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Understanding passive fire protection: Frequently asked questions

Passive fire protection (PFP) is designed to offer integrity, stability and assurance that a building has the best possible chance of containing fire and smoke. We’re often asked about exactly how it works and how buildings can comply with fire safety legislation.

Here, we’ve answered some of FireSealsDirect’s most frequently asked questions to help your project’s decision-making process.

How does passive fire protection work?

Passive fire protection is built into the structure of a building and works to slow or prevent the spread of fire. It’s a vital element of any property’s fire safety strategy and is designed to safeguard lives and protect property. It does this by providing stability in walls, floors and doors, compartmentalising so fire, heat and smoke are contained in one area. Discover more about the importance of passive fire protection.

How much can be cut off a drop down seal?

Generally speaking, 100mm can be cut off the non-mechanical edge of the drop down seal. However, some of our products – Applique 37, for example – can be cut back by 150mm.

What is the maximum gap allowed at the bottom of a fire door?

The maximum gap at the bottom of a fire door is generally 10mm between the door bottom and the floor. The maximum gap for a fire door with smoke protection is 3mm. However, if this isn’t possible, a gap of up to 10mm is permissible with the use of a drop down seal to seal the gap.

What is the maximum gap allowed to the sides of a fire door?

British Standards states there should be a maximum gap around a fire door of 3-4mm.

What is the best retro fit smoke seal for fire doors?

The Batwing seals create an effective retro fit smoke seal that can be installed in existing fire door frames by using a self-adhesive backing to stick to the frame.

Can I use fire foam around pipes to them?

No. Pipes and cables must be fire-stopped with intumescent products that are tested for the application. Fire foam is usually only used for sealing penetrations where there are no services going through. At FireSealsDirect, we recommend intumescent pipe collars or wraps to ensure the integrity of the wall or floor is maintained in a fire.

What do I need to check on my fire doors to make sure they’re compliant? 

There are many areas of a fire door that should be considered to make sure it is compliant. Do check:

  • The gaps around the door don’t exceed 3-4mm and ensure there’s no more than a 10mm gap at the bottom.
  • The intumescent strip and smoke seals to make sure they are in place and creating a seal with the door and the frame.
  • The hinges are fire rated and in good working order.
  • The door closer is working correctly and that it closes the door fully.
  • Any glazing or grilles in the door are fire rated.
  • Any locks or latches are fire rated, in good working order and have intumescent protection.
  • There is clear signage to show users that it should be kept shut.

How do intumescent products work?

Intumescent products are designed to expand and fill any gaps in fire compartments to reinstate the compartment in the case of a fire. This type of fire protection doesn’t extinguish a fire – it contains it and prevents its spread.

Still have questions? We appreciate the very nature of architectural and construction work means there are so many variables when considering passive fire protection. Contact us for expert advice or to simply run a passive fire protection query by us – we’re always happy to help.