Why Master/Slave Communal Lighting Is the Smarter Choice for Residential Stairwells
The problem with individual sensors in stairwells
Stairwells are not corridors. Occupants move between multiple levels, often in low natural light, and they need to see where they’re going before they start moving, not after a sensor has had time to react.
Individual luminaires with independent PIR or microwave sensors create exactly that problem. Lights activate sequentially as occupants move, leaving sections ahead dimmed or dark. For a single storey corridor, that’s manageable. For a six storey stair core, it’s a compliance and safety risk.
What master/slave control actually does?
In a master/slave arrangement, one designated luminaire controls a network of connected slave fittings. When the master detects occupancy, every luminaire in the stairwell activates simultaneously – presenting a fully illuminated route from the moment an occupant enters.
The result is better visibility, a more predictable experience for residents and fewer switching events across the system. It also supports the corridor dimming strategies now increasingly expected under Approved Document L: luminaires hold at a low output level between occupancy events, reducing energy consumption without creating the perception of dark or unsafe spaces.
Compliance considerations you need to plan for
Stairwells sit at the intersection of several regulatory requirements.
Under Approved Document B, they form part of the building’s escape route and must provide adequate artificial lighting at all times. In a mains failure, emergency lighting must maintain illumination to support safe evacuation, in line with BS 5266-1. At the same time, Approved Document L continues to tighten energy performance requirements for communal areas, making occupancy controls and photocell operation standard practice rather than optional extras.
The challenge is meeting both simultaneously: maintaining compliant emergency illumination while keeping operational energy consumption down.
Integrated luminaires simplify the specification
Modern communal lighting products combine standard and emergency functionality in a single fitting, which reduces component count, simplifies installation and makes ongoing maintenance more straightforward.
GL’s Ludlow M-Lux is designed specifically for this application, combining microwave sensing, photocell control, corridor dimming and emergency lighting within one luminaire. For higher output stairwells, the Cheltenham C-Lux provides the same coordinated control philosophy at greater lumen output. Where external escape routes or stairwells need to be included in the strategy, the Exeter E-Lux Bulkhead extends consistent control to outside environments.
Which approach is right for your development?
There’s no single answer. Smaller stair cores with limited floors may function adequately with individual sensor control. But for multi-storey residential blocks where stairwells are a primary circulation route, master/slave systems consistently deliver better outcomes across visibility, resident experience and long term energy performance.
Specifying the right control strategy at the outset, alongside the correct emergency lighting provision, avoids costly remediation later and gives building control teams confidence that both escape route and energy requirements have been addressed.
Want to find out which communal lighting solution is right for your next development?