Building regulations - proposed review of fire safety topics: analysis of responses

3. Hidden cavities, voids, workmanship age and variations from standards

The Expert Panel’s approach to addressing recommendation five of the FAI has been to review the guidance for existing hotels and similar premises and the relevant standards and guidance contained in the Non-domestic Technical Handbook (NDTH).

This chapter addresses various recommendations by the Expert Panel about existing guidance, such as to retain existing guidance or to suggest revisions. For more details on each specific proposal, please refer directly to the consultation paper.

Q5. We propose that the wording of paragraph 2.4 of schedule 5 of the Building (Scotland) Regulations 2004 does not require to be amended. Do you agree or disagree? Provide reasoning for your answer.

Of those answering Q5, 14% strongly agreed and 69% agreed with the proposal (84% combined), while 6% were opposed and 11% were neutral.

Over half of all respondents left a comment explaining their answer. The main theme was agreement with the proposal, though less mentioned themes included suggested changes relating to cavities or regarding the phrase ‘reasonably practicable’.

Agree, amendments are not needed

Many respondents, almost half of whom were local authorities, agreed that the wording of paragraph 2.4 did not need to be amended. Reasons included that it was adequate, that the scope and intent of the standard were clear, and that wiring would be upgraded as part of a conversion, so the risk of cavity fires is low.

“This definition is clear and succinct. There is no need to change it.” - The Fire Sector Confederation

Suggested amendments on cavities/voids

A range of comments on voids were given by some. These acknowledged difficulties in identifying hidden cavities or voids in existing buildings and suggested mitigating actions or amendments to the guidance. These included:

• Highlighting the risks of hidden cavities or voids, such as concealed fires being difficult to detect and therefore suppress.
• Requiring alternative mitigation measures to be put in place if cavities cannot be confirmed to meet regulations, such as reduced travel distances to escape routes upon an outbreak of fire, enhanced detection or water mist systems to fill the cavities.
• Recognising that it can be challenging to investigate existing construction in listed buildings to identify cavities and the cavities being fire stopped as required to prevent movement of smoke and fire.
• Adding the following wording, after the word ‘inhibited’ in paragraph 2.4: ‘to the cavity SCE performance standard of its building risk assessment’.

Clarify ‘reasonably practicable’

A few respondents felt that the term ‘reasonably practicable’ set out in Schedule 6 could be further clarified or qualified. Suggestions included outlining where additional costs may be unreasonable, highlighting situations where an existing hazard may present an intolerable risk if additional measures are not put in place, and acknowledging that someone with appropriate skills, knowledge, and experience should address specific considerations for heritage properties.

“Currently for conversions, the building as converted shall meet the requirements of this standard in so far as reasonably practicable, and in no case be worse than before the conversion. If this is to be applied to conversions, regulations 12, schedule 6 will have to be changed to compliance with the mandatory Standards from the current requirement as ‘no worse than before the conversion’.” - Individual

Other comments

A few respondents made other comments, such as the need to encourage the use of innovations such as cavity barrier technologies, Ground Penetrating Radar surveys, or echo-location scanning. The need to revise guidance in line with recommendations from an expert panel was also raised, as was the suggestion to target guidance at the building owner, designers, and relevant persons to ensure a robust approach prior to the submission of any building warrant application.

Other amendments were suggested by a few. These were to define the word ‘inhibited’ and set performance standards for it based on the risk assessment for higher-risk buildings, to include the Barrier principle of SCEs, and to highlight risks from poor workmanship, ageing materials and variance from standards.

“We believe that the non-prescriptive wording used in schedule 5 of the Building (Scotland) Regulations 2004 leaves much room for interpretation and therefore can result in variations in the application of the standards, thus leading to significant discrepancies in the fire safety of buildings. However, changing the functional requirements given in Schedule 5 of the Building (Scotland) Regulations 2004 would require significant and complex changes to the regulations, which may best be addressed separately to this consultation.” - Rockwool Ltd.

Q6. The Scottish Government publication Fire safety guidance for existing premises with sleeping accommodation (2022) is currently being reviewed. Please provide any comments on the guidance in the text box below with regard to the special risks which existing hotels and similar premises may pose through the presence of hidden cavities or voids, varying standards of workmanship, age, and the variance from current standards (Recommendation 5 of the Cameron House FAI).

Almost two thirds of all respondents left comments on the guidance in relation to the special risks posed. The most prevalent themes were suggested changes to the guidance, the need to address risks and comments on cavities/voids.

Suggested changes to the guidance

Several respondents suggested changes to the current guidance. Topics any review should consider were highlighted, such as:

• Special risks faced by existing hotels and similar properties.
• Inspections for hidden fire hazards.
• Retrofitting and upgrading systems to meet current fire safety standards.
• Poor workmanship and aging materials.
• Fire prevention, evacuation and compartmentation.
• Suppression systems and their benefits and protection methods.
• Restricting the spread of fire and smoke.
• Providing site-specific fire safety protocols addressing the fire risks of each building.

Other views varied but included suggestions to:

• Ensure any review keeps abreast with, and can support, potential changes to standards and guidance through alignment with other policies and guidance.
• Better define guidance on insulated core panels given the ‘various’ insulation types can range from non-combustible to highly combustible (Chapter 6, Clause 192).
• Remove perceived outdated references to Category 0 and 1 in Chapter 6, Clause 195, and replace with the BS EN 13501-1 classification.
• Clarify when EN 12845 or BS 9251 is to be used.

“Chapter 6, Clause 192 - Guidance on insulated core panels (sandwich panels) could be better defined as the 'various' insulation types can range from non-combustible to highly combustible and there are both British Standard tests and insurance testing which can be used to demonstrate levels of safety for these products and this document would benefit from a better understanding of the hierarchy of performances available, instead of the current generic summary.” - Building Systems UK (A Tata Steel Enterprise)

Guidance must address the risks

Addressing the special risks in any guidance was recommended by several respondents. Aspects suggested for inclusion were highlighting risks, acceleration of remediation to address existing risks, including a case study on managing risks, addressing concerns around firestopping and cavity barriers, and the role of risk assessments. One organisation recommended that the industry be financially supported to help minimise risks. Historic Environment Scotland (HES) noted how they had incorporated information about fire risks into their guidance on managing fire in historic buildings:

“Our ‘Managing Change in the Historic Environment: Fire and Historic Buildings’ guidance (2023) provides advice about fire safety and fire damage in historic buildings. Part 1 details the specific fire risks present within historic buildings such as the nature of the building, including its age, history of adaptations, and use of combustible materials. It also outlines the key considerations for decision-making, including the relevant policies, consents and permissions, and can help to mitigate the impacts of potential changes on cultural significance.” - HES

Comments on cavities and voids

Several respondents commented on aspects the guidance should cover concerning hidden cavities and voids to help address their fire risk. Singular points included:

• To require the use of cavity barriers during conversions, or if omitted, to require significant justification.
• Linking suppression systems to the smoke and fire risk through voids in the context of the type of buildings covered by the consultation.
• The view that guidance will not do much to mitigate unknown risks, such as poor workmanship or hidden voids.
• Recognising that modular construction can have specific risks, such as 3D modules that may have voids that can create unseen travel paths for fire and smoke.

One respondent recommended noting the expertise of hotel owners and developers who have experience dealing with hidden cavities and voids.

Comments on workmanship and ageing materials

Risks with varying standards of workmanship or materials were raised by some, with suggestions given to mitigate these risks. These included ensuring assessors are suitably qualified and experienced, improving workforce skills and capacity, improving collaboration between installation contractors on projects, periodic inspection and testing during construction and greater attention to the need for detailed specifications.

“SFRS and other fire and rescue services can cite numerous examples where poor construction has resulted in unexpected fire spread and premature building failure in the event of a fire. The primary responsibility for addressing this lies with the construction industry. However, one of the key failings is the interaction between contractors installing different elements of construction, sometimes resulting in unintended consequences and failures. Therefore, periodic inspection and testing during the construction process, particularly to check elements of construction that will be hidden in the final building, is vital.” – SFRS

Q7. Although planned for review it is proposed that the principles set out in current HES guidance remains suitable guidance for special risks which existing hotels and similar premises may pose through the presence of hidden cavities or voids, varying standards of workmanship, age, and the variance from current standards (Recommendation 5 of the Cameron House FAI). Do you agree or disagree? Provide reasoning for your answer.

The consultation paper notes that guides from Historic Environment Scotland aim to provide advice regarding the application of the Building (Scotland) Regulations 2004 to the conversion of traditional buildings, briefly outlining each.

61% of respondents answering Q7 agreed with the proposal, while 3% strongly agreed with it (64% in total). A further 33% were neutral, and 3% disagreed. While no organisations disagreed with this proposal, 34% were neutral.

Half of all respondents left an open comment to explain their answer. The most prevalent views highlighted differing opinions between those who believe the existing guidance is adequate and does not need updating and those who believe a review is needed.

No change needed

Some respondents agreed that the current HES guidance is sufficient and may not need to be changed, though respondents tended not to comment on whether a review should be undertaken. It was felt that the guidance remained suitable and relevant and should be used in conjunction with other referenced standards.

A review is needed

Support for a review was expressed by some respondents. Views included that an update was overdue, particularly considering recent fires in traditional buildings and innovations in the area, that there should be an increased focus on suppression systems, and that a manufacturing survey could help identify new products that could be applied. A few noted that a review may identify no changes being required.

Clarify for the workforce

Comments that the guidance should help the workforce address the special risks were provided by a few respondents, such as enabling a better understanding of how a proposed change will impact historic or traditional buildings or helping designers deal with challenges. One felt a refined definition of ‘hotel’ would assist the workforce to gain clarity, while another thought appropriate and specific advice would be needed to accompany written guidance.

Stakeholder engagement is needed

A few respondents felt that raising awareness of any guidance changes would be needed, such as with building owners and operators. One organisation felt a separate consultation was required to address key aspects such as alignment with best practices and policies, and with guidance on deteriorated building materials and the use of traditional buildings as sleeping accommodation.

Q8. We propose to change the guidance in the Non-domestic Technical Handbook to recommend cavity barriers at 10m or 20m centres above fire resisting ceilings depending on the European classification for reaction to fire (A-F) of the surface exposed in the cavity. This provision would not apply to small floor or roof cavities above a fire resisting ceiling that extends throughout the building or compartment up to a maximum of 30 m in any direction. Do you agree or disagree? Provide reasoning for your answer.

Of those answering Q8, 14% strongly agreed and 53% agreed (67% in total) with the proposed changes, while 8% disagreed. A quarter (25%) neither agreed nor disagreed with the proposed changes.

Over half of all respondents commented to explain their answer. The main themes were reiterating agreement and the need for more clarity or work on the proposal.

Agreement

Several agreed with the proposed change to guidance, mainly because it would enhance safety. For instance, cavity barriers could help prevent the spread of fire. A few caveated that the proposal should not result in lower safety levels than existing building standards.

“We support an enhancement of cavity barriers to prevent fire spread to other parts of a building affected by fire. Fire suppression is part of a system of fire safety. Experience tells us that cavity barriers are frequently breached during building works affecting compartmentation and therefore this does not in any way negate the need for fire suppression.” - British Automatic Fire Sprinkler Association

More clarity or work is needed

Some respondents called for more work to be done on this proposal. A range of views were expressed, generally seeking further detail to allow a considered response. In terms of the topic, suggestions included considering what the cavity barrier is fixed to and its fire resistance, whether sufficient space exists to install a cavity barrier, defining ‘practitioners’ and expected competencies, and acknowledging that subdivision of cavities above fire resisting ceilings may be of limited benefit in buildings with AFSS. Other areas where it was felt further definition or work was needed included:

• Reasoning behind the proposal and clarity of intent.
• The effectiveness of the proposal to be considered by fire safety experts.
• To better understand the implications for traditional interiors, particularly where the ceiling itself was of cultural significance, e.g. ornamental plaster or painted.
• To review costs to the industry to meet this requirement.
• To assess the level of enforcement required to ensure obligations are met.

“The consultation does not appear to provide sufficient detail of why this specific recommendation is being put forward. On the one hand it appears to be in support of repurposing properties with extensive voids into hotel and on another it appears to be contrary to the comments made in the consultation document. We note that the proposal appears to follow the guidance of other devolved government documents. However, those requirements sit within a broader context of cavity barriers, tighter controls on reaction to fire ratings and therefore cannot alone be the reason to support this proposal. As acknowledged in the consultation there is no redundancy if the fire resisting ceiling is breached. The wording of small roof or wall cavities is imprecise. There needs to be some level of detail to this caveat. We can see that mandating the provision of sprinklers and/or other suitable suppression systems could provide that redundancy for the general case. Outside of this, the detail is not clear enough to conclude.” - The Fire Sector Confederation

Other comments

Two respondents felt cavity barrier installation should be required for all conversions due to the potential for hidden fires. One felt the proposal was in line with provisions in England and Wales. One fire engineering organisation, which was neutral about the proposal at the closed question, commented:

“The fire resisting ceiling is understood in this context to be an alternative to the provision of cavity barriers in line with compartment walls (often used should it be difficult to provide cavity barriers). If this is the case, and cavity barriers are to be required above the fire resisting ceiling, then there may be little benefit in providing the fire resisting ceiling in terms of buildability. Should the cavity be free from combustibles and ignition sources there would be limited benefit to providing cavity barriers. It is understood that this provision is intended to allow redundancy of fire safety systems in case the fire resisting ceiling fails but this type of secondary provision is not required elsewhere.” - OFR Consultants

Q9. It is proposed that the additional guidance indicated in option 2 of question 1 (clause 2.1.9 of the consultation), on identifying risk and implementing proportionate mitigating measures, be included within clause 2.0.7 (alternative approaches) and clause 2.15.7 (Conversion of traditional buildings to hotel use) of the Non-domestic Technical Handbook to strengthen and add to existing guidance. Do you agree or disagree? Provide reasoning for your answer.

Of those who answered Q9, 27% strongly agreed and 57% agreed with the proposed changes at Q9 (84% in total), including all individuals. Of the remainder, 3% were opposed, and 14% neither agreed nor disagreed with the proposal.

Over six in ten of all respondents left an open comment to explain their answer. The most prevalent themes were agreement with the proposal, concerns that guidance should, or that more clarity is needed.

Agreement

Wide-ranging support was given by many respondents to the proposal. Support was expressed for the revised wording, as well as the need for additional information to support the workforce involved in conversions. For instance, it was felt that the proposal would assist designers and verifiers in assessing the suitability of different fire safety systems, improve risk assessment knowledge, prevent further incidents, and promote information and data sharing between professionals.

“Change should be mandated within the guidance to prevent further incidents occurring. The above text provides additional guidance which allows building owners to understand the key risks associated with the conversion of traditional buildings should an alternative approach be identified as appropriate.” - Arup Fire

Aspects the guidance should address

Many respondents identified aspects they felt the guidance should address or identified perceived challenges in this area. Suggestions included, in order of prevalence:

• Practical solutions: put more emphasis on installing suppression systems, minimising the impacts of proposed change on the cultural significance of a traditional asset, determining possible measures when AFSS is not suitable, and mandating the installation of fire prevention measures even where AFSS is not appropriate.
• Cross-referencing with policies: using the ALARP assessment methodology commonly used by those dealing with Major Accident Hazards and ensuring the proposed guidance ‘Fire Safety in Traditional Buildings for Duty Holders’ addresses these issues. One respondent noted the only reasonably practicable standards in Section 2 are 2.2, 2.4, 2.6, 2.7, 2.8 and 2.12.
• Skills and expertise: ensure those involved in design, installation and verification have appropriate training, knowledge and expertise to be aware of, and respond appropriately to, the risks involved.
• Enforcement: Addressing challenges associated with enforcement, ensuring mitigating actions are taken for buildings with extensive voids, such as recognising these may not be suitable for sleeping accommodation.

More clarity needed

Some respondents called for more detail or clarity on the proposals. In order of prevalence, suggestions included:

• Adopting a prescribed process for ‘reasonably practicable’ as it is open to interpretation and to avoid inconsistencies.
• Avoiding loopholes by setting minimum standards to prevent lesser standards from being accepted due to improvements being deemed disproportionate.
• The need to update the Guide for Practitioners 6, which was considered out of date and refers to superseded versions of BS 9251 and other standards.

Two respondents highlighted challenges to achieving higher standards for all conversions, notably that the Scottish Fire and Rescue service may be required to highlight risks and request that hotels continue to be occupied as part of their annual checks on these buildings. Another called for changes to a traditional building to be carefully considered, possibly requiring specific permissions and special technical advice.