Underground car parks present specific lighting challenges. Limited natural light, safety concerns, extended operating hours, and harsh environments combine to make these spaces demanding for LED systems.

Here’s what works, based on projects across numerous basement car parks.

The Regulatory Framework

Car park lighting must comply with multiple requirements:

AS/NZS 1158 - Pedestrian Area Lighting

Part 3.1 covers “roads and pedestrian areas within road reserves,” which influences car park design even though car parks aren’t technically roads.

Key parameters:

• Minimum maintained illuminance
• Uniformity requirements
• Glare limits

Building Code of Australia

The BCA references AS 1680.2.1 for interior lighting in buildings, which provides general principles applicable to car parks.

AS/NZS 2293 - Emergency Lighting

Underground car parks are escape routes. Emergency lighting must comply with AS/NZS 2293, including:

• Illumination of escape paths
• Exit sign visibility
• Battery backup duration
• Testing and maintenance requirements

Fire Services

Fire stair entries, hydrant locations, and similar require adequate illumination for emergency response.

Light Level Recommendations

General car park lighting typically targets:

Circulation areas: 50-75 lux at floor level, reasonable uniformity.

Parking bays: 20-50 lux is common, though uniformity often varies.

Pedestrian paths: 75-100 lux where dedicated pedestrian routes exist.

Ramps and transitions: Higher levels (100+ lux) help drivers’ eyes adapt between daylight and underground conditions.

Special areas: Loading docks, trolley returns, recycling areas may need higher levels.

The Transition Problem

When drivers enter from bright daylight, their eyes need time to adapt. If the entry is too dark, the momentary blindness is dangerous.

Solutions:

• Higher light levels near entries and ramps
• Gradual transition zones
• Daylighting in entry areas where possible
• Avoiding harsh bright/dark contrasts

LED Product Selection

Underground car parks demand robust products:

IP Rating

Minimum IP54 for protected areas. IP65 or higher for areas exposed to vehicle washing, hose-down cleaning, or potential water ingress.

Condensation is common in underground spaces. Fittings must handle humidity.

IK Rating

Impact resistance matters. Vehicles reverse into things. Service vehicles have tall equipment. Vandalism happens.

IK08 minimum for general areas. IK10 for vulnerable locations (near bollards, low mounted, high-traffic areas).

Corrosion Resistance

Underground car parks have exhaust fumes, cleaning chemicals, and sometimes salt tracked in from coastal locations.

Specify fittings with appropriate material and finish for the environment.

High Efficacy

Car parks run 24/7 or extended hours. High efficacy products (150+ lm/W) significantly impact running costs.

Control Strategies

Underground car parks are excellent candidates for intelligent control:

Occupancy-Based Dimming

Traffic varies dramatically. Peak hours are busy; 3am is empty. Occupancy sensing allows:

• Full output when vehicles or pedestrians present
• Reduced output (30-50%) when unoccupied
• Near-off for emergency lighting minimum when completely vacant

Energy savings of 40-60% compared to fixed output are achievable.

Zone-Based Control

Different areas have different patterns:

• Ramps and circulation: more consistently used
• Remote parking bays: often empty
• Lift lobbies: pedestrian traffic even when bays are empty

Control zones matching usage patterns optimises response.

Daylight Contribution

Near entries and light wells, daylight can offset electric lighting during the day. Photosensors can dim electric light accordingly.

Central Management

For larger car parks and multi-site portfolios, networked control enables:

• Central monitoring of all fittings
• Energy reporting and verification
• Fault detection and alerting
• Schedule optimisation

Emergency Lighting Requirements

Underground car parks are enclosed spaces requiring compliant emergency lighting:

Exit signs: Illuminated exit signs at escape route decision points.

Escape route lighting: Minimum 1 lux maintained throughout, higher at changes of direction and level.

Anti-panic lighting: Open areas may need anti-panic lighting (minimum 0.5 lux maintained).

Duration: Minimum 90 minutes (check specific requirements for your jurisdiction and building classification).

Integrating emergency and general lighting is increasingly common. DALI emergency gear allows the same fittings to serve both purposes, with the control system managing emergency testing and reporting.

Specific Design Considerations

Column and Beam Shadows

Underground car parks have structural columns and beams that create shadows. Fitting placement must account for these obstructions.

Strategy: More fittings with lower output often provides better uniformity than fewer high-output fittings blocked by structure.

Low Ceiling Heights

Many car parks have 2.4-2.7m clear heights. This limits fitting options and affects spacing calculations.

Low-profile batten fittings are common. High bay fittings designed for warehouse heights aren’t appropriate.

Multi-Level Transitions

Ramps between levels, split-level layouts, and other transitions need careful treatment. Light levels, sight lines, and emergency egress all converge at these points.

EV Charging Bays

As covered in my earlier article on EV charging, charging bays benefit from higher light levels for user interaction. Coordinate lighting with charging infrastructure.

Accessible Parking

Accessible parking bays need clear identification and adequate lighting for users who may have vision impairment. Ensure compliant signage is well illuminated.

Maintenance Considerations

Underground car parks present maintenance challenges:

Access: Getting equipment to fittings. Scissor lifts fit in most car parks; cherry pickers may not.

Operating hours: 24/7 buildings limit maintenance windows. Work happens overnight or during quiet periods.

Cleaning: Fittings accumulate dust, exhaust residue, and other debris. Schedule periodic cleaning or accept some lumen depreciation.

Warranty coverage: Document initial conditions. Products failing prematurely due to unsuitable environmental exposure may not be covered.

Integration With Building Systems

For buildings with sophisticated management, car park lighting integrates with:

• Access control (know when cars are present)
• CCTV (lighting affects camera performance)
• BMS (energy monitoring, fault alerting)
• EV charging (load coordination)

This level of integration goes beyond standard electrical contracting. Team400 and similar building technology specialists work on these multi-system integrations where car park lighting is one component of an intelligent building.

Cost-Benefit Reality

Car park LED retrofits typically achieve strong returns:

High operating hours: 24/7 or extended operation maximises energy savings.

Existing inefficiency: Many car parks still have T8 fluorescent or even metal halide. The efficiency gap to LED is large.

Control opportunities: The variable occupancy pattern makes control savings significant.

Maintenance reduction: Underground car parks are challenging to maintain. Longer LED life reduces interventions.

Paybacks under 3 years are common. Some projects achieve 18-24 months.

Final Thoughts

Underground car parks are one of the clearer LED opportunities in commercial buildings. The combination of long hours, inefficient existing lighting, and control opportunities creates compelling economics.

Get the product selection right for the environment. Design for safety and compliance. Implement appropriate controls. The result is safer, better-lit spaces with significantly lower energy costs.

James Thornton has been working in commercial lighting for 18 years and is based in Australia.