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Do you know the classification system used in the UK for fire curtains? You need to understand what E, EW and EI mean to get started. Learning it should make checking suitability for your building’s needs a lot easier, and could one day even save lives.
Fire protection in a building is one of THE most important considerations for safety. A fire classification system is used for products like curtains, doors and glass and has been designed to simplify the performance criteria of fire products so that they can be universally understood, regardless of the product. In short, it is a way to judge apples for apples the fire performance of construction products and building elements. The three fire classifications are E, meaning integrity rating; EW, meaning integrity and radiation rating; and EI, integrity and insulation rating.
Here we explain the different classifications starting from the basic to the more advanced, and how products are tested for performance. The three fire classifications are rated in minutes, denoting how long the product lasted under stipulated test conditions. The time it takes for a product to hold back the fire is critical.
E = Integrity
The most common fire classification is the E integrity rating. This is a measure of the ability of a construction element that acts as a separating function (like a fire curtain, door, or shutter) to withstand fire exposure to one side without allowing the fire to pass through to the unexposed side.
Integrity is tested by installing the product into a furnace and raising the temperature to over 1000°C following a standardised heat curve, like BE EN 1363-1; three methods are used to assess if the flame has passed through to the unexposed side. Those three methods are:
- Cracks or openings appear in the product in excess of a given dimensi
- Ignition of a cotton pad
- Sustained flaming on the unexposed side of the product
The test is stopped, and the time is taken once the cotton pad has ignited and the other two aspects have been exceeded; manufacturers also can stop the test when they have reached the desired performance level.
ntIegrity ratings will not measure heat passing through a product.
Once the product has passed the test, it is given the nomenclature dictating the integrity rating E and the time (in minutes) the product lasted, e.g. E120.
EW = Integrity and Radiation
The second level of fire classification is EW integrity and radiation rating. The integrity part of this classification is as described above, and the radiation part of this classification is a measure of the ability of a construction element to withstand fire exposure from one side only whilst limiting radiant heat from its unexposed structures/surfaces.
The EW rating is tested the same as integrity, using the three methods above to assess if the flame has passed through to the unexposed side, plus a fourth criteria; heat flux meters are placed 1m from the unexposed side, one in the centre to read the average and one in the location expected to be the highest.
Heat flux is the thermal energy transferred from one substance to another per unit of time and area denoted by temperature change, measured in watts. In straightforward terms, it is the heat transfer per unit area.
The test is stopped when either:0
- Cracks or openings appear in the product in excess of a given dimension
- Ignition of a cotton pad
- Sustained flaming on the unexposed side of the product
- The heat flux metres read higher than 15kW/m2
Once the product has passed the test, it is given the nomenclature dictating the integrity rating E, the radiation rating W and the time (in minutes) the product lasted, e.g. EW120.
EI = Integrity and Insulation
The highest level of fire classification is the EI integrity and insulation rating. The integrity part of this classification is as described above, and the insulation part of this classification is a measure of the ability to not allow the significant transfer of heat from the exposed side to the unexposed side.
Heat transmission shall be low enough so neither the unexposed surface nor any materials close to the unexposed surface can ignite. The element shall also provide a separating element to heat sufficiently to protect people near it.
The EI rating is also tested the same as integrity, using the three methods above to assess if the flame has passed through to the unexposed side, plus fourth criteria; the temperature of the surface of the unexposed side is measured.
The test is stopped when either:
- Cracks or openings appear in the product in excess of a given dimension
- Ignition of a cotton pad
- Sustained flaming on the unexposed side of the product
- The temperature on the unexposed side of the curtain rises more than 140° above the initial mean temperature
Be sure, be safe, don’t be sorry
To excel in health and safety, for insurance purposes and to be sure your building can withstand a disaster, the highest classification can make all the difference for your peace of mind. At Adexon, we test to the highest standards and insist on UKAS or equivalent 3rd party certification and CE Marking, to ensure our life-safety products perform in the worst circumstances. You should insist on these criteria too. Whilst there are minimum requirements in building regulations, superior quality products are always advisable. Fires are unforgiving. If you want to know more about our excellent fireproof products and to see if they can be used for your building project, drop us a line.
This article was written on the 10th November 2022 by the team at Adexon Fire & Smoke.