What does e, ei, and ew mean?

Updated: Mar 10

A review and explanation of the different BS EN 1634 fire performance criteria.



All Adexon® Fire and Smoke curtains, are named to allow for easy reference, and within each reference is an initial which refers to the specification codes.


These naming codes relate to the type of Fire Curtain that would be manufactured and installed, as the different specifications can feature additional coatings, such as on the Integrity & Radiation ‘ew’ curtain, which features specific aluminium foil layers. Each specification type is best suited for different uses and brings with it different levels of protection. Each specification is rated in minutes and the higher the minute rating, the longer the compartmentation barrier will remain in place, providing the essential fire safety requirements.



How does the name break down?


All Adexon products follow a coded naming system, which can appear complex, but is very simple once decoded.


Adexon is of course the brand name, with the initials ‘FC’ referring to Fire Curtains while the Adexon Smoke Curtain features the initials ‘SC.’


The next part of the code is the maximum number of minutes the Fire Curtain can limit and control the spread of fire, followed by the performance type initial/s. Most Fire Curtains increase in 30-minute intervals, and all options within the range can be ordered, depending on the level of protection you need in your building, usually outlined at the planning stage.

Staff photograph shows installed Vertical Fire Curtain with Integrity ‘e’ rating. Black box shows the bottom bar partially deployed, that would be completely hidden in the standby position.

The Adexon-FC120e

The Adexon-FC120e Active Fire Curtain performance types have Integrity rating and describes ‘the ability of a separating element [fire curtain] to prevent the passage of flames and hot gases,’[1] with the maximum classification of 120 minutes.


It is tested and approved to the UNE EN 1634-1, UNE EN 1363-1 and EN 16034 with CE certification.

The fibreglass and woven stainless steel curtain resists temperatures upwards of 1,000°C, with the integrity rating (e) being the standard specification for Fire Curtains of any configuration- vertical, horizontal, or concertina.


This type of fire curtain specification is best for:

  • covering lift doors.

  • Covering glazing that is not fire-resistant.

  • Replacing non-loadbearing walls to allow for larger open plan rooms.

  • Separating rooms from one another, enabling them to be compartmentalised.

  • Covering voids that could function as smoke shafts.



The Adexon-FC120ei

The Adexon-FC120ei curtain has in-built Integrity (e) and Insulation (i) rating, which is a form of extra protection. This limits and controls the spread of fire and hot gases (e) while also reducing temperatures on the face of the curtain to <140°C (i), with the maximum classification of 120 minutes. It is tested and approved to UNE EN 1634-1 and EN 1363-1.

This specification is used in conjunction with open sprinkler water cooling to ensure the lowered temperature on the face of the curtain and is not yet currently available in the UK as a dry curtain.

This Fire Curtain specification is best suited to:


  • blocking off spaces between rooms and stairwells to allow a clear escape path.

  • Maintaining protected escape routes.


In many commonly misinterpreted situations, clients believe an Integrity and Insulation ‘ei’ curtain is required, however, we find that a lot of the time an Integrity and Radiation ‘ew’ curtain is suitable. This removes the need for the of a sprinkler system, which is preferable for many.


However, in situations with narrower protected escape routes, using Integrity and Insulation rated, ‘ei’ curtains, with associated sprinkler systems, may be required.


Protected escape routes need to be of a minimum width to allow for emergency egress and the following key areas:

  • the deployment zone, the space directly underneath the barrier that is kept continually clear to allow it to descend unobstructed.

  • The deflection zone, which takes ‘into account the deflection of the barrier due to fire pressure.’[2] This area would be left clear to account for the planned bowing of the curtain, in the face of fire pressure. (See section b on the diagram for a visual example.)

  • Then, a tenable zone, which considers the area on the face of the curtain that would be too hot to come into contact with, including the untenable area.


If space were of a premium in your building, using an ‘ei’ rated Active Fire Curtain maybe also preferrable, as it negates the need to widen escape routes, as currently, ‘escape route widths should be increased as necessary to take into account the space needed for the deployment zone, deflection zone, and untenable area.’[3]






[4] The Adexon-FC120ew

The Adexon-FC120ew curtain has in-built Integrity (e) and Radiation (w) rating and provides specialist levels of protection. This limits and controls the spread of fire and hot gases (e) while maintaining lower thermal radiation emissions, around <15 kW/m2 at a distance of 1m from the fabric (w), with the maximum classification of 120 minutes. It is tested and approved to UNE EN 1634-1, UNE EN 1363-1 and EN 16034 with CE certification.


As this Fire Curtain specification is considered specialist, it is not best suited to all Fire Curtain appropriate jobs. It is best to utilise an Integrity & Radiation curtain for the following:

  • maintaining protected escape routes.

  • Providing heat radiation protection to allow people to pass by the curtain if moving towards an escape route, for example along corridors containing rooms with increased fire potential.


‘EW’ rated active Fire Curtains are best utilised in wider protected escape corridors, as they allow for an increased deflection zone, tenable zone, and untenable area. This would remove the need, and mess of associated with sprinkler system, also making the installation process quicker and simpler.


So now you are much the wiser about Fire Curtain specifications, which would work best on your project? Let us know in the comments.

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