What is a Smoke Seal?

Updated: Apr 1

During a fire, smoke is released, and this smoke can be incredibly harmful to your health. The ‘tiny particles of either partially oxidized or fully oxidized or unreacted fuel particles,’[1] may themselves be toxic, which alongside the removal of oxygen from the air, leaves building users trapped by fires with nothing but dangerous particles and carbon dioxide to inhale.

As such, some Fire Curtains come with smoke control to lessen exposure to smoke spread. This is achieved by the inclusion of smoke seals.

But what is a smoke seal, and why do we need them?

What is a Smoke Seal?

Smoke seals on Fire Curtains generally come in two varieties.

Brush Strips

Brush strips, akin to the seals that can be found on Fire Doors and are composed of straight brush piles that come in a variety of lengths and depths.[2]

These are usually attached to the side guides internally, either with adhesive, riveted side guides, or other fixing, but each manufacturer has their own specification, so it is worth asking how the seals are attached if you are interested.

A short, horizontal strip with vertical black fibres.

Tube Side Guides

Tube side guides consist of an inner stainless-steel tube found in the side guides, that the Fire Curtain fabric wraps around. The tube can move forwards and backwards within the side guide, allowing it to move into the gap of the side guide and block smoke from travelling through the side guides themselves.

The inner tube moves when exposed to pressure, which can occur during a fire because of heat and smoke build up. This pressure causes the curtain to bow and moves the tube forwards into the gap, effectively sealing it off and stopping smoke from being able to move through.

By moving from the ‘standby position,’ shown by the grey circle, to the ‘smoke seal position,’ you can see how the open corridor of the side guide, shown in the white circle, would be covered, stopping the passage of smoke and toxic gases through the side guides.

Adexon smoke seal infographic, showing te direction the smoke seal tube can move in, with small, green directional arrows that point forward backwards

This is the structure can be found within Adexon Fire Curtains, including the

  • Adexon-FCe Vertical Fire Curtain, and the

  • Adexon-FCe Horizontal Fire Curtain.

The Adexon-FCe Concertina Fire Curtain however, cannot be fitted with smoke seals for several reasons.

  1. A closed Concertina Fire Curtain will not use side guides, as it is not attached to the structure of the building on any sides and is made of only fabric and a bottom bar.

  2. There will always be an element of smoke leakage through a fabric, be it in the vertical, horizontal, or concertina orientation. This is worsened however if the entire structure of the curtain is fabric, due to the necessary design, as with a Concertina Fire Curtain.[3]

Billowing grey-white smoke outside, behind a dirty window

Why do we need Smoke Seals?

Smoke seals ‘…enable a Fire Curtain to be used on protected escape routes where fire door flexible edge seals are normally recommended.’[4]

Due to their ability to block the passage of smoke around the sides, and through the side guides on the Fire Curtain, it keeps key areas clear of smoke for longer, and reduces the likelihood of building users breathing in potentially harmful particles and carbon dioxide.

Without smoke seals, internal damage to the body from Smoke Inhalation can result in serious, even deadly Smoke Inhalation Injuries, SIIs. When unable to escape smoke, or without early detection and treatment, SIIs can be a major cause of mortality in burn patients, or in the best-case scenario at least indicate an extended stay in intensive care and requiring ventilation due to the increased possibility of developing pneumonia.[5]

A common misconception with smoke seals is that it will remove all smoke leakage. As Fire Curtains are constructed from woven fiberglass fabric, a small proportion of smoke leakage will always occur, but the extent of this is so minimal it will not serve as a hindrance to safe egress and building user safety in a fire.

This smoke leakage is thoroughly tested in fire safety tests, in accordance with BS EN 1634-3:2014. It is classified using the abbreviation ‘Sa,’ and outlines that the maximum leakage rate, measured at ambient temperatures at a pressure of up to m25Pa, does not exceed 3m³/h per metre length of gap between the fixed and moveable components of the Fire Curtain, as specified within BS EN 13501-2:2016.

Adexon smoke seals are guaranteed to minimise smoke leakage in a fire situation, and meet the recommendations for UNE EN 1634-1, UNE EN 1363-1 and EN 16034 with CE certification.

Efficacious smoke seals lessen smoke leakage in a fire situation, ensuring longer egress times, and stops unnecessary smoke inhalation, which kills more people on average per year than burns or other fire-related injuries.[6]

Will you gamble with chance, or include smoke seals on your Fire Curtains?


[1] FireFighter Insider.com, ‘Black Smoke: What Does It Mean And What Causes It?,’ <https://firefighterinsider.com/black-smoke-what-does-it-mean-and-what-causes-it/ > 20.10.2021 [2] Image from CS Group, ‘4 Fire Door checks to prevent the spread of smoke,’ <https://www.c-sgroup.co.uk/blog/4-fire-door-checks-to-prevent-the-spread-of-smoke/> 17.03.2022 [3] Image from Rawpixel.com [4] ASFP Black Book, ‘Active Fire Curtains: Compartmentation and Protected Routes,’ 1st Ed. 2020, page. 23. [5] Egyptian Journal of Chest Diseases and Tuberculosis, ‘Role of fibreoptic bronchoscopy in management of smoke inhalation lung injury,’ Mohamed Amin, Hany Shaarawy and Esam Gad El-Rab, July 2015, <https://www.sciencedirect.com/science/article/pii/S0422763815200908> 25.10.2021 [6] PMC: US National Library of Medicine, National Institutes of Health, ‘Inhalation injury as a prognostic factor for mortality in burn patients,’ written by R.H. El- Helbawy and F.M. Ghareeb, <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3230152/> 20.10.2021 Cover image from pexels.com, courtesy of Vlad Bagacian

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