Physical Security Systems and Technology
Layers, not gadgets
Physical security works in depth: deterrence (lighting, signage, visibility), detection (alarms, sensors, cameras), delay (barriers, locks, bollards), and response (patrol, police). Remove one layer and the others must compensate. Crime Prevention Through Environmental Design adds natural surveillance, natural access control, and territorial reinforcement - clear sightlines, defined entries, and good maintenance.
Core systems
Access control systems manage credentials, schedules, and door hardware. Intrusion detection uses door contacts, motion sensors, and glass-break detectors. CCTV provides recorded and live views; its value depends on placement, lighting, resolution, retention time, and whether anyone monitors or reviews it. Fire alarm and life-safety systems have their own codes and must never be bypassed.
Failure modes
Know whether a door is fail-safe (unlocks on power loss, used where egress is critical) or fail-secure (stays locked, used for asset protection). Test alarms and cameras on schedule, log faults, and report promptly. Alarm fatigue and repeated false alarms erode response - investigate causes, not just resets.
Traps
'Cameras prevent crime' - they mostly record it. 'The system will catch it' - technology supports judgment, it does not replace patrol and verification. Also watch propping doors, taping over sensors, and ignoring privacy and data-protection rules when reviewing or sharing footage.
Rule of thumb
Technology buys time and evidence; people supply judgment. Always know what happens when the power fails.