Uniformity - Stadiums & Arenas

UEFA Stadium Lighting Guide 2023

Content Type
UEFA Guidelines
Category
Stadium & Arena
Subject
Stadium Lighting
Edition
2023
Language
English
Enforcement Date

A critical element of a pitch illuminance system is the uniformity of illuminance across the whole pitch in all of UEFA’s reference planes. The uniformity of illuminance can be defined as how evenly light is distributed over a given reference plane.

The uniformity of illuminance is expressed using two illuminance ratios: U1 and U2.

U1 The total illuminance range, from minimum to maximum, that a person or camera will be exposed to.

The U1 value contributes to the visual performance experience.

U2 The difference between a person’s normal adapted exposure and the lowest illuminance level on the given plane. The U2 value contributes to the visual comfort experience.

Horizontal uniformity of illuminance

U1h A measure of horizontal illuminance uniformity – the ratio of minimum horizontal illuminance to maximum horizontal illuminance across all 96 reference points.

U2h A measure of horizontal illuminance uniformity – the ratio of minimum horizontal illuminance to average horizontal illuminance across all 96 reference points.

Vertical uniformity of illuminance

U1v-(angle°) A measure of vertical illuminance uniformity on the specified reference plane – the ratio of minimum vertical illuminance to maximum vertical illuminance across all 96 reference points.

U2v-(angle°) A measure of vertical uniformity of illuminance on the specified reference plane – the ratio of minimum vertical illuminance to average vertical illuminance across all 96 reference points.

Note that UEFA’s requirements are the minimum standards for the various illuminance levels. Experience shows that the uniformity values calculated during the design process are a good guide but are often higher than the values measured once the illuminance system has actually been installed. For this reason, UEFA recommends that the illuminance uniformity values calculated during the design process be higher than the minimum requirements to allow for potential declines when real values are measured.

Illuminance reference points

At UEFA’s discretion, the UEFA pitch illuminance test reference grid may be offset by 5m along both the X and Y axes if the illuminance conditions are considered poor in positions not assessed by the standard reference grid.