Properties of Glass, Polycarbonate and other Rooflight Glazing Materials

 

In the UK the main glazing materials are glass and polycarbonate and these are the only rooflight glazing materials used in Xtralite products. In addition to allowing the passage of daylight, the material used in a rooflight must be durable and meet the regulatory standards for thermal, fire and safety performance.

 

Glass Glazing

 

Safety glass is commonly used in atria for commercial and retail environments and also in traditional pitched roofs. Glass glazing provides the benchmark against which the optical performance of other glazing solutions are measured.

  • Excellent fire retarding properties
  • Good impact performance
  • High light transmission
  • Long life expectancy with no UV discolouration
  • Can be supplied with various laminates, surface treatments and interlayers to provide coloured and textured surfaces, for obscure and diffused finishes, solar control and total UV protection

Polycarbonate Glazing


Polycarbonate is a clear thermoplastic formed under heat and fixed in shape by cooling. Polycarbonate glazing can be recycled and reused by re-heating to a plastic state.

  • Exceptional impact resistance
  • High levels of light transmission  
  • High levels of UV resistance
  • Good fire resisting properties
  • Wide range of clear, tinted, patterned and opaque finishes
  • Co-extruded UV protection eliminates up to 95% of UV radiation from the inside of the building
Can be moulded into many different shapes including domes and pyramids

PVC, Acrylic and PET in Rooflight Glazing

 

PVC is rarely used in industrial, domestic, commercial or retail environments because it has poor impact resistance, limited UV resistance and is susceptible to degradation, discolouration and demoulding.

Acrylic does not meet the UK standards for fire resistance.

PET is a high impact thermoplastic with good clarity but it has a low temperature distortion value, which makes it unsuitable for rooflights.

 

 

Nanogel® Sheet Technology—Effective Lighting, Thermally Efficient, Lightweight and Acoustic Insulation

 

Xtralite has introduced innovative Nanogel® technology which combines impressive thermal efficiency, light diffusion and acoustic insulation. Nanogel® consists of translucent aerogel granules—filling clear polycarbonate glazing panel constructions—that allow light to pass through whilst serving as a highly effective thermal insulation. The extremely small pore size means that air molecules collide with the silica lattice, rather than each other, transferring energy to it, substantially limiting heat conduction. So, insulation performance is vastly improved, with U values for a triple-walled rooflight reduced from 2.4 W/m²K without Nanogel® to 1.3 W/m²K with the new technology. Nanogel® also offers excellent light diffusion with diffusion giving a ‘shadow-less’ light quality, as well as a 25% reduction in sound transmittance (at 1,000Hz frequency).