Benefits Of Glass Bead Are Clear Cut Says Rennicks UK
High performance, combined with environmental benefits in the cradle-to-grave lifecycle, means the technology has a bright future in the UK.
Iain Borthwick, managing director of the Runcorn-based retroreflective sheeting distributor, cites these factors as the reason behind Rennicks UK’s commitment to offer both glass bead and microprismatic systems to clients.
According to Rennicks UK, more than 90 per cent of traffic signs in the UK use glass bead technology and their supplier, Nippon Carbide Industries (NCI) has seen sales of glass bead sheeting increase significantly over the last two years.
Dr Borthwick said: “Within the industry the environmental merits of microprismatic and glass bead technologies have been the subject of debate.
“From our point of view, as a supplier of both systems, of significance is the fact that glass bead technology emits less CO2 when recycled, when compared to microprismatic sheeting bonded to a metal sign.
“We’ve calculated that the carbon emissions attributable to glass bead signs are comparable to those from microprismatic products – if cradle-to-grave lifecycles are taken into account rather than just manufacturing processes.
“Metallic signs are normally incinerated. During incineration, microprismatic materials – which are made mainly from plastic – emit far greater CO2 than glass bead materials.
“In our opinion both technologies should be made available, and the environmental impacts should be considered when technical specifications are drawn up in terms of functional performance and requirements for public specification, to give clients the flexibility to choose a fit-for-purpose system and meet ‘green’ tendering procedures appropriately.”
Rennicks UK Technical Service Manager Trevor Wren has led the company’s research into the merits of both glass bead and microprismatic technologies, with a focus on environmental impact and safety performance.
He concludes that the view microprismatic sheetings are responsible for significantly less CO2 is far too simplistic.
Mr Wren said: “Our research shows that glass bead sheeting manufacturing at Nippon Carbide Industries (NCI) creates 20 per cent more carbon than microprismatic production, but end of life disposal creates 50 per cent less.
“Our analysis found that glass bead sheeting manufacture at NCI creates emissions of 4.88kg/sqm, compared to 3.91kg/sqm for Crystal grade microprismatics – a difference of 0.97kg/sqm.
“When end of life disposal is taken into account, including the recyclable substrate, the difference is just 0.37kg/sqm –the equivalent of a 1.5 mile journey in a family car.
“Councils and other public sector agencies are facing increasingly stringent carbon reduction targets, which makes it all the more important that they are given accurate and impartial data.
“As well as environmental aspects, safety factors also need to be considered.
“Glass bead technology provides high daytime contrast for legibility, high night time luminance and excellent consistent retroreflective performance at narrow, medium and wide entrance angles.
“We’ve come across claims that some microprismatic materials are always brighter in the daytime than glass bead and that microprismatics give better colour contrast, but we would challenge these views.
“We’ve also seen statements about microprismatics offering higher luminance at night and being more suitable for lorry drivers – but the fact is microprismatics and glass bead have different properties and one could be more suitable than the other depending on the sign location and viewing position.
“In addition to permanent signs, glass bead is preferred for Chapter 8 signs mounted on ’A’ frames where the glass bead sheeting maintains higher reflectivity when tilted back at 22½°.
“In short, customers should have the choice of these technologies, and at Rennicks we intend to give them just that.”