Automotive and showroom lighting design

A dealership is a shop that sells a mirror. Automotive paint, especially dark metallics and anything with a clear coat, will report every luminaire in the ceiling as a bright ellipse on the bonnet. Customers judge panel gaps and colour under that report. Sales staff try to talk across it. At 11 p.m. the same ceiling becomes a flood for the arterial road and a gift for anyone walking the yard. Australian sites add a workshop, a wash bay, a used-car line and a council that has already met the LED billboard next door.

This essay is a contractor’s method for showrooms and the rooms attached to them. It sits on the retail and hospitality hub with merchandise lighting and grocery floors. Colour is CRI and TM-30. After-hours spill is outdoor and civic work, closer to car parks and facades than to a pendant schedule.

Paint is the brief

Horizontal lux on the showroom slab is the number everyone has. It is the least useful number in the building. The customer looks at vertical and raking light on a curved body. A regular grid of small, bright apertures — the default “commercial LED downlight” layout — will polka-dot a black sedan and hide a dent in the shadow between dots. Wide, low-brightness sources, luminous ceilings, or a wash from a cove and a few aimed accents will show the panel as a panel.

Walk a dark car and a white car before you lock the grid. White paint floods and wants glare control. Dark metallic needs a large source so the flake reads as a field, not a star field of downlights. Matte wraps behave more like fabric.

Colour has to be honest enough to compare two “white” cars. Specify a high-fidelity white and a tight CCT. 4000 K is a common Australian compromise near daylight glass; 3000 K can make silver look dusty; 5000 K can cheapen a red. Do not inherit workshop colour without looking at the brand.

Glass is everywhere: windscreens, showroom curtain wall, reception aquariums of keys. Treat it as retail cabinet glass. If the downlight grid is visible in every windscreen from the footpath, you have designed an advertisement for your ceiling, not the car.

Ceiling grids, structure and the franchise manual

Most Australian dealerships are a steel portal, a high roof, and a franchise manual that arrived as a PDF of European photographs. The photographs assume a 3.5 m luminous ceiling. The building is 7 m to the underside of the truss with HVAC hanging in the way. Your job is to translate the brand intent into a structure that can be maintained from a scissor lift without booking a road-occupancy permit.

Write the real mounting height, the obstruction map, and the maintenance access. High-bay “showroom” luminaires with a workshop optic will glare and stripe the cars. Low-glare, wide distributions at a lower suspended plane often beat a pretty grid that cannot physically miss the duct. If the franchise insists on a tight spacing, suspend a plane. Do not pretend a 6 m downlight is a 3 m downlight.

Workshops attached to the same switchboard are not showrooms. They are task rooms: pits, hoists, colour-matching for smash repairs, and a lot of oil. Specify AS/NZS 1680 task values on the working plane that actually exists — a guard at hoist height, a bench, an inspection lamp where the pit is still dark. Our industrial habit of copying one high-bay package across the whole shed is how a technician inspects a brake with a phone torch. Emergency lighting, welding screens and the wash bay IP rating are electrical problems, not brand problems.

Reception and finance offices are workplaces. Faces at the desk, a readable screen. They follow office practice more than the car-paint brief, with a little hospitality at the coffee machine.

Glare, glass walls and the street

A glazed showroom is a lantern. In the day, the sky and the opposite building bounce onto the cars and into the sales desk monitors. At night the interior becomes the facade. If you run full sales output after close, you have built an unpaid billboard and a neighbour complaint. AS/NZS 4282 territory starts at the lot boundary, not at the first bedroom.

Inside, UGR tables for a rectangular room with 0.7 walls do not describe a glass box with a polished floor and a row of windscreens. Sit in the customer’s chair and in the salesperson’s chair. Tilt a tablet. If the proposed luminaire is in the reflection, move the luminaire or change the optic. Polished concrete — still fashionable in used-car halls — is a mirror. Ask the interior designer before you guess a 0.2 floor.

Outside, vehicle display rows along the frontage are flood and precinct lighting. Aim in, shield, and keep vertical light on the cars rather than on the bedroom across the road. A tilt-lock on an adjustable flood is a specification clause, not a hope. Pole height that looks “dealership” on a render is often illegal for glare once you put a 40,000 lm package in it.

After-hours security lighting

This is the part owners get wrong and security companies happily oversell. A showroom left at 80 per cent “so the cameras work” wastes energy, washes out the camera, and lights the footpath for everyone except the person you wanted to see. Cameras want modelled vertical light on a face and a number plate, not a flat blast from the same high-bays that sell cars at noon.

Specify a security scene:

• Low, even light on circulation paths, entries and the safe through the workshop.
• Vertical illuminance on the faces of displayed cars that must remain visible, without sparkle on the glass that blooms the camera.
• Yard and car-park lighting on a CPTED logic: see and be seen, no glare traps behind a pantech.
• A clock, a photocell and an override that logs. Motion on the used-car line can lift a zone; it should not lift the whole facade.

DALI or a BMS is how a multi-building site — showroom, workshop, wash, used yard — avoids five wall clocks that drift. Section J will still count the installed load. A security scene that is actually a dimmed sales scene will fail the intent even if the paperwork passes.

Do not use RGB wash as security. A purple facade is a brand night, not a detection night.

Dealership groups love a national package. Contractors love a substitution that keeps the wattage and loses the optic. Write the optic and a mock-up car as a hold point. A dead luminaire over the hero car is a dark ellipse and a cherry-picker booking. Specify a driver that can be replaced from below.

On a Melbourne franchise we wrote three documents. The showroom used a suspended low-glare plane and two aimed accents per hero bay. The workshop used task lighting at hoist and bench. The yard used shielded floods with a 10 p.m. cut to a security scene, calculated to the residential boundary.

What to write in the specification

1. Name showroom, workshop, wash, offices and yard as separate visual tasks.
2. Name paint: a mock-up car, vertical / raking light, and a fidelity target.
3. Name the ceiling: mounting height, obstructions, access, and the optic — not only watts.
4. Name glare for seated customers, staff screens and the street.
5. Name the security scene, camera requirements, curfew and the 4282 assessment.
6. Name Section J, scenes and a substitution rule that protects the optic.

Measurement on site

Park the darkest car and the lightest car. Stand where a customer stands, then sit where they sit. Photograph the bonnet; if you see your ceiling more than the colour, the grid has failed. Measure the workshop on the actual task, not the floor between hoists. After close, walk the boundary with the security scene on and the sales scene off. If the bedroom across the road can read a newspaper, you have a flood, not a dealership.

Showroom lighting will not choose the paint for you. It will stop you treating a curved mirror as a slab, a workshop as a leftover, and a night-time pylon as a substitute for a security design. Light the panel, hide the source in the glass, and switch the theatre off when the sales floor is empty.