For many years, the FAA has mandated standards for aeronautical ground lighting systems such as runway, taxiway and approach lighting. Other areas near the airport have been operating under guidance in the form of a published ‘RP’ – Recommended Practice guide. Until recently, the recommendations included the IES Aviation Lighting Committee document IESNA-RP-17-1987 (Airport Service Area Lighting), and the IESNA-RP-14-1987 (Airport Road Automobile Parking Area Lighting). Nearly 30 years later, these two RP’s have been combined and updated to IES RP-37-15 .
The document discusses lighting of the non-runway areas while emphasizing the restrictions, regulations, and best practices for the safe movement of aircraft, workers, pedestrians, and airport traffic. Many examples of light levels for various areas are suggested, but the document does not absolutely dictate light levels. This is partially due to conflicting suggested levels based on multiple functions in an area, local regulations, and other expectations and preferences that airports are likely to demand. This document will ‘shine a light’ on some of the RP-37 recommendations and provide additional insights into the important advantages that LED lighting provides
Outdoor lighting in the airfield’s protected environment illuminates activities such as aircraft parking, passenger boarding and deplaning on stairways, loading/unloading luggage, sanitary waste disposal hook-up, external air conditioning hook-up, ground power supply hook-up, aircraft fueling, mechanical checks and pre-flight inspections, plane de-icing, tire changes, and battery & hydraulic maintenance. Proper lighting specifications are critical to engineering an environment with ample safety and illumination for these important tasks.
One of the important concepts from the RP-37-15 document, is that the lighting designer is encouraged to consider many factors in specifying apron and near airport lighting – not only to ensure adequate light levels, but also to reduce spillage and glare in the eyes of pilots and tower personnel. Recently, larger planes, additional service equipment, tighter schedules, and more passenger traffic are presenting new challenges.
Fortunately, new lighting technologies provide opportunities to overcome these challenges and raise the bar in terms of more uniform lighting, truer color rendering, improved energy efficiency, longer service life, and comprehensive control solutions. Since objects are not inherently colored, but rather reflect different proportions of radiant energy, if the light incident on a surface changes, the apparent color of the object will change. LEDs can provide better color rendering due to advances in white LED technology outputting to a higher CRI (color rendering index) – thus producing vivid colors and contrasts. LEDs now provide more lumens per Watt when driven by high efficiency power supplies. Not only are these advanced power supply/drivers capable of accurately operating from a wide input voltage range, they are also capable of repeatable deeper dimming control.
Accordingly, electronic controls can more easily interface to these LED drivers for timed or motion sensed intensity changes, security purposes, guided exit paths, or emergency override sequences. Unlike older technologies, LEDs can be ramped up or turned on instantly and likewise turned down instantly or gradually at any temperature. Traditional lamps with hot vapors inside are plagued by cold temperatures and short cycles which dramatically reduce lamp life due to the gases condensing on colder internal surfaces on each power cycle – especially if not sufficiently warmed up or when cold winds rapidly cool the glass. This can be seen by lamps with black bands near the colder ends or a gradually cloudy film forming on the internal glass surface which further cuts light output and reduces the working gas inside, leading to less light output and premature burn-out and/or color shift. Lamps with internal gases rarely reach their rated lifetime in actual use outside. Further diminished output and color shifting should be expected. In contrast, since they are solid state devices, LEDs are much more reliable and do not suffer from short cycling, start-up, or low temperature issues.