What does a fire rating on a partition mean?
A fire rating describes how long a partition can maintain set performance criteria in a standard fire test. The letters describe what it achieves and the number gives the time in minutes. E stands for integrity, meaning the partition prevents flames and hot gases passing through gaps or cracks. I stands for insulation, meaning the temperature rise on the unexposed face stays within set limits, so people and materials on the safe side are protected from radiant heat.
An EI 30 partition therefore keeps both integrity and insulation for at least 30 minutes, while an E 30 partition keeps integrity for 30 minutes but lets more heat through. Which you need depends on where the partition sits in the building's fire strategy. Escape corridors and compartment walls often need insulation as well as integrity, and some locations need 60 minutes rather than 30.
| Classification | What it means | Typical use |
|---|---|---|
| E 30 | 30 minutes integrity only | Some internal screens where radiant heat is not a concern |
| EI 30 | 30 minutes integrity and insulation | Protected corridors and many escape routes |
| EI 60 | 60 minutes integrity and insulation | Compartment walls, protected shafts and higher-risk areas |
| Legacy BS 476-22 ratings | Older UK test standard for non-loadbearing elements | Existing systems still evidenced to BS 476 |
How are fire rated partitions tested?
Non-loadbearing walls, including glazed partitions, are tested to BS EN 1364-1, and doors and opening assemblies are tested to BS EN 1634-1. The test builds a full-size specimen with the actual frame, glass, gaskets, fixings and seals, then exposes one side to a furnace following a standard time-temperature curve. Results are classified to BS EN 13501-2. Older systems may hold evidence to BS 476-22, which remains in use for some existing products.
Because the test is on a whole assembly, swapping a single component can invalidate the rating. A different glass, a different gasket, an untested joint type or an unapproved door closer means the installed partition is no longer the tested system. Extended application reports and assessments from test bodies can widen the scope, for example to taller heights or different joints, but only within what they explicitly state.
Can glass partitions be fire rated?
Yes. Fire rated glazed partitions use special glass and matching frames, usually steel or aluminium profiles with intumescent seals that expand in heat to close gaps. Integrity-only glass is typically a specialist toughened or wired product, while insulating glass uses multiple layers with intumescent interlayers that foam and turn opaque in a fire, blocking heat. Insulating fire glass is thicker and heavier than standard glass, which affects frame sizes, door weight and cost.
Guide prices for fire rated glazed partitions are £850–£1,400 per m², supply and install, excluding VAT, against £75–£125 per m² for fire rated stud walls. Lead times for fire rated glazing are typically 4–6 weeks from design sign-off, because the glass is specialist and made to order. All prices are guides confirmed after a free site survey.
What is compartmentation and why does it matter?
Compartmentation divides a building into fire-resisting zones that contain a fire, slow its spread and protect escape routes. Compartment walls and floors are part of the building's fire strategy, and any partition that meets or passes through them must maintain their rating. Common failures include services passing through compartment walls without fire stopping, partitions fixed to suspended ceilings that do not form part of a rated barrier, and gaps at the head of partitions left open into the ceiling void.
Before partitioning, establish which existing walls and floors are compartment lines and which new partitions must be fire rated. The building's fire strategy drawings, the landlord's surveyor and the fire risk assessment are good starting points. Ceiling void barriers and fire stopping at penetrations are often needed to complete the protection.
What evidence should you ask for?
Ask for documentary evidence that links the partition you are buying to a test or assessment. Performance applies only to complete tested systems installed as tested, and the evidence comes from the system manufacturer and the test body, not from the installer. You should receive copies of the manufacturer's test evidence and installation requirements, and a record of what was installed, for your fire safety file.
- Test report or classification report to BS EN 1364-1 or BS EN 1634-1
- Any extended application or assessment covering your sizes and details
- Glass type and fire glass markings matching the tested specification
- Door ironmongery schedule matching the tested or assessed configuration
- Installation instructions from the system manufacturer
- As-installed drawings and photographs of concealed fire stopping
What happens to fire ratings after installation?
Fire performance depends on the partition staying as installed. Later alterations, such as drilling for cables, fitting unapproved door hardware, replacing a broken pane with standard glass or removing intumescent seals, can compromise it. Under the Regulatory Reform (Fire Safety) Order 2005, fire safety measures, including fire doors, closers and seals, must be maintained in efficient working order, and the responsible person must keep the fire risk assessment current. Label fire rated partitions and doors on your drawings so maintenance teams and future contractors know which elements are fire rated.
Frequently asked questions
What is the difference between E 30 and EI 30?
E 30 means the partition maintains integrity for 30 minutes, stopping flames and hot gases passing through. EI 30 adds insulation, limiting the temperature rise on the unexposed side for 30 minutes. EI glass is thicker and costlier but protects people and materials on the safe side from radiant heat.
Can I add a fire rated door to a standard glass partition?
A fire rated door on its own does not make a non-rated partition fire resisting. Where the location needs fire resistance, the screen, door, frame, seals and ironmongery must all form a tested or assessed system. Where fire resistance is not required, a fire door adds cost without adding protection.
Does the installer certify the fire rating?
No. Fire performance comes from the manufacturer's tested system and the test or assessment body's classification, provided it is installed as tested. The installer follows the manufacturer's instructions and should hand over the manufacturer's test evidence and a record of what was installed for your fire safety records.
Are fire rated glass partitions much heavier?
Insulating fire glass uses several layers with intumescent interlayers, so it is thicker and heavier than standard glass. That means sturdier frames, heavier doors and careful handling, particularly on upper floors without a goods lift. The survey checks access and floor conditions before the specification is fixed.
Guide prices are supply and install, excluding VAT, and are confirmed by a fixed quote after a free site survey. Regulatory information is general guidance; your Building Control body, landlord or fire engineer has the final say on a specific project.