Monday 17 July 2006

Canopy Fascia: ACM vs. Vinyl

No publication on petrol station design would be complete without a discussion on canopy edge decoration. Here we briefly discuss two protagonists of the industry, vinyl and ACM (aluminium composite material). As with all PSD articles if your opinion differs or have an interesting example to show please send them to us via our forum or email. The canopy fascia is the most visible and instantly recognisable element of a petrol station. The manner in which it is decorated is therefore critical, the material choice being of particular importance. There is a myriad of options, but two of the most popular are vinyl and Alucobond.

Vinyl was first to the market, taking over from acrylic fascias, although simple low-tech arrangements suffered because only short panel lengths were possible. Due to its high coefficient of expansion, acrylic may grow or contract several inches along the length of the canopy, depending on ambient temperature. In cold weather, gaps often appear between adjacent panels, revealing the fluorescent tubes beneath. Conversely during a warm spell the panels can clash and buckle. It is therefore necessary to detail seams to allow for expansion and contraction. Vinyl offers a neat and simple solution here as it came in a seamless roll and is easily decorated or pigmented in a wide range of colours. It is also flexible too, so it can bend with the wind, preventing it from being blown out - a problem that often occurrs with acrylic.

The two most commonly available Aluminium Composite Material (ACM) brands are Alucobond and Alpolic. Both of these consist of a sandwich arrangement of two thin coil coated aluminium sheets bonded to a polyethylene core. As ACM is factory-finished, the consistency, quality and longevity of the paint finish far exceeds what can be achieved with vinyl. ACM came to the petrol station industry from the building industry where it is commonly used as a cladding material for large buildings. Its properties include dimensional stability, lightweight, being easy to fabricate and machine and above all being able to maintain a pristine surface finish. These properties have led to ACM becoming a staple product for the more progressive sign companies. Introducing a shape to the construction can not only serve to heighten the structural properties of the signage, but also to strengthen brand differentiation and achieve an automotive quality appearance. As ACM is opaque, a major challenge is to develop a lighting system that looks good after dark, which requires a degree of ingenuity. A proven solution is to have an external light source that can be easily maintained. However, the engineering required can sometimes be beyond the scope of smaller sign companies. ACMs are not good at disguising abrasion and are not suitable for low level zones where there is a risk of impact.

Despite appearances, vinyl is usually more expensive than ACMs. Colour fading guarantees are short and gaining access to the fluorescent tubes that provide the illumination can be awkward. To maintain a taught surface, vinyl requires a tensioning system and various systems exist, most of which are adequate. Sagging due to the tension being too small is quite a rare problem. More common is over-tensioned vinyl that causes convex distortion. As an off-the-shelf option, vinyl may offer an easy and effective decoration system. However, on larger scale projects where bespoke designs are required, ACM solutions tend to be superior on price, quality, and consistency

© Copyright by Minale Tattersfield Design Strategy

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