Smoke kills – the importance of smoke seals
Smoke is dangerous and deadly but when it comes to fire safety the first thing that usually comes to mind is protection from heat and flames. While fire doors work hard at holding back fire, smoke can fill a room incredibly quickly and find its way out through the tiniest of gaps.
Smoke seals prevent smoke from travelling room to room, giving you more escape time in the event of a fire.
Intumescent seals for fire
An intumescent seal is a piece of material fitted around a doorway that when exposed to heat, expands closing any gaps around the door to stop the fire spreading for a period of time. Intumescent seals usually come with either 30 or 60 minutes of resistance to fire. Ahmarra’s fire doors will be fitted with the relevant intumescent seal to meet the required fire rating.
The issue with this is that smoke doesn’t necessarily mean heat. If the gaps in a fire door have not yet been exposed to the heat of the fire, this may allow cold smoke to pass through the gaps. This is why it’s best to have fire doors fitted with intumescent seals that can stop both fire and smoke.
Fire doors which also require smoke protection, are designated FD30S, FD60S, FD90S and FD120S. Some smoke seals can also have a dual purpose of keeping out drafts and reducing noise.
Smoke only seals
Smoke seals control the leakage of air and smoke through vulnerable parts of the door, around the perimeter and when required at the threshold. Unlike intumescent seals, a smoke seal will be in contact with the door leaf each time it opens and closes.
Types of smoke seals
There are three main types of edge seals capable of providing the specified smoke leakage rates;
- Deflection or compression seals, normally fitted to the doorstop to produce contact with the face of the door.
- Brush or wiping seals fitted in the leaf edge or in the frame opposite the edge, or at the threshold at the bottom of the door.
- Combined fire and smoke seals incorporate intumescent material with a smoke seal and allow for one product to be fitted to perform both fire and smoke protection functions
*Types 1 and 2 are often used in conjunction with intumescent seals to achieve both fire and smoke resistance.