather can introduce additional moisture-related risks. Ice can form on or around loads during winter transport, potentially affecting stability and adding weight. Meanwhile, condensation can build up inside shipping containers as temperatures change, creating damp conditions even when goods were loaded dry.

Maintaining overall load stability

The key consideration is that moisture usually affects the load more than the plastic strapping itself. Businesses should therefore look at the complete load-securing system, taking into account the weight, friction, packaging and conditions the goods will encounter during storage and transport.

By considering moisture as part of the wider operating environment, businesses can select the right strapping solution and take additional steps to keep loads secure in wet or changing conditions.

UV exposure and outdoor storage

Sunlight can gradually affect plastic strapping, particularly when loads are stored outside for long periods. UV exposure can weaken the material over time, making it an important consideration for businesses storing or transporting goods outdoors.

• UV degradation: Prolonged exposure to sunlight can gradually break down plastic, reducing its performance.
• Colour fading: Strapping may fade when exposed to direct sunlight, which can be an early sign of UV exposure.
• Reduced tensile strength: Extended UV exposure can reduce the strap’s tensile strength, increasing the risk of failure.
• Outdoor storage: Construction materials, timber and other goods stored outside may be exposed to UV for weeks or months, making material selection particularly important.
• UV-stabilised options: UV-stabilised PET strapping can provide greater resistance to prolonged sunlight exposure and is worth considering for outdoor applications.

Choosing the right strapping material for different environments

Different storage and transport conditions call for different types of strapping. Choosing the right material for the environment can help maintain tension, improve load security and reduce the risk of strap failure.

Polypropylene (PP) for general indoor use

PP strapping is a practical choice for general warehouse applications where loads are stored indoors and exposed to relatively stable temperatures. It is well suited to lighter-duty applications where extreme environmental conditions are not a major concern.

PET for cold storage and export

PET strapping offers greater durability and tension retention than PP, making it a suitable option for cold storage and export shipments. It can perform more reliably where loads may experience lower temperatures or longer transport times.

UV-stabilised PET for outdoor storage

For loads stored outside and exposed to prolonged sunlight, UV-stabilised PET can provide additional resistance to UV degradation. This makes it particularly relevant for applications such as timber, construction materials and builders’ merchants.

PET or steel for heavy industrial loads

For heavier industrial loads where higher retained tension is required, PET or steel strapping may be more suitable. The right choice will depend on the weight, shape and handling requirements of the load, as well as the conditions it will face.

Ultimately, the best strapping material should be matched to the load and its storage and transport environment. Considering factors such as temperature, UV exposure, load weight and journey length can help businesses improve load security and reduce the risk of failures.

Protecting load stability in every season

Weather conditions can have a significant impact on load stability, with heat, cold, moisture and UV exposure all affecting how plastic strapping performs. Choosing a strapping material suited to the environment is therefore an important part of effective load security.

Businesses that regularly store or transport goods in challenging conditions should review their strapping solutions to ensure they are suitable for the demands of the application. Taking weather into account can help maintain load stability, reduce product damage and avoid unnecessary costs caused by strap failure or shifting loads.

Need help choosing the right strapping for your application? Speak to the team at Swiftpak for advice on selecting a strapping solution needed to suit your load, storage conditions and transport requirements.