Design Principles For Passive Fire Protection

DunbarWallace designs and installs bespoke passive fire protection systems for businesses, construction, utilities and power generation. In every case our goal is to delay the spread of fire long enough to allow for the safe evacuation of the building, and for the fire services to attend. The way we do this is by keeping the fire contained within smoke and fire-resistant compartments.

This larger goal is guided by a set of principles which are applied in any design process. These will always be balanced with active fire protection systems and will include:

  • The use of fire barriers which resist flames and insulate against heat
  • Compartmentalisation to stop the spread of fire
  • Protection against the collapse of the structure
  • Minimisation of the spread of smoke
  • Reducing the risk of damage to adjacent buildings
  • Ensuring access for fire services
  • Consideration of risks caused by water damage


Applying Design Principles in Passive Fire Protection

The principles of passive fire protection are applied practically in the design and installation of fire protection systems. Five clear examples of this process in practice are:

1. Fire Compartments

These are rooms, spaces or storeys that are constructed with the explicit aim of containing any outbreak of fire. Compartment walls are required to run continuously to join the floor above, which means they will run through roof spaces and ceiling voids. The ceiling, floor and walls will be constructed from fire protection materials such as DURASTEEL® fire rated applications.  Windows or doors should provide comparable fire resistance. Cable or utility gaps should be fire-stopped.

2. Fire Walls

Fire walls are designed to provide safe passage for evacuation routes and/or keep fire away from areas of high risk. These might include kitchens, fuel storage or labs using chemicals. These walls need to be able to resist fire, blast and the impact of firefighters’ hoses. Any doorsets, windows or service holes need to be equally fire resistant to the walls.

3. Structural Frame

How the building is built needs to be taken into account when designing passive fire protection systems. A steel framework is particularly vulnerable to fire as it will begin to buckle and bend once certain temperatures are reached. In order to protect the building against collapse in the case of fire, steel will need to be coated with intumescent coating or paint.

4. Fire-Stopping

The term ‘fire-stopping’ applies to the gaps or cavities in walls created for cables or utility pipes. Where these cut into a firewall they need to be kept as small as possible in order to maintain the integrity of the fire protection. No matter how small the gap, they will also need to be fire-stopped using a sealing system which fills the hole.

5. Ducts and Shafts

These need to be afforded the same attention as more visible surfaces within a building. Ducts and shafts can carry smoke, heat and flames threatening the breach of fire compartments. The level of fire resistance applied to these areas needs to be equivalent to the systems in places throughout the building.


About DunbarWallace

DunbarWallace Fire Protection Ltd is an experienced designer of fire protection systems, and a licensed and approved installer of Promat DURASTEEL®. We provide bespoke solutions for a range of applications, including high risk environments such as pharmaceutical labs, or nuclear power stations. We have the in-house capability to manufacture the required components.


DunbarWallace Fire Protection Ltd applies a series of design principles for passive fire protection systems. For more information on our work, call 01525 864438