Stopping smoke: What is a cold smoke seal?

A cold smoke seal is a barrier that goes around a door or door frame to prevent smoke from passing through the gaps. These seals consist of brushes or fixtures made of polypropylene or nylon, and are integral to stopping the spread of toxic smoke.

Given the dangers of smoke inhalation, cold smoke seals are integral to a fire protection system. Without knowing, they could be mistaken for heat insulation or to cushion a hinge, but they simply act as a smoke barrier. They work by blocking smoke, causing it to lose heat and fall towards the ground, thus preventing it from seeping underneath and around doors. This article will offer a basic understanding of smoke seals and how they help to reinforce a building’s fire protection strategy.

Cold smoke seals and fire door regulations

The Fire Safety (England) Regulations 2022 came into effect in January 2023 with the purpose of clarifying duties for responsible persons under The Regulatory Reform (Fire Safety) Order 2005. These regulations stem from recommendations made in the Grenfell Tower Inquiry Phase 1 report. Responsible persons (usually building owners and landlords) are required by law to check fire doors either on a quarterly basis or immediately following any alterations. As part of these checks, those responsible need to ensure that seals (including cold smoke seals) have been properly fitted and are free of any damage or wear-and-tear.

If you are unsure about whether your fire doors comply with the latest regulations, CLM Fireproofing specialises in fire remediation for commercial and residential buildings. You can also consult our updated guide to fire door regulations.

How to fit cold smoke seals

There are two main ways to fit cold smoke seals: the surface-mounted approach and the rebated approach. Most fire doors now come with grooves to accommodate either method of installation.

Regardless of which approach you opt for, start by ensuring that the grooves have been cleaned and are free of grease or dirt. Then measure the height of the door and use this measurement to cut the seal into a strip. Smoke seals will usually come with an adhesive backing – if not, you must purchase an appropriate fire protection adhesive. Before you apply any adhesive, you should also check to make sure the seal does not prevent the door from opening and closing properly.

Once these provisional checks have been completed, you can remove the adhesive backing or apply an adhesive before attaching the strip. If you have chosen the surface-mounted approach, the seal should be attached to the groove on the door frame, otherwise you can opt for the rebated approach which involves fixing the strip to the door itself. If you’ve attached the smoke seal to the door rather than the frame the seal mustn’t be too tight – otherwise the door may jam shut.

What is the difference between smoke seals and intumescent strips?

Intumescent strips are similar to smoke seals, but they’re designed to protect from fire itself as opposed to smoke. This is generally why both are considered necessary for regulatory compliance.

Intumescent strips have a different composition, as they’re designed to expand in response to high temperatures. Cold smoke wouldn’t activate it, but a bare flame certainly would. The seal expands rapidly to fill the gap around a door frame. This is designed to help contain fires and maintain safe fire exit routes.

Smoke seals are used in conjunction with intumescent strips, as they help fight off the smoke. This isn’t an either/or situation, with both of their jobs being vital to modern passive fireproofing methods. Generally, however, it’s common to see intumescent strips being sold with smoke seals already integrated, making it safer and easy for installation. Visit our dedicated page to find out more about intumescent paint.

CLM Fireproofing are the UK’s leading experts in passive fire protection and fire door maintenance. We are on-hand to provide specialist installation and consulting services. Our operatives are fully compliant with the latest industry regulations, so our clients can feel confident that their building is protected from fire. To speak to one of our passive fire protection specialists, contact CLM Fireproofing today.