Alan D. Duer, CPP

Security Analyzer

Baltimore Gas and Electric Company

7309 Windsor Mill Road

Baltimore, MD. 21244

phone 410 597-7783

fax 410 597-7774

e mail alan.d.duer@bge.com

CPTED

90 % of crime occurs after dark

Proper lighting enables law abiding citizens to observe / report crime and to identify suspects.

It makes people feel safe.

Lighting Terminology

Light: Radiant energy that excites the retina of the eye.

Lumen: Volume of light

Candlepower: Intensity of light in a specific location.

Foot Candle: amount of light a candle gives off in a square foot area.

Illuminance: Light on an object

Lighting Terminology

Lux: metric measurement of illumination

Lumen: measurement of light at its source and the amount of light output.

Luminaire:The complete light fixture with the light source and ballast.

Light trespass:Light pollution in unintended areas.

HID: High Intensity Discharge Lamp

Lighting Terminology

LPW: Lumens per watt, a measurement of efficiency

Ballast: A device used with an electric discharge lamp to obtain the necessary voltage and current to start and operate the lamp.

Uniformity: Relative Illuminance, lighting that doesn’t allow dark areas in parking lots.

LIGHTING SOURCES

1) Incandescent

2) Quartz, Quartz-Halogen

3) Fluorescent

4) Mercury Vapor

5) Metal Halide

6) Low Pressure Sodium

7) High Pressure Sodium

Incandescent Lighting

Lamp which produces light by using electric current to heat a filament

Incandescent Lighting

ADVANTAGES:

1) Instant on

2) Low initial cost

3) Excellent color rendition

4) Can be dimmed

5) Compact in size

Incandescent Lighting

DISADVANTAGES:

1) Short Life ( 500-5000 hrs.)

2) Inefficient to Operate

3) High Heat Output

Halogen & Quartz Halogen

Lamps are incandescent bulbs with halogen gas (like sealed -beam auto headlights)

Halogen & Quartz Halogen

Advantages:

1) Good color rendition

2) 25 % better efficiency than ordinary incandescent bulbs.

Halogen & Quartz Halogen

Disadvantages:

1) High heat output

2) Inefficient

Fluorescent

Lamps that pass electricity through a gas enclosed tube to create light

Usually used indoors and in some cases for signage

Fluorescent

Advantages:

1) They create twice the light & less than half the heat of an incandescent

bulb of equal wattage.

2) Long life (10,000 - 15,000 hrs.)

3) Efficient

4) Good color rendition

Fluorescent

Disadvantages:

1) Temperature sensitive

Mercury Vapor

A high intensity discharge device which produces light by excitation of mercury vapors (also passes electricity through a gas)

Emits a bluish white light

Mercury Vapor

Advantages:

1) Long life (16 - 24,000 hrs.)

2) Low initial cost

Mercury Vapor

Disadvantages:

1) Inefficient operation

2) Light output drops over life (2 - 3 yrs.)

3) Delayed hot restart

Metal Halide

High intensity discharge arc tube in which light is produced by the radiation of exited metal halides

100 watt bulb lasts 10,000 hrs.

Metal Halide

Advantages:

1) Excellent color rendition

2) Sparkling white light

a) imitates daylight conditions

b) used in sports stadiums, car dealer

lots, etc.

3) Works well with CCTV

Metal Halide

Disadvantages:

1) Hot restart can take several minutes

2) High initial cost

3) Most expensive light to install and maintain

High Pressure Sodium

High intensity discharge arc tube in which light is produced by radiation from sodium vapor operating under pressure

High Pressure Sodium

Advantages:

1) Very Efficient - 20-28,000 hrs. life

2) Can cut through fog and allow the eyes to see detail at greater distance

( used on streets & parking lots )

3) In some cases it can be used with CCTV

High Pressure Sodium

Disadvantages:

1) High initial cost of fixtures

2) Hot restart can take several minutes

Low Pressure Sodium

High intensity discharge arc tube in which light is produced by radiation from sodium vapor operating under pressure

Emits a dull yellow /gold hew

Low Pressure Sodium

Advantages:

1) Very efficient ( 20 - 24,000 hrs. life, a 90 watt bulb may last 16,000 hrs.)

2) May be used to combat prostitution, drug dealing, or illuminate an area just

to detect movement.

Low Pressure Sodium

Disadvantage:

1) Poorest color rendition

Security Lighting Recommendations

1) Illuminate entrances, fire escapes, etc. with bright white light.

2) Parking lots should be illuminated with bright white lights that allows

for uniformity, (not allowing any dark areas in the parking lot).

3) Implement a maintenance policy

Security Lighting Recommendations

4) Parking lots should be illuminated so one can identify a human face at 33 ft.,(3 foot candles vertically above the surface).

5) Wire cages or industrial strength shatter resistant lenses should be placed over the light to deter vandalism.

6) Position lights to avoid glare areas & blind spots.

Parking Lot Illumination

The general rule of thumb involving the installation of lighting in parking lots, is the height of the light pole multiplied by 4 will give the distance the light poles should be apart.

Building Illumination

The general rule of thumb involving the installation of wall packs, (lights on the sides of a building), is the height of the wall pack multiplied by 6 will give the distance the wall packs should be apart.

Lighting Benefits

1) Less vandalism

2) Fewer Break-ins

3) Improved morale & safety / security

4) Fewer assaults

5) Premise liability enhanced

6) Increased curbside appeal

7) Increased building value

8) Improved Productivity

9) Increased utilization of public areas resulting in more natural surveillance

National Institute of Justice

Research in Brief - April 1996

“The most important CPTED security feature is lighting. Lighting should meet standards of the Illuminating Engineering Society of North America”.

“The most important CPTED security feature a city can mandate is lighting”.

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