The Material...
Aluminium - the historyAluminium is extracted from Alumina, which itself is a product of Bauxite. Bauxite is a very plentiful mineral, it forms 8% of the earths crust, and is mined in many countries. Alumina, (Al2O3), which is the powdery white oxide of aluminium, is then smelted in a continuous process, from which pure aluminium and oxygen contents are separated out. The first commercial extraction of alumina from bauxite has been attributed to Henri Sainte-Claire Deville around 1854. Later, in 1888, Karl Joseph Bayer described what is now known as the Bayer process, which led to a dramatic reduction in the cost of producing aluminium metal. The early annual production volume was very small, only reaching 1000 tonnes by 1900. Aluminium was seen at the time as some sort of “miracle material” – attractive in appearance, easy to work with, lightweight, and non-corroding. Inevitably there were early forays into some odd applications; Queen Victoria had some aluminium jewellery, and while surely not so desirable as gold or silver it did at least have the novelty value in a very fashion-conscious age! But engineers and designers quickly saw the merits of the new material and rapidly seized the benefits for their particular field of operation. Early users found new ways in which the material could be employed to produce finished goods, and manufacturing processes soon included machining, casting, riveting, and welding. Later developments have brought in high pressure die-casting, bonding, and sophisticated extrusion techniques.
Aircraft development was, and remains one of the
principal beneficiaries of aluminium. Early aircraft evolution was largely
limited by the need to increase mechanical durability while keeping within
very low weight limits - aluminium made rapid advances possible, replacing
the wood and canvas that had so far limited development. Modern aircraft
would simply not fly if aluminium were not available! The development of cars has benefited enormously from increased use of aluminium. Audi make the floorpan of their A8 from aluminium, which they also use throughout the famous moon buggy they made for NASA. Both require minimal weight and maximum strength, and aluminium comes out a clear winner in both applications. In everyday life, we see aluminium used in a huge variety of ways. Saucepans, aluminium car wheels, ladders, garden furniture, – the list is seemingly endless. It is in fact the world’s second most used material. Around 32 million tonnes of it is produced new each year. Add to that the material emerging from recycling, and you begin to see some measure of the popularity and success of aluminium. To read more about sources of new & recycled aluminium, click sources. To see more details on the environmental benefits of recycling, click environment. Back to TopAluminium - new & recycledAluminium is available from two sources. The first is “new” aluminium, produced from mineral sources through smelting. This is the original method, you can read more about this source by clicking original The alternative material source is “recycled”. This process takes in scrap and used items, and from a smelting process emerges fresh aluminium. Aluminium can easily be recycled. Not just once, but many times over. The recycled material retains ALL its original characteristics:
There is also the added benefit that the process of recycling uses only a small fraction of the energy needed for the mineral extraction and smelting processes used in the making “original” aluminium. The recycling process draws material from two sources:
Since the material can be recycled endlessly, the tonnage in current use in all products worldwide will inevitably become a material source for recycling in the future, and so aluminium can be clearly identified as a “green” material. Recycling uses only 5% of the energy needed to make “original” material from mineral ore, and we have already passed the level where over 50% of the global demand for aluminium is serviced from the recycling industry. ALL ALC COLUMNS ARE MADE TOTALLY FROM RECYCLED ALUMINIUM. Back to TopEnvironmental benefits of recycling
Energy levels used
in making “original” aluminium:
Comparison with energy levels used in recycling:
Back to TopALC Columns: Durable finish & no maintenanceALC aluminium columns are designed and constructed to be corrosion free. The aluminium material itself is non-corroding, and will form a hard wearing oxide film on exposed surfaces - this “skin” offers extra protection against harmful airborne pollutants. The column root is protected by thermoplastic coating, which extends above ground level, and even protects against dog urine and road salt, known causes of severe corrosion and premature failure in steel columns, and potentially damaging to unprotected aluminium. Equally, with the protected root the damage which can result from mounting directly in concrete is totally avoided. The thermoplastic material has high dielectric strength, and is chemically inert, which means that it is there to stay. Because there is no corrosion taking place, ALC aluminium columns do not deposit residual chemicals in the ground – another environmental benefit. Aluminium loses none of its properties with age. ALC columns have been manufactured since the 1930’s, and are in use across Europe, including places with the most hostile environments. ALC aluminium columns are virtually maintenance free. Steel columns in the UK are routinely monitored and tested to track the progress of corrosion, and the associated structural weakening – such maintenance issues simply do not apply to ALC columns. Back to TopSafety in easy handlingThe whole business of moving and planting columns is a potential risk to safety. Size and weight mean that specialised handling is needed, usually requiring mechanised lifting and shifting gear. Aluminium is light, and typically a column weighs one third as much as its steel counterpart. Handling and moving is therefore easier, and in many cases an aluminium column can be moved purely by manpower. While mechanised handling is standard to many sites, this is not always the case, and the use of aluminium columns will minimise the risks attached to manhandling. Aluminium columns do not need painting, so the risks associated with the spillage on site of preparatory and finishing liquids are eliminated. The absence of painting also reduces the need for lane closure and operatives on the roadside. Back to TopPassive safety explainedAccidents involving a collision between a car and a lighting column are quite frequent. In 2003, the last period for which figures have been published, there were 3,768 such incidents where injury occurred. This is just the number of “one car, one lamppost” instances; there were more where column impact occurred collaterally in a more complex collision. Of those 3,768 injury cases, 23% involved death or serious injury to vehicle occupants. You can see some statistical details by clicking accident figures Aluminium columns offer passive safety in that the material is more energy-absorbent, so that in a collision, vehicle occupants experience slower deceleration, and consequently reduced risk of injury. ALC columns are rated against the current standard BS EN 12767, and qualify as offering enhanced safety. Ratings are determined by crash testing – you can see video clips of an ALC column being tested by logging into our members area. At present, passive safety roadside structures are used routinely only on motorways and trunk roads in the UK. There is a very strong case for adopting a similar strategy on urban roads, simply because a large majority of car-column collisions, and the resulting injuries, occur there. There is a European Standard on passive safety in roadside structures – you can read about the subject in more detail by clicking BS EN 12767 Back to TopPassive safety in vehicle impactsFor the occupants of a vehicle, collision with a lighting column can be a very serious, even a fatal event. Columns do not have “crumple zones”, and they are routinely anchored firmly in the ground. Colliding with a column therefore involves extremely rapid deceleration of the vehicle, and also its occupants, which often results in injury, and sometimes death to the occupants. ALC columns are all constructed in aluminium, which has material properties which in themselves offer passive safety - aluminium absorbs impact energy over a longer deceleration time than either steel or concrete, the two most common materials found in lighting columns in the UK. Decelerative forces are massively reduced where collision is with an aluminium construction, and the risk of injury or death is very much reduced. The material advantages of aluminium are enhanced even further by the unique construction of ALC products, where the integrity of the column is maintained under impact. The rate of energy absorption available from typical column materials can be seen in the following graph:
You can read more about passive safety by clicking here
“Car into lamppost” collisions are common. You can see some statistics on this by clicking accident figures Back to TopAccident figures - collision with column
Note: above figures report ONLY the specific accident type stated, i.e.. Single vehicle impacting lighting column. Other types of accidents (for instance those involving multiple vehicles with lighting columns) are NOT included. Back to Top BS EN 12767 - Passive safety in roadside structuresBack to TopBS EN 12767 - Hierarchy of performance typesExtract from EN 12767:2000 - Table 7
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