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In the field of physical security, security lighting is lighting that intended to deter or detect intrusions or other criminal activity occurring on a property or site. It can also be used to increase a feeling of safety. Lighting is integral to
crime prevention through environmental design Crime prevention through environmental design (CPTED) is an agenda for manipulating the built environment to create safer neighborhoods. It originated in America around 1960, when urban renewal strategies were felt to be destroying the social fram ...
. A 2019 study in New York City found that the provision of street lights, an important type of security lighting, resulted in a "36 percent reduction in nighttime outdoor index crimes."


Planning considerations

Security lighting to prevent intrusions may be counter-productive. Turning off lights halved the number of thefts and burglary in
Övertorneå Övertorneå ( fit, Matarengi; fi, Matarenki) is a locality and the seat of Övertorneå Municipality in Norrbotten County, Sweden with 1,917 inhabitants in 2010. It is located at the shore of the Torne River, opposite to their Finnish twin to ...
Sweden. "Outdoor Lighting and Crime, Part 2"
by Barry Clark 2003, p. 18 and Figure 5
A test in West Sussex UK showed that adding all-night lighting in some areas made people there feel safer, although crime rates increased 55% in those areas compared to control areas and to the county as a whole. Bright, unshielded floodlights often prevent people from noticing criminal activity, and help criminals see what they are doing. While adequate lighting around a physical structure is deployed to reduce the risk of an intrusion, it is critical that the lighting be designed carefully as poorly arranged lighting can create glare which actually obstructs vision. Studies have shown that many criminals are aware of this effect and actively exploit it. The optimal design will also depend on whether the area will be watched directly by humans or by
closed-circuit television Closed-circuit television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly tr ...
, and on the location of the observers or cameras. Security lighting may be subject to vandalism, possibly to reduce its effectiveness for a subsequent intrusion attempt. Thus security lights should either be mounted very high, or else protected by
wire Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm A wire is a flexible strand of metal. Wire is co ...
mesh or tough polycarbonate shields. Other lamps may be completely recessed from view and access, with the light directed out through a
light pipe Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 ...
or reflected from a polished aluminium or stainless steel mirror. For similar reasons high security installations may provide a stand-by power supply for their security lighting. Some typical considerations include: * Reduce and prevent glare and situations mentioned above ** Shielded or full cut-off (FCO) lamp housings which conceal the bulb could be used, which should direct light onto the ground or target and away from observers. These lights should send no light above 80 degrees from the
nadir The nadir (, ; ar, نظير, naẓīr, counterpart) is the direction pointing directly ''below'' a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface. The dire ...
. Lighting should be bright enough, and not "as bright as possible". In many cases a good rule of thumb is 0.5 watts per square metre (0.05 watts per square foot). This might need to be increased in complex environments, but conversely can be reduced in very open environments. Multiple lamps of moderate power instead of a few powerful lamps will reduce glare, provide more even illumination with reduced pools of shadow, and provide some redundancy if one lamp's bulb blows out or develops a bad ballast. * Prevent malicious tampering or interference. This means that besides the lamp itself, the entire circuit from the source ( electric company or generator), through the wires, to the lamp and back should be protected. ** Luminaires should be accessible so that the maintainer can replace blown bulbs as quickly as possible and clean the luminaires periodically. However they should be protected or somehow made inaccessible to tampering. ** Ensure the
electric meter North American domestic analog electricity meter. Electricity meter with transparent plastic case (Israel) North American domestic electronic electricity meter An electricity meter, electric meter, electrical meter, energy meter, or kilowa ...
box is locked or inaccessible, or else power the lights from a different line. ** Control and power lines, where outside or vulnerable, should be either buried well underground (in
conduit Conduit may refer to: Engineering systems * Conduit (fluid conveyance), a pipe suitable for carrying either open-channel or pressurized liquids * Electrical conduit, a protective cover, tube or piping system for electric cables * Conduit curre ...
s preferably) or at a height of at least 8 metres (about 24 feet). ** Ideally multiple circuits should be used to prevent an accidental or malicious short or cut causing all illumination to fail.


Use

Security lighting can be used in residential, commercial, industrial, institutional, and military settings. Some examples of security lighting include
floodlight A floodlight is a broad-beamed, high-intensity artificial light. They are often used to illuminate outdoor playing fields while an outdoor sports event is being held during low-light conditions. More focused kinds are often used as a stage ...
s and low pressure sodium vapour lights. Most lights intended to be left on all night are high-intensity discharge lamps as these have good energy efficiency, thus reducing the cost of running a lamp for such long periods. A disadvantage of low pressure sodium lamps is that the colour is pure yellow, so the illuminated scene is seen without any colour differentiation. Consequently, high pressure sodium vapour lamps (which are still yellowish, but closer to golden white) are also used, at the cost of greater running expenses and increased light pollution. High pressure sodium lamps also take slightly longer to restrike after a power interruption. LED-based security lighting is becoming increasingly popular, due to its low electrical consumption (compared to non-LED lighting technologies), long lifespan, and options for different color spectrum ranges. Other lights may be activated by sensors such as
passive infrared sensor A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors. PIR sensors are commonly used in security alarms ...
s (PIRs), turning on only when a person (or other mammal) approaches. PIR sensor activation can increase both the deterrent effect (since the intruder knows that he has been detected) and the detection effect (since a person will be attracted to the sudden increase in light). Some PIR units can be set up to sound a chime as well as turn on the light. Most modern units have a
photocell Photodetectors, also called photosensors, are sensors of light or other electromagnetic radiation. There is a wide variety of photodetectors which may be classified by mechanism of detection, such as photoelectric or photochemical effects, or b ...
so that they only turn on when it is dark. To reduce light pollution, the
International Dark-Sky Association The International Dark-Sky Association (IDA) is a United States-based non-profit organization incorporated in 1988 by founders David Crawford, a professional astronomer, and Tim Hunter, a physician/amateur astronomer. The mission of the IDA is " ...
recommends the use of downward-facing security lights that preserve and protect the night time environment. During the
South African energy crisis The South African energy crisis is an ongoing period of widespread national blackouts of electricity supply. It began in the later months of 2007 and continues to the present. The South African government-owned national power utility and primary ...
increased rates of metal theft, house breaking and robberies were reported in areas effected by the loss of security lighting due to a loss of electricity in some urban areas.


Limitations

An important limitation to the usefulness of security lighting is the simple fact that it is only useful at night. This is particularly significant for home owners because, contrary to a widespread myth, most household
burglaries Burglary, also called breaking and entering and sometimes housebreaking, is the act of entering a building or other areas without permission, with the intention of committing a criminal offence. Usually that offence is theft, robbery or murder ...
occur during the day,"Lighting & Crime"
from the
British Astronomical Association The British Astronomical Association (BAA) was formed in 1890 as a national body to support the UK's amateur astronomers. Throughout its history, the BAA has encouraged observers to make scientifically valuable observations, often in collaborati ...
's
Campaign for Dark Skies The Commission for Dark Skies (CfDS) (formerly the Campaign for Dark Skies; the name was changed on March 29, 2015) is the United Kingdom's largest anti-light pollution, light-pollution campaign group forming part of the international dark-sky m ...
when the occupants are away at work or shopping. As with any lighting, security lighting can reduce
night vision Night vision is the ability to see in low-light conditions, either naturally with scotopic vision or through a night-vision device. Night vision requires both sufficient spectral range and sufficient intensity range. Humans have poor night vi ...
, making it harder to see into areas that are unlit or are in shadow. Non-uniform illumination may also interfere with surveillance systems, as the
wide dynamic range In photography and videography, multi-exposure HDR capture is a technique that creates extended or high dynamic range (HDR) images by taking and combining multiple exposures of the same subject matter at different exposure levels. Combining m ...
of security cameras may have difficulty adjusting to the changes in light intensity.


See also

*
Access control In the fields of physical security and information security, access control (AC) is the selective restriction of access to a place or other resource, while access management describes the process. The act of ''accessing'' may mean consuming ...
* Environmental design * Light pollution * Physical Security *
Security Security is protection from, or resilience against, potential harm (or other unwanted coercive change) caused by others, by restraining the freedom of others to act. Beneficiaries (technically referents) of security may be of persons and social ...
*
Security engineering Security engineering is the process of incorporating security controls into an information system so that the controls become an integral part of the system’s operational capabilities. It is similar to other systems engineering activities in tha ...


References

{{DEFAULTSORT:Security Lighting Lighting Security Architectural lighting design