NIGHT SKY AND DARK ENVIRONMENTS: BEST MANAGEMENT PRACTICES FOR ARTIFICIAL LIGHT AT NIGHT ON BLM-MANAGED LANDS TECHNICAL NOTE 457 53 5.3 BMPs for Lighting Only When Needed The following BMPs address lighting only when needed for safety, security, and task completion. 5.3.1 Use Lighting Controls to Limit Lighting to Specified Periods Ensure that any lights that are not motion-activated or otherwise automatically controlled are turned off when not in use (USFWS 2016), especially architectural lighting, upper story interior lighting, and lobby or atrium lighting. This practice potentially reduces all types of light pollution, benefitting both wildlife and humans. It also saves money and reduces wasted energy. Notes: To turn lights off when not needed, keep the lighting controls accessible and understandable to the users. Additionally, use lighting controls, such as motion sensors (both interior and exterior), infrared sensors, photo sensors, radar sensors, and timers, to limit lighting to specified periods when it is needed, to turn lighting on automatically when triggered by the presence of humans, and to dim/turn off lighting when there is little or no activity. This practice can reduce effects on wildlife, reduce aesthetic and astronomical effects, save money, and reduce wasted energy. Lighting controls can also change the light source spectrum through spectral tuning for certain times of the night or seasonally (see Section 4.4) Notes: Motion detectors have a variety of capabilities, so choose devices carefully for the intended application. The user can generally adjust the duration of the lighting once triggered. The lighting should stay on no more than 5 minutes before the light is again switched off. Motion detectors have limited distance ranges and are subject to accidental “tripping” by animals. Generally, the user can adjust the sensitivity threshold at which the sensor triggers. Ensure the motion sensor is pointed at the proper location to trigger the light. Maintain and check motion sensors periodically for proper operation. Dusk-todawn lighting controlled by photocell alone is not recommended where required for safety. At Homestead National Historical Park, most visitor center lighting is turned off at night. Artificially illuminated areas may cause some bats to delay emergence from roosting sites.
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