CHAPTER 11. MARKING AND LIGHTING MOORED BALLOONS AND KITES
110. PURPOSE29
111. STANDARDS29
112. MARKING29
113. PURPOSE29
114. OPERATIONAL CHARACTERISTICS29
CHAPTER 12. MARKING AND LIGHTING EQUIPMENT AND INFORMATION
120. PURPOSE31
121. PAINT STANDARD31
122. AVAILABILITY OF SPECIFICATIONS31
123. LIGHTS AND ASSOCIATED EQUIPMENT31
124. AVAILABILITY32
CHAPTER 13. MARKING AND LIGHTING WIND TURBINE FARMS
130. PURPOSE33
131. GENERAL STANDARDS33
132. WIND TURBINE CONFIGURATIONS33
133. MARKING STANDARDS33
134. LIGHTING STANDARDS33
APPENDIX 1: SPECIFICATIONS FOR OBSTRUCTION LIGHTING EQUIPMENT
CLASSIFICATION
APPENDIXA1-2
APPENDIX 2. MISCELLANEOUS
1. RATIONALE FOR OBSTRUCTION LIGHT INTENSITIESA2-1
2. DISTANCE VERSUS INTENSITIESA2-1
3. CONCLUSIONA2-1
4. DEFINITIONSA2-1
5. LIGHTING SYSTEM CONFIGURATIONA2-2
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CHAPTER 1. ADMINISTRATIVE AND GENERAL PROCEDURES
1. REPORTING REQUIREMENTS A sponsor proposing any t ype of construction or alteration of a structure that may affect the National Airspace System (NAS) is required under the provisions of Title 14 Code of Federal Regulations (14 CFR part 77) to notify the FAA by completing the Notice of Proposed Construction or Alteration form (FAA Form 7460-1). The form should be sent to the Obstruction Evaluation service (OES). Copies of FAA Form 7460-1 may be obtained from OES, Airports District Office or FAA Website at http://oeaaa.faa.gov.
2. PRECONSTRUCTION NOTICE The notice must be submitted:
a. At least 30 days prior to the date of proposed construction or alteration is to begin.
b. On or before the date an application for a construction permit is filed with the Federal Communications Commission (FCC). (The FCC advises its applicants to file with the FAA well in advance of the 30-day period in order to expedite FCC processing.)
3. FAA ACKNOWLEDGEMENT The FAA will acknowledge, in writing, receipt of each FAA Form 7460-1 notice received.
4. SUPPLEMENTAL NOTICE REQUIREMENT
a. If required, the FAA will include a FAA Form 7460-2, Notice of Actual Construction or Alteration, with a determination.
b. FAA Form 7460-2 Part 1 is to be completed and sent to the FAA at least 48 hours prior to starting the actual construction or alteration of a structure.
Additionally, Part 2 shall be submitted no later than 5 days after the structure has reached its greatest height. The form should be sent to the OES.
c. In addition, supplemental notice shall be submitted upon abandonment of construction.
d. Letters are acceptable in cases where the construction/alteration is temporary or a proposal is abandoned. This notification process is designed to permit the FAA the necessary time to change affected procedures and/or minimum flight altitudes, and to otherwise alert airmen of the structure’s presence.
Note-
NOTIFICATION AS REQUIRED IN THE DETERMINATION IS CRITICAL TO AVIATION SAFETY.
5. MODIFICATIONS AND DEVIATIONS
a. Requests for modification or deviation from the standards outlined in this AC must be submitted to the OES. The sponsor is responsible for adhering to approved marking and/or lighting limitations, and/or recommendations given, and should notify the FAA and FCC (for those structures regulated by the FCC) prior to removal of marking and/or lighting. A request received after a determination is issued may require a new study and could result in a new determination.
b. Modifications. Modifications will be based on whether or not they impact aviation safety. Examples of modifications that may be considered:
1. Marking and/or Lighting Only a Portion of an Object. The object may be so located with respect to other objects or terrain that only a portion of it needs to be marked or lighted.
2. No Marking and/or Lighting. The object may be so located with respect to other objects or terrain, removed from the general flow of air traffic, or may be so conspicuous by its shape, size, or color that marking or lighting would serve no useful purpose.
3. Voluntary Marking and/or Lighting . T h e object may be so located with respect to other objects or terrain that the sponsor feels increased conspicuity would better serve aviation safety. Sponsors who desire to voluntarily mark and/or light their structure should request the proper marking and/or lighting from the FAA to ensure no aviation safety issues are impacted.
4. Marking or Lighting an Object in Accordance with the Standards for an Object of Greater Height or Size. The object may present such an extraordinary hazard potential that higher standards may be recommended for increased conspicuity to ensure the safety to air navigation.
c. Deviations. The OES conducts an aeronautical study of the proposed deviation(s) and forwards its recommendation to FAA headquarters in Washington, DC, for final approval. Examples of deviations that may be considered:
AC 70/7460-1K CHG 22/1/07
1. Colors of objects.
2. Dimensions of color bands or rectangles.
3. Colors/types of lights.
4. Basic signals and intensity of lighting.
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AC 70/7460-1K CHG 2 2/1/07
5. Night/day lighting combinations.
6. Flash rate.
d. The FAA strongly recommends that owners become familiar with the different types of lighting systems and to specifically request the type of lighting system desired when submitting FAA Form 7460-1. (This request should be noted in “item 2.D” of the FAA form.) Information on these systems can be found in Chapter 12, Table 4 of this AC. While the FAA will make every effort to accommodate the structure sponsor’s request, sponsors should also request information from system manufacturers in order to determine which system best meets their needs based on purpose, installation, and maintenance costs.
6. ADDITIONAL NOTIFICATION Sponsors are reminded that any change to the submitted information on which the FAA has based its determination, including modification, deviation or optional upgrade to white lighting on structures which are regulated by the FCC, must also be filed with the FCC prior to making the change for proper authorization and annotations of obstruction marking and lighting. These structures will be subject to inspection and enforcement of marking and lighting requirements by the FCC. FCC Forms and Bulletins can be obtained from the FCC’s National Call Center at 1-888-CALL-FCC (1-888-225-5322). Upon completion of the actual change, notify the Aeronautical Charting office at:
NOAA/NOS Aeronautical Charting Division Station 5601, N/ACC113 1305 East-West Highway Silver Spring, MD 20910-3233
7. METRIC UNITS To promote an orderly transition to metric units, sponsors should include both English and metric (SI units) dimensions. The metric conversions may not be exact equivalents, however, until there is an official changeover to the metric system, the English dimensions will govern.
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CHAPTER 2. GENERAL
20. STRUCTURES TO BE MARKED AND
LIGHTED Any temporary or permanent structure, including all appurtenances, that exceeds an overall height of 200 feet (61m) above ground level (AGL) or exceeds any obstruction standard contai ned in 14 CFR part 77, should normally be marked and/or lighted. However, an FAA aeronautical study may reveal that the absence of marking and/or lighting will not impair aviation safety. Conversely, the object may present such an extraordinary hazard potential that higher standards may be recommended for increased conspicuity to ensure safety to air navigation.
Normally outside commercial lighting is not considered sufficient reason to omit recommended marking and/or lighting. Recommendations on marking and/or lighting structures can vary depending on terrain feat ures, weather patterns, geographic location, and in the case of wind turbines, number of structures and overall layout of design.
The FAA may also recommend marking and/or lighting a structure that does not exceed 200 (61m) feet AGL or 14 CFR part 77 standards because of its particular location.
21. GUYED STRUCTURES The guys of a 2,000-foot (610m) skeletal tower are anchored from 1,600 feet (488m) to 2,000 feet (610m) from the base of the structure. This places a portion of the guys 1,500 feet (458m) from the tower at a height of between 125 feet (38m) to 500 feet (153m) AGL. 14 CFR part 91, section 119, requires pilots, when operating over other than congested areas, to remain at least 500 feet (153m) from manmade structures. Therefore, the tower must be cleared by 2,000 feet (610m) horizontally to avoid all guy wires. Properly maintained marking and lighting are important for increased conspicuity since the guys of a structure are difficult to see until aircraft are dangerously close.
22. MARKING AND LIGHTING EQUIPMENT Considerable effort and research have been expended in determining the minimum marking and lighting systems or quality of materials that will produce an acceptable level of safety to air navigation. The FAA will recommend the use of only those marking and lighting systems that meet established technical standards. While additional lights may be desirable to identify an obstruction to air navigation and may, on occasion be recommended, the FAA will recommend minimum standards in the interest of safety, economy, and related concerns. Therefore, to provide an adequate level of safety, obstruction lighting systems should be installed, operated, and maintained in accordance with the recommended standards herein.
23. LIGHT FAILURE NOTIFICATION
a. Sponsors should keep in mind that conspicuity is achieved only when all recommended lights are working. Partial equipment outages decrease the margin of safety. Any outage should be corrected as soon as possible. Failure of a steady burning side or intermediate light should be corrected as soon as possible, but notification is not required.
b. Any failure or malfunction that lasts more than thirty (30) minutes and affects a top light or flashing obstruction light, regardless of its position, should be reported immediately to the appropriate flight service station (FSS) so a Notice to Airmen (NOTAM) can be issued. Toll-free numbers for FSS are listed in most telephone books or on the web at http://www.afss.com. This report should contain the following information:
AC 70/7460-1K CHG 2 2/1/07
1. Name of persons or organizations reporting light failures including any title, address, and telephone number.
2. The type of structure.
3. Location of structure (including latitude and longitude, if known, prominent structures, landmarks, etc.).
4. Height of structure above ground level (AGL)/above mean sea level (AMSL), if known.
5. A return to service date.
6. FCC Antenna Registration Number (for structures that are regulated by the FCC).
Note-
1. When the primary lamp in a double obstruction light fails, and the secondary lamp comes on, no report is required. However, when one of the lamps in an incandescent L-864 flashing red beacon fails, it should be reported.
2. After 15 days, the NOTAM is automa tically deleted from the system.
The sponsor is responsible for calling the nearest FSS to extend the outage date or to report a return to service date.
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AC 70/7460-1K CHG 2 2/1/07
24. NOTIFICATION OF RESTORATION As soon as normal operation is restored, notify the same FSS that received the notification of failure.
The FCC advises that noncompliance with notification procedures could subject its sponsor to penalties or monetary forfeitures.
25. FCC REQUIREMENT FCC licensees are required to file an environmental assessment with the Commission when seeking authorization for the use of the high intensity flashing white lighting system on structures located in residential neighborhoods, as defined by the applicable zoning law.
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AC 70/7460-1K CHG 2 2/1/07 CHAPTER 3. MARKING GUIDLINES
30. PURPOSE This chapter provides recommended guidelines to make certain structures conspicuous to pilots during daylight hours. One way of achieving this conspicuity is by pain ting and/or marking these structures. Recommendations on marking structures can vary depending on terrain features, weather patterns, geographic location, and in the case of wind turbines, number of structures and overall layout of design.
31. PAINT COLORS Alternate sections of aviation orange and white paint should be used as they provide maximum visibility of an obstruction by contrast in colors.
32. PAINT STANDARDS The following standards should be followed. To be effective, the paint used should meet specific color requirements when freshly applied to a structure.
Since all outdoor paints deteriorate with time and it is not practical to give a maintenance schedule for all climates, surfaces should be repainted when the color changes noticeably or its effectiveness is reduced by scaling, oxidation, chipping, or layers of contamination.
a. Materials and Application . Quality paint and materials should be selected to provide extra years of service. The paint should be compatible with the surfaces to be painted, including any previous coatings, and suitable for the environmental conditions. Surface preparation and paint application should be in accordance with manufacturer’s recommendations.
Note- In-Service Aviation Orange Color Tolerance Charts are available from private suppliers for determining when repainting is required. The color should be sampled on the upper half of the structure, since weathering is greater there.
b. Surfaces Not Requiring Paint . Ladders, decks, and walkways of steel towers and similar structures need not be painted if a smooth surface presents a potential hazard to maintenance personnel. Paint may also be omitted from precision or critical surfaces if it would have an adverse effect on the transmission or radiation characteristics of a signal.
However, the overall marking effect of the structure should not be reduced.
c. Skeletal Structures . Complete all marking/painting prior to or immediately upon completion of construction. This applies to catenary support structures, radio and television towers, and similar skeletal structures. To be effective, paint should be applied to all inner and outer surfaces of the framework.
33. PAINT PATTERNS Paint patterns of various types are used to mark structures. The pattern to be used is determined by the size and shape of the st ructure. The following patterns are recommended.
a. Solid Pattern . Obstacles should be colored aviation orange if the structure has both horizontal and vertical dimensions not exceeding 10.5 feet
(3.2m).
b. Checkerboard Pattern. Alternating rectangles of aviation orange and white are normally displayed on the following structures:
1. Water, gas, and grain storage tanks.
2. Buildings, as required.
3. Large structures exceeding 10.5 feet (3.2m) across having a horizontal dimension that is equal to or greater than the vertical dimension.
c. Size of Patterns. Sides of the checkerboard pattern should measure not less than 5 feet (1.5m) or more than 20 feet (6m) and should be as nearly square as possible. However, if it is impractical because of the size or shape of a structure, the patterns may have sides less than 5 feet (1.5m).
When possible, corner surfaces should be colored orange.
d. Alternate Bands . Alternate bands of aviation orange and white are normally displayed on the following structures:
1. Communication towers and catenary support structures.
2. Poles.
3. Smokestacks.
4. Skeletal framework of storage tanks and similar structures.
5. Structures which appear narrow from a side view, that are 10.5 feet (3.2m) or more across and the horizontal dimension is less than the vertical dimension.
6. Coaxial cable, conduits, and other cables attached to the face of a tower.
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AC 70/7460-1K 03/1/00
e. Color Band Characteristics . Bands for structures of any height should be:
1. Equal in width, provided each band is not less than 1 1/2 feet (0.5m) or more than 100 feet (31m) wide.
2. Perpendicular to the vertical axis with the bands at the top and bottom ends colored orange.
3. An odd number of bands on the structure.
4. Approximately one-seventh the height if the structure is 700 feet (214m) AGL or less. For each additional 200 feet (61m) or fraction thereof, add one
(1) additional orange and one (1) additional white band.
5. Equal and in proportion to the structure’s height AGL.
Structure Height to Bandwidth Ratio
Example: If a Structure is:
Greater Than But Not More Than Band Width
10.5 feet
(3.2m) 700 feet (214m) 1/7 of height 701 feet (214m) 900 feet (275m) 1/9 of height 901 feet (275m) 1,100 feet (336m) 1/11 of height 1,100 feet (336m) 1,300 feet (397m) 1/13 of height TBL 1
f. Structures With a Cover or Roof . If the structure has a cover or roof, the highest orange band should be continued to cover the entire top of the structure.
g. Skeletal Structures Atop Buildings . If a flagpole, skeletal structure, or similar object is erected on top of a building, the combined height of the object and building will determine whether marking is recommended; however, only the height of the object under study determines the width of the color bands.
h. Partial Marking . If marking is recommended for only a portion of a structure because of shielding by other objects or terrain, the width of the bands should be determined by the overall height of the structure. A minimum of three bands should be displayed on the upper portion of the structure.
i. Teardrop Pattern. Spherical water storage tanks with a single circular standpipe support may be marked in a teardrop-striped pattern. The tank should show alternate stripes of aviation orange and white.
The stripes should extend from the top center of the tank to its supporting standpipe. The width of the stripes should be equal, and the width of each stripe at the greatest girth of the tank should not be less than 5 feet (1.5m) nor more than 15 feet (4.6m).
j. Community Names. If it is desirable to paint the name of the community on the side of a tank, the stripe pattern may be broken to serve this purpose.
This open area should have a maximum height of 3 feet (0.9m).
k. Exceptions. Structural designs not conducive to standard markings may be marked as follows:
1. If it is not practical to color the roof of a structure in a checkerboard pattern, it may be colored solid orange.
2. If a spherical structure is not suitable for an exact checkerboard pattern, the shape of the rectangles may be modified to fit the shape of the surface.
3. Storage tanks not suitable for a checkerboard pattern may be colored by alternating bands of aviation orange and white or a limited checkerboard pattern applied to the upper one-third of the structure.
4. The skeletal framework of certain water, gas, and grain storage tanks may be excluded from the checkerboard pattern.
34. MARKERS Markers are used to highlight structures when it is impractical to make them conspicuous by painting.
Markers may also be used in addition to aviation orange and white paint when additional conspicuity is necessary for aviation safety. They should be displayed in conspicuous positions on or adjacent to the structures so as to retain the general definition of the structure. They should be recognizable in clear air from a distance of at least 4,000 feet (1219m) and in all directions from which aircraft are likely to approach. Markers should be distinctively shaped,
i.e., spherical or cylindrical, so they are not mistaken for items that are used to convey other information.
They should be replaced when faded or otherwise deteriorated.
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AC 70/7460-1K CHG 18/1/00
a. Spherical Markers. Spherical markers are used to identify overhead wires. Markers may be of another shape, i.e., cylindrical, provided the projected area of such markers will not be less than that presented by a spherical marker.
1. Size and Color.
The diameter of the markers used on extensive catenary wires across canyons, lakes, rivers, etc., should be not less than 36 inches (91cm). Smaller 20-inch (51cm) spheres are permitted on less extensive power lines or on power lines below 50 feet (15m) above the ground and within 1,500 feet (458m) of an airport runway end. Each marker should be a solid color such as aviation orange, white, or yellow.
2. Installations.
(a) Spacing. Markers should be spaced equally along the wire at intervals of approximately 200 feet (61m) or a fraction thereof. Intervals between markers should be less in critical areas near runway ends (i.e., 30 to 50 feet (10m to 15m)). They should be displayed on the highest wire or by another means at the same height as the highest wire. Where there is more than one wire at the highest point, the markers may be installed alternately along each wire if the distance between adjacent markers meets the spacing standard. This method allows the weight and wind loading factors to be distributed.
(b) Pattern. An alternating color scheme provides the most conspicuity against all backgrounds. Mark overhead wires by alternating solid colored markers of aviation orange, white, and yellow. Normally, an orange sphere is placed at each end of a line and the spacing is adjusted (not to exceed 200 feet (61m)) to accommodate the rest of the markers. When less th an four markers are used, they should all be aviation orange.
b. Flag Markers . Flags are used to mark certain structures or objects when it is technically impractical to use spherical markers or painting. Some examples are temporary construction equipment, cranes, derricks, oil and other drilling rigs. Catenaries should use spherical markers.
1. Minimum Size. Each side of the flag marker should be at least 2 feet (0.6m) in length.
2. Color Patterns. Flags should be colored as follows:
(a) Solid. Aviation orange.
(b) Orange and White . Arrange two triangular sections, one aviation orange and the other white to form a rectangle.
(c) Checkerboard. Flags 3 feet (0.9m) or larger should be a checkerboard pattern of aviation orange and white squares, each 1 foot (0.3m) plus or minus 10 percent.
3. Shape. Flags should be rectangular in shape and have stiffeners to keep them from drooping in calm wind.
4. Display. Flag markers should be displayed around, on top, or along the highest edge of the obstruction. When flags are used to mark extensive or closely grouped obstructions, they should be displayed approximately 50 feet (15m) apart. The flag stakes should be of such strength and height that they will support the flags above all surrounding ground, structures, and/or objects of natural growth.
35. UNUSUAL COMPLEXITIES The FAA may also recommend appropriate marking in an area where obstructions are so grouped as to present a common obstruction to air navigation.
36. OMISSION OR ALTERNATIVES TO MARKING There are two alternatives to marking. Either alternative requires FAA review and concurrence.
a. High Intensity Flashing White Lighting Systems. The high intensity lighting systems are more effective than aviation orange and white paint and therefore can be recommended instead of marking. This is particularly true under certain ambient light conditions involving the position of the sun relative to the direction of flight. When high intensity lighting systems are operated during daytime and twilight, other methods of marking may be omitted. When operated 24 hours a day, other methods of marking and lighting may be omitted.
b. Medium Intensity Flashing White Lighting Systems. When medium intensity lighting systems are operated during daytime and twilight on structures 500 feet (153m) AGL or less, other methods of marking may be omitted. When operated 24 hours a day on structures 500 feet (153m) AGL or less, other methods of marking and lighting may be omitted.
Note-
SPONSORS MUST ENSURE THAT ALTERNATIVES TO MARKING
ARE COORDINATED WITH THE FCC FOR STRUCTURES UNDER ITS JURISDICTION PRIOR TO MAKING THE CHANGE.
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Chap 4 8
CHAPTER 4. LIGHTING GUIDELINE
40. PURPOSE This chapter describes the various obstruction lighting systems used to id entify structures that an aeronautical study has determined will require added conspicuity. The lighting standards in this circular are the minimum necessary for aviation safety.
Recommendations on lighting structures can vary depending on terrain feat ures, weather patterns, geographic location, and in the case of wind turbines, number of structures and overall layout of design.
41. STANDARDS The standards outlined in this AC are based on the use of light units that meet specified intensities, beam patterns, color, and flash rates as specified in AC 150/5345-43.
T hese standards may be obtained from:
Department of Transportation OTS Subsequent Distribution Office, M-30 Ardmore East Business Center 3341 Q 75th Avenue Landover, MD 20785
42. LIGHTING SYSTEMS Obstruction lighting may be displayed on structures as follows:
a. Aviation Red Obstruction Lights . Use flashing beacons and/or steady burning lights during nighttime.
b. Medium Intensity Flashing White Obstruction Lights. Medium intensity flashing white obstruction lights may be used during daytime and twilight with automatically selected reduced intensity for nighttime operation. When this system is used on structures 500 feet (153m) AGL or less in height, other methods of marking and lighting the structure may be omitted.
Aviation orange and white paint is always required for daytime marking on structures exceeding 500 feet (153m) AGL. This system is not normally recommended on structures 200 feet (61m) AGL or less.
c. High Intensity Flashing White Obstruction Lights. Use high intensity flashing white obstruction lights during daytime with automatically selected reduced intensities for twilight and nighttime operations. When this system is used, other methods of marking and lighting the structure may be omitted.
This system should not be recommended on structures 500 feet (153m) AGL or less, unless an FAA aeronautical study shows otherwise.
Note- All flashing lights on a structure should flash simultaneously except for catenary support structures, which have a distinct sequence flashing between levels.
d. Dual Lighting . This system consists of red lights for nighttime and high or medium intensity flashing white lights for daytime and twilight. When a dual lighting system incorporates medium flashing intensity lights on structures 500 feet (153m) or less, or high intensity flashing white lights on structures of any height, other methods of marking the structure may be omitted.
e. Obstruction Lights During Construction . A s the height of the structure exceeds each level at which permanent obstruction lights would be recommended, two or more lights of the type specified in the determination should be installed at that level. Temporary high or medium intensity flashing white lights, as recommended in the determination, should be operated 24 hours a day until all permanent lights are in operation. In either case, two or more lights should be installed on the uppermost part of the structure any time it exceeds the height of the temporary construction equipment.
They may be turned off for periods when they would interfere with constructio n personnel. If practical, permanent obstruction lights should be installed and operated at each level as construction progresses.
The lights should be positioned to ensure that a pilot has an unobstructed view of at least one light at each level.
f. Obstruction Lights in Urban Areas . When a structure is located in an urban area where there are numerous other white lights (e.g., streetlights, etc.)
red obstruction lights with painting or a medium intensity dual system is recommended. Medium intensity lighting is not normally recommended on structures less than 200 feet (61m).
g. Temporary Construction Equipment Lighting .
Since there is such a variance in construction cranes, derricks, oil and other drilling rigs, each case should be considered individually. Lights should be installed according to the standards given in Chapters 5, 6, 7, or 8, as they would apply to permanent structures.
1/1/07 2/1/07 AC 70/7460-1K CHG 2 Chap 4 89
AC 70/7460-1K 3/1/00
43. CATENARY LIGHTING Lighted markers are available for increased night conspicuity of high-voltage (69KV or greater) transmission line catenary wires. These markers should be used on transmission line catenary wires near airports, heliports, across rivers, canyons, lakes, etc. The lighted markers should be manufacturer certified as recognizable from a minimum distance of 4,000 feet (1219m) under nighttime conditions, minimum visual flight rules (VFR) conditions or having a minimum intensity of at least 32.5 candela.
The lighting unit should emit a steady burning red light. They should be used on the highest energized line. If the lighted markers are installed on a line other than the highest catenary, then markers specified in paragraph 34 should be used in addition to the lighted markers. (The maximum distance between the line energizing the lighted markers and the highest catenary above the lighted marker should be no more than 20 feet (6m).) Markers should be distinctively shaped, i.e., spherical, cylindrical, so they are not mistaken for items that are used to convey other information. They should be visible in all directions from which aircraft are likely to approach. The area in the immediate vicinity of the supporting structure’s base should be clear of all items and/or objects of natural growth that could interfere with the line-of-sight between a pilot and the structure’s lights. Where a catenary wire crossing requires three or more supporting structures, the inner structures should be equipped with enough light units per level to provide a full coverage.
44. INSPECTION, REPAIR AND MAINTENANCE To ensure the proper candela output for fixtures with incandescent lamps, the voltage provided to the lamp filament should not vary more than plus or minus 3 percent of the rated voltage of the lamp. The input voltage should be measured at the lamp socket with the lamp operating during the hours of normal operation. (For strobes, the input voltage of the power supplies should be within 10 percent of rated voltage.) Lamps should be replaced after being operated for not more than 75 percent of their rated life or immediately upon failure. Flashtubes in a light unit should be replaced immediately upon failure, when the peak effective intensity falls below specification limits or when the fixture begins skipping flashes, or at the manufacturer’s recommended intervals. Due to the effects of harsh environments, beacon lenses should be visually inspected for ultraviolet da mage, cracks, crazing, dirt build up, etc., to insure that the certified light output has not deteriorated. (See paragraph 23, for reporting requirements in case of failure.)
45. NONSTANDARD LIGHTS Moored balloons, chimneys, church steeples, and similar obstructions may be floodlighted by fixed search light projectors installed at three or more equidistant points around the base of each obstruction. The searchlight projectors should provide an average illumination of at least 15 footcandles over the top one-third of the obstruction.
46. PLACEMENT FACTORS The height of the structure AGL determines the number of light levels. The light levels may be adjusted slightly, but not to exceed 10 feet (3m), when necessary to accommodate guy wires and personnel who replace or repair light fixtures. Except for catenary support structures, the following factors should be considered when determining the placement of obstruction lights on a structure.
a. Red Obstruction Lighting Systems . The overall height of the structure including all appurtenances such as rods, antennas, obstruction lights, etc., determines the number of light levels.
b. Medium Intensity Flashing White Obstruction Lighting Systems. The overall height of the structure including all appurtenances such as rods, antennas, obstruction lights, etc., determines the number of light levels.
c. High Intensity Flashing White Obstruction Lighting Systems . The overall height of the main structure including all appurtenances such as rods, antennas, obstruction lights, etc., determines the number of light levels.
d. Dual Obstruction Lighting Systems . T h e overall height of the structure including all appurtenances such as rods, antennas, obstruction lights, etc., is used to determine the number of light levels for a medium intensity white obstruction light/red obstruction dual lighting system. The overall height of the structure including all appurtenances is used to determine the number of light levels for a high intensity white obstruction light/red obstruction dual lighting system.
e. Adjacent Structures. The elevation of the tops of adjacent buildings in co ngested areas may be used as the equivalent of ground level to determine the proper number of light levels required.
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