Glossary of lighting terms

Colour rendering index: Ra: The degree to which a specific light source

reproduces a set of reference colours compared with the same colours under

daylight conditions. This index is measured on a scale of Ra0 to Ra100.

Colour temperature: Tk: The colour appearance of the light emitted by a light

source, in kelvins. 

Eye sensitivity curve: V(a) : The human eye is more sensitive to some colours

than to others, e.g. it is 20 times more sensitive to green and yellow light than to either red or blue light.

Field camera vertical: Efieldv: Illuminance on a plane 1m above the pitch and parallel with the pitch aimed towards the sideline.

Fixed camera vertical: Efv: Illuminance on a plane 1m above the pitch and 20º above the horizon aimed towards the camera positions.

Glare rating: The degree to which a lighting installation is disturbing to a person on or near the pitch. GR is defined by the Commission Internationale de l’Eclairage in publication 112, 1994, Glare Evaluation System for use within Outdoor Sports and Area Lighting.  

Horizontal illuminance: Eh/Eh ave p Light incident (falling) on a horizontal plane 1m above the pitch.

Illuminance: E : The quantity of light falling (incident) on a surface at a specific point, expressed in lux.

Illumination: E ave : Average horizontal illuminance as a result of either calculation or measurement.

Illuminance gradient %: The difference in illuminance between two adjacent points on the pitch.

Illuminance towards camera: E cam p Illuminance on a plane 1m above the pitch and perpendicular to the camera position.

Illuminance uniformity: Describes how evenly light is distributed over the pitch surface and is expressed by the ratios of U1 and U2.

Initial illuminance: E init : The illuminance after the first 100 hours of use.

Initial lumens: The output of a light source (lamp) after the first 100 hours of use.

Intake mains: The incoming utility service, which would be the metered feeders.

Light trespass: The amount of light spill and glare leaving the premises

Lumens: Lm: The spectral power distribution of a lamp weighted by the eye sensitivity curve.

Lux: The unit of illuminance in lumen/m2, incident on a pitch surface. 1 lux = 1 lumen/m2.

Maintained illuminance: E maint/E ave maint: The (average) illuminance below which the installation should not fall; below which the lamps should be replaced and or the installation cleaned.

Maintenance factor: A factor less than 1. Initial illuminance x maintenance factor = the maintained illuminance. This compensates for the depreciation in lamp output and light fitting surfaces.

Maximum vertical: Illuminance recorded on a light meter aimed at the brightest light source.

Mounting heights: Hm: The mounting height of the light fittings with respect to a point on the pitch. Hm = distance “d” x tan d.

Primary player view angle: PPVA: Normal players’ view angle in relationship to the playing field and the spill light fittings.

Ride-through: The ability of a power system to maintain continuous uninterruptible stable power during an outage, or during bumps/spikes, while waiting for a generator to start.

Temporary lighting: Light fitting poles and structures support event head frames that are removable after an event.

Vertical illuminance: Ev: Light incident on a vertical plane 1m above the pitch. Orientation to be specified.

-Refer to “FIFA lighting and Power Guide”

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