Fire safety in listed and historic buildings

Fire safety listed building planning work fails when it is treated as two separate projects. The fire engineer specifies compartmentation and half hour doors. The conservation officer sees new partitions through decorative plasterwork and the loss of original joinery. Both are right, and the scheme stalls because nobody brought them into the same room before the drawings were fixed.

The way through is to start from the fire engineering objective rather than from the standard solution. Approved Document B is one way of showing compliance. It is not the only way, and on a historic building it is frequently the worst one.

Why standard solutions conflict with historic fabric

The guidance in Approved Document B was written around buildings that can be built to suit it. A Georgian townhouse cannot.

The recurring conflicts:

• Protected stairways. Historic stairs are often open well, rising through a hall that is the principal architectural space. Enclosing it in fire resisting construction destroys the space.
• Compartment floors. Achieving a notional fire resistance between storeys can mean lifting historic floorboards or losing lath and plaster ceilings with decorative cornices.
• Doors. Original panelled doors rarely meet a modern door standard on their face, and replacing them removes the single most characteristic internal feature of many listed interiors.
• Travel distances. Historic plan forms produce long single direction escape routes with no second stair to add.
• Fire stopping at junctions. Timber framed party walls and unsealed voids run continuously in ways no modern detail anticipates.
• Cavity barriers in a building with no cavities, or with voids that are themselves of interest.

The statutory framework makes this a balance rather than a choice. Section 16 of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires the decision maker to have special regard to the desirability of preserving the building and its features of special architectural or historic interest. At the same time the Regulatory Reform (Fire Safety) Order 2005 puts a duty on the responsible person for any building in use, and Building Regulations apply on material alterations or a change of use.

Compartmentation and the loss of original features

Compartmentation is the intervention with the highest heritage cost, so it is the one to test hardest.

Questions worth asking before accepting a compartmentation strategy:

1. What does the existing construction actually achieve? Lath and plaster on timber joists frequently performs better than assumed, and a properly evidenced assessment of existing construction can remove the need for an intervention entirely.
2. Can the upgrade be made from the less sensitive side? Working from above a floor, or from within a later partition, often leaves the historic surface untouched.
3. Can the compartment line be moved to a later, less sensitive wall a metre away?
4. Is the compartment needed for life safety, or for property protection and insurance? The answers may differ, and the second is not a Building Regulations requirement.
5. Would suppression allow the compartment to be omitted or reduced?

That last question resolves the most cases, and suppression is usually where the answer lies.

Where compartmentation is unavoidable, reversibility is the argument that wins consent. An intervention that can be removed in future without damage to the historic fabric is materially easier to justify than one that cannot, and saying so explicitly in the heritage case matters.

Doors, glazing and intumescent detailing

Original doors can very often be retained and upgraded rather than replaced. The techniques are established: deepening the rebate in the frame to the required overlap, fitting intumescent seals into the frame rather than the door leaf, applying thin intumescent linings behind existing panels, and upgrading the panel thickness from the less visible face.

Whether a particular upgrade achieves the performance needed is a question for someone who can assess it against test evidence. What matters for the consent is that the upgrade is specified, drawn and justified rather than asserted.

Glazing is a second common pressure point. Fire resisting glazing in a historic screen changes sightlines, bar widths and reflectivity, and slim profile fire rated systems are not always slim enough. Where a screen is of high interest, consider whether the room it serves can be managed differently instead.

Self closing devices are the detail most often overlooked and most often refused. Surface mounted overhead closers on a panelled door in a principal room are visually intrusive. Concealed jamb mounted closers cost more and are usually accepted.

Detection and suppression as alternatives to fabric change

This is where a fire engineered approach earns its fee.

The risk based standards, BS 9991 for residential buildings and BS 9999 for other building types, allow trade offs between measures. Enhanced automatic fire detection to the appropriate category buys earlier warning and a longer available escape time. A residential sprinkler or watermist system to the relevant standard can justify relaxations in compartmentation, travel distance and stair enclosure that would otherwise require substantial fabric change.

The trade is not free. Pipework has to run somewhere, and concealing it in a historic building takes design effort and sometimes localised intervention. A sprinkler installation with exposed pipework in a decorated room can cause more harm than the wall it was meant to avoid building.

Management measures also count. A simultaneous evacuation strategy, a staff fire warden regime in a building in institutional use, restrictions on the use of particular rooms, or a controlled occupancy figure can all form part of the justification. They have to be secured, which usually means they appear in the fire risk assessment and the management plan rather than in a planning condition.

A Fire Safety Strategy drawing all of this together is a fire engineering document. It requires someone with the necessary fire engineering competence, and on higher risk buildings a Fire Statement at Planning Gateway One is a separate statutory requirement under the Building Safety Act 2022 framework and Article 9A of the Development Management Procedure Order 2015. Neither is a document to draft and submit without that professional input.

Listed building consent for fire works

Most fire safety interventions in a listed building need listed building consent, including ones that feel purely technical.

Works that ordinarily require consent:

• New partitions or compartment walls, including plasterboard partitions in historic rooms.
• Replacement of doors, or alterations to door frames and rebates.
• Removal or replacement of ceilings, including later ceilings where they conceal earlier fabric.
• New or replacement glazing in fire resisting specifications.
• Surface mounted closers, signage, emergency lighting and detection wiring where visible.
• Sprinkler and detection pipework and cabling runs.

Consent applications carry no fee, but they need the same evidence as a planning application and usually more drawings. A Heritage Statement has to establish the significance of the building and each affected element, then assess the harm from each intervention and set out the public benefits, which in this case include life safety. That framing is important. Fire safety is a strong public benefit, and a heritage case that names it explicitly is far stronger than one that treats the works as regrettable necessity.

Where the building is a place of worship, the ecclesiastical exemption may apply to some works, with the denomination's own consent system operating instead. Check which regime applies before submitting anything.

Working with the conservation officer and fire engineer together

The single most useful thing you can do is get them in the same meeting, early, with the significance assessment already done.

A workable sequence:

1. Complete the significance assessment room by room, ranking elements from highest to lowest sensitivity.
2. Have the fire engineer state the objectives rather than the solutions: warning time, escape time, compartment lines, occupancy.
3. Test each objective against the significance ranking, looking for routes that intervene in the least sensitive fabric.
4. Hold a joint meeting with the conservation officer and, where the building is in use, the fire and rescue service, and record the positions taken.
5. Fix the strategy before the detailed drawings start.
6. Submit the consent application with the fire strategy as a supporting document, so the officer can see why each intervention is proposed.

Where the building has structural issues alongside the fire works, a Structural Survey keeps the two from being resolved separately, and material choices at this stage carry fire implications of their own, as our note on mass timber frames and planning stage fire questions shows for new build.

Recording what is lost

Where harm is accepted, recording is part of the mitigation and will usually be conditioned.

The scope should match the significance of what is being altered. A photographic and drawn record of the affected elements before works, at an appropriate Historic England recording level, with the archive deposited with the local historic environment record. A Historic Building Recording exercise at level 2 or 3 is typical for internal alterations of this kind, and the level should be agreed rather than assumed.

Record the retained fabric too. A drawing set showing which original doors survived, where upgrades were applied and what was replaced is worth having in twenty years when the next scheme comes along and someone asks what is original.

This is general guidance, not legal advice. Fire safety design and heritage significance are both building specific, so check the position with your local planning authority or a qualified professional before relying on it. For specialist technical reports, qualified professional input may be required.

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