40 King Street is an existing 100-year old eight storey office building in central Sydney. Due to a proposed major refurbishment, the building had to comply with the requirements of the current Building Code of Australia. The existing concrete slabs within the building could not comply with the current concrete code requirements due to insufficient concrete cover to the reinforcing bars. To upgrade the existing slabs to comply with the current code requirements would involve the addition of passive fire protection to the slab soffit; this would not only have been costly but time consuming and would damage the existing heritage fabric of the building.
Holmes Fire carried out advanced analyses to determine the inherent fire resistance of the existing slab. The analysis demonstrated that the existing slab had enough inherent fire resistance to withstand a realistic fully developed fire, thereby negating the requirement to apply additional passive fire protection or to thicken the slab to meet the prescriptive requirements of the Code and Standards. This provided significant cost savings to the project and minimised disruption to the fabric of the existing building.