The five year, £750m redevelopment of Birmingham New Street was one of the UK’s largest and most complex redevelopment projects in recent times. It involved integrated refurbishment of the train station in central Birmingham – the busiest interchange station in the UK – 43 shops at concourse level and the new Grand Central shopping complex above, housing one of the UK’s largest John Lewis department stores.
Designed in the 1960s, the railway station was operating at double its intended capacity by 2010 and needed upgrading. All construction work for the redevelopment needed to be undertaken whilst maintaining the operation of the train station and shopping centre. This introduced significant risk to what was already a challenging project due to the high density environment, complex construction phasing programme and large number of works areas.
Fire risks during construction were considerable. Property protection and business interruption risks were key considerations as false alarm activations and subsequent evacuations of the station would have resulted in substantial costs and penalties.
The involvement of Arup’s fire engineering team was integral to the successful completion of the project. Our work involved supporting Mace (the principal contractor) to meet the relevant fire safety legislation and regulations, together with the operational requirements of the site management, station management and shopping centre management teams. We also enforced fire safety practice on site.
However, Arup’s fire engineering support extended far beyond pure compliance. Our specialist team developed a dynamic fire safety strategy that enabled a 24 hour working environment.
The team was permanently based on site throughout the five year construction programme and gained trusted advisor status with key project stakeholders such as Mace, Network Rail, Birmingham City Council and West Midlands Fire Service. Given that the train station and shopping centre remained operational throughout construction, reassuring these stakeholders that all risks had been considered and mitigated was the only means of progressing construction work.
This complex, city centre project of integrated redevelopment and construction above a live, continuously operating railway station was completed, without fire incident, in September 2015.
We also provided other specialist technical services such as a pedestrian assessment, glare assessment and a review of façade details.
Arup’s dynamic fire safety strategy was central to the successful completion of this project. Our role was to ensure that temporary fire safety arrangements were suitable and sufficient for the densely occupied building and that the station had the capability to manage an evacuation in accordance with the objectives of the Fire Risk Assessment (FRA).
Throughout the project lifecycle Arup provided over 400 FRAs. Each FRA assessed the suitability of the fire safety systems provided and detailed required changes to the evacuation management procedures. As part of this process we undertook third party witness testing of the operation of fire safety systems in the event of fire alarms. This enabled us to provide reassurance to stakeholders that fire safety systems could be relied upon to operate as required under the FRA process. Crowd management was also integral to FRA measures as it was required in order to manage, direct and restrict the flow of people during events, holidays and other peak travel times.
Arup proposed both practical management and temporary mitigation solutions. These included providing advice around the phasing of construction work, producing guidelines such as no ‘hot’ work such as welding on platforms, restricting the use and amount of flammable materials on platforms at any one time and educating sub-contractors on fire safety.
In order to keep to programme and reduce life safety risks to an acceptable level, Arup had to fully understand the station emergency response procedures and communicate the mitigation measures and changes required to all responsible persons.
Visualisation and modelling
Visualisation techniques and modelling were not only vital in successfully engaging with stakeholders who were not fire experts but also to test calculations. Arup created a 3D model of the entire station, concourse and shopping centre. The modelling was dynamic as it had to respond to the changing structure and risks during construction. It included Computational Fluid Dynamics (CFD) and pedestrian modelling of 12 underground station platforms and the concourse above, smoke and fire modelling, structural modelling and evacuation modelling using Mass Motion.
Total Fire Engineering
The project was an ideal opportunity to develop innovative solutions to project delivery. Being based on-site throughout the project, our team advanced its specialist knowledge of construction feasibility in relation to fire safety to enhance the Total Fire Engineering approach. We were brought in at the start of construction and our knowledge was leveraged throughout project development, all the way to handover, adding significant value.