When purchasing a glass rooflight it is always necessary to consider impact loads; this means that the product is able to hold a certain amount of weight in order to prevent a person or object from falling through the glass accidentally.
However the loadings to which your glass rooflight can withstand depends on what application the rooflight has been designed for, i.e. loadings for a unit installed on a pitched roof with no access will be different to those units installed in a terrace that can be walked on.
Your supplier should fully understand the differences and be able to explain in detail what the glass can withstand and provide specific loadings in accordance with current legislation. For example, UK guidelines currently require a 2.0kN/m2 uniform distributed load (UDL) and 1.5kN concentrated load for walk on specification glass designed for domestic foot traffic.
When choosing a rooflight supplier, ensure that he is aware of this information and is able to prove that their glass is strong enough to safely withstand the appropriate loads.
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