Safety Glazing At Roof Level

A frequent question often asked at the Glass & Glazing Federation is "What type of glass should be used in overhead applications?" People are puzzled about this for two reasons. Firstly, in most cases there is no British Standard which they can consult and secondly, they have an instinctive feeling that ordinary annealed glass should not be used on safety grounds, which leaves open the question as to what type of glass should be used instead?