When protection is required for a large or awkward objects such as machinery, plant, buildings or boats, companies have traditionally used tarpaulins to meet this need. However, in recent years many companies have been turning to a new way of packaging large objects for storage and transportation, and shrink wrapping their products using a heavy duty ‘industrial grade’ shrink wrap.
Whilst boat builders and modular building manufacturers were among the first to take advantage of industrial shrink wrap, increasing numbers of manufacturers are now looking at shrink wrap as an alternative way to ensure their products reach the customer in the same condition they left the factory. This post looks at why such a change has been occurring by examining tarpaulins and shrink wrap in more detail.
First we will look at the various types of tarpaulin available and their typical uses, before looking at shrink wrap. We will look at issues such as the performance of each product in different scenarios and how easy the products are to fit.
Polythene tarpaulins are available in a range of grades and sizes. Normally the lowest grade tarpaulin is around 100gsm. Tarpaulins are made from a 100% waterproof lightweight woven polyethylene and laminated with eyelets at approximately one metre intervals set into a re-enforced hem. These tarpaulins can tear easily in a gale and will chafe on sharp corners.
Canvas tarpaulins are more expensive. These sheets are the old fashioned way of covering lorries, narrow boats, vintage vehicles etc. and are made up with double stitched seams and hems fitted with eyelets. Although fairly rugged, the main problem is that canvas tarpaulins are heavy and may require a number of people to fit over a large object. They may be difficult to fit tightly around more complex shapes. Finally they are difficult to clean and can subsequently quickly look tired and scruffy.
Mono type covers are a reinforced polythene heavy grade waterproof tarpaulin which is suitable for more rugged purposes, most commonly found to wrap scaffolding around buildings. Ready to use eyelets are spaced at one metre intervals in the reinforced hems and all four corner eyelets are reinforced by a corner patch. Although they are more rugged, than a standard polythene tarpaulin they are usually only available in a narrow range of sizes.
Shrink wrap should not be confused with ‘pallet wrap’ or ‘cling film’ that is stretched around an object and gives minimal protection. Heavy duty shrink wrap is draped over an object before shrinking tight. It is the shrink process that gives shrink wrap the strength and durability vital for industrial storage and transport applications.
Fitting shrink wrap:
Whilst a tarpaulin is simply thrown over an object and tied down, fitting a shrink wrap cover can be a lengthier process. Unlike a tarpaulin which is held down by ropes attached to eyelets located around the hem of the tarpaulin, a shrink wrap cover uses an alternative method. Instead of metal eyelets, which can damage the product being protected, a ‘perimeter’ band of tough strapping or rope is run around the bottom of the object being covered. The shrink wrap is then placed over the object, flipped around this perimeter and then heat welded back on to itself. Once the shrink wrap is anchored in this way it can be ‘shrunk off’ using a hot air tool. The ‘shrinks to fit’ characteristic makes shrink wrap particularly good at protecting awkwardly shaped products.
Although shrink wrapping is a very simple process, there are a number of techniques required to get the best result. If staff are not available to carry out the application yourself or the requirement for shrink wrapping products is occasional, we can offer an on-site shrink wrap installation service.
Tarpaulins are generally only available in a limited range of standard sizes. Shrink film is available in rolls up to 12 metres wide by 70 metres long. However, because shrink film can easily be heat fused together there are no limitations as to the size of object which can be protected. Done correctly, two sheets of shrink film heat welded together will be a strong and waterproof as the original wrap. In addition, unlike a tarpaulin, a shrink wrap cover can be fitted with a zipped access door, and can be fitted with self adhesive vents accorded to requirements.
Shrink Wrap Durability:
Unlike a tarpaulin, because shrink wrap is heat shrunk around an object, it becomes tight and does not flap and ‘self destruct’. This is the secret of it’s durability. Shrink wrap has been tested on large objects in the harshest conditions – such as deck cargo crossing the worlds oceans (with very positive results).
Once the product has reached it’s destination, the shrink film must be removed and recycled as shrink wrap cannot be re-used. The ability to re-use a tarpaulin is often cited as the main advantage to tarpaulins when compared to shrink wrap. Although the cost of tarpaulins is generally higher, because they can be re-used it is normally thought that the overall cost compared to shrink wrap is lower. Whilst this can be true, in many situations, companies may find it difficult to get tarpaulins returned and there will certainly a cost of doing so which must be taken into account. Using tarpaulins also requires additional expenditure on periodic maintenance.
Another benefit of using a shrink wrap cover is that, because it fit’s so tight, entry is impossible beneath the cover. To gain entry, the cover must be cut which makes it obvious if the product has been tampered with in any way.
In a competitive market, where the product is being delivered to a customers premises, the smooth, slick glossy white shrink wrap covering has an aesthetic advantage over a dirty tarpaulin. It is no surprise that boat builders, who previously had been delivering a vessel worth upwards of £250k + covered in road grime were the first to see this aspect of shrink wrap.
What to look for when buying shrink wrap:
When purchasing shrink wrap for large scale industrial and marine projects it is important to ensure that the film is of the correct grade. Lightweight grades (50-100) micron may be ideal for packaging regular products but to shrink wrap machinery, plant and equipment will require a wrap that is around 180 micron thickness. Additives such as ultra violet inhibitors will prevent the film breaking down in sunlight and also protect the item underneath whilst EVA will ensure that the film remains supple and does not become brittle in low temperatures. White shrink wrap is generally the preferred choice, reflecting heat and keeping the product cool.
In conclusion, it is clear that both shrink wrap and tarpaulins have a valuable role in protecting large pieces of plant, machinery and equipment during storage or delivery to customers. Tarpaulins are readily available and require little skill to fit, whilst industrial grade shrink wrap is available from a limited number of specialist suppliers and may require some staff training to get the best results.
Tarpaulins are best suited to smaller, lower cost items where the tarpaulin cover can be returned once the product has been safely delivered or stored.
Using shrink wrap is most advantageous for particularly large or particularly valuable objects, which need to be transported long distances with 100% peace of mind that they will remain protected from damage.