Heritage Buildings

BACKGROUND

The range of heritage properties in the UK is enormous with immense differences in scale, complexity and construction. Built with little or no concern for fire safety, heritage properties are often more vulnerable to fire and its effects than a new build.

The vulnerability to fire also varies considerably as each building is unique and may be vulnerable in its own distinct manner requiring individual assessment and, if necessary, precautionary measures. 

The construction of such buildings can have a distinct lack of fire compartmentation or protected routes, with complicated means of escape. Unprotected roof voids of complex design can cover vast distances. In addition, ducts, chases, chimney flues and ventilation shafts all provide easy routes for fire and smoke spread and may allow a fire to smoulder unnoticed for many hours before breaking out some considerable distance from the point of origin. The very remoteness and lack of occupancy of some heritage buildings creates another issue.

Many heritage buildings have been destroyed or seriously damaged by fire over the years, of which Clandon Park, an 18th-century mansion in Surrey owned by the National Trust, is just one example. The fire, which occurred on 29th April 2015, was concluded to have been caused by a defect in an electrical distribution board located in a cupboard in the basement. The fire spread from the basement through the lift shaft, voids and into the roof. The wind blew the fire from one side of the roof to the other. The fire then burnt down to the floors below, leaving 95% per cent of the house seriously damaged by the fire.

Major Fires in England’s Cultural Heritage buildings from 2010 to 2020 (taken from Historic England Data)

On 15 March 2020 a fire occurred in Bristol Guildhall. Around 50 firefighters and ten appliances from Bristol and the surrounding area attended and pumped water from Bristol Harbour to tackle the blaze. Because of structural damage the firefighters were withdrawn from the building and tackled it from outside. The fire started in the roof space. The roof collapsed spreading the fire to the rest of the building.

GRADING AND LISTING OF BUILDINGS

A Listed Building, in the United Kingdom, is one that has been placed on the Statutory List of Buildings of Special Architectural or Historic Interest. The statutory bodies maintaining the list are Historic England in England; Cadw in Wales; Historic Scotland in Scotland; and the Northern Ireland Environment Agency in Northern Ireland.

As a rule, all buildings built before 1700 which survive in anything like their original condition are listed, as are most of those built between 1700 and 1840. The criteria for listing has become tighter with time, so that post-1945 buildings have to be exceptionally important to be listed. A building has normally to be over 30 years old to be eligible for listing.

Listing is not a preservation order, preventing change. It does not freeze a building in time, it simply means that listed building consent must be applied for in order to make any changes to that building which might affect its special interest.

In England and Wales listed buildings are graded as follows:

• Grade I: buildings are of exceptional interest, sometimes considered to be of international importance; only 2.5% of listed buildings are Grade I.

• Grade II*: buildings are particularly important buildings of more than special interest; 5.5% of listed buildings are Grade II*

• Grade II: buildings are of special interest; 92% of all listed buildings are in this class and it is the most likely grade of listing for a homeowner.

  
  

In Scotland, there are three categories of listed buildings:

• Category A: Buildings of national or international importance, either architectural or historic; or fine, little-altered examples of some particular period, style or building type. (About 8% of total listed buildings.) 

• Category B: Buildings of regional or more than local importance; or major examples of some particular period, style or building type, which may have been altered. (About 50% of total listed buildings.) 

• Category C: Buildings of local importance; lesser examples of any period, style or building type, as originally constructed or moderately altered; and simple, traditional buildings that group well with other listed buildings. (About 42% of total listed buildings.)

In Northern Ireland, the following grades are employed:

• Grade A: Buildings of greatest importance to Northern Ireland including both outstanding architectural set-pieces and the least altered examples of each representative style, period and grouping.

• Grade B+: Buildings which might have merited grade A status but for detracting features such as an incomplete design, lower quality additions or alterations. Also included are buildings that because of exceptional features, interiors or environmental qualities are clearly above the general standard set by grade B buildings. A building may merit listing as grade B+ where its historic importance is greater than a similar building listed as grade B.

• Grade B: Buildings of local importance and good examples of a particular period or style.

A degree of alteration or imperfection of design may be acceptable.

Consultants should be aware of the importance of identifying listed buildings, for which appropriate enquiries are to be conducted. Where a listed building has been identified, reference to this factor, together with the listed status is to be included in the survey report.  

A search facility for listed buildings in England is available at Historic England -  historicengland.org.uk/listing/the-list/

Searches across Britain can also be made at British Listed Buildings – www.britishlistedbuildings.co.uk/search#.WBcfKY_XKHs

RISK ASSESSMENT AND CONTROL

Features requiring consideration for fire risk assessment and control of heritage buildings are many and varied, of which key measures include:

1.      Statutory Fire Risk Assessment

The fire risk assessment of heritage buildings can often be challenging requiring a high level of competency. In these circumstances, the services of a third party certificated or registered fire risk assessor should be employed. In addition to complying with statutory obligations, the risk assessment should be expanded to take account of the property and business risks.

(Where fire safety improvements are needed to comply with legislation, this does not exempt the owners of listed buildings from applying for and obtaining the necessary listed buildings consent.)

2.     Listed Building status

As stated above, listed building status should be ascertained as this is likely to have significant impact on reinstatement values and rebuilding periods.

3.     Building Construction

Close attention should be given to building construction, with particular regard to combustible framing, floors and linings, and the presence of unprotected roof voids.

The potential for fire spread via voids and cavities, flues, ducts, shafts etc., should also be scrutinised, together with the presence of any fire stopping (otherwise referred to by an older term of fire safing). This will include flues and other long forgotten ducts and shafts which formed part of the original construction, such as waste shafts, natural ventilation stacks, bell-pulley routes, dumb waiters, etc.… Such voids, often interconnecting, are extremely hazardous providing an easy route for fire and smoke spread.

Recognition should also be taken of highly ornate external or internal structural features and finishes.    

In the case of thatched buildings, reference should be made to RiskSTOP Technical Bulletin 17.

(In most cases where timber floor construction is involved, a 100% EML is to apply.)

4.     Fire Safety Management

Once a risk assessment has been completed and suitable protective measures are in place, a robust management system in the form of a fire safety management plan should be formulated, including such measures as:

• The review/revisit of fire prevention measures and protection systems.

• Maintenance of protective measures to ensure capable performance.

• Comprehensive and regular training of staff in evacuation procedures, raising the alarm, first-aid firefighting and salvage plans.

• Emergency drills conducted, and any shortcomings recorded and rectified as soon as possible.

• Periodic review of the risk assessment and fire safety management plan, especially after a change in use of the building or a ‘near-miss’ incident.

5.     Fire Brigade and Water Supplies

Heritage buildings will often be situated in remote rural areas for which the correct assessment of the availability of the Fire and Rescue Service and the nature of water supplies is crucial.

6.     Automatic Fire Suppression Systems

 The use of water-based fire suppression systems to protect major heritage buildings has increased in recent years and a significant body of experience has been developed in relation to designing and installing these systems in a sympathetic and non-intrusive manner.

In cases where there are genuine concerns relating to potential water damage to valuable artefacts and archived objects/materials, a water mist-system may be considered (which will apply considerably less water than a conventional sprinkler system). Other protection options might include gaseous protection for specific rooms perceived to be at high risk such as archive storage, vaults and plant rooms, or the installation of an oxygen reduction system. 

7.     Fire Detection and Alarm Systems

 Subject to the availability of prompt and adequate brigade response and the presence of an adequate water supply, remotely monitored fire detection and alarms systems can have a role to play in the protection of heritage buildings.

The design of such systems in heritage buildings will sometimes call for special consideration owing to factors such as aesthetic requirements where ornate surroundings are concerned and high ceilings, typically encountered in larger heritage buildings. In these situations, aspirating smoke detection and linear beam smoke detectors are often employed, the former providing the additional benefits of speed of detection, as compared with conventional point detectors. In addition, linear heat detection may be employed for the protection of tunnels and voids to which access is limited.

Recent years have witnessed significant developments in radio-linked (wire-free) fire alarm technology which can have a major application in architecturally sensitive heritage buildings, owing to the ease and discreteness of installation. Such systems should comply with BSEN 54-25: Fire detection and fire alarm systems; components using radio links.

8.     Unoccupied Buildings

History has shown unoccupied heritage buildings to be particularly at risk, yet these structures often attract little interest from the authorities, including central government.

Consultants should pay close attention to such buildings based on Technical Procedures 6 (Unoccupied Property Surveys) and the RISCAuthority code of practice for the protection of empty buildings: fire safety and security, which are posted in ATLAS.

9.     Basements

Many heritage properties have basements, cellars or some form of underground storage facility. Ideally, these should be adequately separated from the upper floors by fire-resisting construction. Close attention should be paid to housekeeping in these areas and the presence of boilers and other items of plant.

10.  Electrical Installation and Equipment

Ensuring that the electrical installation is correctly installed, inspected and tested, and suitably maintained is a fundamental fire safety consideration in heritage buildings. It remains possible that some heritage buildings continue to be served by extremely old wiring systems employing vulcanised India rubber (VIR) insulation, which over time becomes hard and prone to cracking. The indiscriminate use of multiple adaptors and extension leads should be avoided. 

Formalised PAT testing should be carried-out in which close attention should be given the condition of any old textile braided leads/flexes.

Lampshades to ceiling pendants, wall lights and table lamps should be observed for scorching, arising from the use of incorrectly rated bulbs.

Electrical switch rooms and cupboards should be kept free from storage and combustible materials kept away from sources of heat. Particular care needs to be taken to ensure that drapes and other combustibles are kept a suitable distance from sources of ignition such as halogen lamps.

11.   Open Fires and Stoves 

Normal fire safety measures should be taken, including ensuring that chimneys are swept at appropriate intervals as per the following guidance recommended by the Guild of Master Chimney Sweeps:

12.  Contractors Operations

All such activity should be closely controlled and the impact on general fire safety continually monitored. A robust hot work permit system requires to be in place.

13.  Cooking

Cooking is a major cause of fire in heritage buildings. Rigorous controls should be exercised, particularly in respect of deep fat frying.

14.  Lightning

Protection against lightning plays a major role for many heritage buildings. Newly installed lightning protection systems (LPS) should be designed and installed to the requirements of BS EN 62305:2011. Correct maintenance of the LPS is of paramount importance; BS EN 62305 recommends that visual inspection and testing by a lightning protection specialist should be carried out at least annually.

It is recommended that all work relating to the installation and maintenance of lightning protection systems is carried out by a company which is a registered member of the Association of Technical Lightning & Access Specialists (ATLAS) - www.atlas.org.uk/

It must not be assumed that all lightning protection systems installed prior to the introduction of BS6651 (in 1985) are defective, resulting in the need for them to be upgraded to the current BS EN. Subject to correct inspection and maintenance, many such systems may continue to provide an adequate level of protection, particularly for “low to medium risk” sites. However, where systems have fallen into disrepair, or where changes or alterations to the structure render an existing system inadequate, upgrading to BS EN 62305 will be required. 

In addition to structural strike protection, normal consideration should apply in respect of lightning-induced, transient overvoltages and surge protection (RiskSTOP Technical Bulletin 7 refers).

1.      Special Events

Where a heritage building is used as a house in multiple occupation, or for events where a license is required (either permanent or temporary), including for example the sale or provision of alcohol, music and dancing, theatrical entertainment and weddings, the licensing authority will consult with a range of bodies, including the fire and rescue authority.

In these circumstances a suitable and sufficient fire risk assessment must be carried out, which should include, amongst others, the following features where appropriate:

• Seating provisions

• Catering arrangements

• Pyrotechnics

• Fabrics, drapes and curtains

• Tents/marquees and air-supported structures

• Electricity supplies and lighting

• Smoking

• Naked flames, candles and open fires

• Filming activities

2.     Salvage Plan/Damage Limitation

Depending on the fabric and contents of the building and the impact of a fire, it may be necessary to consider drawing up a salvage plan, the key components of which should include:

• Salvage priorities and how to go about recovering a building’s contents in the event of fire.

• A list of equipment to be used in any salvage operation.

• Identification of key personnel on site who will assist in the execution of the plan.

• Ensuring that measures are in place to manage items after they have been recovered – for example, where they should be stored and how they should be secured. 

• For this process, it is vital to liaise with the local fire and rescue service to devise appropriate emergency procedures. The fire and rescue services will be asked to consider artefact salvage through their Integrated Risk Management Plans (IRMP’s) and will obviously need to know priority items, location and which members of staff form the salvage team and any training that they may have had.

All staff involved with salvage operations must be fully trained and made aware of the risks and dangers involved with such tasks.

Where involving major heritage buildings, the salvage plan is unlikely to stand alone, but would be a key element of the wider business continuity/damage limitation plans for the premises.

STORM/WATER DAMAGE/LIABILITIES

In addition to paying close attention to the fire risk, heritage buildings will also warrant vigilance when assessing the risk of storm/water damage.

Owing to the prohibitive cost of maintenance, heritage buildings can often fall into a state of serious disrepair presenting in an extremely adverse storm/water damage risk, particularly when associated with valuable artefacts and other contents. Basements can be prone to flooding.   

In the circumstances described, similar concerns are also likely to arise in respect of liability covers.