We lease the space out for outside users when not in use by the school. The reactions from staff, students and outside groups have all been very positive and we are very pleased with the appearance of the facility at night. It definitely enhances the reputation of the school to have such a facility.
Project Description
LDP Ltd was engaged by Westlake Girls High School for the lighting component of their outdoor hockey fields.
Concept Brief
LDP Ltd was engaged to design a lighting solution, for the new hockey field for school and local club games, that provided a maintained average illuminance of 350 lux with minimum uniformities of 0.7 min/avg and 0.5 min/max.
Limitations
The hockey field is located immediately adjacent to SH1 northern motorway to the west and a main arterial highway and major intersection to the north and east, with residential properties on the far side of the arterial road.
For safety reasons it was essential to limit spill light to a maximum of 50 lux and Threshold Increment (TI) less than TI 20 to motorists on SH1 and the arterial road network. It was also necessary to limit glare to prevent any nuisance to the nearby residential properties with a maximum luminous intensity visible to residents of 7,500cd from any one luminaire.
The concept was to locate poles and aim luminaires to minimise off-site effects whilst ensuring excellent conditions on the field for the players and spectators.
The pole structures were left in a plain galvanised finish to blend with the daytime sky and kept as low as practical while having sufficient height to provide an economical means of achieving the required lighting design parameters.
Solution
With the restrictions imposed by the closeness of SH1 and main arterial road, the lighting poles were strategically located and at a height that did not interfere with, or intrude into any major view shafts, whilst still providing excellent playing conditions.Â
By carefully locating and aiming the luminaires we were able to minimise spill light and glare and, in conjunction with the pole height, ensured all light was projected downwards to achieve the required 350 lux maintained average illuminance on the field whilst minimising all off-site effects.
Design Criteria
The design has met all of the design criteria, i.e.
- Maintained average of 350 lux
- Uniformity of 0.72 min/avg & 0.5 min/max.Â
- Less than 50 lux at the SH1 and arterial road kerb line with a Threshold Increment of less than TI 20 to any motorists.
- An intensity of less than 7,500cd from any one luminaire when viewed from the surrounding residential properties.
Check measurements have been taken confirming that the initial values relating to these calculations have been achieved.
Visual Comfort
Glare is the most important element to consider for Visual Comfort. With all light projected in a downward direction, neutral colour temperature lamps of 4300K and good CRI (greater than 80) combined with placement of poles and luminaires, resulted in an effect that is indeed visually comfortable for players and off-site viewing.
Budget Restrictions
The budgets were set based on our estimates, then tendered and delivered within the agreed budget.
Dark Sky Considerations
The luminaires have been installed with zero upward tilt.
There is no direct light emitted above horizontal, reflected light is minimised and the wasted spill light is within very tight limitations. As such, the potential sky glow has been minimised as much as possible and the night sky preserved.
