Security design and access control is more than bars on windows, a security guard booth, a camera, or a wall. Crime prevention involves the systematic integration of design, technology, and operation for the protection of three critical assets-people, information, and property. Protection of these assets is a concern and should be considered throughout the design and construction process.
The most efficient, least expensive way to provide security is during the design process. Designers who are called on to address security and crime concerns must be able to determine security requirements, must know security technology, and must understand the architectural implications of security needs.
The process of designing security into architecture is known as "crime prevention through environmental design" (CPTED). It involves designing the built environment to reduce the opportunity for, and fear of, stranger-to-stranger predatory crime. This approach to security design is different from traditional crime prevention practice, which focuses on denying access to a crime target with barrier techniques, such as locks, alarms, fences, and gates. CPTED takes advantage of opportunities for natural access control, surveillance, and territorial reinforcement. It is possible for natural and normal uses of the environment to meet the same security goals as physical and technical protection methods.
CPTED strategies are implemented by:
- Electronic methods: Electronic access and intrusion detection, electronic surveillance, electronic detection, and alarm and electronic monitoring and control
- Architectural methods: Architectural design and layout, site planning and landscaping, signage, and circulation control
- Organizational methods: Manpower, police, security guards, and neighborhood watch programs
Concepts involved in crime prevention through environmental design are described below.
Oscar Newman coined the expression "defensible space" as a term for a range of mechanisms, real and symbolic barriers, strongly defined areas of influence, and improved opportunities for surveillance that combine to bring the environment under the control of its residents.
Natural Access Control
Natural access control involves decreasing opportunities for crime by denying access to crime targets and creating a perception of risk in offenders. It is accomplished by designing streets, sidewalks, entrances, and neighborhood gateways to mark public routes, and by using structural elements to discourage access to private areas.
A design concept intended to make intruders easily observable, natural surveillance is promoted by features that maximize visibility of people, parking areas, and entrances. Examples are doors and windows that look onto streets and parking areas, pedestrian-friendly sidewalks and streets, front porches, and adequate nighttime lighting.
Physical design can create or extend a sphere of influence. In this setting, users develop a sense of territorial control, while potential offenders perceive this control and are discouraged from their criminal intentions. Territorial reinforcement is promoted by features that define property lines and distinguish private spaces from public spaces, such as landscape plantings, pavement design, gateway treatments, and fences.
Management and Maintenance
It is important to maintain neighborhoods and residences, and keep security components in good working order. Equipment and materials used in a dwelling should be designed or selected with safety and security in mind.
Legitimate Activity Support
Legitimate activity for a space or dwelling is encouraged through the use of natural surveillance and lighting, and architectural design that clearly defines the purpose of the structure or space. Crime prevention and design strategies can discourage illegal activity and protect a property from chronic problem activity.
Designing CPTED and security features into buildings and neighborhoods can reduce opportunities for, and vulnerability to, criminal behavior and help create a sense of community. The goal is to create safe places through limited access to properties, good surveillance, and a sense of ownership and responsibility.
Natural Access Control and Surveillance
- Use walkways and landscaping to direct visitors to the proper entrance and away from private areas.
- All doorways that open to the outside as well as sidewalks and all areas of the yard should be well lit.
- Make the front door at least partially visible from the street and clearly visible from the driveway or parking lot.
- Windows on all sides of the building should provide full views of the property. The driveway should be visible from the front or back door and from at least one window.
- Properly maintained landscaping should provide good views to and from the building.
- Entryways or vestibules create a transitional area between the street and the building.
- Define property lines and private areas with plantings, pavement treatments, or fences.
- The street address should be clearly visible from the street, with numbers a minimum of 5 in. high and made of nonreflective material.
Subdivisions and Office Parks
Natural Access Control
- Limit access to the subdivision without completely disconnecting it from neighboring areas. However, try to design streets to discourage cut-through traffic.
- Paving treatments, plantings, and architectural design features such as columned gateways can guide visitors away from private areas.
- Locate walkways where they can direct pedestrian traffic and remain unobscured.
- Landscaping should not create blind spots or hiding places.
- Locate open green spaces and recreational areas so they can be observed from nearby houses.
- Use pedestrian-scale street lighting in areas with high pedestrian traffic.
- Design lots, streets, and houses to encourage interaction between neighbors.
- Accent entrances with changes in street elevation, different paving materials, and other design features.
- Clearly identify residences with street address numbers that are a minimum of 5 in. high and are well lit at night.
- Property lines should be defined with post-and-pillar fencing, gates, and plantings to direct pedestrian traffic.
- All parking should be assigned.
Natural Access Control
- Balcony railings should never be made of a solid, opaque material or be more than 42 in. high.
- Define parking lot entrances with curbs, landscaping, and/or architectural design; block dead-end areas with a fence or gate.
- Common building entrances should have locks that automatically lock when the door closes.
- Limit access to the building to no more than two points.
- Define property lines with landscaping or post-and-pillar fencing, but keep shrubbery and fences low to allow visibility from the street.
- Accent building entrances with architectural elements and lighting and/or landscape features.
- Doorknobs should be 40 in. from window panes.
- Clearly identify all buildings and residential units with well-lit address numbers a minimum of 5 in. high.
- Common doorways should have windows and be key-controlled by residents.
- Locate mailboxes next to the appropriate residences.
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