Fire strategy challenged at BSA Gateway 2

You are the architect and Principal Designer under the Building Safety Act 2022 on an 11-storey residential scheme of 64 flats for a private build-to-rent client in Birmingham. The building is unambiguously a higher-risk building under section 65 of the BSA 2022 (at least seven storeys or eighteen metres, containing at least two residential units). Construction is due to start in March 2027. The Gateway 2 application was submitted to the Building Safety Regulator on 1 September 2026 with a full plans set, a fire strategy by an independent fire engineer, structural calculations, and signed compliance declarations from the Principal Designer and Principal Contractor. The eight-week target determination period under regulation 13 of the HRB Procedures Regulations 2023 has elapsed without a decision. On 27 October 2026 the BSR wrote to you (as Principal Designer) requesting further information under regulation 14. The BSR's queries are substantive. First, the fire strategy specifies a mechanical smoke extract system in the single internal stair lobby on each floor, on the basis that natural ventilation could not be achieved given the floor plate. The BSR's review notes question whether the mechanical solution provides equivalent safety to the natural ventilation route preferred in Approved Document B Volume 1, and request justification by reference to BS 9991:2024 and the fire engineer's modelling assumptions. Second, the BSR has queried the use of cross-laminated timber as a secondary structural element at podium and amenity levels, asking how the proposal complies with regulation 7(2) of the Building Regulations 2010 (restriction on combustible materials in external walls and specified attachments). Third, the BSR has questioned the fire engineer's competence, noting that the Engineering Council register entry does not list a recognised fire safety qualification. The client's development director telephones you the same afternoon. The funding agreement is tied to a March 2027 construction start. The director instructs you to "push back hard" on every BSR query, says the fire engineer is their long-standing consultant and will not be removed, and warns that if the BSR is not satisfied within two weeks they will move the Principal Designer appointment to a competitor. The fire engineer, when telephoned, dismisses the BSR's concerns as "box ticking".