Fire Statement for a change of use application

A change of use can create a relevant building for Planning Gateway One purposes even though not a brick moves on the elevation. Convert a 1970s office block of nine storeys into flats and you have produced a building containing two or more dwellings at more than 18m in height, which is exactly what article 9A of the Town and Country Planning (Development Management Procedure) (England) Order 2015 catches. The application then needs a Fire Statement on the published form, and the Health and Safety Executive becomes a statutory consultee.

Applicants converting existing buildings are caught by surprise more often than those building new, because the fire issues on a conversion are mostly inherited. You did not choose the stair core, the corridor lengths, the external wall build-up or the distance from the street to the far corner of the plan. You still have to describe them and justify them.

When a change of use is caught

The trigger is the creation of a relevant building, which in broad terms means a building containing two or more dwellings or educational accommodation that meets the height criteria of 18m or more, or seven or more storeys. Both the use and the height tests have to be satisfied.

That produces some results worth knowing before you design.

• An office block converted to flats at 18m or above is caught, even with no external alteration
• The same block converted to a single large house in multiple occupation is not caught, because it does not contain two or more dwellings
• Adding two storeys to a 15m block of flats so that it reaches 19m is caught
• A ten storey block converted to student accommodation may be caught, depending on whether the accommodation falls within the educational accommodation definition
• Works to a relevant building that already exists, such as a new balcony arrangement, can be caught where planning permission is required

Height is measured from ground level to the floor surface of the top storey, which excludes roof-top plant and machinery areas. On a sloping site that measurement is taken from the lowest ground level adjoining the building. A block that reads as five storeys from the front and seven from the rear can fall either side of the line depending on how it is measured, so get the measurement agreed before the application rather than after.

The Fire Statement is a document that must be prepared by someone with the necessary fire engineering competence. The Building Safety Act 2022 framework and article 9A both proceed on that basis, and an AI-assisted draft is a starting point for that professional rather than a substitute for them.

What the statement has to cover on an existing structure

The published form asks about the principles of the fire safety design, and on a conversion the honest answer to several of its questions is that the existing building constrains the options. Say so, and say what you have done about it.

The areas that generate the most consultee comment on conversions are the number and position of stairs, the travel distances in the existing corridor layout, the construction of the existing external walls, the provision for firefighting including dry or wet risers, and vehicle access. A Fire Safety Strategy prepared to BS 9991 usually sits behind the statement and provides the technical reasoning, and on a conversion it should be written before the layout is fixed rather than after.

The government has confirmed a second staircase requirement for new residential buildings above 18m through an amendment to Approved Document B, with transitional arrangements for schemes already in progress. Check the current text and the transitional dates before you design a conversion around a single existing stair, because a single core office block is the hardest case this change creates.

External wall information you probably do not have

On a new building the external wall build-up is a design decision. On a conversion it is an archaeological question, and the answer usually requires opening up.

Expect to need intrusive investigation at several locations to establish the insulation type, the cavity barrier arrangement, the presence and condition of any combustible material, the spandrel panel construction and the detail at window reveals and floor junctions. Drawings from the original construction are a starting point and nothing more, because what was built and what was drawn frequently differ, and later recladding or window replacement may have changed the build-up again.

Where the external walls are being retained, say what you know, say how you know it, and say what remains to be established. A statement that asserts compliance without any investigation behind it is the fastest route to a holding objection. Where investigation is still outstanding at application stage, identify the locations and the programme, and expect a condition requiring the results before any works to the external envelope.

A structural survey of the existing frame is worth commissioning at the same time as the opening-up works, because the two investigations need the same scaffolding and the same access arrangements.

Fire service access on a tight site

Access is where urban conversions fail. Approved Document B sets out requirements for fire service vehicle access, including route width, headroom, turning provision and carrying capacity, and distances from the appliance position to building entry points and to dry riser inlets. An office block built with a service yard that has since been built over, or one whose only frontage is a narrow one-way street with controlled parking, may not be able to satisfy those requirements without works outside the site.

Deal with it in this order. Establish the appliance position that is actually achievable, check it against the building geometry, then identify what has to change. Where the solution needs works in the highway, a section 278 agreement with the highway authority will be needed, and that should be flagged in the application rather than discovered at discharge of conditions. Where it needs land you do not control, the scheme may not be deliverable in its current form.

The fire evidence expected for a building just below the threshold is lighter, but access is assessed on any residential scheme regardless of height, so the work is not wasted if the height measurement comes out below 18m.

Prior approval and where the requirement does not reach

The article 9A requirement is framed around applications for planning permission. A prior approval application under Schedule 2 of the General Permitted Development Order, such as a Class MA application for commercial to residential conversion, follows a different procedure, and the Fire Statement requirement does not attach to it in the same way. That does not mean fire safety is not assessed.

The Building Safety Act 2022 gateways still apply to the building work itself. Gateway Two is a hard stop before construction begins on a higher-risk building, and the Building Safety Regulator will want the information that a Fire Statement would have surfaced at planning stage, only later and with the programme already committed. Finding out at Gateway Two that the single stair arrangement is unacceptable is considerably more expensive than finding out at planning.

Where a full application is the safer route

There is a tactical judgement here. Prior approval is faster, less costly and narrower in scope, and for a block below the height threshold it is usually the right choice. For a tall single core building, the narrow scope cuts both ways, because you reach Gateway Two without having tested the fire strategy against a consultee who would have told you the answer for nothing.

Submitting a full application instead gives you a Fire Statement, a consultation with the Health and Safety Executive and a documented position on the stair, the external walls and access before you spend money on technical design. It also lets you resolve matters that Class MA cannot accommodate anyway, such as external alterations, balconies or a change to the entrance arrangement.

The decision usually turns on whether the existing building can plausibly meet current expectations without alteration. If it can, prior approval is efficient. If the stair, the corridors or the external walls need work, pay for the full application and get the fire position settled at planning stage. For specialist technical reports, qualified professional input may be required, and the fire statement is firmly in that category.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.