This classification effectively demonstrates the ability to prevent the passage of flames or hot gases through the glass when exposed to fire on one side, and to prevent the occurrence of flames on the unexposed side.

E – Integrity offers effective and economical protection from flames and smoke, but does not prevent the transmission of heat in the event of a fire.

Fire safety glass in the EW category: Radiation Control maintains all the integrity performance of E Classification (resistance to flames and smoke) when exposed to fire on one side, but also provides some heat resistance, keeping the amount of radiant heat transfer to below 15 kW/m2 on the unexposed side.

Fire safety glass with EI Classification – Insulation offers the highest level of protection from flames, smoke and heat. This classification of fire safety glass performs to the standard of E when exposed to fire on one side, and also restricts temperature rise on the unexposed face to below the required standard.

Integrity – the ability of the fire rated glass to withstand fire exposure on one side for the defined period without the spread of fire from the passage of flames or hot gases. The integrity barrier helps prevent the spread of flames and hot gasses only for the defined period. It does not provide any heat resistance. Classified by the letter E; a rating of E30 means that glass in question has a 30 minute Integrity Period. This type of glass is also sometimes referred to as non-insulating.

Insulation period – the length of time the glass will, on it’s non-fire side, limit the temperature to an average of no more than 140°C and in any one position by no more than 180°C. The insulation period is usually classified by the letters EI followed by the applicable period of protection for both integrity and insulation. For example, a rating of EI 60/30 would mean that the glass in question, when used as per the appropriate test evidence,provides a 60 minute integrity period and 30 minutes insulation whereby the temperature on the non-fire side of the glass will be restricted.

Radiation – the W is reference to Radiated Heat which essentially means that unlike E rated glass alone it does provide a degree of heat resistance but no protection for a defined period (unlike EI rated glass). For example, glass rated E60 provides a 60 minute period of integrity with no heat resistance at all. Glass rated EW 60 still has a 60 minute period of integrity and does have some heat resistance but not sufficient for any given period and it does not restrict the temperature of the glass on its non-fire side in the same way that EI rated glass will. Building Regulations specify where different integrity and insulation periods are required and this generally depends on the building type and how long it may take to evacuate the building, or a specific area of a building, in the event of fire. Generally speaking and from a Building Regulations point of view EW rated glass is effectively integrity only as it provides no set insulation period.