FEATURE
INCORPORATING COLD CHAIN
About insulated panels By Benjamin Brits
Insulation , and more specifically insulated panels - are considered critical in many aspects of the cold chain today , and several other industries too .
Dalucon Refrigeration Products Panel World
One may think that an insulated panel is the same from supplier to supplier and that the ‘ material ’ that they are made out of is all the same too . However , this is far from the reality as these essential components come in many configurations – and may deceive the eye when installed while at a glance you would need an intricate knowledge of this subject to know the difference .
Insulated panels , sandwich panels , composite panels , or also known as structural insulated panels were first a product of the built environment for homes and were invented in the 1930s . Wood chips were used as the insulating material . Their popularity gained traction for industrial applications from the 1970s when foam insulation was conceived , and with that , the use of chlorofluorocarbons ( CFC ) – which we know was harmful to the earth ’ s ozone layer . ( Subsequently CFC use was replaced for foaming applications with hydrochlorofluorocarbons ( HCFCs ) and later hydrofluorocarbon ( HFC ). The use of these gasses too will be phased out in the near future and be replaced with one of the hydrocarbons ( such as n-pentane , isopentane , or cyclopentane ).
With the advancement of technology and the discovery of new and safer ways to manipulate and handle raw materials , as well as their properties under differing conditions , the world of insulation has taken great leaps since the early 2000s with designs and formulas to meet many requirements .
For applications in the cold chain , insulation material performs the function of keeping the temperatures inside and out of any space separated , thus requiring less work from the refrigeration system to maintain the temperature and so conserve energy . You could imagine trying to cool down a plain steel shed that is fully exposed to the peak heat of the day would not be very effective , or extremely difficult – not to mention the challenges one would experience at night or in erratic climatic conditions . It is therefore essential to manage the heat load factors – and insulated panels are the obvious answer .
For the most part , insulated panels are associated with storage rooms for produce , but their application in the cold chain extends further into cold and freezer rooms , food production facilities , display fridges , food preparation areas , abattoirs , medical
A high pressure polyurethane injecting machine used in the manufacture of insulated panels .
An example of a polyurethane ( PUR ) core panel . rooms , growing environments , specialist applications , distribution and transportation services – any area where conditions for control are required in order to avoid premature decay of the product . This may include temperature as well as hygiene safety factors .
South Africa has , over the last few years , gained countless facilities – particularly cold stores and distribution centres directly related to the cold chain . This expansion has also seen several entries from international organisations and along with their investment has come high standards and requirements . This is of course good for the local manufacturing sector and especially for those providers who have kept up to speed with technology and global standards . New facilities are also pushing the boundaries of storage heights here locally with some sites now boasting 22m tall walls .
The transportation sector has also seen a boost over the last two years owing to the growing-ecommerce sector and has also been fuelled by the changing habits of the consumer . This is another very active sector that utilises these products with home delivery services of all kinds .
THE HOW AND WHAT OF INSULATED PANELS The concept of the insulated panel construction is very simple – it is a material ( the core ) ‘ sandwiched ’ between two pieces of metal ( also known as the skins ). The production of these panels in South Africa is primarily through two methods - namely the use of pre-cut blocks bonded to the facings or through a process known as foam in place / injection – where the core material is blown into a cavity and expands to fill the void .
Now although a very simple product construction to understand , ‘ the devil is in the detail ’ as they say , and both the core and the skins that are available come in different forms - and of course these elements ultimately create different quality end-products . One such example is that profiles can come in a range from 25mm all the way through to 300mm in thickness , however the thickness of the product is not the only factor that needs to be considered – the profile density offers different thermal properties too .
Similarly , the skins could be a material that is anything from 0.25mm to a few mm in thickness and be a composite of several different combinations of metals , and , as another example – lower quality could result in premature corrosion or altering of structural limits . The skins not only protect the core insulation , they have other useful functions such as protection against weather ( in the case of SA – the harsh sun ), hygienic surfaces and a level of protection against fire or open flame . This is achieved via the various coatings that can be applied .
Fire risk rating has been covered extensively in previous issues of Cold Link Africa which can be referred to in terms of this subject matter . Also , several studies can be found online that offer insights into the optimum panel thickness and core choice for the categories of the cold chain based on application and geographical location . Wall panels can be freestanding and interlocked using different joining techniques and can also be installed using a full frame support . They could further be used as wall cladding in the cases where a concrete structure already exists . Ceiling panels would be installed using the panel walls as the predominant supports with the addition of supporting hangars / steel cables . Both ceiling and wall panels can come in different span lengths and profiles , and the maximum production length is really only limited by the ability to transport the product . The longest panels ( without a join ) produced locally come in at 16.5m ! Most reputable manufacturers will have guidelines as to appropriate and best installation practices for their respective products - be they for wall or ceiling applications .
A particular feature of these panels - which is supplier dependant - is the various methods of joining the panels together . This can be through a unique locking design , simple dovetail , direct insulation engagement with skin overlaps , or a separate extrusion system .
Insulated panels have a life expectancy of up to 30 years . The core material for the panels that is available in South Africa is listed as follows . Special formulations that are unique to some international suppliers are also available locally . As a highlight , the pros and cons of each material are available through various associations both locally and internationally . For example , some materials may degrade faster over time compared to others or permeability of liquids is more with one material over another , affecting performance .
• Expanded polystyrene is produced by expanding polystyrene beads , which are then bonded together to form rigid boards . “ Bead boards ” as they are often referred to are manufactured in three densities . Polystyrene will “ break down ” if left exposed to sunlight for prolonged periods . This material must also be protected from solvents and only compatible adhesive and sealants can be used .
• Phenolic foam is manufactured from phenol formaldehyde resin and is available as either an open or closed cell product . It should be protected from prolonged exposure to sunlight and water . It is suitable for wall sheathing , and for use on the interior , both above and below ground .
20 www . coldlinkafrica . co . za COLD LINK AFRICA • June 2022