Company: Delmatic

Project title: Crossrail – Elizabeth Line

Location: London, UK

Category: Large indoor projects - HIGHLY COMMENDED

What did the project set out to achieve?

Crossrail is the UK’s largest ever single public infrastructure development and the world’s sixth largest construction project. The new high-frequency, high-capacity railway covers 118km of track and the boring of 42km of new tunnels deep beneath London. Crossrail will change the way people travel around London, forging links between east and west, connecting outer suburbs to the heart of the City and the West End, and, for the first time, providing direct connections between London’s main business centres.

DALI technology and Delmatic systems were selected to manage front-of-house (concourse, ticket halls, platforms and public spaces), back-of-house and external lighting within seven key central London stations - Paddington, Bond Street, Tottenham Court Road, Farringdon, Liverpool Street, Custom House and Whitechapel - as well as across the network of shafts, portals and depots. The state-of-the-art systems play a key role in minimising energy consumption and supporting Crossrail’s goal to deliver energy-efficient, sustainable solutions for London’s transport network.

The DALI systems enhance sustainability through energy-efficient digital dimming, presence/absence detection, and photocell control in daylit areas, coupled with operational efficiencies gained through real-time management and monitoring of the lighting network. The systems log the number of hours each lamp has been in operation and generate relamping plans which avoid the premature replacement of luminaires (with the associated environmental and disposal issues) by ensuring that lamps are retired at the optimum point. The systems also monitor individual lamp operation and highlight lamp and ballast failures in real time.

How is DALI used?

The DALI systems provide individually addressable control and monitoring of around 35,500 DALI assets (30,000 DALI lamps, 3,500 DALI sensors and 2,000 DALI switches) within the project managed by over 1,000 DALI Buswire lighting control modules networked across the 20 sites.

The DALI systems operate across an IP backbone within each station or location and comprise the following DALI controllers and devices:

• DALI Buswire Three Module (with 100% PSU backup and redundancy)
• DALI Multisensors
• DALI Switch Interface
• DALI External Photocells
• DALI Scene Set Panels

To achieve the architect’s vision that the tunnels should have minimal clutter, a ground-breaking lighting scheme features indirect DALI uplighting from fittings on top of totems along the walkways which reflect off the white contoured panels of the tunnels. In addition, many of the platforms are lit by vertically-mounted DALI LED luminaires over the edge of the platform, another radical departure from traditional norms on the UK’s rail network.

Why was DALI chosen?

DALI was selected as the technology for the project to benefit from the following features and functionality:

Accurate digital control:

The DALI system enables lighting levels to be adjusted and optimised to provide comfortable and safe lighting for passengers throughout the station network. Lighting in front of house areas is typically capped to achieve average required illuminance levels which both conserves energy as well as increase the lifespan of the lighting outputs. The DALI system also enables lighting levels to be adjusted and incremented over time to compensate for LED and light level degradation. A unique feature of the Delmatic system supplied for the Crossrail project monitors individual DALI driver or lamp failures and boosts the output from adjoining drivers to compensate for the specific failure to maintain safe and uniform lighting levels within the space.

Addressable flexibility:

The totally flexible DALI networks provide individual addressing and monitoring of each of the 30,000 DALI drivers. Selected lighting outputs, such as the sides of the passenger tunnel totems, are configured to remain at 0% and only illuminate in an emergency to assist with passenger egress.

Single buswire network for DALI luminaire drivers, sensors and switches:

DALI technology was specified as it enables DALI luminaire drivers as well as the DALI sensors and switches to connect to a shared DALI buswire cabling reducing the extent of control cabling compared to other lighting control approaches.

Integrated emergency light monitoring:

The DALI systems integrate with the central battery network to provide emergency light monitoring and testing via the DALI protocol as well as comprehensive monitoring of normal and emergency lighting across the network and throughout each site.

IP networking and integration with other project and station systems:

The DALI systems within each station integrate via BACnet and SCADA with the BMS overt the IP LAN network, forming a key part of the energy-management systems throughout the stations and supporting Crossrail’s goals to deliver energy-efficient, sustainable solutions for London’s transport network.

What benefits does DALI provide?

Energy efficiency and sustainability

The Delmatic DALI systems enhance energy-efficiency through digital dimming, presence/absence detection, and photocell control in daylit areas: sustainability is enhanced by operational efficiencies through real-time management and monitoring via Delmatic’s active graphical user interface.

Enhanced sustainability

The systems monitor and log the number of hours each lamp has been in operation and generate optimised relamping plans which avoid the premature replacement of luminaires (with the associated environmental and disposal issues) and ensure lamps are retired at the optimum point. The systems also monitor individual lamp operation and highlight lamp and ballast failures in real time.

Comfort and safety of passengers

The DALI technology plays a crucial role in station security and safety. The systems integrate with the central battery to provide comprehensive DALI emergency light monitoring and testing as well as tracking the performance of every lamp across the network of stations and highlighting failures in real time. To ensure public safety and comfort, Delmatic developed custom operational algorithms for the project, and a unique adaptive-lighting feature boosts the output of adjoining DALI lamps and fittings in the event of a neighbouring lamp failure.

Open protocol integration with other station systems

The DALI systems integrate seamlessly via open protocol BACnet and SCADA with the network Fire Alarm, BMS and UPS systems. The Fire Alarm Interface drives all lighting outputs to 100% output in the event of a fire alarm being activated or a fault with either the fire alarm or lighting control system. Integration with the BMS enables the lighting network to share status and fault intelligence with the BMS and rail command centre. Interfaces with the station UPS system activate regular emergency lighting tests via the lighting control system to simulate power failure scenarios.

Integrated DALI Emergency light monitoring

The Delmatic Lightscape software provides comprehensive real-time and granular data on the lighting installation and operation including detailed documentation of emergency lighting tests including times, duration and pass or fail status, including operational status of each Emergency LED fitting.

24/7/365 real-time monitoring

The networked system provides graphical feedback of the lighting installation including active status of each lamp. Graphical software provides a “window” into the lighting installation enabling the user to manage and monitor the complete online system network, adjust operational lighting levels and scenarios, reconfigure sensor time-out periods and optimise daylight-linking thresholds, etc to suit changing operational requirements and situations.

Unique environmental assessment

Crossrail’s approach to sustainability ensures that the energy and carbon impacts of the network are minimised, while setting new standards for the delivery of major infrastructure projects around the world. The Crossrail design process included the development of a unique set of criteria using the Building Research Establishment’s Environmental Assessment Methodology (BREEAM) for underground stations, enabling the project team not only to objectively assess Crossrail’s environmental performance but also to create a benchmark for future projects. All Crossrail station buildings are rated BREEAM ‘Very Good’ and are the first underground stations in the world to be rated under such a scheme. 

The DALI systems provide the following headline features:

• fully flexible individual addressing of every DALI luminaire
• DALI LED and driver failure monitoring
• DALI emergency monitoring and testing
• DALI presence/absence detection with software configurable time-out period
• DALI photocell daylight-linked control
• granular monitoring on graphical user interface
• virtual wiring allows changes to configuration without wiring alterations
• open protocol ISO14908 communication enables multi-vendor support
• distributed intelligence at DALI modules
• LED run time monitoring and relamping schedules
• interfacing with the BMS, UPS and fire alarm systems
• automated scheduled and manual emergency tests
• scene set control via DALI scene set panel
• configurable and switchable signage control via DALI scene-set panel

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Parties involved

► Architects: Aedas, Allies & Morrison, Atkins Global, BDP, Burns & Nice, Gillespies, Grimshaw, Hawkins Brown, John McAslan + Partners, Urban Initiatives, Weston Williamson, WilkinsonEyre ► Consultants: Arup, Atkins, Hyder, Mott MacDonald, Scott Wilson, WSP ► Contractors: Balfour Beatty, Costain Skanska, Laing O’Rourke, NG Bailey ► Lighting: Designplan Lighting, GIA Equation ► DALI Lighting Controls: Delmatic.