💡Challenges and Issues:

•    Ineffective Lighting:
  •    Severe contrasts between light and shadow can disorient surveillance (human or electronic).
  • Poor lighting can facilitate intruders' attempts to hide or evade detection.
  • Inappropriate lighting can make security officers or other response forces more visible and vulnerable.
•  Too Much Lighting:
  • Glare caused by excess lighting can blind security officers or response forces.
  • Imbalance between exterior and interior lighting can permit undesired visibility into a facility from the outside.
  • Over lighting can create blind spots or "white out" for security cameras.
  • Increased contrast between light and shadow can impede effective observation
• Contrast is a critical concept; a well-lit complex in a remote area might appear dim if adjacent to an extremely brightly lit neighbor (e.g., a car dealership). Therefore, lower lighting levels might be suitable for remote areas.
• Glare Management:
  • Intentional glare can be used to inhibit an intruder's vision by aiming luminaires away from the property.
  • Care must be taken to ensure intentional glare does not inhibit cameras or security personnel or disrupt legitimate activity.
  • Unwanted glare can be minimized by increasing fixture mounting heights and using steeper aiming angles.
• Light Pollution and Light Trespass:
  • Light spillage: Light that overshoots its intended area.
  • Light trespass: Light spillage that extends onto a neighbor's property, interfering with activities and potentially leading to hostility or lawsuits.
• Beam Direction (shape and coverage):
  • Affected by lamp type, luminaire design, mounting technique, location, and environmental conditions.
  • Poor beam direction (e.g., lighting straight down) may only illuminate a small area, leaving larger spaces dark.
  • Appropriate beam overlap and avoiding coverage gaps are crucial for both pole-mounted and wall-pack lighting units.
  • A rule of thumb recommends a spacing between poles of twice the mast height for proper overlap, though this can vary.

💡Characteristics of Light and Lighting:

The quantity of light refers to the overall amount of light a fixture produces. In contrast, light level (or illuminance) describes how much of that light actually reaches and illuminates a target surface. For adequate security, it's not just about brightness—it's about delivering the right amount of light to the right place.

Foot-candles (fc) and lux are both units used to measure illuminance, which is the concentration of light over a particular area. The primary difference lies in the measurement system they belong to:

• Foot-candles (fc) are English units.
  • They represent the number of lumens per square foot.
• Lux are metric units.
  • They represent the number of lumens per square meter.

To provide a conversion, one foot-candle is equal to 10.76 lux, though this is often approximated to a ratio of 1:10.

• Reflectance
  • The ratio of light falling on an object to the light being reflected from it, expressed as a percentage.

 When evaluating the amount of light needed for a video surveillance camera or the human eye to perceive a scene, the illuminance (measured in fc or lux) over the area of the lens iris is critical.

• Corrected Color Temperature (CCT):
  • A measure of the warmth or coolness of a light, measured in degrees Kelvin (°K).
  • ~2,700°K is red hot (perceived as warm); ~4,100°K is white hot (neutral); ~5,000°K is blue hot (cool/daylight).
  • Has a considerable impact on mood and ambiance.
• Color Rendition Index (CRI):
  • Measures a lamp's ability to discriminate, grade, and faithfully reproduce colors.
  • Scale from 0 to 100: 70-80 is good, >80 is excellent, 100 is daylight.
  • Low CRI lamps (e.g., high- and low-pressure sodium, mercury vapor) should not be used with color cameras or where color identification is critical, as they can distort colors.
  •   High CRI increases visual clarity, morale, and productivity, and makes pedestrians feel safer outdoors at night.
• Brightness: The perception of the amount of light that reaches a person's eyes.

🎥 Illumination for Surveillance

Cameras require specific light levels:

• Color Cameras: Need 2x more light than monochrome
• Infrared (IR): Useful for covert monitoring, monochrome imaging
• CRI & CCT: Essential for image clarity and color accuracy

Recommended Light Levels (Foot-candles):

• Lighting standards vary by agency (IES, NRC, DOAFM)
• Perimeter: 0.2–0.5 fc
• Open lots: 0.2–2.0 fc
• Entrances: 5–10 fc
• Interiors: 10–70 fc
• ATMs, teller counters: up to 50–70 fc

Always consult reliable references, such as IES and NRC, as well as industry vendors like GE, Philips, and Sylvania, for guidance.

💡Lighting System Components

A lighting system consists of several essential components:

• Lamp (Light Bulb):
  • The manufactured light source, including the filament/arc tube, glass casing, and electrical connectors.
  • Types (e.g., incandescent, mercury vapor) describe the technologies used to create light.
• Luminaire (Fixture):
  • The complete lighting unit, comprising the lamp, its holder, and reflectors/diffusers to distribute and focus light.
  • A fixture contains means of connecting to the power source and may include ballasts (for correct voltage/current) and photosensors (for light control based on ambient conditions).
  • Selection depends on both performance characteristics and aesthetics.
  • In industrial settings, luminaires should include a secondary restraint (e.g., metal cable) if vibration is a concern, for safety.
• Mounting Hardware:
  • Examples include wall brackets or light poles, used to fix the luminaire at the correct height and location.
• Electrical Power:
  • Operates the lamp, ballasts, and photocells.
  • Some lamp technologies, particularly high-intensity discharge (HID) lamps, are sensitive to reduced voltages, as they rely on an arc discharge.
  • If the supply voltage is sufficiently reduced, the arc can be extinguished, and restart times can be lengthy (up to 20 minutes).
• Backup batteries, generators, and uninterruptible power supply (UPS) systems should be considered for high-security and high-safety areas (e.g., vaults, cash registers, emergency egress paths) to ensure continuous lighting.

💡Economic Considerations

Cost is a significant factor in determining the level of security lighting.

While codes or regulations mandate some lighting, elective security lighting needs to be justified by identifiable savings or quantifiable risk reduction.

• Typical Lighting Operating Costs:
  • Energy: Approximately 88% of the total operating cost.
  • Capital items (lamps and ballasts): Approximately 8%.
  • Maintenance: Approximately 4%.
• Energy Efficiency (Efficacy):
  • The most critical cost factor.
  • Measured by a lamp's output in lumens divided by its power draw in watts.
• Replacement Lamps:
  • The next highest cost, varying by lamp technology and quality.
• Maintenance Costs:
  • Includes labor to replace lamps and clean them.
  • Lumen output declines due to dirt accumulation (3-4% annually in clean environments, up to 20% in dirty environments after one year).
  •  Regular cleaning is essential to maintain the designed light output, as power consumption remains the same regardless of dirt.
  • Lamp performance generally declines with age, producing only 80% of designed output by the end of their rated life, even when clean.
• Planned Replacement:
  • More economical to perform a planned replacement of all or a group of lamps rather than waiting for individual failures.
  • Ensures there are no dark areas, even for a short time, due to individual failures.
  • Economically sensible to time re-lamping with cleaning cycles (e.g., replace all lamps every three cleaning cycles if average life is six years and cleaning is every two).
• Number of Luminaires Required:
  • A function of the area to be covered, required light levels, luminaire height and design, and lighting technology used.
• Uniformity of Light Distribution:
  • Achieving uniform light distribution, especially outdoors, can be expensive.
  • Measured as the ratio between the average light level and the minimum light level.
  • Typical ratios: 1:0.7 for working environments, 4:1 on a pedestrian walkway, and 10:1 on a roadway.
  • Higher uniformity provides better depth perception and a greater perception of security