FD30 vs FD60 Fire Doors:
Which Do You Need?

What the Ratings Actually Mean

The "FD" stands for fire door and the number is the minimum period, in minutes, that the door resisted fire when tested to BS 476-22 or the European equivalent BS EN 1634-1. An FD30 door held back fire for at least 30 minutes under test conditions; an FD60 door for at least 60 minutes.

Two details matter here. First, the rating applies to the whole doorset — leaf, frame, hinges, closer, seals and glazing tested together — not just the slab of timber. Swap any component for an untested one and the rating can no longer be relied on. Second, you will sometimes see an "S" suffix, as in FD30S. The S means the door is also fitted with cold smoke seals, which block the toxic smoke that kills long before flames do. Flat entrance doors, for example, are normally specified as FD30S.

FD30 at a Glance

• — 30 minutes tested fire resistance; typically 44mm thick
• — The standard rating for houses, flats and most HMOs
• — Lighter, cheaper and available in far more styles than FD60

FD60 at a Glance

• — 60 minutes tested fire resistance; typically 54mm thick
• — Common in commercial buildings, plant rooms and higher-risk areas
• — Noticeably heavier — hinges, closers and frames must be rated to match

Where Each Rating Is Required

The requirement comes from two directions: Approved Document B (the fire safety volume of the Building Regulations guidance for England) sets out where fire doors are needed in new work and conversions, and the Regulatory Reform (Fire Safety) Order 2005 requires the "responsible person" for non-domestic premises and the common parts of multi-occupied residential buildings to maintain adequate fire precautions — which a fire risk assessment translates into specific door ratings.

Typical FD30 Situations

• — Loft conversions creating a three-storey house — doors onto the protected stairway generally need to be fire doors under Approved Document B
• — Integral garages — the door between the garage and the house is normally FD30 with a self-closer
• — HMO bedroom and escape-route doors — widely specified as FD30S following the LACORS housing fire safety guidance used by local authorities
• — Flat entrance doors opening onto shared corridors or stairs — normally FD30S with a self-closer

Typical FD60 Situations

• — Commercial premises where the fire risk assessment demands 60-minute compartmentation — shops, offices, restaurants and workshops
• — Plant rooms, boiler rooms, commercial kitchens and storage areas with elevated fire loads
• — Doors separating commercial units from residential accommodation above — a common arrangement in town-centre buildings in Marlow, High Wycombe and similar market towns

If you are unsure which rating applies to a specific door, the honest answer is that it depends on the building's fire risk assessment — a survey visit settles it quickly. We cover the whole area, including Marlow and the surrounding South Bucks towns.

Certification and Labelling

A fire door without evidence of certification is, for compliance purposes, just a heavy door. Certified doors carry identification from a third-party scheme — most commonly a BWF-Certifire label on the top edge of the leaf or a coloured BM TRADA Q-Mark plug set into it, recording the rating and tracing the door back to its test evidence.

Keep the manufacturer's installation instructions and any certificates supplied with the door. Inspectors, landlords' agents and fire risk assessors will ask for them, and the instructions define exactly how the door must be fitted — permitted gap sizes, seal specification, hardware and how much may be trimmed from the leaf — for the certification to remain valid.

Intumescent Strips and Smoke Seals

Every fire door relies on intumescent strips — seals set into grooves in the door edge or frame that expand to many times their size when heated (activation is typically around 200°C), sealing the gap between leaf and frame so fire cannot bleed around the edges. FD60 doors generally need a larger or doubled-up intumescent arrangement compared with FD30 doors; the exact specification comes from the door manufacturer's data sheet.

Smoke seals are the second half of the system: brush or fin seals that block cold smoke in the early stages of a fire, before the intumescent material activates. Where a door is specified with an S suffix (FD30S, FD60S), combined intumescent-and-smoke seals are required, and the gap under the door usually needs to be tighter as a result.

Typical Supply-and-Fit Costs in South Bucks

Prices vary with door style, finish, glazing and how much work the existing frame needs, but as a realistic guide for the High Wycombe, Beaconsfield and Marlow area:

Multi-door projects — an HMO conversion or a commercial corridor, for example — usually bring the per-door price down. New frames, fire-rated glazing and decorative finishes add cost; we itemise everything in a written quote so there are no surprises.

Installation Mistakes That Void Certification

Most fire door failures found during inspections are installation problems, not product problems. The ones we see most often:

• — Oversized gaps — the gap between leaf and frame should typically be around 3mm (2–4mm is the commonly accepted range); anything wider lets fire past before the intumescent seal can close it
• — Excessive trimming — manufacturers permit only a small amount to be planed off each edge; trim beyond it and the core is exposed and the certification is void
• — Non-rated hardware — hinges must be fire-rated and CE/UKCA marked to BS EN 1935, and there must be at least three of them on a fire door
• — Site-cut glazing apertures — cutting a vision panel into a fire door on site voids its certification; glazed fire doors must be factory-prepared under the certification scheme
• — Expanding foam around the frame — standard PU foam is not a fire-stopping material; the frame-to-wall gap needs appropriate fire-rated packing and sealing
• — Painted-over seals — decorating a door and painting across the intumescent or smoke seals stops them working as designed

This is why fitting matters as much as the door itself. Our fire door installation service covers survey, specification, supply and fitting to the manufacturer's instructions, with a compliance check on completion.