Designing for gaps in smoke curtains

Posted by Paul Compton on 13/10/15 11:30

In the UK, as with the rest of the EU, smoke curtains have to comply with the EN 12101-1 Product Standard. 

The Standard specifies the maximum amount of smoke leakage at the edges of a smoke curtain in order to ensure that any openings only allow small amounts of smoke to pass the curtain. However any smoke which passes the curtain through such a gap is likely to be mixed with the unpolluted air on the protected side of the curtain and thus is unlikely to represent a significant threat to people.

EN 12101-1 defines the maximum permissible gaps between the building’s wall and the smoke curtains (no matter at what angle they are positioned relative to the wall) based on the of the depth of the curtain, as follows:

  1. A gap of up to 20mm where the curtain depth is no more than 2m
  2. A gap of up to 40mm where the curtain depth is 2m-6m
  3. A gap of up to 60mm where the curtain depth is more than 6m.

However, if there is a fire, smoke movement past a smoke curtain can be significant and these gaps can easily increase. One reason for this is that when the curtain is deployed it can deflect excessively.  The greater the drop of the curtain is, the higher the risk is of this happening, so deep curtains need special attention.

Another design consideration is the angle of positioning of the curtain to the wall. Obviously if the curtain is located at 90o to a wall, then edge gaps are not going to be a major problem if the curtain billows. However if for example the curtain is located at an angle to another curtain or is positioned next to a column, then those edge gaps can become quite significant. In such instances it unlikely that side guides can be fitted to prevent against deflection.

If the curtain has to change direction over its length, this too can lead to excessive gaps.

The answer is to specify a smoke curtain with well-engineered corners. Colt’s own curtains can be specified with specially designed metalwork where the corners meet, as shown in the images on the right. These permit the rollers to be closely positioned within the corner system, with the result that there is a very small gap between the two curtains as they roll down.

If you want to know more, you can read previous blogs on smoke and fire curtains.

Whitepaper - “Design considerations when integrating smoke and fire curtains into a building”

This whitepaper explains the differences between smoke and fire curtains, the standards which they comply with, and how to install, test and maintain them.

Webinar - “Design considerations when integrating smoke and fire curtains into a building” 

Join Paul Compton, Technical Director at Colt UK, from 12.30-13.30 BST on Friday 23rd October 2015, as he presents a free CPD webinar on the design considerations when integrating smoke and fire curtains into a building. 

In this webinar we cover:

  • The differences between smoke and fire curtains.
  • The standards which each type of system has to comply with.
  • The design aspects to consider when integrating these systems into a building            

Register for the webinar

Paul Compton Paul Compton is Technical Director for Colt, experienced in smoke control, HVAC, solar shading and louvre systems.

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Topics: Smoke Containment, Curtains