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Buildings can be designed with the best fire protection strategy in mind, but subsequent building works may compromise that safety. 

Service lines installed after fire rated floors and walls are already in place can create gaps and voids that seriously increase the risk of fire spreading, despite the strong initial design. 

Void fillers and fire sealants provide solutions to close any penetrations – restoring the building to its original performance levels.   

Learn how ROCKWOOL products can help ensure all fire-stopping points in your construction are secure.

Why do we need void fillers and fire sealants?

In both original construction and renovation projects, ensuring the best fire safety levels throughout the entirety of a building’s lifetime is essential. This means achieving compliance with the latest building standards such as Approved Document B in England and Wales. 

Ongoing work, improvements and changes can compromise existing fire rated materials or constructions and plans – with service line penetration or accidental damage on-site just two examples. 

Before a site can be declared fit for purpose, every single fire stopping point needs to be checked to ensure its integrity is intact. Void fillers and fire rated sealants can be used to secure tested gap widths that have appeared, and ensure maximum safety.

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Fire resistant sealant products are designed to improve building safety. Their application can be the difference between a controllable fire and one that causes serious, costly damage – and puts lives at risk. 

The amount of sealant, coatings or penetration fillers required will depend on the size of your building and areas that may be at risk of compromise. Refer to Firestopping Standard Details or contact the Technical Solutions team for guidance.

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Stone wool products can either permanently or temporarily seal penetrations.

Rob Kooiker

ROCKWOOL Group Product Manager
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HVAC Systems Guide

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RockLap H&V Pipe Section Packaging Guide

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Thickness of ROCKWOOL Insulation



What is fire stopping?

Fire stopping is the process of safeguarding joints, imperfections and openings that could allow the passage of fire and smoke in a construction. It addresses any element that could compromise the integrity of a fire-resistant structure – going beyond simply insulating the service lines.



Is fire sealant heat resistant?

ROCKWOOL Sealants are tested to European Fire Resistance standards to provide up to 4 hours fire protection. Some high performance sealants are designed to react at certain temperatures in order to provide the fire rating.

What is fire stop sealant?

Fire stop sealant is used to close off gaps and openings between walls, floors, ceilings or imperfections of fit within the fire rated construction. This aims to prevent the spread of fire, smoke and hot gases and maintain a building’s safety standards.