What Is a Fire Rated Partition and When Do You Need One?
A fire rated partition is an internal wall built from a tested system of boards, studs and seals that holds back fire for a set time, usually 30 or 60 minutes. It splits a building into compartments and protects escape routes. The rating only holds if the wall is built exactly as tested and every opening is sealed.
Fire rated partitions do most of the quiet work in keeping a fire to one part of a building. This post explains what they are, what the ratings mean, when you need one and what most often goes wrong.
What a fire rated partition is
A fire rated partition is a non-loadbearing internal wall that has been tested as a complete system. The system covers the board type, the number of layers, the stud size and spacing, the fixings and how the head and edges are sealed. Change any one of these and the tested rating no longer applies.
What the ratings mean
Ratings are given in minutes. In the UK you will see two ways of writing them:
- BS 476 Parts 20 to 22, the older British test, for example "60 minutes integrity and insulation"
- BS EN 13501-2, the European classification, for example EI 60
E stands for integrity: the wall stops flames and hot gases passing through. I stands for insulation: the unexposed side stays cool enough not to set fire to things on it. A partition rated EI 30 holds both for 30 minutes.
When you need one
A fire rated partition is usually needed to:
- Separate an escape corridor or stair from the rooms around it
- Divide a building into compartments of a set size
- Enclose higher risk rooms such as plant rooms, kitchens, stores and electrical cupboards
- Separate different occupiers in a shared or mixed use building
Approved Document B sets the minimum performance for new work and material alterations. In an existing building, the fire risk assessment identifies where compartmentation is missing or damaged. Our guide to fire safety requirements for offices covers how this applies to workplaces.
What breaks a partition's rating
Most failures happen after installation, not during it. The common ones are:
- Holes cut for new cables, pipes or data that are not sealed again
- The partition stopping at a suspended ceiling instead of running to the structural soffit
- Non-rated sockets, vents or glazing added later
- Mixed board types used to patch damage