Do I Need Fire Rated Internal Steel Doors?

The requirement comes from Approved Document B and, on larger projects, from the fire strategy prepared for the building. In practice the decision is made by your architect or designer and confirmed by Building Control or an approved inspector. A glazing supplier does not set the requirement; we build to the schedule that comes out of it.

That is worth saying plainly because homeowners are sometimes told a door 'has to be' fire rated by whoever is quoting for it. Ask where the requirement comes from. If the answer is a drawing, a door schedule or a Building Control comment, it is real.

• The door between an integral garage and the house — the most consistent domestic requirement.
• Rooms opening directly onto a protected stairway, where the stair is the escape route.
• Plant rooms, boiler rooms and spaces holding batteries, inverters or heat pump equipment.
• New habitable rooms created by a loft conversion, which usually triggers a protected route.
• Entrance doors to apartments, which form a compartment line and typically carry a higher rating.
• Compartment walls and corridors in offices, hotels, schools and hospitality interiors.

Three storeys is the point at which domestic requirements change noticeably. Adding a floor — whether a loft conversion or a new build over three levels — changes the escape strategy, and a set of rated doors on the landing usually follows.

A certified doorset is a tested assembly: leaf, frame, glass, seals, hinges and closer together. The frame has to be fixed into a wall build-up compatible with the test evidence. Knowing that before the studwork goes up means the opening is formed correctly the first time.

1. 01ConceptMark which openings are likely to be rated on the plan, even approximately.
2. 02Detail designConfirm the rating, configuration and wall build-up with us and with Building Control.
3. 03SurveyFinal sizes taken on site; hardware and closer specified as part of the certified set.
4. 04HandoverCertification issued with the doors for the Building Control file.

Less than most people expect. The visible profile and finish match the unrated collection. The glass changes to a certified fire-rated make-up, seals sit within the frame rebate, and a self-closing device is required. Pane sizes are limited by the certification, which occasionally nudges the bar layout — a three-over-three grid rather than a single pane, for example.

The larger constraint is movement. Certification is achieved with hinged doorsets, so sliding, pivot and bifold configurations stay in unrated openings. In a well-planned interior that is rarely a problem: the rated opening is usually a garage, utility or stair door, and the moving pieces belong elsewhere.