Emergency lighting is one of the most heavily documented areas of commercial lighting regulation, yet it remains one of the most frequently non-compliant areas on practical completion inspections. In mixed-use buildings, the complexity multiplies significantly, and the consequences of getting it wrong extend well beyond a snagged item on a contractor's list.
This guide is aimed at early-career lighting designers and specifiers working on mixed-use or multi-tenancy developments. If you're new to emergency lighting fundamentals, start with our Guide to Emergency Lighting before reading on.
BS 5266-1 is the British Standard governing emergency lighting design in non-domestic premises. It requires that all escape routes, open-area (anti-panic) spaces, and high-risk task areas are illuminated for a minimum sustained duration, typically one or three hours, following a mains power failure.
The key performance benchmarks set by the standard are:
For a deeper dive into the regulatory framework, see our post on Emergency Lighting Law in UK Commercial Buildings.
In a single-use office or retail unit, the emergency lighting zone is relatively straightforward to define. In a mixed-use development, for example, ground-floor retail with commercial offices above and residential apartments on the upper floors, the complexity increases across several dimensions simultaneously.
Retail may be vacated by 9pm; a gym may operate until midnight; residential occupants are present around the clock. Emergency lighting must be designed to serve all occupancy patterns, not just the primary use. A staircase that serves both commercial floors and residential apartments cannot be treated as a commercial-only escape route during its design.
A staircase or corridor shared between commercial tenants and residents requires emergency lighting designed to the more demanding of the two standards that apply. This affects both the luminaire specification and the inspection and testing regime, which must satisfy the requirements for all uses simultaneously.
Residential common areas fall under the Regulatory Reform (Fire Safety) Order 2005 and the Building Safety Act 2022 (particularly relevant for buildings over 18 metres). Commercial spaces carry additional requirements under the Health and Safety at Work Act and associated fire safety regulations. These frameworks do not always align neatly, and in some cases require specific coordination with the appointed fire engineer and building control officer.
This is one of the most commonly misunderstood distinctions in emergency lighting specification:
In a mixed-use building, you will almost certainly need both types in different zones. Specifying non-maintained fittings throughout, which is cheaper and simpler, is a common error that creates compliance failures in residential and 24-hour areas.
For a full breakdown of fitting types, see our post on Types of Emergency Lighting.
For straightforward single-tenancy buildings, individual self-test emergency fittings are often the most practical and cost-effective solution. For larger mixed-use schemes with multiple tenants and common areas managed by a building owner or facilities team, a Central Monitoring System (CMS) or central battery system is generally more appropriate.
A CMS allows:
This is particularly valuable in buildings where the landlord is responsible for common areas while individual tenants manage their own demise, the CMS provides a clear boundary between responsibility zones.
To understand how self-test systems work in more straightforward applications, see our post on How Self-Test Emergency Lighting Works.
BS 5266 sets clear requirements for the testing and ongoing maintenance of emergency lighting installations. These requirements don't end at practical completion, they follow the building for its operational life. Designers have a responsibility to ensure the scheme they specify is actually maintainable in the building as built.
Key testing requirements include:
For more detail on compliance testing, see our post on Emergency Lighting Testing.
Emergency lighting is too often treated as a contractor's responsibility, added late, specified from a schedule, and value-engineered at tender. For mixed-use buildings, this approach creates serious risk.
Best practice is to integrate emergency lighting design from RIBA Stage 2, in coordination with:
A scheme that is designed early, coordinated properly, and specified clearly is almost always cheaper to build and easier to sign off than one that is retrofitted to a base build that wasn't designed to accommodate it.
Emergency lighting in complex mixed-use buildings is not a commodity procurement decision. The combination of regulatory complexity, occupancy diversity, and the need for coordinated design means that working with a specialist lighting partner from early project stages significantly reduces risk.
At 299 Lighting, we work alongside architects, interior designers, M&E consultants, and contractors across all stages of the project, from initial brief and specification through to product supply and post-installation compliance support. If you have a mixed-use project in design, get in touch with our team to discuss how we can support you.