Vigilante Stadium Lighting Design
Helena Public Schools’ Vigilante Stadium is in Helena’s South-Central neighborhood and home field to both Helena High and Capital High schools. In the fall during football season, it is busy nearly every Friday night as both schools take turns hosting home games and again throughout the spring for middle and high school track meets.
The stadium, with its 1970-era HID lighting system, regularly sent the district’s maintenance staff scrambling for replacement parts that were extremely difficult to find and, in most cases, obsolete. Most of the poles had at least one fixture that did not function, and the lighting output for the remaining lights had degraded past their useful life. Vigilante Stadium is surrounded by residential homes that were regularly blinded by the glare from the old lighting system. Power consumption of the obsolete HID lights and light spill gave the Helena schools staff reason to pursue a new lighting solution.
The existing field had two separate existing electrical services, one on each sideline with no connection between them. Staff operated the lights via a keyed switch on each sideline and had to allow 10-15 minutes for the lights to come to full brightness. All of the stadium lights could not be turned on concurrently because it took time to walk across the field to go from one switch to the other which was located on the opposite side.
Morrison-Maierle supplied electrical engineering design, control, and fixture choice for the project. The main goals of the project were to:
- Improve the light levels on the field.
- Supply a central location for light controls.
- Reduce maintenance costs.
- Reduce light spill into the surrounding neighborhoods.
- Reduce power consumption.
Morrison-Maierle took lighting levels of the existing lights to establish a baseline and then performed lighting calculations for the new LED fixtures. Vigilante Stadium is an IES Class III field. The recommended lighting level is an average of 35 footcandles (fc.) on the field of play. The existing lighting level was measured at an average of 19.4 fc., far below the recommended level. The new LED lighting was calculated to be 35 fc. average, but was measured to be 37.8 fc. after the installation was complete. Morrison-Maierle performed lighting measurements on a 10-yard grid of the entire football field for initial and verification measurements.
The maintenance staff required that the new fixtures have only the LED array in them and that the drivers for each fixture be mounted low on the pole. With the top of the existing poles 100 feet above the field of play, they did not want to climb or rent a crane to replace any fixture drivers. The system design included remote mounted driver enclosures—located 10-15 ft above the ground to minimize vandalism potential—that allow servicing from a ladder or bucket truck. With an estimated life of 200,000 hours for the LED compared to the 12,000-15,000 hours for the existing metal-halide lights, the district reduced the need to put a person at the top of the poles for repairs.
The reduction in light spill to the surrounding neighborhoods was accomplished by the LED optics and glare shields built into the fixtures. The combination of these two design parameters reduced the light spill into these neighborhoods.
Power consumption of the overall system was reduced from 44 fixtures at 1500W/ea. for the existing metal-halide, to 44 fixtures at 934W/each for the LED. This is an overall drop of 38% in power consumption. Each new fixture is rated at 120,000 lumens, translating into 128 lumens/watt.
To reduce the overall cost of the system, Morrison-Maierle inspected the two existing electrical services and circuiting to each pole. The team also inspected the existing poles to decide if they could be reused. This ended up being a cost-savings measure because in the end, they were able to use the existing feeders and poles for the new LED fixtures.
Morrison-Maierle’s design included a new system control panel for the existing press box. Since the playing surface is one of two remaining natural turf AA football fields in the state, the school district did not allow any digging across the field for control wiring. This required wireless control signals from the main panel to connect each driver enclosures located on each pole.
Morrison-Maierle’s Survey Department took drone photos and video of the field to gather data that accurately located the existing electrical service(s), stadium light poles, and football field boundaries. Data from the drone created an accurate comparison between the former lighting system and the new LED lighting using high quality video.
Partnering with WiLL (Wisconsin Lighting Labs), the team used high-output WiLLsport KB8 LED light fixtures and remote drivers with wireless controls. The new system incorporated enhanced lighting on the field, custom aiming and glare shields to channel the light to the field rather than creating spill into the adjacent residential neighborhood, and lighting controls that included WiLL’s entertainment package.
Coupled with increased energy savings and reduced maintenance costs, Helena Public Schools now has a stadium with remote-controlled lights that are brighter, yet more concentrated on the field itself. The amount of light the new system supplies went from just over 19 fc. to a little over 37 fc. meeting the requirements of an IES class III stadium lighting system. The new lights illuminate instantly and are controlled in the press box.
Further enhancements include being able to highlight different parts of the field—the center of the field, each endzone along with a variety of flashing patterns that can be activated after a touchdown or dimming at the end of the game.