Page 34 - Energize December 2022

TECHNICAL

Understanding sports

stadium lighting

by Mike Rycroft, Energize

tadium lighting has changed significantly in recent years. Lighting for top level international sports must not only meet
Sports facilities have traditionally been lit using high the requirements of the players and spectators but broadcast
Sintensity discharge (HID) lighting systems. These have high- requirements as well. Sports broadcasting at the highest level
power consumption, delayed turn-on time, fixed output (i.e., no uses slow-motion replays which require higher lighting levels
dimming) and a low power factor. than at normal speed. So-called “third umpire” decisions by an
Modern stadium lighting must comply with various off-the-field official using a video recording of the game, also
regulations regarding vertical illuminance, uniformity of light requires the correct lighting.
intensity, spatial three-dimensionality, colour temperature, and In stadium lighting there is more to consider than just
the colour rendering index of the light source. The need to meet the playing surface. Where a sport involves the use of the
these requirements has meant that HID luminaires are being height above the playing area, as in athletics throwing events,
replaced by more innovative and flexible lighting systems which baseball, cricket or rugby, consideration of the volume of the
use LEDs. playing area is important. Here, consideration of lighting in
both horizontal and vertical planes must be considered. The
The benefits of LED floodlights over other forms of lighting area around the pitch, a court’s perimeter lines, and safety or
include: run-off zones must also be lit. Consideration must be given to
• Lower power requirement due to higher efficacy the lighting levels both on the surfaces of and in the volume
• Reduced maintenance costs above each of these zones.
• LED floodlights turn on immediately, with no warm-up period
• LED floodlights have lower inrush currents when turning on Horizontal illuminance
• Improved flexibility in design due to LED modularity The illuminated playing surface takes up a major part of the
• Higher system efficiency due to unidirectional nature of LEDs field of view in a sporting venue. Horizontal illuminance
(Eh) represents the illuminance on this horizontal plane at
Stadium lighting levels (classes) ground level. It serves primarily to create a stable visual
Sports lighting is a complex business. International, national, background against which the eye can discern players and
regional and local competitions all have their different lighting objects.
requirements, while practice sessions and recreational For non-televised lighting classes, an average horizontal
sports call for different lighting regimes than competitive illuminance of between 100 and 750 lux is sufficient, depending
and professional events. A sporting facility’s capacity and the on the sport in question and on the lighting class. For televised
distances from which spectators are viewing the action must competitions, the ratio between the average vertical and
also be considered. horizontal illuminance should match as closely as possible, as
Lighting levels are determined by the type of sport played, this ensures that the television picture has a well-balanced
the speed of play and the size of the ball. Smaller ball size brightness.
and higher speed requires higher lighting levels. Lighting
requirements also differ according to the level of competition. Vertical illuminance
EN 12193, the European regulation for sports lighting, defines The athletes in any particular sporting event, as well as the
three different lighting classes. ball they’re using, can be understood as vertical surfaces.
This means that vertical illuminance (Ev) needs to be kept
• Class I - Top-level competition: International and national in mind. To guarantee an optimal view and make it possible
televised matches which generally involve large numbers of for the human eye to identify players from every direction,
spectators and potentially long viewing distances. Ev is measured at a height of 1,5 m, which corresponds
• Class II - Mid-level competition: National and local matches approximately to the faces of the players. Experience shows
which often involve a medium number of spectators and that there’s an intimate relationship between vertical and
medium viewing distances. horizontal illuminance. For sports with no specific vertical
• Class III - Low-level competition: Local or small matches with illuminance criteria, vertical illuminance will be sufficient if the
few spectators. required horizontal illuminance is achieved.

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