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The 5 most common mistakes in firestopping

Avoiding these common firestopping pitfalls

The 5 most common mistakes in firestopping

Fri, June 04, 2021

Author: SharpFibre

At Sharpfibre we know our stuff about fire stopping, a fundamental requirement of the fire safety design in buildings. But we too often find that they are specified and installed incorrectly, often by non-specialist contractors as part of the plumbing, M&E or general building package. In the majority of buildings with fire protection concerns, the problems are with service penetrations passing through fire resistant walls, ceilings and floors, which have not been fire stopped or which have been fire stopped incorrectly.

Here are the five most common mistakes we, as fire protection specialists, encounter when we are out on site. Sometimes it is caused right at the beginning of the process with incorrect specification, often it happens at the installation stage, and sometimes the problems arise because of inadequate or non-existent inspection protocols.

1. Using an untested firestop product using products that aren’t third party accredited. It is best practice to ensure all firestopping products specified and fitted in a building must be properly third party tested and certificated. Not just reputation rests on these products – they save lives and property.

Third-party accreditation provides assurance that the product is fit for purpose, is made using a defined quality system and proves a traceable link between what is made in the factory and what was tested in the lab. The Association of Specialist Fire Protection, of which Sharpfibre is a member, only recommends third-party product certifications schemes that have been accredited by UKAS.

Needless to say, properly tested products specified on a project cannot be simply “swapped out” later in the build process.

2. Using the wrong firestop material for the application: too often a “that’ll do” attitude leads to the wrong products being used or used incorrectly. The worst culprit for this is  Polyurethane (PU) foam fillers - also known as ‘fire foam’ – often coloured pink to differentiate it from other foam fillers. The Local Authority Building Control (LABC) has recently issued warnings about its use saying they should only be used in narrow gaps and, if possible, avoided all together. Too often we see bulky foam masses, sprayed randomly into a gap or around a penetration in the mistaken belief that it constitutes effective firestopping – it doesn’t!

3. Not installing firestop: hard to believe isn’t it but we often arrive on site to carry out remedial work on firestopping to find that it simply isn’t there! The building cannot be effective compartmentalised if the service penetrations through walls and floors simply allow flames, heat and smoke to pass through unhindered.

4. Firestopping not included early enough in the design process: at Sharpfibre we like to get involved when the project is still on the proverbial drawing board – at RIBA plan of works stage 2 at least. This will eliminate so many mistakes later on in the build and potentially save money and time too if there is no need for remedial work later. We have decades of experience in providing firestopping schemes and can advise and guide specifiers and contractors through the process.

5. Poor installation. Even if the right product, correctly specified, has made it on site and fitted in the right place, if it has been installed incorrectly, then the whole scheme will fail. Always use an accredited firestopping contractor, like Sharpfibre, who has the expertise, experience and certification, to offer protection and peace of mind.

If you would like to talk to Sharpfibre about firestopping call us on 01268 413084 or email We will be happy to advise.

To find out more about Sharpfibre, and our range of products and services, contact us on 01268 413084, or email us at

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