TABLE 3-7. TYPICAL PORTABLE LUMINAIRES FOR SUPPLEMENTARY LIGHTING (Sheet 5 of 7) (Courtesy of McMaster-Carr Supply Company) FLUORESCENT TROUBLE LIGHTS (Continued) Cordless Rechargeable Trouble Light.
This light provides the convenience of going anywhere without the hassle of an electrical cord. The light operates for about two hours before needing a recharge and can be recharged in three hours. It had a 6- watt 3.6 halogen lamp, protected by a stainless steel wire guard. The body is made of durable antishock plastic.
length is about 14 inches. Lights come with three 1.2V rechargeable nickel cadmium batteries with a rated life of 8 years.
is available for use with 120V AC or 12V DC and comes with a battery charger. It is UL Compact Twin-Tube Trouble Light. The light has a 13-watt double tube fluorescent lamp to provide twice the illumination of other lights of the same size. It has a rubber handle and end cap and impact resistant plastic tube shield with built-in reflector. The overall size is 14 inches long by 2 9/16 inch diameter. It operates on 120V AC and is UL listed and CSA certified.
g - Hazardous Location All-Purpose Trouble Light. This light has a non-sparking all aluminum body with annealed glass lamp shield and built-in reflector. The lamp is protected by shock absorbers and an aluminum guard. The light is 27 inches long by 3 1/4 inch diameter with a 15-watt T-8 1amp. It meets National Electrical Code Class I, Div. 1 and 2, Group D; Class II, Div. 1 and 2, Groups E, F, and G; Class III, Div. 1 and 2. The cord, ballast, and lamp unit are FM approved.
Hazardous Location Compact Twin-Tube Trouble Light. The light has bumper guards falling objects, bumping'is protected by an and end caps to protect against damage from and dropping.
The annealed glass globe aluminum guard. It is 14 3/4 inches long by 3 1/2 inch diameter and comes with a 16/3 so cord and 13-watt lamp. It operates on 120V AC, is FM approved, and meets National Electrical Code Class I, Div. 1, Groups C and D; Class II, Div. 1, Groups E, and G; and Class III, Div. 1 Chap 3 Par 301 Page 93
TABLE 3-7. TYPICAL PORTABLE LUMINAIRES FOR SUPPLEMENTARY LIGHTING (Sheet 6 of 7) (Courtesy of McMaster-Carr Supply Company)
FIBBER-OPTIC ILLUMINATORS a . Quartz Halogen Fiber-Optic Illuminator. The illuminator is used to produce a high-intensity light beam from the tip of fibber optic bundles to light hard-to-reach places. The light is cold after it passes through a fiber-optic light guide, which keeps heat away from the point of inspection.
The illuminator is equipped with a basic 0.625 inch opening with reducer bushings provided for adaptability to various other lights guides. It has a variable intensity control with preset divisions to allow for repetitive presettings. The lamp is 150 watt, 3350° Kelvin, 21V. Fiber-optic guides and accessories are normally ordered separately.
b. Xenon Fiber-Optic Illuminator. This illuminator is twice the brightness of the above quartz halogen unit. It is meant for applications where an ultra-high intensity light source is necessary such as long borescopes that use fiber-optic illumination or for illuminating light absorbing materials.
The unit operates on 110V, 50/60-hertz AC, 6.2 amps. The lamp is a 300 watt, 6000° Kelvin, 35 to 50V DC. Fiber-optic accessories are normally ordered separately.
FIBBER-OPTIC LIGHT GUIDES a . Flexible Light Guides. These light guides are made to be used with fiber-optic illuminators. These light guides are flexible and will not support themselves. They are generally used in applications where the light guide has to be fastened to a part that is movable or they are used with a light guide stand.
b. Light Guide Stand. A light guide stand allows a flexible fiber-optic light to be positioned where it is needed and also has an adjustable lens that projects a clear circle of light that can be adjusted from a large area to an intense spot. The stand has 6 1/4-inch vertical travel and 2-inch horizontal travel at the base, and 5 1/2-inch travel at the lens barrel. It also features 360° vertical and horizontal rotation.
c. Free-Standing Light Guides. These light guides are made to be used with fiber-optic illuminators and are adjustable at any angle to the workpiece.
They can be used as secondary lighting to built-in illumination systems where the primary light source is insufficient due to long working distances or light absorbing workpieces. They are available in single or double styles.
TLLUMINATION ACCESSORTES
a. Ring Illuminators. Ring illuminators are made to be used with fiberoptic illuminators. They provide a circle of light over 360° leaving no shadow pockets, which is not possible with other illumination systems. The ring illuminator can be used as the prime light source for measuring microscopes, monocular, or sterno-viewing microscopes. or as a secondary light source for profile projectors, 35-mm cameras or closed-circuit TV systems.
b. Micro-Probe Illumination. These illumination systems are used with fiber-optic illuminators and are used in illuminating ultra-small holes and cavities that pose special viewing problems. Available probe diameter are
0.032 and 0.120 inch.
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TABLE 3-7. TYPICAL PORTABLE LUMINAIRES FOR SUPPLEMENTARY LIGHTING (Sheet 7 of 7) (Courtesy of McMaster-Carr Supply Company) ILLUMINATION ACCESSORIES (Continued) Co-Axial Illuminator. A co-axial illuminator is used with fiber-optic illuminators. It can illuminate the workpiece 10 to 12 inches and further from the lens system. It is used where the workpiece needs illumination where a deep cavity is involved that the present ring illuminators or separate fiber-optic bundles cannot illuminate properly as they are off the optical axis. The unit is used for machine vision video applications, optical comparators as well as microscope usage provided that there is sufficient microscope working distances.
Back Light Illumination System. The illuminator is used with fiberoptic illuminators. It illuminates an area of 3 square inches and can be switched from bright field to dark field by a simple control knob on the side of the unit. It can be used as an inspection tool for electronics where dark field illumination is desired and it can be used as background illumination for various microscopes and video applications.
Flashlights. Flashlights used for aircraft inspection should be suitable for industrial use and, where applicable, safety approved by the Underwriters Laboratory or equivalent as suitable for use in hazardous atmospheres. Military Specification MIL-F-3747E, Flashlights: Plastic Case, Tubular (Regular, Explosion-Proof, Explosion-Proof icat Resistant. Tras.
fic Directing, and Inspection-Light) provides requirements flashlights suitable for use in aircraft inspection. However, at the present time, the flashlights covered by this specification use standard incandescent lamps, and there are no standardized performance tests for flashlights with the brighter bulbs (Krypton, Halogen and Xenon). Each flashlight manufacturer currently develops its own tests and provides information on its products in its advertising literature. Therefore, when selecting a flashlight for use in visual inspection, it is sometimes difficult to directly compare products. The following characteristics should be considered when selecting a flashlight: footcandle rating, explosive atmosphere rating, beam spread (adjustable, spot, or flood), efficiency (battery usage rate), brightness after extended use, rechargeable or standard batteries, if rechargeable, how many hours of continuous use and how long for recharging. If possible, it would be best to take it apart and inspect for quality of construction and to use the flashlight as it would be used in the field. inspection flashlights are available in several different bulb brightness levels:
a. Standard incandescent for long battery life; b. Krypton for 70 percent more light than standard bulbs; c. Halogen for up to 100 percent more light than standard bulbs; and d. Xenon for over 100 percent more light than standard bulbs. Table 3-8 shows some of the typical types of inspection lights that are available.
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TABLE 3-8. TYPICAL INSPECTION FLASHLIGHTS (Sheet 1 of 5) (Courtesy of McMaster-Carr Supply Company) Ribbed-Grip Flashlight. This flashlight has a ribbed-grip and a highimpact thermoplastic body that resists oll, grease, chemicals, corrosion. and It is available with standard filament bulbs or Krypton bulbs.
explosion-proof only with the standard bulb and uses 2 or 3 D-cell batteries.
Underwriter laboratories (UL) listed Class I Groups C and D (hazardous vapors and gasses), and Class II Group G, Mine Safety and Health Association (MSHA) approved. The three D-cell model meets American Society for Testing and Materials (ASTM) F1014-86 Type III.
This flashlight is shitable for use in Explosive Atmosphere Flashlight.
an explosive atmosphere and has a highimpact ABS resin body. It uses Xenon bulbs and 3 or 4 C-cell batteries.
three cell model has a pocket clip, hanging ring, and wrist lanyard.
four cell model features a backup satety switch and adjustable beam for spot to Factory Mutual (FM) and Mine Safety and Health Association (MSHA) approved, Class I Groups A, B, C, and D.
Canadian Standards Association (CSA) certified.
Explosive Atmosphere Penlight.
flashlight has a polycarbonate resin body and pocket clip. It is FM approved. Class I Groups A, B, C, and D.
Class II Group G. Class III Div. 1 and
2. CSA certified.
d. Flexible Light Tool Kit. This light tool kit includes: penlight with extension mirror 1/8-inch-diameter by 10-inch flexible shaft six-inch handle and recovery magnet.
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TABLE 3-8. TYPICAL INSPECTION FLASHLIGHTS (Sheet 2 of 5) (Courtesy of McMaster-Carr Supply Company) Right Angle Explosive Atmosphere Flashlight. A two D-cell model with standard bulb has a waterproof ABS plastic body and three-position switch.
is UL listed, Class I Groups C, and D, and MSHA approved. A rechargeable model with halogen bulb has a waterproof high impact nylon housing with o-ring seals.
It is FM approved for use in hazardous locations.
this light contains a krypten balb that Flexible Krypton Inspection Light.
produces a 10,000-candlepower beam.
lamp diameter is 3/16 inch. The flashlight is made of a brass alloy and has a 15-inch-long flexible shaft that bends and keeps its shape.
batteries.
Flexible Probe Flashlight. This flashlight stores a 10-inch-long metal probe in the body which snaps out for inspecting tight areas. The body is plastic and has a metal hanging ring.
It uses two D batteries and a number PR- 2 (standard) bulb.
Pocket Flex Inspection Lights.
These lights can be clipped to a nearby spot leaving both hands free while work is accomplished. Flexible cables bend and hold their shape. Cases are plas-
• A mini-flex light has a head that fits through 13/16-inch-diameter openings. Length is 9.8 inches. It uses two AA batteries and a MB22NE (standard) bulb.
• An extra power flex light fits through 7/8-inch-diameter openings.
Length is 7.5 inches. It uses three AA batteries and M838G3E bulb.
An extra reach flex light has a 5/8- inch-diameter bulb. Flexible cable is 8 inches long. It uses two AAA batteries and a E30111 bulb.
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TABLE 3-8. TYPICAL INSPECTION FLASHLIGHTS (Sheet 3 of 5) (Courtesy of McMaster-Carr Supply Company) 1 ° Skinny Probe Inspection Light. PRESE light has 44-inch-long flexible cable and the lamp head can pass through a 7/32-inch-diameter opening.
cable lets you lower the bulb into deep areas and put the flashlight case in your pocket while working.
inch-diameter bulb is mounted on the end of a rigid 10-inch-long stem.
is impact resistant, waterproof and withstands most chemicals.
three D batteries and a number 187 (standard) bulb.
j. Explosion-Proof Inspection Light.
This explosion-proof flashlight has a 14-inch rigid brass or flexible stem that lets you examine fuel tanks and other flammable liquid containers.
uses three D batteries and a number 13 (standard) bulb.
k. Porta-Power Flex Lights. These inspection lights have a black anodized aluminum case with sliding on-off switch. They focus with a twist of the lens head for pinout or broad beam illumination and they are powered by two D batteries; the lamp head fits through a 21/32-inch opening; they use a number 14 (standard) bulb; and they are available with flexible cable lengths of 9, 18, and 36 inches. A combination unit is available that has a 6-inch rigid shaft and a 9-inch flexible cable.
Inspection Light Accessories.
justable illuminating mirrors and magniiers are available for some model in- ›pection lights. The glass mirror is 1 1/4 inch diameter, has a stainless steel back and nickel plated brass extension arm. Overall length is 4 The illuminating magnifier has a straight line viewing 6X lens.
1 1/2 inch diameter with a polished optical glass lens.
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TABLE 3-8. TYPICAL INSPECTION FLASHLIGHTS (Sheet 4 of 5) (Courtesy of McMaster-Carr Supply Company) Illuminating and Magnifying Inspection Kit. All parts of this kit are interchangeable, interlocking and chrome It uses two D batteries and a 1/8-inch and 1/4-inch-diameter bulb.
The kit includes 0.1 inch and 0.3 inch diameter rigid probes in lengths from 3 to 14 1/4 inches, a 0.3-inch-diameter by 14 1/4-inch-long flexible probe, illuminated magnifier; a 10X duplex magand adjustable mirror for use on the rigid probes, 0.9 and 1.5-inchdiameter short stem mirrors; recovery magnet and hook; and accessory handle.
Mini Bench Lights. These lights are the workbench. Lamps can enter a 21/32-inch opening. Each light has a nonsparking aluminum case with a -exiole cable (0, 9, or 12 inches long) that bends and stays electric bench light comes with a 2.5- volt transformer and switch for 110-volt AC outlet. The 5/8-inch-diameter head has a focusing ring for a circle of light or pinpoint beam. The case is shockproof and it uses a number 13 The battery operated bench light uses two AA batteries and a number 222 (standard) bulb.
kit uses a penlight with a Lucite rod and mirror to see around corners. Light Bender Inspection Kit. This uses one or two AA batteries. The kit includes: one and two cell penlight; 6 and 2 1/2-inch-long straight Lucite rods; clip-on mirror; 4-inch curved Lucite rod; and soft plastic case.
Extended Reach Inspection Kit.
kit has up to five-foot reach interchangeable probes, each with its own attached light. The kit includes; a fivefoot flexible cable probe; a 12-inch straight and flexible probe; a five-inch angle probe and two-inch bendable probe;
a 1.2-inch and 0.6-inch diameter mirror;
a 22-mm-diameter mirror; magnifying lens; recovery magnet and hook; shrouded and side aperture lamps; probe adapter;
and case.
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TABLE 3-8. TYPICAL INSPECTION FLASHLIGHTS (Sheet 5 of 5) (Courtesy of McMaster-Carr Supply Company) Twist-Beam Penlights. These flashlights use standard two AA-cell batteries and the beam adjusts from spot to flood.
LIGHTING SYSTEMS. Lighting systems are often classified in accordance with their layout or location with respect to the visual task or object lighted (general lighting, localized general lighting, local [supplementary] lighting, and task-ambient ignting). They are also classified in accordance with the CI ype of luminaire used (direct, semi-direct, general diffuse [direct-indirect], semi-indirect, and indirect), as shown in Figure 3-9. Luminaires for general lighting are classified by the CIE in accordance with the percentages of total luminaire output emitted above and below horizontal. The light distribution curves may take many forms within the limits of upward and downward distribution, depending on the type of light source and the design of the luminaire. Light distribution curves for some typical lamp and fixture types that might be used for visual inspection tasks of aircraft and related articles are shown in Figure 3-10. Light distribution curves may be available in technical literature available from manufacturers of light sources.
Horizontal tasks and high, narrow spaces can be most efficiently lighted with fixtures that concentrate most of their light straight down. Such fixtures usually appear to be quite comfortable. However, tasks that are more vertical require light coming from the luminaire at relatively high angles. Luminaires emitting light at high angles are apt to be excessively bright and uncomfortable unless carefully designed. Broad-distribution luminaires are more effective in letting light out of the unit than narrow-distribution ones, but are less effective in getting light to the horizontal work plane in high-bay, narrow spaces since walls absorb a greater portion of the light. Manufacturers generally provide a coefficient of utilization table, which is the ratio between the amount of light or lumens reaching the horizontal task to the lumens generated within the luminaire. The manufacturer's recommended spacing-to-height ratio (or spacing criterion) indicates whether the output of the fixture is broad or General Lighting. General lighting systems provide an approximately uniform illuminance on the work plane over the entire work area. The luminaires are usually arranged in a symmetrical plan fitted into the physical characteristics of the area and therefore blend well with the room architecture. They are relatively simple to install and require no coordination with furniture or machinery that may not be in place at the time of Chap 3 Page 100 Par 301
installation. Perhaps the greatest advantage of general lighting systems is that they permit complete flexibility in task loca-
system consists of a functional arrangement of luminaires with respect to the visual task or work areas. It also provides illumination for the entire room area. Such a lighting system requires special coordination in installation and careful consideration to ensure adequate general lighting for the room.
system has the advantages of better use of the light on the work area and the opportunity to locate the luminaires so that annoying shadows, direct glare, and veiling reflections are prevented or minimized.
Local Lighting. A local lighting system provides lighting only over a relatively small area occupied by the task and its immediate surroundings. The illumination may be from luminaires mounted near the task or from remote spotlights. These an economical means of providing higher illuminances over a small area, and it usually permits some adjustment of the lighting to suit the requirements of the individual. Improper adjustments may, however, cause annoying glare for nearby workers.
cal lighting by itself is seldom desirable. To prevent excessive changes in adaptation, local lighting should be used in conjunction with general lighting that is at least 20 to 30 percent of the local lighting level; it then becomes supplementary lighting.
Task-Ambient Lighting. Task-ambient lighting is a type of lighting arrangement where the lighting is built into the furniture in an open plan office layout. Task lights are located close to work areas (as in local lighting above) and are supplemented by indirect ambient illumination from sources concealed in the furniture and directed to the ceiling (as in general lighting above). These systems usually have extensive ceiling areas almost totally devoid of lighting equipment. Electrical service to the lighting equipment is often through the floor.
e. Direct Lighting. When luminaires direct 90 to 100 percent of their output downward, they form a direct lighting system. The distribution may vary from widespread to highly concentrated, depending on the reflector material, finish, and contour and on the shielding or control media employed.
(1) Direct Glare Control. Direct lighting units can have the highest room utilization factor of all types, but this utilization may be reduced in varying degrees by brightness control media required to minimize direct glare. Direct glare may also be reduced by using area units with minimum number of lamps,
e.g., a two-foot-wide fluorescent unit with just two lamps.
Chap 3 Par 302 Page 101
(2) Veiling Reflections. Veiling reflections may be excessive unless distribution of light is designed to reduce the effect.
(3) Reflected Glare and Shadows. Reflected glare and shadows may be problems unless close spacings are employed.
Large area units are also advantageous in this respect. Highreflectance room surfaces are particularly important with direct ighting to improve the brightness relatlonships, and higher illuminances provided by controlled brightness equipment will alsc tend to improve the brightness relationships throughout the room.
with very concentrated distributions, care should be taken to ensure adequate wall luminances and illuminances on vertical sur- Other Forms of Direct Lighting. Luminous ceilings, louvered ceilings, and large-area modular lighting elements are forms of direct lighting having characteristics similar to those of indirect lighting discussed in later paragraphs. These forms of lighting are frequently used to obtain the higher illuminances. Care should be taken to limit the luminance of the shielding medium to 80 candelas per square foot or less to prevent direct glare if critical, prolonged seeing is involved. Reflected glare may be a problem with systems employing cellular louvers as the shielding medium, since the images of the light sources above the louvers may be reflected by shiny surfaces at the work plane.
f. Semi-Direct Lighting. The distribution from semi-direct units is predominantly downward (60 to 90 percent), but with a small upward component to illuminate the ceiling and upper walls.
The characteristics are essentially the same as for direct lighting, except that the upward component will tend to soften shadows improve room brightness relationships. Care should be exercised with close-to-ceiling mounting of some types to prevent overly bright ceilings directly above the luminaire. The room utilization factor can approach or even exceed that of wellshielded direct units.
g. General Diffuse Lighting. The lighting system is classified as general diffuse when downward and upward components of light from luminaires are about equal (each 40 to 60 percent of total luminaire output). General diffuse lighting units combine the characteristics of direct and indirect lighting. The room utilization factor is somewhat lower than for direct or semidirect units, but it is still quite good in rooms with high reflectance surfaces. Brightness relationships throughout the room are generally good, and shadows from the direct component are softened by the upward light reflected from the ceiling.
(1) Direct Glare Control. Excellent direct glare control can be provided by well-shielded units, but short suspensions can result in ceiling luminances that exceed the luminaire Chap 3 Page 102 Par 302
luminances. Close spacings or layouts that locate units so that they are not reflected in the task result in reductions of reflected glare from the downward component.
_Pendant Mountings. Luminaires designed to provide a general diffuse or direct-indirect distribution when pendant bani direct face ha can note he a cop potector tossecting the upward light back through the luminaire. Photometric data, obtained with the luminaire equipped with top reflectors or installed on a simulated ceiling board, should be employed to determine the luminaire characteristics for such application condi-
special (non-CIE) category within the classification for luminaires which emit very little light at angles near the horizontal. Since this characteristic results in lower luminances in the direct glare zone, direct-indirect luminaires are usually more suitable than general diffuse luminaires which distribute the light about equally in all directions.
i. Semi-Indirect Lighting. Lighting systems which emit 60 to 90 percent of their output upward are defined as semiindirect. The characteristics of semi-indirect lighting are similar to those oi indirect systems, except that the downward component usually produces a luminaire luminance that closely matches that of the ceiling. However, if the downward component becomes too great and is not properly controlled, direct or reflected glare may result. An increased downward component improves utilization of light somewhat over that of indirect lighting. This factor makes somewhat higher illuminances possible with fewer semi-indirect luminaires and without excessive ceiling luminance.
j. Lighting for the Cathode Ray Tube (CRT). Cathode ray tubes are commonplace, with visual display units appearing on the shop floor with ultrasonic equipment, eddy current equipment, video adapters for borescopes and microscopes, etc. Their typically convex surfaces act like curved mirrors that reflect large areas of ceiling, walls, windows, and other room surfaces.
any of these surfaces are intrinsically bright, such as windows and fixtures, or are brightly lighted, their reflected images will reduce the visibility of the information being processed on the screen and annoy the operator. The CRT problem could be solved by turning off all the lights and shading the windows;
however, this is usually not practical. Many of the screen reflection problems can be reduced by the following methods:
(1) Screen Orientation. Proper screen orientation or using hoods or anti-reflection screens or filters.
Chap 3 Par 302 Page 103
(2) Shades. Using blinds, shades, or dark curtains to help eliminate window brightness.
(3) Dark Colors. Finishing walls and other vertical surfaces in darker colors.
(₴) Worker Clothing. Equipping operators with dark smocks.
(5) Luminaires. Using luminaires with dark-tinted lenses, deep parabolic baffles, or parabolic wedge louvers to control fixture brightness. Bright lamp images seen in shiny surfaces directly beneath the fixture can be eliminated by laying a thin plastic diffuser on top of the lens or louver.
(6) Indirect Lighting. When indirect lighting is used to correct CRT reflection problems, leveis should not exceed 30 footcandles; otherwise, vertical surfaces get too bright. Ceiling brightness should be uniform with no hot spots. At this level, supplementary task lighting often will be required.
(7) Parabolic Lenses. Parabolic lenses can be used to obtain levels up to about 100 footcandles. If higher levels are needed for specific tasks, supplementary lighting can also be
303.-399. RESERVED Chap 3 Pages 104 through 116 Par 302