Lighting terms
Australian lighting terms organised by calculation job rather than alphabet alone: units, task planes, beam geometry, light quality, enclosure language, driver assumptions and maintenance factors.
Lux
Lux measures illuminance: lumens per square metre on a surface.
Lumen
A lumen is a measure of visible light output.
Beam Angle
Beam angle is the spread of light from a fitting, measured in degrees.
Colour Temperature
Colour temperature is a kelvin value for the appearance of white light. It does not describe brightness, colour rendering quality or glare.
CRI
CRI, also called Ra in many lighting contexts, is a colour rendering index. It should be read beside CCT, lumens, beam spread and the task surface.
IP Rating
An IP rating is an enclosure code for ingress protection. It helps describe exposure conditions but does not choose a wiring method or installation location.
Task Plane
A task plane is the surface used for the lux assessment, such as a floor, desk, bench, shelf, wall or display face.
Maintained Illuminance
Maintained illuminance is the estimated light level on the assessed plane after utilisation and maintenance assumptions are applied.
Task Lighting
Task lighting is local lighting for a named task plane or visual task. It should be recorded separately from broad ambient lighting.
Ambient Lighting
Ambient lighting is the general room layer for broad visibility. It should stay separate from task lighting, accent lighting, emergency lighting and measured-light records.
Calculation terms
Units, output, measured light, connected load, operating hours and energy terms used by calculators and tables.
Lux
Lux measures illuminance: lumens per square metre on a surface.
Lumen
A lumen is a measure of visible light output.
Watt
A watt is a unit of input power. In lighting it belongs with connected load and energy calculations, while brightness still needs lumens and lux.
Efficacy
Efficacy is usually expressed in lumens per watt. It helps compare light output against electrical input for the same type of lighting task.
Connected Load
Connected load is the total input power of a lighting group. It supports energy and load summaries, not circuit design.
Kilowatt-hour
A kilowatt-hour, or kWh, is power used over time. Lighting cost estimates combine kWh with user-entered cents per kWh.
Illuminance
Illuminance is light arriving on a surface, normally expressed in lux. It depends on the assessed plane, area, light output and delivery assumptions.
Luminous Flux
Luminous flux is visible light output, expressed in lumens. It is the quantity used before area, spacing and delivery assumptions turn output into illuminance.
Lumen Method
The lumen method is an average-lighting estimate that relates target lux, area, utilisation factor and maintenance factor to a lumen allowance.
Measured Illuminance
Measured illuminance is the lux value read at a named plane under recorded operating conditions. It should not be mixed with estimates that use a different plane or condition.
Lighting Power Density
Lighting power density is connected lighting load divided by area, usually expressed in W/m2. It describes load intensity, not visual performance.
Operating Hours
Operating hours are the hours a lighting group is expected to run. They convert connected load into kWh and annual cost estimates.
Geometry terms
Task surfaces, mounting heights, workplane height and beam footprints used before layout decisions.
Beam Angle
Beam angle is the spread of light from a fitting, measured in degrees.
Task Plane
A task plane is the surface used for the lux assessment, such as a floor, desk, bench, shelf, wall or display face.
Effective Height
Effective height is the mounting height minus the assessed plane height. It is a geometry input for beam diameter, not a proof of lux or glare performance.
Beam Diameter
Beam diameter is the approximate beam footprint from beam angle and effective height. It is a geometry result, not a measured usable-light value.
Workplane Height
Workplane height is the height of the surface being assessed, such as a bench, desk, floor route or shelf face. It changes effective height for beam and spacing estimates.
Mounting Height
Mounting height is the luminaire height used in a lighting estimate. Together with workplane height, it sets the effective height for beam geometry.
Ceiling Height
Ceiling height is the distance from finished floor to ceiling or mounting surface. In lighting estimates it affects effective height, beam footprint, utilisation assumptions and glare notes.
Light quality terms
Maintained illuminance, daylight contribution, colour appearance, rendering, intensity, uniformity and glare terms.
Colour Temperature
Colour temperature is a kelvin value for the appearance of white light. It does not describe brightness, colour rendering quality or glare.
CRI
CRI, also called Ra in many lighting contexts, is a colour rendering index. It should be read beside CCT, lumens, beam spread and the task surface.
UGR
UGR means unified glare rating. It is a glare-design concept for visual comfort, not a result that this public site calculates from simple room inputs.
Maintained Illuminance
Maintained illuminance is the estimated light level on the assessed plane after utilisation and maintenance assumptions are applied.
Daylight Factor
Daylight factor is a daylighting relationship between indoor illuminance and outdoor illuminance. It does not turn outdoor daylight ranges into guaranteed indoor task light.
Candela
Candela is the unit for luminous intensity in a direction. It is useful for optical and glare discussions, not for a whole-room lumen total.
Luminous Intensity
Luminous intensity is directional light output, expressed in candela. It helps explain beam control and glare risk.
Uniformity
Uniformity describes the relationship between brighter and darker parts of the assessed area. A good average lux value can still hide poor uniformity.
Glare
Glare is visual discomfort or reduced visibility caused by bright sources, reflections or contrast in the field of view.
Vertical Illuminance
Vertical illuminance is illuminance on a vertical plane. It helps separate shelf, wall, face, board or display visibility from horizontal floor or desk lux.
Lighting layer terms
Ambient, task, plane, zone and dimming terms that decide which calculator or table owns the record.
Task Plane
A task plane is the surface used for the lux assessment, such as a floor, desk, bench, shelf, wall or display face.
Lighting Zone
A lighting zone is a defined group of lights, surfaces or tasks assessed together. Clear zone boundaries keep lux, load and control records from being mixed.
Dimming Range
Dimming range is the usable span between a low output condition and full output. It affects comfort and energy estimates but does not prove control compatibility.
Task Lighting
Task lighting is local lighting for a named task plane or visual task. It should be recorded separately from broad ambient lighting.
Ambient Lighting
Ambient lighting is the general room layer for broad visibility. It should stay separate from task lighting, accent lighting, emergency lighting and measured-light records.
Installation environment terms
Enclosure, driver, dimming, zoning, reflectance, maintenance and luminaire terms that support records without becoming wiring instructions.
IP Rating
An IP rating is an enclosure code for ingress protection. It helps describe exposure conditions but does not choose a wiring method or installation location.
LED Driver
An LED driver is control gear for LED loads. Driver type, voltage or current rating, dimming method and load range must match the luminaire system.
Dimmer
A dimmer is a lighting control device. Compatibility depends on the dimmer type, driver, load range, control method and installation context.
Utilisation Factor
Utilisation factor, or UF, is an estimate of the luminaire output that reaches the assessed plane. It is a delivery assumption, not a substitute for photometric design.
Maintenance Factor
Maintenance factor, or MF, is an allowance for depreciation, dirt and maintenance condition in maintained-light calculations.
Luminaire
A luminaire is the complete light fitting or lighting unit. In calculations, use the published output and input data for the complete fitting where available.
Driver Headroom
Driver headroom is spare rated capacity above the calculated LED load. It does not settle voltage drop, heat, enclosure, control compatibility or wiring checks.
Spill Light
Spill light is light reaching outside the intended target surface. It should be recorded with aiming direction, surrounding views and the relevant outdoor-lighting source boundary.
Reflectance
Reflectance is the share of light reflected by room surfaces. It affects utilisation factor and how much luminaire output reaches the assessed plane.
Constant-Voltage Driver
A constant-voltage driver supplies a nominal output voltage, commonly used with compatible LED strip and other voltage-rated LED loads.
Constant-Current Driver
A constant-current driver regulates output current for compatible LED modules. It must not be substituted for a constant-voltage load just because the wattage looks similar.
Lux Meter
A lux meter is a measuring instrument for illuminance. The reading is useful only when the plane, position and operating condition are recorded.
Lighting Zone
A lighting zone is a defined group of lights, surfaces or tasks assessed together. Clear zone boundaries keep lux, load and control records from being mixed.
Dimming Range
Dimming range is the usable span between a low output condition and full output. It affects comfort and energy estimates but does not prove control compatibility.