Physical security is used to to deny unauthorized access to certain areas, to restricted facilities, as well as equipment and resources. It also describes security measures that are designed to protect staff, personnel and property from damage or harm (such as terrorist attacks, espionage, or theft.) Physical security involves the use of camera and remote surveillance, security guards and officers, protective barriers, locks, access controls, among other techniques.

Physical security is often overlooked and underestimated. However, breaches of physical security can be carried out with little or no technical knowledge on the part of an attacker. Moreover, accidents and natural disasters are a part of everyday life, and in the long term, are inevitable.

Physical security can be increased by implementing these 3 components:

  1. Obstacles can be placed in the way of potential attackers and sites can be hardened against accidents and environmental disasters. Protective measures can include multiple locks, walls, fencing, fireproof safes, and water sprinklers.
  2. Surveillance - notification systems can be installed on the premises: alarms, cameras, lighting, heat sensors, smoke detectors, etc...
  3. Methods can be implemented to apprehend attackers and to recover quickly from accidents, fires, or natural disasters.



Physical security systems for protected facilities are generally intended to:

  1. Deter potential intruders (detect intrusions and monitor/record intruders)
  2. Trigger appropriate incident responses (e.g. security guards and police).

Security controls should be balanced against risks. Physical security measures that are appropriate for a high security prison or a military site may be inappropriate in an office, a home or a vehicle, although the principles are similar.


Deterrence methods

The goal is to convince potential attackers that an attack is unlikely due to strong defenses.

The security layer for a campus, building, office, or other physical space uses environmental design to deter threats. Some examples are: warning signs or window stickers, fences, vehicle barriers, vehicle height-restrictors, restricted access points, security lighting and trenches.


Physical barriers

Fences, walls, and vehicle barriers act as the outermost layer of security. They prevent, or at least delay, attacks, and also act as a psychological deterrent by defining the perimeter of the facility and making intrusions seem more difficult. Fencing, topped with barbed wire, razor wire or metal spikes emplaced on the perimeter of a property, warn people not to attempt to enter. 


Natural surveillance

Natural surveillance, include spaces that are more open and visible to security personnel and authorized users, so that attackers cannot perform unauthorized activity without being seen. Measures such as decreasing dense, tall vegetation in the landscaping, or placing critical resources in areas where intruders would have to cross over a wide, open space to reach them.


Security lighting

Intruders are less likely to enter well-lit areas for fear of being seen. Doors, gates, and other entrances, should be well lit to allow close observation of people entering and exiting. It is important to place lighting in a manner that makes it difficult to tamper with, and to ensure that there is a backup power supply so that security lights will not go out if the electricity is cut off.


Alarm systems and sensors

Alarm systems alert security personnel when there is unauthorized access. Alarm systems work to trigger a response when physical barriers, mechanical systems, or security guards have been breached.
Sensors including motion sensors, contact sensors, and glass break detectors.


Video surveillance

Surveillance cameras can deter when placed in visible locations, and are useful for incident verification and historical analysis. Photography can sometimes be useful as well.


Access control

Access control is used to monitor and control traffic through specific access points and areas of the secure facility using surveillance, identification cards, security guards, locks, doors, turnstiles and gates.


  1. Mechanical access control systems
    1. Mechanical access control systems include turnstiles, gates, doors, and locks. 
  2. Electronic access control systems
    1. Electronic access control manages large user populations, controlling for user lifecycles times, dates, and individual access points.
  3. Identification systems and access policies
    1. Includes the use of policies, processes and procedures to manage the ingress into the restricted area. This form of access control is usually supplemented by the earlier forms of access control, or simple devices such as physical passes.


Security personnel

Security personnel play a central role in all layers of security. They are a security force that is trained in their use and maintenance, and which knows how to properly respond to breaches in security. Security personnel perform many functions: as patrols and at checkpoints, to administer electronic access control, to respond to alarms, and to monitor and analyze video.