A Comprehensive Guide to Lighting: Types, Applications, and Photometric Factors
Photometric Factors Affecting Lighting Quality
The main factors affecting the quality of lighting are:
- Color Reproduction
- Color Temperature
- Levels of Illumination
- Glare
- Flashes and Strobe Effects
Color Rendering Index (CRI)
CRI represents the ability of a light source to allow good color vision.
Table 1. Color Rendering Index
| Grade | Color Rendering Index | Level of Color Rendering |
|---|---|---|
| 1 | 85 to 100 | Excellent |
| 2 | 70 to 84 | Good |
| 3 | 40 to 69 | Fair |
| 4 | Less than 40 | Limited |
Note: A lamp with Re = 100 shows all colors accurately.
The UNE 12464-1 standard establishes minimum CRI standards for virtually all workspaces. In spaces with uninterrupted work, the standard requires a minimum of 80 Ra. Only in some cases, such as in the heavy metal industry, is 60 accepted as the minimum. Thus, some lamp types, known generically as standard, cannot be applied due to insufficient color reproduction properties.
Color Temperature
The color of light refers to the appearance of warmth or coolness of light. It is characterized by color temperature, measured in Kelvin (K).
For general interior lighting, light is divided into three color temperatures:
- Warm White (below 3,300 K)
- Neutral White (3,300 to 5,000 K)
- Cool White (above 5,000 K)
In medical wards and areas where color-critical inspection work is carried out, a minimum color temperature of 4,000 K is recommended. Dental offices, color inspection laboratories, and pharmacies require a color temperature of 6,000 K.
Lighting Levels
Lighting levels must be designed and measured on the working area of the room.
The UNE 12646-1 standard establishes thresholds for illumination levels in professional buildings:
- Areas with people present: Minimum 200 lux
- Areas with occasional occupancy: Minimum 20 lux
Increase Lighting When:
- Visual work is crucial
- Errors are difficult to correct
- Accuracy and higher productivity are very important
- The worker’s eyesight is below normal
- Task details are small or have low contrast
- The task is performed for an extended period
Reduce Lighting When:
- Task details are large and have high contrast
- Work is conducted for a short time
Types of Lamps
Incandescent Lamps
Standard Incandescent Lamps
Characteristics:
- Low luminous efficiency
- High operating cost
- Excessive heat production
- Half-life of approximately 1,000 hours
Applications:
- General lighting in homes, offices, shops, etc., where the ceiling height is not very high
Table 2. Standard Incandescent Lamps
| Power (W) | Luminous Flux (lm) | Luminous Efficacy (lm/W) |
|---|---|---|
| 25 | 230 | 9.2 |
| 40 | 430 | 10.7 |
| 60 | 730 | 12.1 |
| 100 | 1,380 | 13.8 |
| 150 | 2,100 | 14 |
| 200 | 2,950 | 14.7 |
| 300 | 4,700 | 15.6 |
| 500 | 8,400 | 16.8 |
| 1,000 | 18,800 | 18.8 |
| 1,500 | 29,500 | 19.6 |
Incandescent Lamps with Halogen
Characteristics:
- Longer half-life than standard incandescent lamps (about 2,000 hours)
- Clear, constant light throughout their lifespan
- Smaller size
- Higher luminous efficiency
- Brighter, more aesthetically pleasing light
Applications:
- Projectors for illuminating buildings, monuments, sports fields, pavilions, plazas, large parking areas, and more
Table 3. Incandescent Lamps with Halogen
| Power (W) | Type of Bulb | Luminous Flux (lm) | Luminous Efficacy (lm/W) |
|---|---|---|---|
| 500 | Ceramic Bushes | 11,000 | 22 |
| 1,000 | Ceramic Bushes | 22,000 | 22 |
| 1,500 | Ceramic Bushes | 33,000 | 22 |
| 2,000 | Ceramic Bushes | 44,000 | 22 |
| 500 | Double Wrap | 11,500 | 22 |
| 1,000 | Double Wrap | 24,000 | 24 |
Fluorescent Lamps
Characteristics:
- Long lifespan (6,000 to 9,000 hours)
- Require auxiliary equipment for power-on
- Color rendering and color temperature depend on the fluorescent powder inside the lamp
- Connecting a capacitor across the lamp is advisable to improve power factor
- Light output depends on temperature; optimal range is +5°C to +30°C
Applications:
- Lighting homes, shops, offices, schools, bars, factories, workshops, hospitals, etc.
Types of Fluorescent Lamps
- Small Fluorescent Lamps: Used for localized lighting (mirrors, furniture) or special lighting applications.
- Colored Fluorescent Lamps: Used for effects in storefronts, theaters, nightclubs, etc.
- Fluorescent Lamps for Illuminated Signs: Used for signs and illuminated displays in commercial and public spaces, as well as neon signs. Different colors are achieved depending on the gas inside the tube.
- DC Fluorescent Lamps: Primarily used in small, self-contained luminaires.
- Compact Fluorescent Lamps (CFLs): Replacing incandescent lamps in some applications.
- Consume 25% of the energy of an incandescent lamp for the same light output
- Emit warm white light with good color rendering
- Average lifespan of 5,000 hours
- Common wattages: 9W, 13W, 18W, and 25W
- Used in homes, offices, shops, restaurants, etc.
- Available in various forms
Table 4. Standard Fluorescent Lamps (38mm Diameter)
| Power (W) | Tube Length (mm) | Color Tone | Color Rendering Index | Light Level | Luminous Flux (lm) | Luminous Efficacy (lm/W) |
|---|---|---|---|---|---|---|
| 15 | 438 | Cool White | 2 | Daylight | 600 | 40 |
| 15 | 438 | Daylight | 3 | Daylight | 800 | 53 |
| 20 | 590 | Daylight | 2 | Daylight | 1,000 | 50 |
| 20 | 590 | Warm White | 3 | Warm White | 1,200 | 60 |
| 20 | 590 | Cool White | 3 | Cool White | 1,200 | 60 |
| 20 | 590 | Inner Light | 1 | Inner Light | 700 | 35 |
| 40 | 1,200 | Cold White | 2 | Cold White | 2,400 | 60 |
| 40 | 1,200 | Daylight | 3 | Daylight | 3,200 | 80 |
| 40 | 1,200 | Warm White | 3 | Warm White | 3,200 | 80 |
| 40 | 1,200 | Inner Light | 1 | Inner Light | 1,750 | 44 |
| 65 | 1,500 | Cold White | 2 | Cold White | 4,000 | 62 |
| 65 | 1,500 | Daylight | 3 | Daylight | 5,100 | 78 |
| 65 | 1,500 | Warm White | 3 | Warm White | 5,100 | 78 |
| 65 | 1,500 | Inner Light | 1 | Inner Light | 2,900 | 45 |
Table 5. Fluorescent Lamps (26mm Diameter)
| Power (W) | Tube Length (mm) | Color Tone | Color Rendering Index | Light Level | Luminous Flux (lm) | Luminous Efficacy (lm/W) |
|---|---|---|---|---|---|---|
| 18 | 590 | Daylight | 1 | Daylight | 1,350 | 75 |
| 18 | 590 | Warm White | 1 | Warm White | 1,450 | 80 |
| 36 | 1,200 | Warm White | 1 | Warm White | 3,200 | 89 |
| 36 | 1,200 | Daylight | 1 | Daylight | 3,450 | 96 |
| 58 | 1,500 | Warm White | 1 | Warm White | 5,100 | 88 |
| 58 | 1,500 | Daylight | 1 | Daylight | 5,400 | 93 |
Table 6. Fluorescent Lamps (16mm Diameter)
| Power (W) | Tube Length (mm) | Color Tone | Color Rendering Index | Light Level | Luminous Flux (lm) | Luminous Efficacy (lm/W) |
|---|---|---|---|---|---|---|
| 4 | 136 | Universal White | 2 | Universal White | 120 | 30 |
| 6 | 212 | Universal White | 2 | Universal White | 240 | 40 |
| 8 | 288 | Universal White | 2 | Universal White | 350 | 44 |
| 13 | 517 | Universal White | 2 | Universal White | 650 | 50 |
Discharge Lamps: Mercury Vapor
Characteristics:
- Luminous efficacy varies by type and power, ranging from 30 to 95 lm/W
- Average lifespan of 6,000 to 9,000 hours
- Non-instantaneous power-on; takes about 5 minutes to reach maximum light output
- Require a 5-minute cool-down period before restarting
Types of Discharge Lamps: Mercury Vapor
- Clear Mercury Vapor Lamps: Limited use today due to low color rendering. Used for garden lighting due to their strong blue and green color reproduction.
- Color-Corrected Mercury Vapor Lamps: Improved color reproduction compared to clear lamps. Used in industrial lighting, outdoor lighting, and public spaces (streets, squares, roads).
Table 7. Color-Corrected Mercury Vapor Lamps
Power (W) Luminous Flux (lm) Luminous Efficacy (lm/W) 50 3,800 76 80 6,300 78.75 125 13,500 108 250 23,000 92 400 42,500 106.25 700 60,000 85.71 1,000 60,000 60 2,000 120,000 60 - Mixed Light Lamps: Do not require auxiliary equipment for ignition. Used in installations where high-power incandescent lamps need replacement without changing the fixture or setup.
Table 8. Mixed Light Lamps
Power (W) Luminous Flux (lm) Luminous Efficacy (lm/W) 160 3,100 19.38 250 5,600 22.4 500 14,000 28 1,000 32,500 32.5 - Metal Halide Lamps: Used in interior lighting (production halls, storefronts, malls, sports halls) and exterior lighting (streets, parks, architectural lighting).
- High luminous efficiency of up to 95 lm/W
- Excellent color rendering, similar to sunlight
Table 9. Metal Halide Lamps
Power (W) Type of Bulb Luminous Flux (lm) Luminous Efficacy (lm/W) 250 Ellipsoidal with Diffusing Layer 17,000 68 360 Ellipsoidal with Diffusing Layer 24,000 67 1,000 Ellipsoidal with Diffusing Layer 80,000 80 250 Tubular Clear 20,000 80 360 Tubular Clear 25,000 70 1,000 Tubular Clear 80,000 80 2,000 Tubular Clear 190,000 95 3,500 Tubular Clear 300,000 86 - Mercury Vapor Lamps with Fluorescent Bulb and Reflector: Feature a reflective surface on top to direct light output. Used for light effects and decorative lighting.
Discharge Lamps: Sodium Vapor
Low-Pressure Sodium Vapor Lamps
Characteristics:
- High luminous efficiency (over 180 lm/W)
- Half-life of approximately 6,000 hours
- Monochromatic light output (yellow-orange), altering the perceived colors of illuminated objects
- Take 5-10 minutes to reach maximum light output
Applications:
- Lighting systems requiring high light output without regard for color quality, such as highways, parking lots, ports
- Architectural and landscape lighting
Table 10. Low-Pressure Sodium Vapor Lamps
| Power (W) | Luminous Flux (lm) | Luminous Efficacy (lm/W) |
|---|---|---|
| 18 | 1,800 | 100 |
| 35 | 4,800 | 137 |
| 55 | 8,000 | 145 |
| 90 | 13,500 | 150 |
| 135 | 22,500 | 167 |
| 180 | 33,500 | 186 |
High-Pressure Sodium Vapor Lamps
Characteristics:
- Luminous efficiency lower than low-pressure sodium lamps (80-130 lm/W) but higher than mercury vapor lamps
- Long lifespan, exceeding 9,000 hours
Applications:
- Exterior lighting (highways, ports, airports)
- Interior lighting (stores, warehouses)
Table 11. High-Pressure Sodium Vapor Lamps
| Power (W) | Type of Bulb | Luminous Flux (lm) | Luminous Efficacy (lm/W) |
|---|---|---|---|
| 70 | Ellipsoidal with Diffusing Layer | 5,800 | 83 |
| 150 | Ellipsoidal with Diffusing Layer | 14,000 | 93 |
| 250 | Ellipsoidal with Diffusing Layer | 25,000 | 100 |
| 400 | Ellipsoidal with Diffusing Layer | 47,000 | 117.5 |
| 1,000 | Ellipsoidal with Diffusing Layer | 120,000 | 120 |
| 150 | Tubular Clear | 14,500 | 97 |
| 250 | Tubular Clear | 25,500 | 102 |
| 400 | Tubular Clear | 48,000 | 120 |
| 1,000 | Tubular Clear | 130,000 | 130 |
Special Discharge Lamps
§ ultraviolet lamps: These are special lamps mercury vapor discharge ultraviolet radiation sources. The different types there are:
q black light lamps: His light is black, the radiation emitted is virtually zero. They are used in philately, banks, medical, decorative lighting, night clubs, discotheques, etc..
q Solar lights: In addition to visible light, emit strong ultraviolet and infrared radiation which is used for tanning and aging of plastic people.
q lamps ozone and ultraviolet radiation sources are used in sterilization and disinfection of medical instruments.
§ infrared radiation lamps: These are special incandescent lamps that emit mostly infrared radiation, ie heat. They have many applications in them, the drying of materials, casting and welding of plastics, animal husbandry, medical applications, etc..§ neon lamps: These are similar to the filament. They have a light output and very small consumption, and a long life. They are used only in signaling.