Aluminium finds broad application in the construction industry, more than almost any other metal.
The use of aluminium in design and construction has a strong history, primarily due to its ability to be flexible, lightweight and durable. With regulatory changes and an increased focus on compliant cladding solutions, many within the design and construction industry are now wondering about their options.
While aluminium comes in various grades, each grade is suited to different applications. Once you have selected aluminium as the material to feature in your project, the next step is to select the right grade of aluminium.
Understanding aluminium grades
There are seven different alloys (or blending agents) commonly used in aluminium manufacturing. Each series starts with a number between one and seven – that number identifies what alloying element has been added to the aluminium.
Specifying the suitable grade of aluminium for your project, be it industrial or architectural, will depend on the qualities of that alloy. Different alloys have different benefits, including workability, corrosion resistance, heat treatability, electrical conductivity, strength and flexibility.
An overview of the different series is listed below:
- 1000 series: The purest commercial aluminium grades, containing at least 99% pure aluminium. Because of its superior corrosion resistance, it is mainly used in specialised chemical tanks or conductive bus bars.
- 2000 series: Alloyed with copper for increased strength, it is often used for aircraft and aerospace industries.
- 3000 series: These alloys contain manganese, and are often used for chemical and food equipment, and buildings.
- 4000 series: These alloys are wrought with silicon, lowering their melting point.
- 5000 series: Known as ‘marine grade’ aluminium, it is alloyed with magnesium. It is corrosion resistant but non-heat treatable; hence it is widely used in fabrication such as transportation, tanks, vessels and bridges.
- 6000 series: Alloyed with magnesium and silicon, it responds well to heat treatment.
- 7000 series: Containing zinc, it is the highest-strength commercial grade of aluminium, and is often used in high performance applications such as aircraft, aerospace and competitive sporting equipment.
The most common aluminium used in the general construction and fabrication industry is 3000 or 5000 series.
While 5000 marine grade aluminium sounds stronger, is it the right choice for your architectural application?
It is important for engineers and architects to have a clear understanding of the features, benefits and pitfalls of these different grades of aluminium when requesting a specific type for a project. For example, when it comes to the 5000 series marine grade of aluminium, this type of aluminium alloy has a high tensile strength and is highly resistant to corrosion, which leads people to think it’s ideal for the Australian coastal market where buildings are exposed to a saltwater environment.
However, it is the ultimate choice for use in building ships, or for the finer, decorative details on marine vessels. The pitfall of using 5000 series on a building’s façade, however, is the lack of machinability and thermal expansion, compared to the 3000 series.
Because of these concerns, fabricated aluminium, similar to what’s used on wall panels and general construction facades, would be better engineered with 3000 series aluminium, which forms very well (without cracking or fracturing) but also has a reliable tensile and impact strength.
3000 series aluminium is preferred by builders and installers due to its multiple benefits:
- More rigidity providing increased spanning performance.
- Machinability ensuring cleaner and faster cutting and routing speeds over 5000 series.
- Corrosion resistance due to the presence of copper – this grade of aluminium is considered architectural grade (Vitradual has a 4000-hour salt spray resistance test).
- Lower thermal expansion rate resulting in less oil canning.
3003 series characteristics:
- Corrosion Resistance: Very Good
- Formability: Very Good
- Weldability: Very Good
- Anodising: Very Good
- Braze Ability: Excellent
Source: Aluminium Datasheet from Austral Wright Metals
When designing and manufacturing Vitradual, Fairview decided to use the 3000 series based on its machinability, performance and durability, as it ultimately is an architectural grade aluminium, suited specifically suited for façades.
Vitradual is proud to showcase the following tests and assessments:
- Required By BCA: Elected additional testing
- AS 1530.3 – referenced in C1.9(e)v: AS 1530.1 – Confirmed non-combustibility of solid aluminium
- 4000 hours salt spray resistance – corrosion resistance performance
- 4 point bending – structural performance
- Fatigue testing – performance of folds on cassette panel relating to repeated wind loadings and thermal movement
- Grade & Temper testing – added assurance of material properties
- AAMA2605 – coating performance specification
- Codemark – confirmed collation of BCA compliance
- RED Fire Assessment – added confirmation of compliance
- IGNIS BAL rating assessment – for use in bushfire zones
- Euroclass A1 testing – further confirmation of performance
- Fairview’s 15-year standard warranty – covers paint and panel, warranted by Fairview Australia (not any overseas supplier)
Additionally, the backing and support of the largest technical division location in Australia for the aluminium cassette façades, and Fairview’s ongoing commitment to innovation of simplified, verified and certified systems are key to reducing liability of trades as well as principal contractors.