Lamp Selection and Applications – Lighting Fixture Selection and Applications
This article is for lamp and lighting fixture selection and applications. Main keywords for this article are Lamp Selection and Applications, Lighting Fixture Selection and Applications, HID Lamp Advantages, Fluorescent Light Fixtures, Fluorescent Lamps.
Illuminating Engineering Society Of North America (IESNA)
RP7 Recommended Practice for Industrial Lighting
National Electrical Manufacturers Association (NEMA)
LE 4 Recessed Luminaires, Ceiling Compatibility
National Fire Protection Association (NFPA)
70 National Electrical Code
Underwriters Laboratories Inc (UL)
844 Electric Lighting Fixtures for Use in Hazardous Areas
935 Ballasts, Fluorescent Lamps
1029 Ballasts, HID Lamps
1570 Fluorescent Light Fixtures
1571 Incandescent Fixtures
1572 HID Lighting Fixtures
For the purpose of understanding this standard the following definitions apply:
A device used with an electric discharge lamp to obtain the necessary circuit conditions (voltage, current, and wave form) for starting and operating.
Used for, for example, refractors, reflectors, lenses, and sealed beam lamp parts because of its high chemical stability, high heat shock resistance and excellent electrical resistivity.
A transparent or diffusing enclosure intended to protect a lamp, to diffuse and redirect its light or to change the color of the light.
The density of luminous flux incident on the surface. The quotient of the total luminous flux by the area to be lighted, assuming the area is uniformly illuminated. (Footcandles or Lux (1 FC = 10.76 Lux)).
Light Loss Factor.
A multiplier that is applied to account for aging of the lamp and for dirt build up on the luminaire during the period for which a lamp is in place. Lamp aging and luminaire dirt build up both reduce
light output, the amount of reduction usually increasing with time. In common practice, light loss factors are applied to initial foot candles to derive the minimum light level on the area being illuminated.
SI unit of luminous flux. The time rate of the flow of light.
A complete lighting unit consisting of a source (lamp) together with parts designed to distribute the light.
The metric unit of measurement of illuminance. The light on a surface of one meter square on which there is a uniformly distributed flux of one lumen. 10.76 lux equals 1 foot candle. Decalux = 10 lux.
The ratio of reflected luminous flux from a surface to incident flux.
A device used to redirect the luminous flux from a source by the process of reflection.
The process by which the direction of a ray of light changes as it passes obliquely from one medium to another in which its speed is different.
A device used to redirect the luminous flux from a source, primarily by the process of refraction.
Ratings given to hazardous rated fixtures that refer to the operating temperatures of the complete fixture. It is based on criteria such as ambient temperature, lamp characteristics, optics of the fixture, and hazardous environment.
Lamp and Lighting Fixture Selection and Applications
Lamp Selection and Applications in Process Industry
High-Intensity Discharge Lamps
- The term ‘high-intensity discharge’ lamp applies to any enclosed intense light source of the arc-discharge type. This class of light source includes mercury vapor, metal halide, and high- and low-pressure sodium lamps. Mercury vapor and metal halide lamps shall only be used when fully enclosed in an approved polycarbonate or heat-treated glass enclosure, as they are subject to violent failure.
- In mercury vapor (MV) lamps, light is produced by passing current through mercury vapor. In metal halide (MH) lamps the current is discharged through a combined vapor of mercury and other metals, for example thallium, indium, scadium, and dysprosium. The current discharge in high-pressure sodium (HPS) lamps is through a combined vapor of mercury and sodium.
- HID lamps are constructed with two bulbs; an inner bulb, called the arc-tube, which contains the vapor, and an outer bulb which provides protection and insulation for the arc-tube. The arc-tube in most mercury vapor and metal halide lamps is quartz. The arc-tubes of mercury vapor and metal halide lamps contain three electrodes. Two of these are the operating electrodes and the other, the starting electrode. The starting electrode is located adjacent to the operating electrode nearest the base end of the lamp and introduces the voltage which strikes an arc to the adjacent operating electrode.
- HID lamps produce light more efficiently than incandescent lamps. Mercury vapor lamps are the least efficient of the HID lamps and are not recommended for new installations. The light output of the high-intensity discharge lamp gradually decreases with operating age. During the life of the lamp, the emission material of the electrodes is lost very slowly from the electrode and is deposited on the inner surface of the arc-tube. Lumen maintenance is better for HPS lamps than for MV or MH lamps.
- Long life is an important characteristic of HID lamps. Based on 10 hours per start, the rated average life of MV lamps is 24,000 hours; MH lamps, 7,500 – 15,000 hours and HPS lamps, 24,000 hours. Metal halide lamps should only be used where their superior color characteristics are an advantage. HPS lamps have longer life and greater efficiency.
- The operating temperatures of high-intensity discharge lamps are usually higher than comparable wattage incandescent lamps. The outer bulb temperature ranges between 200 and 400 °C.
- HID lamps vary widely in their color rendition characteristics. MH and color-improved MV lamps are the best. Colors to be used in areas lighted by HPS lamps should be tested under that light source before final selection.
- HID lamps do not start instantly as do incandescent and fluorescent lamps. Depending upon ambient conditions, the type, and the age of the lamp, it requires 1 to 10 minutes for a lamp to reach rated output. Lamps are also susceptible to power interruptions. Severe voltage dips will extinguish the arc and the lamp then has to cool to reduce the vapor pressure to permit restriking the arc. HPS lamps are the quickest and MV lamps the slowest to restrike.
HID Lamp Advantages
a. Long life reduces maintenance
b. High lumens per watt produces energy savings
HID Lamp Disadvantages
a. Delay in producing full light output
b. Lamp and ballast life affected by frequency of starting
c. Reliable starting affected by low ambient temperatures
d. Loss of light output due to power dips (typically 70-80 percent rated voltage)
e. Variations in applied voltage may cause overheating of ballast
f. Requires auxiliary starting equipment, thus increasing weight and maintenance
g. High surface temperature of bulb may present ignition source in hazardous areas
h. Possible stroboscopic effect on MV and MH
i. Possible adverse color rendition (primarily on HPS)
- The fluorescent lamp is another form of electric discharge light source. Its operation differs from the mercury lamp in that the arc discharge radiates most energy in the ultraviolet area of the spectrum. Current flows between electrodes which are separated from each other by the length of a glass tube. In the operating lamp, current is conducted by gas (vaporized mercury) inside the lamp. Light is given off by the phosphor-coated glass tubing, which is excited by the ultraviolet radiation produced by the electric current flow through the low-pressure mercury vapor. The fluorescent lamp gets its name from the fact that the phosphor coating on the inside of the tube fluoresces. The chemical makeup of the phosphor determines the color of the light produced.
- The rated average life of a fluorescent lamp varies between 10,000 and 20,000 burning hours depending upon the lamp type. These ratings are affected greatly by operating voltage, frequency of
starting, and ambient temperature. Both lamp life and efficiency are decreased by terminal voltages below the operating range of the ballast. Life ratings are published based upon the lamp operating three hours per start. Lamp life can be extended by lengthening the period of operation per start. It likewise is shortened when the operating period is decreased.
- Under normal operating conditions, the light output depreciation of a fluorescent lamp averages approximately 15 percent of the initial rated output of the lamp over the life span of the lamp. Depreciation is due to the gradual deterioration of the phosphor, and blackening of the tube with emission material.
- Fluorescent lamp lumen output and efficiency increase in direct proportion to the frequency of the power source to the lamp.
Fluorescent Lamps Advantages
a. High efficiency for energy savings
b. Comparatively low surface brightness
c. Comparatively cool
d. Long life
e. Linear source lends itself to many architectural treatments
f. Variations in color available
g. Available with battery packs for emergency operation
Fluorescent Lamps Disadvantages
a. Not suitable for accurate beam control
b. Requires auxiliary starting equipment, thus increasing weight and maintenance
c. Requires special auxiliaries to operate in cold temperature locations
d. Size makes mounting and weather sealing difficult
e. Lumen output is more than similar wattage incandescent but less than HID
Lamp Operating Temperatures
- The operating temperature of lamp components (bases, bulbs, and tubes) is important because:
a. It often determines the satisfactory performance of the lamp itself
b. Energized lamps heat adjacent or surrounding parts for example sockets and wire which could result in an early failure of the unit and, in some cases, create a fire hazard c. Lamp heating is a factor in determining whether the lamps are suitable for use in hazardous locations where atmospheres of flammable vapors, or dusts, or easily ignitable fibers and flyings,
prevail or may exist.
- Operating temperatures of lamps vary with the fixture used and type of mounting. All application decisions for installation in hazardous areas shall be based on certified testing data from a Nationally
Recognized Testing Laboratory (NRTL).
- When a lamp is installed in an enclosed fixture, the maximum lamp temperature will be approximately 35°C higher than the maximum bare lamp bulb temperature.
- Maximum lamp temperatures are considerably higher when burning in any position other than base up. Usually, manufacturers’ lamp test data is referenced to a 25°C ambient in still air. Hazardous area
equipment shall be tested and approved for 40°C ambient. The ambient temperature which vendors’ data is based upon shall be determined and adjusted for plant operating ambient.
Lighting Fixture Selection and Applications in Process Industry
Light Fixture Voltage Ratings
- HID and fluorescent fixtures shall require ballasts, which are available for a wide variety of system voltages. For normal plant applications the following voltages shall be used:
a. Outdoor lighting HID (excluding flood lights) 120 V, 1 phase
b. Outdoor lighting incandescent 120 V, 1 phase
c. Outdoor floodlighting 277 V, 1 phase
d. Indoor high bay HPS 277 V, 1 phase
e. Indoor fluorescent lighting 120 V, 1 phase
- We will consider other utilization voltages to match existing systems in plant expansions, and for very large plot areas. Any deviation from the voltage levels shown above shall require company approval. If lighting fixtures are to be installed connected phase to neutral (277 V fixtures) on a resistance grounded system, a lighting transformer shall be installed to provide 277/480 V, 4 wire distribution with a grounded neutral. All lighting circuits shall contain a separate ground connected to all metal parts of lighting fixtures.
Light Fixture Ballasts
- Fluorescent Fixtures
a. New installations shall use electronic ballasts. Ballasts shall comply with UL 935.
b. Electronic ballasts permit operation of fluorescent lamps at higher frequencies which increase lamp efficiency. Solid-state, high-frequency ballasts are available that convert 60 Hz line frequency
into their operating frequency of 20-25 kHz. These ballasts are manufactured to operate with 2, 3, or 4 standard or energy efficient rapid-start lamps. Units are available for use on 120 and 277 volt
c. Advantages of the electronic ballasts are:
(i) Dissipate less heat and reduce air conditioning load
(ii) Reduce lamp flicker. The eye can not perceive flicker at the higher operating frequency.
(iii) Quieter than magnetic ballasts
- HPS Fixtures
a. Conventional magnetic type ballasts shall be used for HPS fixtures. The ballasts shall be energy efficient, regulating, constant wattage, and high-power factor type. Ballasts shall comply with UL 1029. b. The power factor of the lamp ballast system shall not drop below 90 percent at any lamp voltage for ±10 percent line voltage variation.
c. Ballast shall be designed in a way that the normal manufacturing tolerance for capacitors ±3 percent shall not cause more than a ±8 percent variation in regulation of lamp watts throughout rated lamp life for nominal line voltage.
d. Ballasts shall be furnished with non-PCB capacitor with bleed-off circuit to meet NFPA 70, Article 460-6.
e. HPS fixtures used for emergency lighting shall be equipped with a ‘hot restrike starter’.
Light Fixture Hazardous Area Requirements
- The hot surface of a lamp or light fixture can be an ignition source for gases and vapors in hazardous areas. All fixtures installed in hazardous locations shall meet the requirements of NFPA 70 and UL 844.
- Lighting fixtures for fixed lighting in Class I, Division 1 and Class II, Division 1 locations, and for fixtures intended for portable use in Class I and II, Divisions 1 and 2, shall be stamped with the Class,
Division and Groups that they are approved for. They shall also be stamped with their T-Rating and the maximum ambient temperature they are listed for. Temperature limitation in Class I, Division 2 locations is a function of lamp surface temperature and ambient temperature, whereas in Class I, Division 1; Class II, and Class III, Divisions 1 and 2 it is a function of fixture surface temperature.
- All fixtures in classified areas shall be protected against physical damage by a suitable guard, or by location.
- In Class 1, Division 1 locations, the fixtures shall be approved, and shall be marked to show the maximum wattage, the Class, Group, and operating temperature or temperature range. NFPA 70 provides for designation of temperature range by using ‘T’ numbers, see NFPA 70, Table 500-5(d).
- In Class 1, Division 2 locations, where there is danger that falling sparks or hot metal from lamps or fixtures might ignite localized concentrations of flammable vapors or gases, suitable enclosures or other effective protective means shall be provided. Where lamps are of a size or type that may, under normal operating conditions, reach surface temperatures exceeding 80 percent of the ignition temperature of the gas or vapor involved, fixtures shall be explosion proof type or shall be of a type which has been tested and found incapable of igniting the gas or vapor for which they are rated.
- In Class II, Division 1 locations, fixtures shall be approved for Class II locations and shall be marked clearly to indicate the maximum wattage of the lamp for which it is approved. In locations where dust from magnesium, aluminum, aluminum bronze powders, or other metals of similar hazardous characteristics may be present, fixtures for fixed or portable lighting, and all auxiliary equipment, shall be approved for the specific location.
- In Class II, Division 2 locations, lighting fixtures for fixed lighting, when not of a type approved for Class II locations, shall have enclosures for lamps and lampholders, designed to minimize the deposit of dust on lamps and to prevent the escape of sparks, burning material, or hot metal. Each fixture shall be marked clearly to indicate the maximum wattage of lamp that shall be permitted, without exceeding an exposed surface temperature of 165 °C under normal conditions of use.
- In Class lII, Division 1 and 2 locations, lighting fixtures for fixed lighting shall provide enclosures for lamps and lampholders that are designed to minimize entrance of fibers and flyings, and to prevent the escape of sparks, burning material, or hot metal. Each fixture shall be marked clearly to show the maximum wattage of the lamps that shall be permitted, without exceeding an exposed surface temperature of 165°C under normal conditions of use.
Fluorescent Light Fixtures
- All electrical parts including ballasts, lampholders, and connectors shall be listed by the Underwriters Laboratories, Inc. The fixtures shall comply with UL 1570.
- General Purpose Indoor Fixtures. Lighting fixtures shall be open end industrial-type for surface and suspension mounting, and for use with two or three fluorescent lamps per fixture section. These fixtures shall be in 1.2 m and 2.4 m long sections (nominal dimensions) for individual and continuous row installation, and equipped with the following:
a. The fixtures shall have an integral raceway which can be made continuous by joining fixtures end to end. The raceway shall be formed of minimum 0.92 mm (20 gage) sheet steel, adequately
reinforced for rigidity. The raceway shall be completely covered. The raceway cover, when not a part of the reflector, shall be sheet steel and readily detachable from the raceway channel. Latching or
holding devices shall be of the captive type.
b. The reflector shall be formed of minimum 0.92 mm (20 gage) sheet steel, and shall be of one piece construction, flanged or beaded at the edges, ribbed to provide stiffening, and completely
covered by fused porcelain enamel. Latching or holding devices shall be of the captive type.
c. All metal parts of the fixture, except reflector, shall be rust proofed by the Bonderite or other approved process, and shall be finished with hot spray baked corrosion resistant enamel. The reflecting parts shall have a reflection factor of at least 85 percent. Hardware shall be cadmium or zinc plated.
d. Ballasts shall be in accordance with Click Here.
e. Lampholders shall be white and shall be of depressible, spring loaded type, to prevent lamps from disengaging the lampholder under vibration, and falling from the fixture.
- Office and Control Room Fixtures
a. Troffer-type fluorescent lighting fixtures shall be used to illuminate the administration building, engineering building, the control building and other similar locations with finished ceilings.
b. Troffer-type fixtures shall comply with NEMA LE 4. The fixtures shall be UL listed.
c. Fixtures shall be made from sheet steel of the following minimum thicknesses:
(i) Housing and end plates, 0.76 mm (22 gage)
(ii) Socket support straps 0.92 mm (20 gage)
(iii) Wireway cover 0.61 mm (24 gage)
d. The fixtures shall be factory assembled to ensure all four supporting sides rest on supporting tee bar members.
e. Fixtures shall have integral raceway with knockouts provided in the top and sides near each end, for field wiring. The raceway cover shall be readily removable without use of tools.
f. All metal parts of the raceway and reflector shall be rust-proofed and shall be finished with hot spray baked corrosion-resistant enamel. The reflecting parts shall be white, having a reflection factor
of at least 80 percent. Hardware shall be cadmium or zinc plated.
g. All electrical parts, for example ballasts, lampholders, and connectors shall be UL listed.
i. Lampholders shall be white tombstone type, provided with pin guides. All contacts shall be silver plated.
j. Wiring used throughout the fixtures shall be UL listed for the required temperature(s). Field connection leads shall extend a minimum of 152 mm through wiring adapter plate.
k. A bottom closure panel shall be provided on each troffer fixture. This panel shall consist of a 0.76 mm (22 gage) hinged door frame with a prismatic lens, or a frameless prismatic lens with integral hinge. Panel frame shall be internally braced with mitered corners. Light tight sealing shall be provided around all four sides. Safety hinges and unobtrusive positive finger cam latches shall be
provided. Lens shall be made from acrylic resin.
High Intensity Discharge HID Fixtures
- Electrical components shall be totally enclosed to minimize or exclude the entrance of dust, and to prevent the escape of sparks or other hot particles. The fixtures shall comply with UL 1572.
- Fixtures shall be suitable for mounting as follows: ceiling, rigid pendant, flexible pendant, straight stanchion, angle stanchion or wall mount.
- The ballast housing shall be of die cast aluminum with heat radiating fins, and with corrosion resistant and powder epoxy finish. The ballast housing shall be completely pre wired with class H or higher
insulation system. Quick disconnect connector between wiring in fixed top portion and bottom removal portion of fixture is desirable.
- Mogul base lamps shall be used where feasible. Smaller wattage fixtures shall be acceptable in medium base styles.
- A supplementary bonding jumper between cover and ballast housing shall be furnished where cover and ballast housing are hinged.
- Stainless steel external hardware with captive type external fastening screws shall be used.
- Separation of ballast and capacitor shall be maintained by a positive means, to prevent a short circuit if capacitor expands under failure mode.
- Reflectors for walkway and platform lighting shall be dome or 30° angle type, and made from fiberglass reinforced polyester material.
- High bay fixtures shall have porcelain steel or spun aluminum reflectors with adjustable distribution from narrow to wide beam. Aluminum reflectors shall be anodized for maximum efficiency and minimum maintenance. When a glass globe is not utilized, the bottom of the reflector shall be sealed with hinged-latched, gasketed door frame with thermal shock and impact resistant glass. Top of the reflector shall be capable of producing approximately 5 percent up light.
- Globes or refractors shall be thermal/shock/impact resistant, borosilicate glassware.
- Guards shall be provided, to protect globes from damage.
- Vendor shall supply photometric data, with lux distribution curves or tables, or both; overall optical efficiency (lumens out as a percent of lumens produced); and the fixture’s coefficient of utilization.
Safety Light Fixtures
- Illuminated markers are used to indicate the locations of various types of safety equipment, and to signal certain conditions or hazards. This standard suggests certain distinctive colors to be used for the
various services; however, marker types and colors shall be coordinated with established systems.
- Typical installations of fire-alarm boxes mounted outdoors on poles are indicated by plain red globes. Blue globes are used in outdoor areas where it is desirable to indicate the location of fire hose boxes.
- Red globes may be used indoors for indicating the location of fire-alarm boxes and other fire-fighting equipment, providing their location, physical shape, and red color will not be readily mistaken as indicating that of an exit. Where this is the case, amber globes are recommended for indicating the location of fire-alarm boxes and other fire-fighting equipment.
- Safety showers are usually marked with indicating lamps fitted with plain green globes.
- Illuminated markers are used to show the position of platforms at tank-car loading and unloading stations. Typically, a red signal globe is lighted when platform is extended, and a green signal globe is lighted when platform is in a completely stored-away position.
- Any warning and signal lights set up to control the flow of traffic, or to indicate that precautionary measures should be taken, shall have lenses or globes colored to agree with standard highway traffic
lights, for example red for stop, green for go, flashing amber for caution, flashing red for stop and proceed with caution.
Obstruction Light Fixtures
- Fixed position flashing beacons shall be 300 mm electrical code type equipped with two lamps and ‘aviation red’ color filters. The two lamps of the beacon shall burn simultaneously and each shall be 620 W, PS 40 Clear. Beacons shall be Crouse-Hinds Type FCB 12, Catalog No. 41257F.
- Disconnecting and lowering types of flashing beacons shall be of the same type as the fixed-position units, except Crouse Hinds Catalog No. 44389TH.
- Flashing beacons shall be controlled by a flashing mechanism producing 30 flashes per minute with a two-thirds ‘on’ and one-third ‘off’ cycle. Flashers shall be Crouse Hinds Type TSS 24, Catalog No. 48361 for 1 circuit; 48362 for 2 circuits; 48363 for 3 circuits.
- Single fixed position obstruction light fixtures shall be ‘aviation red’ color Fresnel or prismatic globe type equipped with 116 W, A 21 clear traffic signal type lamp. Fixtures shall be Crouse Hinds Type VAW,
Catalog No. 43958.
- Duplex, fixed position obstruction-light fixtures shall be ‘aviation red’ color Fresnel or prismatic globe type equipped with two 116 W, A 21 clear traffic signal-type lamps. Fixtures shall be Crouse Hinds Type VAW, Catalog No. 43961.
- Duplex disconnecting and lowering type obstruction light fixtures shall be the same type as the duplex fixed position units except they shall be Crouse Hinds Catalog No. 43950A.
- Incandescent fixtures shall comply with UL 1571.
Main keywords for this article are Lamp Selection and Applications, Lighting Fixture Selection and Applications, HID Lamp Advantages, Fluorescent Light Fixtures, Fluorescent Lamps.