FAQ’s

Ballistic Glass

What is Ballistic Glass?


Ballistic glass is a type of strong but optically transparent material that is particularly resistant to being penetrated when struck by bullets. Thin layers of a clear, tough plastic called polyvinyl butyral (PVB) are sandwiched between sheets of standard glass, and bonded together by heat. Alternating layers of plastic and glass are then built up. The more layers, the better the bullet-stopping power.

How does it work?


Bullets don’t just bounce off it, of course. Fire a bullet at a pane of bullet-resistant glass and it will break the outer glass layer, and probably layers of glass deeper inside the pane. But the tough PVB inter-layers are designed to absorb its energy, preventing it from breaking through to the other side. Bullet-resistant glass is tested for strength using different calibres of guns. A shot from a modern rifle will need a much higher spec of product to stop it than a shot from a small hand gun, since the bullet speed is so high, typically around 820 metres a second.

How do I know which product to choose?


Obviously selecting the correct product for your project is extremely important. The glass you will need will depend on a number of factors such as the perceived threat level, whether splinters are acceptable (spall or non-spall) and the glazing system into which the glass will be fitted. Without the correct glazing system the glass will be rendered ineffective.

Who can help me to choose?


Diamond Glass is a market leader in the manufacture of Ballistic Glass products. All of our products are manufactured to the highest European standards and are independently tested and certified by the most respected test houses. If you need any assistance in selecting ballistic glass please contact us and our technical sales advisers will be happy to help.

Fire Glass

How does fire-rated glass differ from ordinary glass?


Fire-rated glass has been tested to act as a barrier to the spread of flames and smoke. Ratings are given based on the length of time the glass remains intact. The test concludes by blasting the heated glass with water from a two-man fire hose to determine the system’s ability to withstand impact pressure and its resistance to thermal water shock. Fire-rated glass ratings range from 30 minutes up to three hours, depending on the product and framing system.

When using glass in fire-rated locations, is impact safety glass also required?


No but building regulations determine where impact safety glass is required. Any glass lower than 800mm from the floor, or within 300mm of a door—and any door glass itself— has to be safety glass.

What types of fire-rated glass are available?


The type of Fire Glass required depends on the level of protection necessary and the location of the glazing screen. Diamond Glass can supply the full range of fire rated glass products, both single glazed and incorporated in to IGUs, to meet your requirements. To see what products your application needs please go to the Pilkington Specifire.

Is fire-rated glass limited to interior applications?


No, the Diamond Glass can supply products suitable for both internal and external use. Please contact us for help in selecting the correct option.

Security Laminates

EVA & PVB – What’s the difference?


EVA Interlayer Film and PVB Interlayer Film are both used to make safety laminated glass. EVA is a relatively new product which has some advantages over PVB in certain circumstances. However, PVB is a proven, versatile and easy to use substance, so which one do you use?

PVB stands for Polyvinyl butyral. It is made of polyvinyl alcohol by reaction with butyraldehyde. The major application is laminated safety glass for architectural building windows and car windscreens. PVB Interlayer Film is very sensitive to moisture, which makes it difficult to store and process and makes it less suitable for exterior applications.

EVA is the copolymer of ethylene and vinyl acetate. Architectural EVA (Ethylene-vinyl acetate) Interlayer Film can be used in Vertical Safety Glass, Sloped Safety Glass and Overhead Safety Glass. The great benefit of Architectural EVA Interlayer Film is its reliable and long-term weather resistance.

Other benefits of EVA film are:

  • Excellent Light Transmission, ≧92%
  • Almost Total UV Protection, ≧99%
  • Tensile Strength, ≧21 Mpa
  • Good Adhesive Strength, ≧50N /cm
  • Qualified Impact Resistance (As has PVB)
  • Qualified Moisture Resistance As PVB Does

However EVA is more costly than PVB film so you need to weigh the costs of EVA versus its benefits for your project. For expert advice on which film is best for you please contact us.