Fire safety: risk prioritisation in existing buildings - summary of responses to the call for evidence
Updated 1 June 2022
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Introduction
1. On 20 January 2020 the Department launched a Call for Evidence seeking views on factors contributing to building fire risk and approaches to prioritising risk within buildings and prioritising action between different buildings. A question was also asked on the areas and approach any further research in this space could and should consider.
2. The consultation was open for four weeks and closed on 17 February 2020.
Number and type of responses
3. There were 160 respondents to this Call for Evidence.
4. The majority of respondents focussed on factors related to residential buildings although some responses provided information regarding different building types and uses.
5. The figure below sets out the number of respondents in each category as set out in the Call for Evidence paper.
Approach to existing buildings
6. Dame Judith Hackitt’s Independent Review of Building Regulations and Fire Safety, and advice from the Independent Expert Advisory Panel, has recommended building owners adopt a case-by-case risk-based approach for assessing existing buildings.
7. A majority (66%) of respondents to a previous consultation were in favour of this approach. Respondents to this Call for Evidence were also in favour of this approach, with 90% (144 responses) in agreement (No – 4%/6 responses, a single response was received for “don’t know”). A small number of respondents (6%/9 responses) were not clear on their response to this question or did not include a response.
8. Several respondents suggested that a case-by-case approach could give a more accurate depiction of building risk and result in more relevant and effective fire safety interventions. There was a view that a blanket approach does not provide sufficient detail and that there should be no difference in the level of safety between residents/users of new buildings versus existing buildings.
9. Respondents did note that this approach could be onerous on building owners and lengthy (considering the potential number of buildings and industry capacity to provide inspectors), especially if further fires or Government advice were to expand the scope of buildings. A common concern raised was that of subjectivity and the reliance on the experience/opinion of different inspectors which could impact the quality/consistency of risk assessments.
10. Additional comments:
- Guidance should be dependent on building type;
- Minimise different interpretations, one approach could be to ensure assessments are quantifiable;
- Worked examples could be helpful to ensure consistent application;
- Building owners will require sufficient time to implement;
- Resident-centred approach, especially in specialised housing.
Factors influencing building fire risk
Factors aside from height
11. The Call for Evidence asked which factors, aside from height, respondents thought should be considered when classifying building risk. There were extensive responses to this question with the factors discussed breaking down into the following themes: Firefighting, Construction/Design, Occupancy, Building Type, Means of Escape, Management, and Other. There are factors that sit within multiple themes as expected.
12. The most commonly cited factors were:
- Occupancy (mentioned by nearly all respondents in some form, a focus on vulnerability/mobility of residents)
- Building Use
- Type of construction/materials
- Management
- Means of Escape
- Compartmentation
- Presence of automatic fire suppression systems (AFSS)
- Access for Fire and Rescue services (FRS)
- Building age
13. The factors raised by respondents are included in the tables below, roughly in order of number of responses. Additional contextual information is provided where possible.
Firefighting
| Factor | Additional Information |
|---|---|
| Access for FRS | Perimeter access, access to voids/compartments |
| Firefighting provisions | Including water supply, risers, firefighting stairs/lifts |
| FRS response time | Link to building location |
| Danger of falling debris during a fire | Link to construction/design |
Construction/design
| Factor | Additional Information |
|---|---|
| Type of construction/ materials | Combustibility, modern materials/methods, timber frame, use of green walls, composite materials on balconies, solar panels, temporary accommodation, etc. |
| Building age | Building Regulations at time of build, wear |
| Automatic fire suppression system | Sprinklers/ misting, coverage |
| Compartmentation | Compartment construction quality, defects, maximum size |
| Combustibility of external wall components | Cladding combustibility, insulation combustibility, balcony layout and construction, presence of photovoltaic panels, connectivity of façade materials across the face of the building |
| Alarm system | Type, coverage, maintenance |
| Building complexity | Including impact of layout/access on users and FRS |
| Building location | Proximity to other buildings, type of nearby buildings |
| Number of stairs | |
| Fire doors | Type, maintenance |
| Converted building | Type of conversion, date of conversion |
| Refurbishment works/ modifications | Quality and safety of design |
| Ventilation/ smoke control | |
| Building size/ area | |
| Fire safety measures | Not expanded on |
| Storey number | |
| Fire stopping | |
| Building condition | Linked to age |
| Number of dwellings | |
| Quality of construction | |
| Protected lobbies | |
| Provision of refuges | |
| Utility services (e.g. gas) | |
| Electrical installations | Age, type |
| Basements | Size, area, number |
| Waste storage |
Occupancy
| Factor | Additional Information |
|---|---|
| Occupants | Vulnerability, age, familiarity, condition, owner/rented, socioeconomics, ability to self-evacuate, number of occupants |
| Fire load | Use of common parts, storage of flammable/hazardous materials, normal contents |
| Level of occupancy | Density, number of occupied dwellings |
| Visitors (number, duration, familiarity etc) |
Building type
| Factor | Additional Information |
|---|---|
| Building use | Mixed use, purpose group, sleeping risk |
| Fire load | Use of common parts, storage of flammable/hazardous materials, normal contents |
| Building size/ area | |
| Ignition sources | |
| Visitors | Number, duration, purpose, familiarity |
| Process hazards | Industrial, commercial functions, e.g. commercial kitchen |
| Fire statistics | For relevant building type |
Means of escape
| Factor | Additional Information |
|---|---|
| Occupants | Vulnerability, age, familiarity, condition, owner/rented (impact of leasehold/rental status on ability to effect change), socioeconomics, ability to self-evacuate |
| Means of escape | Presence of alternative means of escape, ease of use |
| Alarm system | Type, coverage, maintenance |
| Building complexity | Including impact of layout/ access on users and FRS |
| Evacuation strategy | Several concerns with “stay-put” raised, link to occupant mobility/ capacity to evacuate |
| Number of stairs | |
| Level of occupancy | Density, number of occupied dwellings |
| Travel distances | |
| Ventilation/ smoke control | |
| Time to evacuate | |
| Visitors | Number, duration, purpose, familiarity |
| Protected lobbies | |
| Provision of refuges | |
| Emergency lighting |
Management
| Factor | Additional Information |
|---|---|
| Management | Staffing (including training, numbers, expectations), on-site monitoring, whether building operating as expected/originally planned |
| Evacuation strategy | Including provision of assembly point/ signage |
| Building condition | Link to age |
| Building records | Extent of records, compliance with Regulation 38 |
| Maintenance | |
| Overall fire strategy | |
| Implementation of fire risk assessment recommendations | |
| Security | |
| Resident concerns/ complaints |
Other
| Factor | Additional Information |
|---|---|
| Fire history | |
| Arson risk | Link to security/ management, location etc. |
| Community impact | Major or community infrastructure |
| Environmental impact | Link to location – proximity to water courses, etc…and building use |
The importance of height
14. Most respondents took the view that height is a significant factor, although height was assigned a range of importance. There was a clear view that other factors should be considered when determining building risk.
15. Several respondents noted that storey height could be used alongside a height threshold to reduce ambiguity around requirements (e.g. differences in measurement approaches) and to reduce the number of buildings built to be just below a height threshold.
16. Respondent answers could be summarised in the points below:
- that height can be a less significant risk factor than others, dependent on the specific building situation;
- that the importance and relevance of height is influenced by a range of other risk factors;
- that height influences the contribution of other factors to building risk.
17. There was a common view that the importance of height is influenced by a variety of other building factors such as type (the rarity of high-rise office fires was noted), use, occupancy, construction (attention was drawn specifically to construction impacting means of escape in several responses), AFSS, and others. Respondents often noted that risk would likely be higher in a low-rise building occupied by vulnerable residents with poor mobility than a general use high rise residential building. Although some responses noted that the status of occupants in general use blocks should not be assumed.
18. Height thresholds for fire safety provisions have historically been used to group the risk presented by factors that are affected by increasing height. Many of the respondents noted that height influences a large variety of other factors contributing to risk. This included that increasing height impacts on firefighting capacity, availability of alternative means of escape, often correlates with increased numbers of occupants (and subsequently fire load), and increased time to evacuate. Some respondents noted that increasing height would exacerbate the impact of a complex layout, inadequate fire stopping/compartmentation, and the potential contribution to fire of combustible building materials (due to the impact on firefighting capacity).
19. However, several respondents drew attention to Dame Judith Hackitt’s Independent Review of Building Regulations and Fire Safety and analysis of Home Office fire statistics which suggest height has a large impact on fire-related fatalities only when buildings have ten storeys or more.
20. Due to current prescriptions in the Building (Amendment) Regulations 2018 and associated statutory guidance (Approved Document B) regarding fire safety measures that are based on height thresholds, it was noted that increasing height also comes with features that could mitigate risk, such as sprinkler installation in residential buildings.
Approaches to assessing risk in existing buildings
21. Respondents were asked to provide innovative ideas and supporting evidence on approaches to prioritising different hazards within a building and for prioritising action between a group of buildings.
22. Respondents provided both general comments on recommended features of an approach to risk assessment and referenced to available methodologies or those in development. The methodologies raised are discussed below in no particular order.
Type 3 and 4 fire risk assessments
23. Several respondents referred to the Local Government Association guidance on Fire Safety in Purpose-Built Flats. Respondents noted that type 3 (common areas and flats, non-destructive) risk assessments should be adopted, with type 4 (common areas and flats, destructive) risk assessments required for “high-risk” buildings.
Fire risk indexing
24. Many respondents described approaches that would score and rank different fire risk factors to provide an overall building score or rating, which could be used to identify the most high-risk building in a portfolio. These methods are forms of Fire Risk Indexing.
25. Several respondents noted that such an approach could focus on risk factors related to means of escape summarised in the mnemonic MOCTET (Management, Occupancy, Construction, Time, Exits, and Travel distance). Others noted that such an approach should account for most if not all of the risk factors identified in their response to this Call for Evidence. Very few respondents provided information as to the weighting/score they would recommend for different risk factors.
26. It was noted that research would be required to rank/score any selection of risk factors for use in an indexing approach. Some respondents noted that this should consider the impact of the risk factor, related maintenance requirements, and historical performance/contribution to fires.
27. Several respondents discussed the development of a matrix of different risk factors to apply a “risk status” to a building following inspection and assessment by a competent professional. This approach would identify hazards to act on, and buildings requiring action, but on its own may not necessarily be able to assign a priority between two buildings in the same risk status, e.g. intolerable/high-risk.
28. Several respondents noted a Fire Risk Index approach could produce a publicly available report, similar to an Energy Performance Certificate (EPC). A number of respondents, including many from FRS, were in favour of a national database of some form noting the fire safety standard of buildings.
29. The single response from an academic noted that Fire Risk Indexing approaches are often rapid and cost-effective, although this is reliant on building information being available. It was also noted that ongoing research into different indexing approaches was highlighting the complexity of implementing such approaches and that this approach may not be appropriate where a more detailed approach is possible.
Fire service emergency cover
30. Several respondents referred to a toolkit provided to FRS by Her Majesty’s Inspectorate of Constabulary and Fire and Rescue Services (HMICFRS) called the Fire Service Emergency Cover (FSEC) Toolkit. This is used around the country as a risk assessment tool to help FRS align resources in a cost-effective way across different geographical areas.
31. The National Fire Chiefs Council, whose response was supported by multiple FRS respondents, described this approach as incorporating “census output areas, local historical incident data and socio-demographic factors, and multivariate analysis to enable geographic targeting of Community Fire Safety. It also considered historical incident data, plus the intervention activities, to establish the total dwelling fire risk level after intervention has been considered”. It was suggested that FSEC should be reviewed based on an up-to-date understanding of risk.
32. FSEC is based on a Fire Risk Indexing approach where buildings are assigned a risk score based on building type/use, a site assessment (resulting in scoring of fire safety measures and management), and the estimated probability of a fire occurring. In designating a risk score to a geographical area, the toolkit also considers an estimated value of property loss and total cost of resource allocation.
Bowtie method
33. One respondent referred to a risk assessment methodology developed by the University of the Fraser Valley and the University of British Columbia in Canada using a bowtie approach to analysing building risk. Bowtie analysis is used in various sectors to visualise and assess risk considering hazards and mitigating factors. It was noted by several respondents that any approach to prioritising action between buildings should consider both hazards and mitigating factors.
34. This methodology describes a fire risk assessment methodology applicable to residential buildings with multiple dwellings. The approach considers the probability and frequency of various scenarios such as arson, open fires, arson by children, heating, cooking, electrical cables, heat radiation from other sources, natural fires (e.g. lightning), and explosions/fireworks. The impact of protective measures such as sprinkler systems are considered and the impact of a fire scenario on people, property, environment and reputation is then considered before a final “risk level” is calculated for the building which prescribes whether action is required, and the degree of action.
Building information modelling
35. There were several respondents that recommended the adoption of Building Information Modelling (BIM) into a risk assessment methodology and noted they were aware of ongoing work in this area. BIM is a 3D modelling program that respondents suggested could provide a more holistic approach to building performance.
36. No further details on how BIM could be used in a risk assessment methodology was provided and one response noted that the application of BIM to existing buildings could be hampered by poor records of construction and modifications since completion of the original building work.
Exterior Façade Fire Evaluation and Comparison Tool (EFFECT)
37. One respondent recommended use of the EFFECT tool which assesses the risk from external wall systems and is available for public use, although this is currently designed only for buildings over 18m in height. The respondent noted that data was available to expand this tool to buildings below 18m. Another respondent recommended the tool be reviewed for use in the UK.
38. The Call for Evidence paper noted that the Department was already aware of EFFECT which may have reduced the number of respondents identifying the tool as a potential approach.
KRESNIK
39. One respondent referred to KRESNIK, a statistical approach to determining façade fire performance based on 252 commercial façade fire tests.
RIDGE
40. One respondent raised ongoing research in adopting RIDGE methodology to building safety questions, although provided no further detail. This is an approach developed to make risk predictions where the number of events to draw evidence from is low. This has previously been developed for healthcare settings to make predictions based on patient characteristics.
Building Fire Performance Evaluation Methodology
41. One respondent recommended the use of the Building Fire Performance Evaluation Methodology (BFPEM) to appraise the risk profile of a building. This approach was published in 1999 following development from an original approach in the USA some 20 years earlier and adaptation to the British regulatory context.
Victoria Building Authority Cladding Risk Assessment Tool
42. One respondent noted that in response to a fire involving aluminium composite material cladding in Melbourne, the Victorian Building Authority in Australia had developed a risk assessment tool to assess dangerous cladding and prioritise remedial works.
43. This approach is described as a “starting point to better understand the elements of a building that contribute to the risk of a cladding fire” and requires assessment by an expert panel and an on-site inspection.
General comments
44. General comments were provided by many respondents on the style and approach of any risk assessment approach that was to be developed by government. These comments included:
- Consideration should be given to international approaches;
- Any approach should stick to straightforward questions with a quantifiable answer;
- A British Standard could be developed or a national fire risk assessor register recording third party building type-specific accreditation to ensure national standardisation;
- Ensuring a “golden thread” document and compliance with Regulation 38 over a building’s lifetime would be essential for proper application of any methodology;
- Approaches should be systematic and require management systems to reduce subjectivity;
- Consideration should be given to developing national mapping of building information for FRS use;
- Risk classifications should be adaptable so they can be updated.
Areas for further research
45. Almost all respondents proposed further research into the risk factors previously described in response to this Call for Evidence. This could provide a broader understanding of different factors contribution to building risk and underpin the prioritisation of different factors within a building for improvement, or the prioritisation of action between different buildings. Factors that were highlighted by many respondents included:
- Occupancy;
- Evacuation strategies and means of escape provisions;
- Height;
- Construction materials and maintenance/resilience of components;
- Compartmentation;
- Detection and alarm systems;
- AFSS;
- Smoke control;
- Modern fire load and fire growth;
- Management;
- Building age.
46. Many respondents suggested areas of research that are already planned under the overall technical review of Approved Document B such as: compartmentation, fire resistance, places of special fire hazard, specialised housing and care homes, toxicity of building components, means of escape, resident behaviour, evacuation procedures, purpose groups, and modern FRS operational capacity.
47. The following research areas were also suggested:
- Testing methodology for building components;
- Realistic timelines for FRS action in high rise buildings;
- Protective benefits of 24/7 staffing/on-site management;
- How window design could be improved to prevent “break out”;
- Effectiveness of personal emergency evacuation plans (PEEPs);
- Impact of building access on FRS operational capacity;
- Fire risk reduction strategies;
- Review of fire case studies to identify common causes of fire, morbidity and mortality during fire;
- Compilation and assessment of Fire Safety Audit and other inspection data gathered by the FRS;
- Review of relationship between other (environmental, food safety, etc…) inspection data and fire safety management/performance;
- Failure rates of passive/active fire safety measures.
48. We will continue to use the responses to the call for evidence, together with other insights to inform the continuing policy development work in this area.