Vehicle conspicuity markings can save lives. Reflective products light up vehicles during dark hours, making them more visible to other road users and, as a result, prevent collisions. As vehicle reflectives play such a critical role in saving lives and making roads safer, new technology and materials are constantly being created to improve visibility, durability, and reflectivity.

From glass bead to micro prismatic reflective materials and various constructions of both, there is plenty of variety when it comes to products that make vehicles safe and compliant. In this guide our expert team at Lakeside explain the difference between air gap and metallised micro prismatic products, outlining the construction as well as the advantages and disadvantages each provides.

For advice on purchasing materials, check out our buyer’s guide to reflective materials for vehicles.

Air gap micro prismatic products

Air gap products, otherwise known as air cell products, are the more traditional form of micro prismatic materials used since the beginning of reflective vehicle conspicuity markings in the UK. All current air gap products on the market are designed for traffic sign usage and were selected for vehicle use as they offer superior reflectivity to glass bead products. As such, air gap micro prismatic materials have been used for many years for all sorts of applications, from Chapter 8 chevrons to emergency vehicle livery.

Air gap micro prismatic products use micro prismatic technology instead of glass bead to enhance reflectivity and ensure the effective reflection of light, even at long ranges. The use of micro prismatic technology ensures superior reflectivity regardless of whether air gap or metallised construction reflective materials are used.

How are air gap micro prismatic products formed?

As the name suggests, air gap (or air celled) construction consists of gaps of air between different layers of the material. The base of the material is the adhesive and release layer, followed by the backing film, then the air gaps, with the micro prismatic materials sitting above.

When used, air gap micro prismatic products require edge sealing during converting. This helps to seal the edges against the ingress of materials (as the below figure shows).

Edge sealing is a slow process and is not always effective; it does not guarantee the prevention of water and dirt getting into the air cells. Over time, the edges of air gap products can turn black, caused by jet washing and general wear and tear, leaving vehicles looking unkempt. However, for assured quality and effectiveness, approved converters can perform professional edge sealing.

Advantages of air gap micro prismatic products

  • – Compliance – air cell micro prismatic materials exceed requirements and offer superior reflectivity to glass bead technology.
  • – Tried and tested – air gap products have been used for many years for many applications.
  • – Damage visibility – any damaged cells lose reflectivity, therefore showing the damage and highlighting where a product should be replaced.
  • – Durability – air gap micro prismatic products offer up to 10 years durability.

Disadvantages of air gap micro prismatic products

  • – Lose reflectivity – if knocked and crushed, the air cells can lose reflectivity.
  • – Spread of damage – connecting air cells to any damaged cells can also fill with water and debris and lose reflectivity.
  • – Delaminating – over time layers can separate and delaminate causing complete loss of reflectivity.
  • – Pressure washing – air gap micro prismatic materials can deteriorate or peel when pressure washed.
  • – Rigid construction – difficult to work with as they are not very flexible.
  • – Edge sealing required – slow and never 100% resulting in many vehicles on the road which are often less than 18 months old show severe edge seal failure.
  • – Difficult to remove – it is not possible to remove air gap products in one piece, making removal very expensive.

Metallised micro prismatic products

Otherwise known as solid construction, metallised micro prismatic products are single layer and have no air gaps.

The latest generation of this construction method is relatively new and addresses the issue of loss of reflectivity when damage occurs to air gap products.

How are metallised micro prismatic products formed?

Instead of having air cells that can be potentially penetrated by debris and water, solid construction materials have no gaps, formed by a single layer of construction bolstered by an aluminium coating.

Unlike air cell construction products, metallised products do not require an edge seal as they are a single layer. This means the vehicle appearance stays in top condition for many years, with no peeling or black edges, as well as resistance to ingress of dirt and water.

Find out more about the difference between air cell and solid cell construction micro prismatic materials with the comparison video from Avery Dennison.

Advantages of metallised micro prismatic products

  • – Durability – solid construction products are more durable to possible damage on roads.
  • – Maintained reflectivity – even if damaged, solid construction products maintain reflectivity.
  • – Single layer – due to the single layer construction, solid cell products do not require lengthy edge sealing.
  • – Flexibility – solid cell products are extremely flexible and easily fit contours, ideal for contour tape or emergency vehicle livery.
  • – Quick removal – metallised products are simple and quick to remove, which is useful when decommissioning vehicles.
  • – Low conversion costs – without the requirement for edge sealing, kits can be cut faster.
  • – Pressure washing – solid cell metallised micro prismatic products can withstand pressure washing without possible damage.

Disadvantages of metallised micro prismatic products

  • – Deterioration – metallised micro prismatic products will still eventually deteriorate after years of general wear and tear; however, durability is ensured for far longer than air gap products.
  • – Not suitable for all applications – the effectiveness of micro prismatic products is so bright it may not be suitable for all applications, such as permanent traffic signs in dark areas, therefore customers should seek expert advice to determine which material is most suitable for their particular application.

Air gap VS metallised micro prismatic products – which is best?

Whether you are purchasing specialised conspicuity markings for emergency vehicles or contour tape for HGVs, durability and reflectivity are key. Therefore, metallised products are the preferable option compared to air gap products. The increased durability, resistance to damage, and maintained reflectivity make solid cell products the ideal long-lasting solution.

However, air gap products have been commonly used for years and are compliant with legislation governing vehicle reflective markings. At Lakeside we supply a full range of compliant and effective air gap products such as Avery Dennison T6500, renowned for its excellent day and night visibility.

Chapter 8 part 3 of the UK Traffic Signs Manual specifies Class R3B or Class R2 retroreflective materials on vehicles. There is no explicit legislation on the use of either air or solid celled construction materials for other applications, so both are equally recommended. The assurance of durability and longevity, as well as reduced evidence of damage, does however make solid celled materials the best choice for a range of applications.

See more: Chapter 8 Compliant Vehicle Reflectives

Find the ideal reflective material for your application with Lakeside. We have a full range of reflective conspicuity marking materials for emergency vehicles, Chapter 8 chevrons, ECE 104 contour tape, traffic signs and more.

Industry leading retroreflective vehicle materials from Lakeside

From glass bead and micro prismatic technology to innovative metallised micro prismatic products, Lakeside have your reflective material needs covered!

As members of REMA (Reflective Equipment Manufacturers Association) for over a decade, we are experts in all aspects of reflective legislation and can advise on the best material for your application. Our range of metallised micro prismatic materials include Aura Optical Systems 191, Avery Dennison V8000 Visiflex, and Avery Dennison V6700B contour tape.

Get in touch with a member of our team today for expert advice on the right reflective material to suit your requirements.