Introduction

1 Shelley Street in Sydney is a landmark commercial building within the city’s bustling CBD, offering premium office spaces over multiple levels, with an interconnected atrium space that creates a dynamic, open-plan environment. As part of a major asset upgrade project commissioned by Charter Hall and managed by Solutions Consulting, the building required a fire safety solution that could address the inherent design challenges of the existing structure while maintaining compliance with the National Construction Code (NCC) 2022 and the building’s base Fire Engineering Report (FER) prepared by Arup in 2008. MCD Fire Engineering was engaged to prepare a comprehensive Fire Engineering Performance Solution Report (FER) to address various Deemed-to-Satisfy (DtS) non-compliances identified in the BCA Assessment. One of the critical fire safety issues was the requirement to provide a compliant fire separation at the top of the escalator void between the Ground Floor and Level 1. The original FER specified the use of FireMaster Concertina™ fire curtains as the approved solution. However, detailed site investigations during design development revealed that the existing building structure did not have the capacity to accommodate the Concertina system.

This presented a significant challenge: the fire separation was an essential life safety measure under the Performance Solution strategy, and without a compliant system, the project could not achieve certification. A conventional solution was therefore not viable, and a bespoke alternative had to be developed urgently, ensuring it met all fire safety performance requirements while integrating seamlessly into the building’s architectural and services design.

The Challenge

The fire safety objective was clear: to maintain the integrity of the building’s fire compartments, specifically the atrium separation at the top of the escalators, as part of the approved FER strategy. The solution needed to ensure compliance with critical performance criteria, including fire resistance levels (FRL) of at least -/120/-, smoke containment, obstruction detection, fail-safe operation under emergency conditions, and seamless integration with the building’s essential services, including the Emergency Warning and Intercommunication System (EWIS) and Building Management System (BMS). The complexity of the challenge stemmed from several factors. Firstly, the spatial constraints within the existing atrium ceiling void limited available fixing points, restricted access for maintenance, and reduced clearance for system deployment. Secondly, the building’s high foot traffic at the escalator interface demanded a solution that would not compromise egress during normal operations yet could rapidly provide fire separation when activated. Thirdly, the solution had to accommodate the building’s architectural features, such as ceiling finishes, lighting layouts, and mechanical services zones, all while ensuring compliance with the intricate requirements outlined in the FER, including smoke detection, obstruction detection, audible and visual warning systems, and power supply resilience.

The Greene Fire Approach

Greene Fire’s engineering team undertook a detailed review of the FER, the BCA compliance pathway, and the structural limitations of the site. This collaborative process involved close engagement with MCD Fire Engineering, the project’s fire engineers, as well as the client team and builder Buildcorp. The review confirmed that a performance-based design alternative was the only feasible pathway. The proposed solution replaced the originally specified FireMaster Concertina™ curtains with a custom-designed system comprising multiple direct-fixed FireMaster fire curtains. Each curtain was designed and engineered to match the specific dimensions of the escalator void and its surrounding architectural features. Six individual FireMaster curtains were specified, each tailored to precise width and drop requirements, ranging from 7.7 metres to 10 metres in width and 2.9 metres in height. These curtains were integrated into the atrium soffit, requiring careful coordination with the ceiling grid, lighting, and mechanical services to avoid clashes and ensure full, unobstructed descent during activation.

System Design and Integration

Beyond the physical curtain assemblies, Greene Fire’s solution incorporated a robust control and safety system to satisfy the stringent operational requirements outlined in the FER. This system included two ERU6 grouped control panels, each with integral battery backup to ensure continued operation during a mains power failure, providing a minimum two hours of standby power as required by the performance criteria. The control panels interfaced with six strategically located obstruction detection sensors recessed within the ceiling void. These sensors continuously monitor the descent path of each curtain, triggering an audible and visual alarm if an obstruction is detected for longer than a predetermined threshold, ensuring that the system does not deploy onto an object that could prevent full closure. In such an event, localised voice warnings sound an automated message instructing occupants to remove the obstruction, with the system ceasing the alarm once the path is cleared. Six visual light warning devices were installed adjacent to each curtain to provide additional visual cues during curtain deployment, enhancing safety for building occupants. Two voice warning systems were provided. An emergency retract button was incorporated at the escalator landing to allow occupants in the immediate vicinity of the curtain deployment zone to temporarily retract one curtain, enabling safe egress. This feature was specifically designed to satisfy the FER’s requirement for maintaining a minimum 1-metre clear width for path of travel adjacent to the fire curtain during operation, accounting for potential curtain distortion due to smoke control pressures. The system was also designed to interface with the building’s smoke detection network, with detectors installed within 1.5 metres on each side of the curtains, ensuring immediate activation on smoke detection within the atrium. The system’s sequence was programmed to ensure the fire curtains deploy prior to the activation of the smoke exhaust system, avoiding pressure differentials that could affect curtain operation. This precise sequencing was confirmed during commissioning and recorded as part of the baseline essential fire safety measures for the building.

Outcome and Certification

The final solution was rigorously reviewed and validated by MCD Fire Engineering, who confirmed that the design met the performance objectives of the NCC and the FER. The building certifier, Group DLA, subsequently approved the solution as part of the Construction Certificate process. The outcome delivered by Greene Fire not only addressed the complex technical and spatial challenges of the site but also provided a more economical and streamlined solution than the originally specified system. This case study exemplifies Greene Fire’s ability to deliver innovative, performance-based fire safety solutions tailored to the unique constraints of complex commercial buildings. The project demonstrates the critical importance of close collaboration between fire engineers, contractors, and system specialists in resolving design challenges and ensuring safe, compliant, and cost-effective outcomes for clients.

Conclusion

The successful delivery of the fire curtain solution at 1 Shelley Street reinforces Greene Fire’s position as a trusted partner for complex fire safety projects, particularly where performance-based solutions are required. By adapting a highly specialised fire protection system to meet the specific demands of the site, Greene Fire ensured the safety of occupants while supporting the broader architectural vision of the asset upgrade. This project underscores the value of expertise, flexibility, and problem-solving in the fire safety industry, principles that continue to guide Greene Fire’s approach to every project.