Asbestos Fire Doors & Fire Protection Guide

Why AIB was used as a fire-door core#

AIB (commercial names: Asbestolux, Marinite, Turnasbestos) is a low-density calcium silicate board with 15–40% amosite or chrysotile fibre. It gave joinery manufacturers a lightweight, dimensionally stable, easily machined core that achieved 30 or 60 minutes of fire resistance to BS 476-22 in a slim door section. Solid timber cores of equivalent rating are heavy and prone to warping; mineral-fibre cores of the 1990s onwards are equivalent but post-date the AIB era. From around 1985 onwards manufacturers moved to alternative cores (vermiculite board, ceramic-fibre board, solid laminated timber), so AIB-cored doors are overwhelmingly a pre-1985 product.

Where they are still found#

Asbestos-cored fire doors are still in service in large numbers in: NHS estate (corridor and ward doors in 1960s–1970s hospital blocks); local authority schools (corridor cross-doors, plant room doors, classroom doors in 1960s–1980s blocks); council housing (flat entrance doors and riser cupboard doors in 1960s–1970s blocks); commercial property (basement plant rooms, service risers, escape stair doors in 1960s–1980s office blocks); and listed and heritage buildings where door changes have been resisted on conservation grounds.

• •NHS corridor and ward doors (1960s–1970s)
• •School corridor and plant room doors (1960s–1980s)
• •Council block flat entrance doors and riser cupboards
• •Office basement plant rooms and escape stair doors
• •Heritage buildings where doors are listed and original

Identification — what surveyors actually look for#

Visual cues: a heavier-than-modern feel (a 44mm AIB door weighs noticeably more than its modern equivalent), original brass or anodised ironmongery, painted-over intumescent strips, vision panel beads that look added after the door was made, and a flush plywood or veneer face with no visible joints. A small core sample taken with a Forstner bit from a discreet hinge or lock edge by a competent surveyor confirms the material — usually around £80–£150 per door including UKAS analysis. On large estates a representative sample of doors of each type and age is more proportionate than every single door.

Why doors specifically are a problem#

A door is unlike most other AIB products in three ways. First, it is constantly disturbed in normal use — every door closer adjustment, every new lock, every vision panel upgrade, every kick plate, every signage screw is a potential disturbance event. Second, it is a building safety component: the fire rating must be maintained, which means any damage triggers either a like-for-like replacement (impossible without disturbing the AIB) or a like-for-modern replacement (planned removal). Third, fire-door inspections under the Regulatory Reform (Fire Safety) Order 2005 and the Fire Safety (England) Regulations 2022 now require quarterly inspections of common-parts flat entrance doors in higher-risk buildings — and inspectors handle, push, pull and adjust doors during inspection.

Managing in service — the right way#

Doors that are intact, painted, in good condition and on the register can stay in service indefinitely. The asbestos management plan must show every AIB-cored door with location, condition, ironmongery type, and an explicit instruction that no new ironmongery, vision panel, kick plate, signage screw, closer or hinge may be fitted without an AIB-aware permit-to-work. Trades carrying out fire-door inspections must be briefed. Where a door must remain in service but new ironmongery is required, controlled drilling under HSG210 with local controls (hand-held shroud, H-class vacuum, half-mask P3) by a competent contractor is an option.

Removal — when and how#

Whole-door removal by a licensed contractor is the standard approach. The door is unscrewed from its hinges intact, wrapped in 1000-gauge polythene in situ, double-bagged or skip-bagged and removed on a Hazardous Waste Consignment Note. The frame is usually retained — most AIB cores are bonded to thin timber facings, and the door leaf is the asbestos item, not the frame (although some 1960s frames have an AIB lining and should be sampled). Replacement is a modern certified FD30 or FD60 door from a current manufacturer with matching ironmongery. Removal is licensed work under Regulation 8 of CAR 2012, ASB5 notified 14 days in advance, with four-stage clearance before reoccupation of the area.

What it costs in 2026#

Single-door removal as a standalone job is rarely economic — mobilisation dominates the cost. Typical 2026 rates for licensed removal of AIB-cored fire doors, bundled across a programme: £450–£900 per door on a programme of 10+ doors in a single building; £900–£1,800 per door as standalone work in occupied premises; £350–£650 per door on whole-floor strip-out where the area is vacated. Replacement certified FD30 door, frame, ironmongery and intumescent strips, supplied and fitted: £600–£1,400. Plan a fire-door replacement programme to bundle 10–30 doors per phase to get the per-door rate down.

• •Bundled removal (10+ doors, one building): £450–£900 per door
• •Single-door occupied-premises removal: £900–£1,800
• •Strip-out removal (vacated area): £350–£650 per door
• •Replacement door, frame, ironmongery, fitted: £600–£1,400
• •Sampling to confirm AIB core (one per type): £80–£150
• •Four-stage clearance per phase: £600–£1,200

Fire doors in flat entrance doors — the 2022 Regulations#

The Fire Safety (England) Regulations 2022 require responsible persons in high-rise residential buildings to undertake quarterly checks of fire doors in common parts and annual checks of flat entrance doors. Many flat entrance doors in 1960s and 1970s council blocks are AIB-cored. Inspectors handling these doors must be briefed in writing, the register must flag the door, and any door that fails inspection should be replaced under licensed conditions — never repaired in situ by unscrewing the existing leaf and refitting new ironmongery.

Listed buildings and conservation#

Where the original door is listed and the local authority conservation officer will not consent to replacement, the proportionate approach is: leave the door in service, refit any damaged ironmongery on existing screw holes only, never introduce new penetrations, log the door on the register with explicit no-penetration instructions, and reassess every five years. Where a fire-engineering case can be made that the door can be deemed FD30 with intumescent intumescent strips applied non-invasively, the conservation officer may accept retention.

Other fire-protection AIB to check at the same time#

AIB-cored doors are rarely on their own. The same era of buildings often has AIB linings to: riser cupboard internals, plant-room ceilings, electrical intake cupboards, stair-soffit underdraws, kitchen extract duct boxing, and the underside of access hatches. A fire-door removal programme is the right moment to audit these adjacent items and bundle them into the same licensed mobilisation, which typically reduces the per-item cost by 30–50%.

Frequently asked questions