Lighting Control System

A lighting control system decides when lights are on and how bright: time clocks and astronomical timers, photocells, occupancy and absence sensors, daylight sensors that dim lights near windows, switches and scene controllers, and networked systems that address each luminaire individually, such as DALI and proprietary wired and wireless platforms, often linked to the building management system. In common areas and car parks, controls cut most of the lighting energy; in offices they are part of how a tenancy works.

Energy codes in all three jurisdictions require automatic controls in new and substantially altered buildings, and energy ratings reward them. A good system that has been overridden or never commissioned saves nothing.

What shortens life:

• Vendor end of support for proprietary hardware, software and apps.
• Lost programming, passwords and documentation.
• Fit-outs that move partitions without moving sensors or regrouping fittings.
• Overrides left in place after complaints.

Software and apps age faster than hardware: a system with sound sensors can become unmanageable when the commissioning software stops running on supported computers.

Overrides and defeat

Occupants and facilities staff defeat controls that annoy them: sensors taped over, time clocks bypassed with a switch, lighting held on through the BMS. Car parks then run at full output 24 hours a day, and common areas stay lit all night.

Poor commissioning and drift

Daylight dimming set too conservatively or switched off; time delays too short (lights going off on people) or too long (saving little); groups that no longer match the floor layout after fit-outs; time clocks that lost their schedule after a power failure or never adjusted for daylight saving.

Sensor placement

Sensors behind partitions, too far from desks, aimed at corridors or above glazed walls switch lights off on occupants or on for passers-by. Car park sensors that cannot see along aisles leave drivers in the dark.

Obsolescence and lock-in

Proprietary systems depend on the vendor's gateways, software and commissioning tools. When support ends, faults cannot be fixed and layouts cannot be changed without replacing the system.

Integration failures

Links to the BMS, security system and automatic emergency lighting tests break when either side is upgraded; automated tests stop silently.

Cyber exposure

Networked lighting systems on the building or corporate network, with default passwords or unpatched gateways, can be a route into other systems.

Sensor drift and dirt

Daylight sensors drift and collect dust, so they read less daylight than there is and keep lights brighter than needed. Battery-powered wireless sensors stop reporting when batteries run flat, and systems may default to lights on.

Emergency lighting test integration

Many DALI and networked systems run automatic emergency lighting tests and log results. When the integration breaks, tests stop running, but the building may still believe it is compliant.

On site

• Lights on in empty areas after hours; car parks at full output all night.
• Sensors covered, disconnected or missing; switches added to bypass controls.
• Perimeter lights at full output on bright days.
• Controllers and gateways in plant rooms with fault lights.
• Complaints of lights switching off in meeting rooms or toilets.

In the records

• Programming backups, group schedules and documentation.
• Vendor, software and firmware versions; support status.
• Interval meter data showing night-time lighting load.
• Complaint records about lighting.

• Wireless sensors with flat or low battery warnings.
• Emergency lighting test logs that stop at a date.
• Time clocks showing the wrong time.

Findings are graded by what they demand: safety (can hurt someone now), failure (failed and damaging the building), condition (distress present and progressing), lifecycle (renewal due on age and exposure), deadline (a regulator or ordinance sets the date), check (investigate before sizing works) and nil (cosmetic or stable).

An electrical or lighting controls specialist.

• Night audit: walk the building after hours and note what is on and why.
• Interval meter analysis of lighting loads by time of day and day of week.
• Controls inventory: types, vendors, versions, gateways and support status.
• Sensor and setting review against current layouts: placement, time delays, daylight levels, groups.
• Safety check: stairs and egress paths stay lit when occupied.
• Integration testing with the BMS, security and emergency lighting test systems.
• Documentation and ownership review: programming backups, tools, passwords, who holds them.

The report should quantify energy wasted by poor control, list safety issues, give support status, and recommend recommissioning or replacement.

• Car park check: lighting levels in dimmed mode against the minimum for safe movement.

• Recommissioning: reset schedules, time delays and daylight levels; regroup to current layouts; remove overrides. Usually the cheapest energy saving in the building.
• Sensor relocation and replacement to suit layouts.
• Car park controls: dim to a background level when unoccupied rather than switching off, so drivers are never in the dark.
• Replacement with an open-protocol system such as DALI-2, with programming, tools and passwords held by the owner.
• Integration repair with BMS and emergency lighting tests.
• Network security: segregate lighting networks and change default credentials.
• Documentation: groups, schedules, settings and backups.

• Training for facilities staff so settings are changed properly rather than overridden.

Audits and recommissioning are lump sums and usually pay back quickly in energy. Sensor replacements are per unit. System replacement is per floor or per area, often combined with LED conversion so both are done once with ceilings open.

Recommissioning is repairs and maintenance; replacement is lifecycle or an energy upgrade; safety fixes on egress paths are immediate.

Combining control upgrades with LED conversion avoids paying twice for ceiling access.

• Australia. NCC Section J requires automatic lighting controls in many spaces in new and altered buildings; NABERS Energy ratings reward effective control.
• United Kingdom. Approved Document L requires lighting controls in new and refurbished buildings; BS EN 15193 sets methods for lighting energy.
• United States. ASHRAE 90.1 and the IECC set mandatory controls (occupancy, daylight, scheduling); California Title 24 adds further requirements.

Energy rating and disclosure schemes in all three countries make lighting energy a lettability and compliance issue: NABERS and Commercial Building Disclosure in Australia, Energy Performance Certificates and minimum standards in Britain, and building performance standards in several United States cities. Controls are usually the cheapest way to improve these ratings.

Where controls dim or switch egress lighting, the minimum levels for safe movement in each jurisdiction still apply in every control state, including car parks and stairs.

• Programming backups, group and schedule documentation.
• Vendor, software and firmware details and support status.
• Interval meter data for lighting.
• Complaint records.
• Who holds programming tools and passwords.

• Energy ratings and disclosure certificates.
• Records of fit-outs that changed lighting groups.
• Commissioning reports for the original installation.