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CROSS Safety Report

Concern over the quality of a fire safety design submission

Report ID: 1029 Published: 17 November 2022 Region: CROSS-UK


A Building Control Officer is disquieted by the quality of a design submission and the approach of a fire engineer in assessing structural fire matters.

Key Learning Outcomes

For fire engineers:

  • Designers ought to understand the limits of their knowledge and work within them
  • Fire safety designs should take into account all aspects and objectives of fire safety, holistically
  • The fire engineer should consider the evacuation capabilities of all occupants expected to use the building as part of a Fire Engineered solution

For Building Control Officers:

  • Ensure that fire engineered solutions cover sufficiently all design objectives
  • Consider requesting a third-party peer review by a competent professional

Full Report

Find out more about the Full Report

The Full Report below has been submitted to CROSS and describes the reporter’s experience. The text has been edited for clarity and to ensure anonymity and confidentiality by removing any identifiable details. If you would like to know more about our secure reporting process or submit a report yourself, please visit the reporting to CROSS-UK page.


The reporter is a Building Control Officer and they review fire safety designs. This report is about a submission for a project in which an existing building is being incorporated into a very large new building. The concern was raised from the fact that the justification of the solution provided was deemed by the reporter inadequate and lacking consideration of fundamental concepts.

The reporter was alarmed because the expected structural fire performance of the existing structure, or any fire resistance rating, were unknown and yet this issue was left unaddressed by the designer. In contrast, the requirement in technical guidance for the new development was a fire-resistance rating of 120 minutes, in terms of resistance (R), integrity (E), and insulation (I). Additionally, there was no separation provided between the old and the new structure. Finally, without any explicit consideration or rationale for the decision, suppression was not being extended to the existing part. 

The analysis and justification provided by the fire engineer was only the conduction of an RSET analysis (Required Safe Egress Time) for occupants, which demonstrated evacuation of the building after 6 minutes.

fundamentally...does not understand the structural performance of a building in a fire

The reporter considers that this not only fails to acknowledge the evacuation of persons with reduced mobility, but also fundamentally shows that the fire engineer does not understand that the structural performance of a building in a fire (usually addressed through fire resistance ratings) also contributes to other aspects than means of escape, such as compartmentation to address internal fire spread, the potential for external fire spread, and any concerns related to firefighter safety and persons around the building.

This occurrence demonstrated to the reporter that the designer attempted to address the design process inadequately, and that “it is happening frequently and makes me question the competence of fire engineers in assessing structural fire matters”.

The reporter is disquieted because had such a submission been accepted, then a very large building could have been constructed with a lower resistance to structural failure when exposed to fire, increasing the probability of structural collapse in case of a fire event.  

They think that fire engineers should acknowledge the limits of their knowledge and consult with other parties where and when necessary, highlighting for this specific case that fire safety is not just about the provision of means of escape but satisfying a breadth of fire safety objectives.

Expert Panel Comments

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Expert Panels comment on the reports we receive. They use their experience to help you understand what can be learned from the reports. If you would like to know more, please visit the CROSS-UK Expert Panels page.

The issue of design submissions and their quality has been touched upon in past CROSS reports, focusing on issues of structural safety, namely report 14 and report 65

Unfortunately, this has been noted as an all too common approach where 'fire engineering' (a term loosely used in this specific case) is employed to create an ASET/RSET analysis as a means to justify the consideration of life safety only of the occupants, and then as the reporter states, does not consider those that may need assistance or other design objectives. A fire engineered solution is not just an ASET/RSET analysis, and the fire engineer should consider the evacuation capabilities of all occupants expected to use the building as part of a fire engineered solution. This incident could potentially be perceived by some as intentional, an example of unethical practice, and an excellent example of the need for culture change.

failing in understanding the holistic nature of the functional requirements

The report showcases a complete failure to understand the holistic nature of the functional requirements. The lack of competency exhibited by the fire engineer in not carrying out a holistic analysis of how the proposed development could worsen the fire safety condition with regard to all of the functional requirements of Part B of the Building Regulations, and proposing mitigating solutions to meet Building Regulations requirements, is worrying.

The panel is happy to hear that the building control body (BCB) refused the application while acknowledging the eventuality that this could in some other circumstances potentially be 'accepted'. This of course relies on the BCB having the time, support, resources, understanding, and skills to question and interrogate thoroughly the proposals. A proposal from a fire engineer should ideally never be accepted without question, especially when the proposal has not been subjected to a third-party peer review by a competent person. 

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