Key Considerations while designing a Sports Field

1. Horizontal Illuminance (Eh)- the average illuminance on the horizontal plane of field of play

2. Vertical Illuminance (Ev) – the average illuminance on the vertical plane perpendicular to the field of play

The vertical illuminance is more significant for televised sports matches. This provides better visibility of players and the ball.

3. Uniformity is the ratio of

• the ratio of the lowest to the highest illuminance (U1 = Emin/Emax)
• the ratio of the lowest to the average illuminance (U2 = Emin/Eaverage)

The uniformity is measured as both ratios of minimum to average and as a minimum to maximum lighting levels.

The uniformity or ratio of variation in lighting level across the field is a major factor during the design. Too much difference in lighting levels at various points along the field will cause visual discomfort to players. Also, this will affect the visual comfort of spectators and television screening cameras.

4. Design Precision

A well-designed lighting system is required for any indoor and outdoor sports facility because of the high precision required in light levels and uniformity. For Sports fields conducting televised events, light level, and uniformity requirements are very high as per Internal Standards.

5. Energy Consumption & Optimum Design

Due to the huge amount of light level required especially for televised and international level matches, the energy consumed is very high. The luminaire design and optic were chosen should be fair enough to optimize the luminaire quantity and energy. With a proper design, we can optimize the number of luminaires, masts in the case of outdoor installations and minimize the amount of energy spent. Proper reliable third-party software should be used for this high-precision computing.

6. Visual Comfort by Avoiding Glare & Shadow

More than any other application, due to the higher lighting level, creating an appealing visual atmosphere using artificial lighting is required in Sports Fields. Poorly designed lighting with shadows and glare can cause fatigue and discomfort to both the players and spectators.

Luminaires should be aimed out of the direct view of players as it might cause glare while playing.

CIE112 defines glare evaluation for outdoor sports fields. It rates glare rating factor(GR) ranging from 10 to 90 as its value. Lowering the glare factor better the visual comfort for players and spectators.

Note: GR value of 50 is generally specified as the maximum allowable for outdoor sports projects.

7. Light Loss Factor

The light loss factor is chosen for the design according to the installation area and the periodic cleaning and maintenance cycle. We consider light loss factors during lighting design in order to account for the lighting deterioration over the period of use. So, it will be possible to maintain the average illuminance for a particular period. For example, consider the average lux level required is 100 lux and the installation time chosen is 100,000 hours. Then the sports field will have a maintained average of 100 lux or above for 100,000 hours starting from day 1.

8. Stray Light or Light Pollution

The stray light from the outdoor installation can cause disturbance to drivers on adjacent roads, nearby properties, or users. The lighting system should be properly designed and aimed to control light spills as per the guidelines.

9. Colour temperature of Light Source & Colour Rendering

Sports lighting normally demands a color temperature of between 4000 and 6500 K for the light source. The lower the colour temperature warmer the light colour is.

Colour rendering index (CRI) is a measure of how accurately an object’s colour is reproduced by the light source. Higher colour rendering light sources shall be used for televised events.

LED lighting has brought up debate as CRI is no more the correct color measurement metric for TV broadcasting. CRI was based on the human eye response curve and is not appropriate for sports broadcast cameras that transmit in saturated colors.

Due to the above reason, for televised events Television Lighting Consistency Index (TLCI) is the metric being developed by the European Broadcasting Union (EBU) which is based on camera response. The accepted value right now is that it should be easy to get colors accurate if the TLCI is > 80.

10. Flicker Control

Flicker effect is caused during a replay super slow-motion mode in the camera in TV broadcasting.

This is because of the interference due to the non-uniform ratio between Camera scanning frequency and the frequency of alternating current input of artificial lights. This is visible only during slow-motion replay.

A flicker factor of less than 3 percent is recommended for sports lighting by Sports federations.

11. Spectator Area Lighting

Safety lighting for easy movement of spectators should be taken care of. Proper emergency lighting as per local lighting standards should be made in case of power outages for providing a safe atmosphere inside the stadium and also during the evacuation of spectators.

A well-designed Sports lighting installation should comply with the following:

• Illuminance Level as per Standards.
• Uniformity.
• Glare Control.
• Colour Rendering.
• Optimised luminaire selection, quantity, and Energy usage.
• Control of Shadows.
• Flicker-Free.
• Control of Light Spill or Light Pollution to the surroundings and to the sky and should be within the specified limits.
• Visual comfort for both players and spectators.
• Contrast
• Proper Luminaire Mounting Height, Arrangement, Locations & Mast locations.
• Colour temperature between 4000 to 6500K.