Transcript CRIME PREVENTION THROUGH ENVIRONMENTAL DESIGN

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 [email protected]
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)
2)
3)
4)
5)
6)
7)
Incandescent
Quartz, Quartz-Halogen
Fluorescent
Mercury Vapor
Metal Halide
Low Pressure Sodium
High Pressure Sodium
Incandescent Lighting
Lamp which produces light by using electric
current to heat a filament
Incandescent Lighting
ADVANTAGES:
1) Instant on
2)
3)
4)
5)
Low initial cost
Excellent color rendition
Can be dimmed
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)
2)
3)
4)
5)
6)
7)
8)
9)
Less vandalism
Fewer Break-ins
Improved morale & safety / security
Fewer assaults
Premise liability enhanced
Increased curbside appeal
Increased building value
Improved Productivity
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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