Protect from Fire
It may be that the Building Control Department will ask you to install fire-resistant glass in a window, in case there is the possibility that fire could endanger your neighbour's property, even if it just overlooks a garden area and always if the new window is within 1 metre of a boundary wall. Fire-resistant glass is also often required in buildings such as residential homes, hotels or B&B accommodation, for providing safety zones or passageways for escape.
The performance of fire resistant glass is expressed in periods of time for different qualities. The most common is 'integrity', which is how long the glass will keep the flames and hot gases back. Regulations demand that the minimum time is 30 minutes. The other requirement is 'insulation' which also starts at 30 minutes. Insulation is the ability of the glass to additionally hold back the heat of the fire to keep the glass temperature below specified levels.
Pilkington have made the market leading range of products to suit the most demanding of situations for more than 100 years, and continue to develop the products to meet changing needs.
Note that any fire rated glass needs to be installed into a frame that works with the glass to ensure the whole installation performs to the required standard. The design and installation of fire products is best left to accredited specialist contractors.