CHAPTER 13. MARKING AND LIGHTING WIND TURBINES
13.1 Purpose.
This chapter provides guidelines for the marking and lighting applicable to single wind turbines and wind turbine farms. For the purpose of this AC, wind turbine farms are defined as a wind turbine development that contains more than three turbines. The recommended marking and lighting of these structures is intended to provide day and night conspicuity and to assist pilots in identifying and avoiding these obstacles.
13.2 General Standards.
The development of wind turbine farms is a very dynamic process, which changes based on the terrain. Each wind turbine farm is unique, therefore it is important that a lighting plan is developed that provides sufficient safety for air traffic. When developing lighting plans for wind turbine farms, it is best to use an aerial-view map or diagram of the turbine farm to plan the location of the required lighting. This way, a certain degree of strategy planning can be applied, which, in many instances, results in a minimal number of lights. Proximity to airports and VFR routes, extreme terrain where heights may vary widely, and local flight activity should be considered when developing a lighting plan. The following guidelines are recommended for wind turbines.
13.3 Wind Turbine Configurations.
Prior to marking and lighting the wind turbine farm, the configuration and the terrain of the wind turbine farm should be determined. The following is a description of the most common configurations (see Figure A-26):
1. Linear. Wind turbine farms in a direct, consecutive configuration, often located along a ridgeline, the face of a mountain, or along borders of a mesa or field. The line may be ragged in shape or be periodically broken, and may vary in size from just a few turbines to many turbines forming a line that is several miles long.
2. Cluster. Wind turbine farms arranged in circular configuration. A cluster is typically characterized by having a pronounced perimeter, with various turbines placed inside the circle at various, erratic distances throughout the center of the circle.
3. Grid. Wind turbine farms arranged in a geographical shape, such as a square or a rectangle, in which the turbines are placed a consistent distance from each other in rows, giving the appearance that they are part of a square pattern.
13.4 Marking Standards.
13.4.1 Wind turbines should be painted white or light grey, as these colors have been shown to be the most effective method for providing daytime conspicuity (see Figure A-26). Wind turbine manufacturers typically use a European color-matching system that is referred to as the RAL Color Standard. The RAL system uses a four-digit code to identify a specific color of paint, for example, an RAL 9xxx code would represent a color in the white/black range. The preferred white paint color is pure white, RAL 9010, or an equivalent, however most wind turbines currently produced are painted light grey, RAL 7035, which is the darkest acceptable off-white paint allowed. Any shade of white between these two RAL specifications is strongly recommended (see Table 13-1).
Table 13-1. Wind Turbine Paint Standard Colors
Color
RAL Number
Pure White (preferred color)
9010
Light Grey (Darkest Acceptable)
7035
13.4.2 In geographic areas that experience lengthy periods of snow cover (i.e., Alaska), and where it is deemed necessary, the mast of the turbine may be painted alternating bands of aviation orange and white to provide additional contrast against the snow. The nacelle and blades of the turbine must remain solid white or light grey (see Figure A-27).
13.4.3 Blades or blade tips must not be painted or manufactured in colors to camouflage wind turbines with the surrounding terrain.
13.4.4 For turbines that are constructed with lattice-type masts, the mast structure must be painted with alternating bands of aviation orange and white paint, in accordance with Chapter 3. The turbine’s nacelle and blades must remain solid white or light grey.
13.5 Lighting Standards.
13.5.1 Studies have shown that red lights provide the most conspicuity to pilots, therefore during nighttime hours and periods of reduced visibilities, wind turbine obstruction lighting should consist of FAA L-864 aviation red flashing, strobe, or pulsed obstruction lights. Any array of flashing, strobe, or pulsed obstruction lighting should be synchronized to flash simultaneously (within ±1/20 second (0.05 second) of each other). Light fixtures should be placed as high as
possible on the turbine nacelle so they are visible by a pilot approaching from any direction (see Figure A-28). Should any lighting fixture or the lighting system synchronization fail, a lighting outage report should be prepared in accordance with Chapter 2, paragraph 2.4.
Daytime lighting of wind turbines is not required. See paragraph 14.4 for daytime marking requirements.
13.5.2 In most cases, not all wind turbine units within a wind turbine farm need to be lighted.
Obstruction lights should be placed along the perimeter of the wind turbine farm so that there are no unlit separations or gaps more than 1/2 SM (0.80 km). Wind turbines within a grid or cluster should not have an unlighted separation or gap of more than 1 SM (1.61 km) across the interior of a grid or cluster of turbines (see Figure A-25).
1. Linear Turbine Configurations: Lights should be placed on the turbine positioned at each end of a line or string of turbines. Lights should also be placed along the line of turbines so that there is no more than a 1/2 SM (804.67 m) gap between the lighted turbines. In the event the gap between lights on the last segment of turbines is significantly short, it may be appropriate to move the lights on the turbine string back toward the starting point to present a wellbalanced string of lights. High concentrations of lights should be avoided.
2. Cluster Turbine Configurations. A turbine should be selected as a starting point along the outer perimeter of the cluster. The turbine should be lighted, and a light should be placed on the next turbine along the perimeter of the cluster (clockwise or counterclockwise) so that no more than a 1/2 SM (804.67 m) gap exists. This pattern should be continued around the perimeter of the cluster until the starting point is reached. In the event that the gap between the lights on the last segment of turbines is significantly short, it may be appropriate to move the lights along the perimeter of the cluster back toward the starting point to present a wellbalanced perimeter of lights. If the distance across the cluster is greater than 1 SM (1.61 km), additional lights should be placed on other turbines throughout the center of the cluster so that there are no unlighted gaps across the cluster. For example, if the distance across a wind turbine farm is 1.8 SM (2.90 km), a light should be placed on a turbine at approximately every 0.9 SM (1.45 km).
3. Grid Turbine Configurations. Turbines on the corners of the farm should be lit, and then use the same concept for selecting which turbines should be lit as outlined in paragraph 13.5.3.
13.5.3 Special Considerations.
Occasionally, some wind turbines may be located apart from the main group of turbines. If one or two wind turbines protrude from the general limits of the turbine farm, these turbines should be lighted in addition to those identified in the main group.Additional lighting may be necessary on wind turbines located on the interior of a cluster or grid configuration whose height is 100 feet
(30.48 m) or higher than the other wind turbines located within the farm.
13.6 Wind Turbines Above 499 Feet (152.10 m).
13.6.1 For wind turbines with a rotor tip height, while at top dead center, greater than 499 feet (152.10
m) AGL, but less than 699 feet (213.06 m) AGL, the turbines should be lighted in accordance with paragraph 13.5. In addition to these requirements, the top of the turbine’s nacelle should be equipped with a second L-864 flashing red light (see Figure A-28).
13.6.2 The two obstruction lights should be arranged horizontally, positioned on opposite sides of the nacelle, visible to a pilot approaching from any direction, and flash simultaneously. Using this lighting configuration ensures the conspicuity of turbines in this size category.
13.6.3 In the event one of the two obstruction lights fails, no light failure notification is required;
however, the light should be restored to service as soon as possible.
13.6.4 All turbines within this size category should be illuminated, regardless of their location within a wind turbine farm, and should be configured to flash simultaneously with the other turbines in the same farm. This requirement ensures the pilots operating at low altitudes above 500 feet AGL have sufficient warning that a wind turbine obstruction may be within their flight path.
13.7 Wind Turbines at or Above 699 Feet (213.36 m).
13.7.1 For wind turbines with a rotor tip height, while at top dead center, at or above 699 feet (213.06
m) AGL, additional lighting is required. All wind turbines of this size, regardless of number or configuration should be lighted.
13.7.2 In addition to the lighting identified in paragraphs 13.5 and 13.6, an additional level of lights is required at a point midway between the top of the nacelle and ground level. The location of the additional lights may be adjusted as necessary to allow mounting at a seam within the turbine’s mast.
13.7.3 The additional level of lights should consist of a minimum of three L-810 F flashing red lights configured to flash in unison with the two L-864 red flashing lights located at the top of the nacelle at a rate of 30 fpm (± 3 fpm). The L-810 F lights should be spaced at equal distances around the mast to ensure a pilot approaching from any direction has an unobstructed view of at least two of the lights (see Figure A-28).
13.7.4 For wind turbine structures with a mast diameter greater than 20 feet (6.10 m), four L- 810 red lights should be used.
13.7.5 All turbines within this size category should be illuminated, regardless of their location within a turbine farm, and should be configured to flash simultaneously with the other turbines in the same farm. This requirement ensures the pilots operating at low altitudes above 500 feet AGL have sufficient warning that a wind turbine obstruction may be within their flight path.
13.8 Lighting of Wind Turbines During Construction Phase.
To ensure proper conspicuity of turbines at night during construction, all turbines should be lighted with temporary lighting once they reach a height of 200 feet (60.96 m) or greater until the permanent lighting configuration is turned on. If practical, permanent obstruction lights should be installed and operated at each level as construction progresses. As the structure’s height continues to increase, the temporary lighting should be relocated to the structure’s uppermost height (see Figure A-30). An L-810 steady-burning red light must be used to light the structure during the construction phase, if the permanent L-864 flashing-red lights are not in place. The temporary lighting may be turned off for short periods if they interfere with construction personnel. If power is not available, turbines should be lighted with a self-contained, solarpowered, LED, steady-burning red light that meets the photometric requirements of an FAA L- 810 lighting system. The lights should be positioned to ensure a pilot has an unobstructed view of at least one light at each level. Using a NOTAM to justify not lighting the turbines until the entire project is completed is prohibited.
13.9 Lighting and Marking of Airborne Wind Turbines.
The FAA is currently conducting research to develop special lighting and marking standards for Airborne Wind Turbines. Sponsors should consult with their respective FAA OE Specialists for updated information.
13.10 Lighting and Marking of Offshore Wind Turbines.
FAA lighting and marking recommendations for Offshore Wind Turbines applies to structures in United States territorial seas, which extends from the coastline to 12 NM offshore. The Bureau of Ocean Energy Management (BOEM), which maintains jurisdiction of land leases beyond the 12 NM, is developing their own marking and lighting standards for offshore wind turbines and new construction must comply with those standards.
CHAPTER 14. MARKING AND LIGHTING TEMPORARY STRUCTURES
14.1 Purpose.
This chapter provides general guidelines for marking and lighting temporary structures, such as construction equipment, cranes, derricks, oil and drilling rigs, etc. The purpose of marking and lighting these obstructions is to indicate the presence and general outline of the structure to assist pilots when approaching from any direction to identify and avoid these obstacles. These guidelines are not to be considered all-inclusive, each obstacle must be evaluated individually and the determination will provide lighting requirements that are specific to the structure.
14.2 General Standards.
Due to the temporary nature, potential mobility, and ability to instantaneously extend to full height, accommodations must be made to mitigate the effects of these structures on the airspace for safe operations. Temporary structures are unique based on the structure type, size, and use, and the aeronautical study evaluates the potential effect on airspace. Proximity to airports, navigational aids (NAVAIDS), air routes, and local flight activity, as well as the duration of the project are considered during the evaluation process.
Marking and/or lighting of these structures is intended to provide day and night conspicuity and to assist pilots in identifying and avoiding these obstacles. In some cases, the Sponsor will also be required to initiate a NOTAM to provide additional mitigation procedures for the safe operation of the temporary obstacle due to the proximity of these aviation elements.
14.3 Marking Standards.
Marking is used to increase conspicuity of structures for daytime conditions. Flags are used to mark certain structures or objects when it is technically impractical to use paint. When using paint, various types of paint colors and patterns are used to mark structures and the pattern should ensure the paint contrasts with the surrounding environment.
14.3.1 Flag Markers.
Flag markers must be mounted at the highest point of the structure to ensure visibility. Some common examples of structures that may utilize this type of markers include, temporary construction equipment and vehicles, oil and drilling rigs, cranes, and derricks. Refer to Section
3.5.2 for full details.
1. Minimum Size. Each side of the flag marker should be at least two feet (0.61 m) in length.
2. Color Patterns. Flags should be colored as follows:
a. Solid colored flag must be aviation orange.
b. When using two colors, arrange two triangular sections, one aviation orange and the other white to form a rectangle.
c. Flags three feet (0.91 m) or larger should be a checkerboard pattern of aviation orange and white squares, each one foot (0.30 m) plus or minus 10 percent.
3. Display. Flag markers should be displayed around, on top, or along the highest edge of the obstruction. The flag staff should be strong enough to support the flag and be higher than the surrounding ground, structures, and/or objects of natural growth.
14.3.2 Paint.
1. Ideally cranes should be painted aviation orange or alternating aviation orange and white, however with flags and/or lights, contrasting bright colors that do not merge into the surrounding environment are acceptable. Colors that camouflage with the surrounding environment (i.e., sky blue, forest green, etc.) should be avoided.
2. Refer to paragraph 3.2, Paint Standard, for details.
14.3.3 Alternative to Marking.
1. Along with, or as an alternative to paint, medium intensity white lighting can be used to make the obstacle more conspicuous during daytime conditions for structures over 200 feet AGL.
2. High intensity lighting is not recommended on temporary structures.
14.4 Lighting Standards.
Lighting is used to increase conspicuity of structures for day or nighttime conditions and must be visible to a pilot approaching in any direction. When a temporary structure cannot be removed from site or lowered below the no-effect height, the addition of lighting will be used to alert pilots of their presence. Generally, red lights are recommended during the hours between sunset and sunrise and periods of reduced visibility, using marking for the remainder of the time with occasional exceptions. Lights must be mounted at the highest point of the structure, and in cases of more extensive structures additional lights may be necessary at intermediate levels and furthest horizontal points (i.e., horizontal boom ends, etc.) to clarify the outline of the structure (see Figure A-31).
1. Structures 150 feet (45.72 m) AGL or less . Two or more steady -burning or flashing red (L - 810/L-810 F) lights should be installed on the highest part of the structure in a manner to ensure an unobstructed view of one or more lights by a pilot.
2. Structures exceeding 150 feet (45.72 m) AGL and not more than 350 feet (106.68 m) AGL.
At least one red flashing (L-864) light should be installed on the highest part of the structure and intermediate levels of one or more flashing red lights (L-810 F) should be mounted in a manner to ensure an unobstructed view of one or more lights by a pilot.
a. Mounting Intermediate Level Lights. The number of light levels required is determined by the height of the structure, including all appurtenances, as shown in, Figure A-6. The number of lights on each level is determined by the shape and width of the structure. At least two or more of these lights (L-810 F) should be mounted diagonally or on diametrically opposite positions to ensure an unobstructed view of at least one light at each level by a pilot approaching in any direction. These lights should be configured to flash simultaneously with the L-864 flashing light on the top of the structure at a rate of 30 flashes per minute (fpm) (± 3 fpm). Steady burning lights (L-810) and red flashing lights (L-864) are not used as intermediate level lights on these types of structures.
3. Structures exceeding 350 feet (106.68 m) AGL. At least one red flashing (L-864) light should be installed on the highest part of the structure in a manner to ensure an unobstructed view of one or more lights by a pilot. In addition, intermediate levels of lights of flashing red (L -864) will be required.
a. Intermediate Levels Lights. The number of light levels required is determined by the height of the structure, including all appurtenances, as shown in, Figure A-6. The number of lights on each level is determined by the shape and width of the structure. At least two or more of these lights (L-864) should be mounted diagonally or on diametrically opposite positions to ensure an unobstructed view of at least one light at each level by a pilot approaching in any direction. These lights should be configured to flash simultaneously with the L-864 flashing light on the top of the structure at a rate of 30 flashes per minute (fpm) (± 3 fpm). Steady burning lights are not used on these types of structures.
14.4.1 Construction Cranes or Rigs (Oil and Drilling).
When a crane or rig cannot be removed from site or lowered below the no-effect height, the addition of lighting will be used to alert pilots of their presence during the hours between sunset and sunrise and periods of reduced visibility. Lights must be mounted at the highest point, and in cases of more extensive structures additional lights may be necessary at intermediate levels and furthest horizontal (i.e., horizontal boom ends, etc.) points to clarify the outline of the structure (see Figure A-32).
1. Systems. Steady burning and flashing red lights (L-864/L-810) may be used to light cranes and rigs. High-intensity lights (L-856) are not recommended.
2. Display. The flashing light (L-864) should be displayed on the highest point, and the steady light (L-810) at the ends of boom, and other various locations along the top of the structure to best define the outline. Additionally, in certain cases, intermediate level lighting or sidelights (L-810) may be required. For construction cranes with angular booms, the lights must be mounted on a pivot axis so the fixture remains level when the boom tilts to ensure the lights remain level and is not obscured by the structure.
3. Exceptions.
a. Architectural lighting or floodlights may be used in addition to, but not in place of, standard lighting provided they do not cause an adverse effect on the obstruction light fixture’s photometrics and do not result in an obscured view of one of more obstruction lights by a pilot.
b. In some cases, the boom or rig may be lowered below the no-effect height or removed from site, and nighttime lighting is not required.
14.4.2 Container Cranes.
1. These structures are generally used in brightly lit areas, however lighting must be used to alert pilots of the current configuration and presence of the obstruction during the hours between sunset and sunrise and periods of reduced visibility. Extensive structures require additional lights at intermediate levels and furthest horizontal points, (i.e., horizontal boom ends, etc.), as well as horizontal mid-points as necessary, to clarify the outline of the structure for pilots approaching from any direction.
2. Systems. Medium intensity white lights (L-865) may be used, however high-intensity lights (L-856) are not recommended.
3. Display. The lights should be displayed on the highest point, ends of boom, and other various ways to best define the size and shape of the structure. Lights must be mounted at the highest point at all times during usage. For large container cranes with angular booms, the lights must be mounted on a pivot axis so the fixture remains level when the boom tilts to ensure the lights remain level and is not obscured by the structure (see Figure A-33).
4. Exceptions. Architectural lighting or floodlights may be used in addition to, but not in place of, standard lighting provided they do not cause an adverse effect on the obstruction light fixture’s photometrics and do not result in an obscured view of one of more obstruction lights by a pilot.
14.5 Operational Characteristics.
When using flashing lights, the lights should flash simultaneously.
CHAPTER 15. MARKING AND LIGHTING EQUIPMENT AND INFORMATION
15.1 Purpose.
This chapter lists documents relating to obstruction marking and lighting systems and where they may be obtained.
15.2 Paint Standard.
15.2.1 Paint and aviation colors/gloss, referred to in this AC, with the exception of wind turbines, should conform to Aerospace Material Specification Standard, SAE-AMS- STD-595, Colors Used in Government Procurement, previously known as FED-STD- 595 (cancelled February 14, 2017). Wind turbines must meet the standards in Chapter 13, paragraph 13.4, of this AC.
15.2.2 Approved colors must be formulated without using lead, zinc chromate, or other heavy metals to match international aviation orange, white, and yellow, as listed in Table 3-1. All coatings must be manufactured and labeled to meet Federal Environmental Protection Act Volatile Organic Compound(s) guidelines, including the National Volatile Organic Compound Emission Standards for architectural coatings.
1. Exterior Acrylic Waterborne Paint. Coatings should be ready-mixed, 100 percent acrylic, exterior latex formulated for application directly to galvanized surfaces. Ferrous iron and steel or non-galvanized surfaces must be primed with a manufacturer-recommended primer compatible with the finish coat.
2. Exterior Solvent-Borne Alkyd-Based Paint. Coatings should be ready-mixed, alkyd-based, exterior enamel for application directly to non-galvanized surfaces, such as ferrous iron and steel. Galvanized surfaces must be primed with a manufacturer-recommended primer compatible with the finish coat.
Table 15-1. Aerospace Material Specification Standard, SAE-AMS-STD-595
Color Number Orange EA 12197 White EA 17875 Yellow EA 13538
15.3 Availability of Specifications and Advisory Circulars.
1. Federal and military specifications describing the technical characteristics of various paints and their application techniques are available through the ASSIST Database at https://assist.dla.mil/online/start/. ASSIST is a robust, comprehensive website used by standardization management activities to develop, coordinate, distribute, and manage defense and federal specifications and standards, military handbooks, commercial item descriptions, data item descriptions, and related technical documents prepared in accordance with the policies and procedures of the Defense Standardization Program (DSP).
2. For Federal Product Description line items only (for download, refer to ASSIST), use the following Uniform Resource Locator (URL):
https://www.gsa.gov/buying-selling/purchasing-programs/requisition- programs/gsa-globalsupply/supply-standards/index-of-federal- specifications-standards-and-commercial-itemdescriptions.
3. Copies of FAA Advisory Circulars may be obtained online at:
https://www.faa.gov/regulations_policies/advisory_circulars/
15.4 Lights and Associated Equipment Standards.
The lighting equipment referred to in this AC should conform to the latest edition of one of the following specifications, as applicable:
1. Obstruction Lighting Equipment.
a. AC 150/5345-43, FAA Specification for Obstruction Lighting Equipment.
b. Military Specifications MIL-L-6273, Light, Navigational, Beacon, Obstacle, or Code, Type G-1.
c. Military Specifications MIL-L-7830, Light Assembly, Marker, Aircraft Obstruction.
2. Certified Equipment.
a. AC 150/5345-53, Airport Lighting Certification Program, lists the manufacturers that have demonstrated compliance with the specification requirements of AC 150/5345-43, FAA Specification for Obstruction Lighting Equipment.
b. Other manufacturers’ equipment may be used provided the equipment meets the specification requirements of AC 150/5345-43, FAA Specification for Obstruction Lighting Equipment.
3. Airport Lighting Installation and Maintenance.
AC 150/5340-30, Design and Installation Details for Airport Visual Aids.
4. Vehicles and Structures.
a. AC 150/5210-5, Painting, Marking, and Lighting of Vehicles Used on an Airport, contains provisions for marking vehicles principally used on airports.
b. FAA Standard FAA-STD-003, Paint Systems for Structures. Obstruction marking for FAA facilities must conform to FAA Drawing Number D-5480 (page 39 of 42).
15.5 Availability of Military Specifications.
The military standards and specifications listed above may be obtained from:
DAP/DODSSP Building 4, Section D 700 Robbins Avenue Philadelphia, PA 19111-5904 Telephone: (215) 737-8000 FAX: (215) 737-7155
URL: https://quicksearch.dla.mil/ (ASSIST Database)