NCC Version:
NCC 2022, Volume One
Area of NCC Requirements:
Part G3 - G3.8
Problem:
A mezzanine addition was proposed to an existing tenancy. However, due to the building’s original warehouse design and structural constraints, the mezzanine level did not meet the minimum 2.4 m ceiling height, nor did it provide adequate natural light and ventilation in accordance with Deemed-to-Satisfy provisions. This raises compliance concerns regarding its classification, whether it constitutes a separate storey, and the adequacy of fire safety and egress provisions.
Solution:
A Performance Solution was developed to justify the reduced ceiling height and limited natural light and ventilation. The justification included reference to the space being used for non-habitable purposes (like storage or display), ensuring mechanical ventilation to compensate for lack of natural air, and confirming safe access and egress. The mezzanine is accessed via a stair constructed in accordance with NCC Part D2 (safe movement and egress), and two compliant exits are provided to meet travel distance and occupant load requirements.The solution demonstrated that the mezzanine, as designed, would still achieve the NCC Performance Requirements.
Finalised Report:
A Performance-Based Design Report was issued confirming that the proposed mezzanine design satisfies the relevant NCC 2022 Performance Requirements through a Performance Solution approach, despite not complying with certain DtS provisions.