Fire-Rated Partitions

What fire-rated partitions are

Fire-rated partitions are tested wall assemblies that provide compartment integrity and insulation performance for a defined period in a fire condition: EI 30, EI 60, EI 90 or EI 120 minutes. They form the compartment boundaries required by a building's fire strategy: walls between different building uses, between floor levels, between escape routes and the spaces they serve, and around lift and services risers. Getting fire-rated partitions wrong is a building safety issue, not a snagging issue.

The critical principle is that the EI rating is a property of the complete tested assembly, not of the fire board used. Using a fire-rated plasterboard product in a partition that does not otherwise match the tested system document does not produce a fire-rated partition: it produces a partition with a fire-rated board in it. The stud specification, board layers and fixing centres, insulation specification and perimeter detailing must all match the manufacturer's current tested system.

Construction

The standard fire-rated partition uses galvanised steel C-stud sections at reduced centres (typically 400 to 600 mm depending on the rating and height), faced with multiple layers of fire-rated plasterboard. The number of board layers, board specification (standard, fire-rated, or high-performance fire board) and mineral wool infill specification all vary with the EI rating required.

At EI 30: typically one or two layers of fire-rated board each side with mineral wool infill, on 70 mm stud at 600 mm centres up to around 3.6 m in height.

At EI 60: typically two or more layers of fire-rated board, denser mineral wool infill, with stud gauge and fixing centres confirmed against the tested assembly for the partition height.

At EI 90 and EI 120: multiple layers of high-performance fire board (British Gypsum Fireline, Knauf Fire Panel, Siniat Frameboard or equivalent), specialist insulation, and perimeter detailing that maintains the rating at the head-of-wall condition where structural deflection must be accommodated.

The head-of-wall condition

At the top of a fire-rated partition, the partition meets the underside of the floor structure above. In a building with a cast concrete soffit, the partition head can be fixed directly to the structure. Where the soffit has structural movement under live load (composite deck, post-tensioned flat slab), the partition head must accommodate deflection without cracking the boards or breaking the compartment seal. Deflection heads using slotted track details allow the structure to move while the partition maintains its fire seal. The deflection allowance, track detail and sealing at the deflection gap all need to match the tested system. We address this at pre-construction with the structural engineer and fire engineer where the head-of-wall condition is not standard.

Firestopping at penetrations

Every service penetration through a fire-rated partition is a potential compartment breach. The partition itself achieves its EI rating in the wall area between penetrations; the penetration points reduce the compartment to the fire performance of the penetration firestopping, which must match the partition's EI rating.

Firestopping at penetrations is a separate specialist trade and is not part of the Eastledge scope. We coordinate with the principal contractor's appointed firestopping specialist at pre-construction, identify all penetrations in advance, and sequence our partition installation around their work. Our partition installation is documented at handover and the firestopping contractor is responsible for the penetration documentation that completes the compartment record.

Sectors

Fire-rated partitions are required in every sector where we work: escape route enclosures in offices; clinical and compartment walls in healthcare; classroom fire separation in education; riser and plant enclosure walls in industrial and commercial fit-out. The specification driver is always the building's fire strategy, and we work to the fire engineer's partition schedule from pre-construction through to handover.

Get in touch

If you are scoping fire-rated partitions, we would be glad to discuss the brief. Send drawings, the fire strategy or the fire engineer's partition schedule with the form on this page and we will come back with a clear next step within one working day. For urgent enquiries call 01332 757830 or email enquiries@eastledge.co.uk.