Premier Manufacturing, established in 1990, are a leading UK ‘off site’ manufacturer of modular buildings and extensions for residential and commercial applications. They use modular building transport bags to ensure that their buildings reach the construction site and client in good condition.
Previously, the team at Premier had used a type of heavy weight, re-usable cover to protect modules during road transport. Whilst these covers had worked OK, the challenge with this type of cover bag is that it is very difficult to get it to fit really tightly around the module or pod. As it travels down the road, the cover tends to flap and move and this can start to rub against finished surfaces of the module. For this contract, the modules had a rendered external finish which might be chafed and damaged by a loose fitting bag. In addition, a re-usable modular building transport bag needs to be returned after each use and over time and it will require occasional repairs and cleaning. For a large contract, where there could be dozens of covers ‘in the system’ keeping up with this maintenance can be a challenge.
When Premier needed to ensure that hundreds of modular buildings for a major client in London reached their destination clean and dry after a 150 mile / 3 hour trip from the manufacturing facility in Shropshire they contacted us to enquire about our industrial shrink wrap covers. Shrink film is typically supply on large ‘industrial sized’ rolls. However, after speaking with Premier and finding out a little more about their objectives, we suggested that because of the number of modules that needed to be packaged and because the modules were relatively small and mostly consistently sized, a pre-made custom sized shrink to fit bag might be more cost effective and easier to install.
This short ‘case study’ describes how we worked with Premier to specify and test which type of modular building or pod cover would work best for them.
For many manufacturers, a custom made re-usable type of transport cover is a good option. There are some great covers on the market, which are normally made from a heavy weight tarpaulin type material and come in a variety of designs. Some are made just to fit open sides of modules whilst others are designed to encapsulate the entire module, (including roof and sides.)
At Rhino we specialise in a different kind of covering for modules. All our products are based around our industrial and construction grade shrink wrap sheeting and they are designed to be used once and then recycled. Shrink wrap sheeting provides a taught, shrink to fit covering and because it is significantly lighter than a tarpaulin type cover it is particularly suited to projects where complete encapsulation of the modular building or pod is required because it can easily be lifted over the module roof.
When using shrink wrap you have two options / approaches. One option is to use sheeting which is supplied on a roll. The advantage of this is that rolls are typically available ‘off the shelf’ in a range of standard sizes. At Rhino we stock films from 7m to 16m wide and from 190 to 500 microns thickness. The sheeting is unfolded over the roof of the module and then is out and welded ‘in situ’. This is ideal if there is just the occasional module which needs covering or the modules which need covering vary in size and shape. Our own installation teams will always use shrink wrap supplied by the roll when carrying out shrink wrap projects on customer sites. When shrink wrapping a modular building, the process is very similar to wrapping a birthday present! You need to ensure that there is enough material to be folded around the each end of the module and overlap.
However, in a manufacturing environment, where the covers will be fitted by operatives who are not ‘professional shrink wrappers’ then using shrink wrap straight from the roll can be a bit ‘hit and miss’. The process may take longer than expected, the results may be inconsistent from module to module and there may be a fair bit of wastage as it can be difficult to judge just how much extra shrink wrap to allow to cover the ends. So, if the modules being shipped have a consistent size then a shrink tight modular building transport bag can be a better option.
Specifying shrink to fit modular building transport bags is a fairly straightforward process. After an initial conversation with Premier we were able to get the finished dimensions of the modules they wished to protect.
We then proceeded to make an sample bag which we took to the off site manufacturing facility to demonstrate the installation process. These first modules were shipped to the construction set and received positive feedback. For one of the modules we had covered, the bag had been a little too tight to fit easily so we manufactured a second round of samples and once again travelled to the customer site in order to ensure that the fit was right and that Premier’s operatives were familiar with the heat shrink process.
Once all parties were happy, we were able to proceed with a production order of a sufficient quantity of bags to meet the contract. Because Premier needed to start and protect modules immediately we were able to provide them with a roll of our 12m (40′) x 50m (164′) shrink wrap film to shrink wrap modules which were shipping before the bags were ready.
Remember, for an overview of the installation process please watch the ‘modular building transport bags’ video at the top of this page.
This is not required for every type of module but if there are any very sharp edges these need to be padded out.
For modules with solid sides this will not be required. However, for large modules that have large open areas, we recommend running a woven strapping or similar at 2-3m intervals. When this strapping is tensioned it provides a support structure for the shrink wrap cover.
The shrink wrap modular building transport bag is unwrapped and unfolded over the top and down the sides of the module.
To get the tightest possible finish to any shrink wrap covering it is recommended that the cover / bag is secured around the bottom of the module or pod. Without this, during the heat shrink process the cover will have a tendency to ride up the sides of the module and it will nit have the same tightness or professional looking finish to the cover – there will always be wrinkles and creases. A quick way to secure the cover around the bottom of the module is to use wooden batten, however, for some modules this will not be possible and so an alternative technique is to run a band of strapping around the module. The strapping is then tensioned and the bag is folded around the strapping and heat welded to itself.
For some modules that require complete encapsulation, even underneath, we lay a shrink wrap footprint on the ground on to which the module is lifted. This footprint is designed to be larger than the module by approx. 500mm on all four sides. The footprint is folded up on to the side of the module and then joined to the top covering by heat welding the two parts of the cover together. This method of complete encapsulation is much easier than it sounds and is very robust – ideal for modules which will be transported long distances.
Modular Building Transport bags may be manufactured in a number of ways. Our favoured technique is to use a side weld technique as this keeps production costs low. The only difference in a side weld cover as compared to a more costly ‘block bottom’ cover is that after fitting the bag will have a triangular shaped ‘ear’ at each end of the module which needs to be heat sealed back to the cover. This is quick and easy to achieve using a propane gas hot air gun.
The final stage of the shrink wrap installation process is to use our propane gas hot air tools to heat shrink the sheeting ‘drum tight’ over the entire surface of module using propane to create a smooth and tight finish.
Sometimes it can be useful to gain access to the module after it has been shrink wrapped, perhaps to carry out last minute work or inspections. In this case, it is possible to tape on a zipped access door.
Thank you for taking the time to read this case study. Please do contact us with your questions or comments. We look forward to hearing from you.