Objective 1.2Critical Priority8 min read

Physical Security Monitoring

Surveillance and detection systems used to monitor facilities and detect unauthorized access. Includes video surveillance, access badges, lighting, and various sensors such as infrared, pressure, microwave, and ultrasonic.

Understanding Physical Security Monitoring

Physical security monitoring detects unauthorized access and suspicious activity. While physical mechanisms (locks, fences, bollards) prevent or delay entry, monitoring systems detect when something is wrong and enable response.

Monitoring serves multiple purposes: • Detection — Identify intrusions and suspicious activity • Deterrence — Visible cameras discourage bad actors • Documentation — Record evidence for investigation • Verification — Confirm identity at access points

Effective physical security combines mechanisms (barriers) with monitoring (detection). Barriers slow attackers; monitoring alerts defenders and captures evidence.

Why This Matters for the Exam

Physical security monitoring is tested both as standalone knowledge and within broader security scenarios. Questions may ask about selecting the right sensor type for a specific environment or understanding how monitoring supports incident response.

Understanding different sensor types helps with scenario questions. Each sensor type has strengths and weaknesses—knowing when infrared vs. microwave vs. ultrasonic is appropriate demonstrates practical knowledge.

This connects to detective controls from Domain 1.1. Cameras, sensors, and access logs are all detective physical controls—they detect rather than prevent.

Deep Dive

Video Surveillance (CCTV)

  • Cameras that monitor and record activity in physical spaces.

Types:

  • Analog CCTV — Traditional closed-circuit systems
  • IP Cameras — Network-connected, often higher resolution
  • PTZ (Pan-Tilt-Zoom) — Movable cameras for wide coverage
  • Fixed cameras — Stationary coverage of specific areas

Features:

  • Motion detection and recording triggers
  • Night vision and low-light capability
  • Video analytics (facial recognition, object detection)
  • Remote viewing and management
  • Storage and retention policies

Placement Considerations:

  • Entry/exit points
  • Parking areas
  • Sensitive areas (data centers, vaults)
  • Public areas for safety
  • No blind spots in critical areas

Functions:

  • Detective — Identify incidents
  • Deterrent — Visible presence discourages
  • Evidentiary — Record for investigation

Access Badges

  • Identification cards that control and log physical access.

Types:

  • Proximity cards — Contactless, short-range
  • Smart cards — Chip-based, can store credentials
  • Magnetic stripe — Swipe cards (older technology)
  • Mobile credentials — Smartphone-based access

Features:

  • Unique identification
  • Access logging (who, when, where)
  • Integration with access control systems
  • Photo ID for visual verification
  • Multi-factor (badge + PIN)

Security Lighting

  • Illumination that supports security and deters intrusion.

Purposes:

  • Eliminate shadows and hiding spots
  • Support surveillance camera effectiveness
  • Deter intruders who prefer darkness
  • Enable guard observation

Types:

  • Continuous lighting — Always on
  • Motion-activated — Triggers on movement
  • Emergency lighting — Battery backup during outages
  • Smart lighting — Programmable, integrated with security

Sensor Types

Infrared (IR) Sensors

  • Detect body heat (passive infrared/PIR)
  • Common for motion detection
  • Affected by heat sources and temperature changes
  • Best for indoor use

Pressure Sensors

  • Detect weight on floors, mats, or fences
  • Identify when someone steps in an area
  • Can count people (for mantrap verification)
  • Weather-resistant options available

Microwave Sensors

  • Emit microwave signals, detect reflection changes
  • Cover larger areas than IR
  • Can penetrate some materials
  • May have more false alarms (movement behind walls)

Ultrasonic Sensors

  • Emit high-frequency sound waves
  • Detect movement via reflected sound changes
  • Sensitive to air movement (HVAC)
  • Good for enclosed spaces

Sensor Comparison

Sensor TypeDetection MethodBest ForLimitations
InfraredBody heatIndoor motionHeat sources cause false alarms
PressureWeightFloor/perimeterLimited to specific areas
MicrowaveRadio wave reflectionLarge areasPenetrates walls (false alarms)
UltrasonicSound wave reflectionEnclosed spacesAir movement causes false alarms

Integration and Response

Effective monitoring requires: • Central monitoring station — View and respond to alerts • Alert escalation — Automated notification workflows • Integration — Video + sensors + access control • Response procedures — What to do when alarms trigger • Regular testing — Verify systems work correctly

How CompTIA Tests This

Example Analysis

Scenario: A data center needs to detect unauthorized entry into the server room. The room has controlled climate (HVAC) and is enclosed with no windows. Security wants motion detection that triggers camera recording.

Analysis: Best sensor choice is Passive Infrared (PIR): • Detects body heat from intruders • Works well in enclosed spaces • Not affected by the environment (no windows) • Limitation: HVAC shouldn't cause issues if properly installed

Why not others:Microwave — Could detect movement in adjacent rooms (walls) • Ultrasonic — HVAC air movement could cause false alarms • Pressure — Only detects on specific floor areas

Key insight: Sensor selection depends on the environment. Indoor, enclosed spaces typically favor PIR. Large open areas might use microwave. Each has trade-offs.

Key Terms to Know

physical security monitoringvideo surveillanceCCTVaccess badgesinfrared sensorsmotion sensorspressure sensorsultrasonic sensors

Common Mistakes to Avoid

Thinking all motion sensors are the same—different sensor types have different detection methods and different false alarm triggers. PIR detects heat, microwave detects radio wave changes, ultrasonic detects sound changes.
Forgetting that cameras are both detective AND deterrent—visible cameras deter attackers (they don't want to be recorded). This dual function is important.
Missing that monitoring requires response—detection without response is worthless. Monitoring systems must be watched, alerts must be acted upon.
Ignoring environmental factors—choosing sensors without considering the environment leads to false alarms or missed detections. Match sensor type to environment.

Exam Tips

Know the four sensor types: Infrared (heat), Pressure (weight), Microwave (radio waves), Ultrasonic (sound waves).
Visible cameras = Deterrent + Detective. Hidden cameras = Detective only. Visibility determines deterrent value.
Access badge logs provide the "who, when, where" for investigations—they're both an access control and a monitoring mechanism.
False alarm considerations: Ultrasonic → air movement, Microwave → movement through walls, PIR → heat sources.
Lighting supports other monitoring—cameras need adequate light, guards need visibility. Lighting is foundational.

Memory Trick

"IPMU" for Sensor Types

  • Infrared — detects Internal heat (body heat)
  • Pressure — detects People stepping
  • Microwave — detects Movement via radio waves
  • Ultrasonic — detects via soUnd waves
  • Camera Functions:
  • Visible = Deter + Detect
  • Hidden = Detect only

The Complete Picture: Barriers STOP → Sensors DETECT → Cameras RECORD → Guards RESPOND

  • False Alarm Memory:
  • Ultrasonic hates AIR movement
  • Microwave sees through WALLS
  • Infrared triggered by HEAT
  • Pressure needs WEIGHT

Test Your Knowledge

Q1.Which type of sensor detects motion by sensing changes in body heat?

Q2.A security camera is prominently displayed at a building entrance with a sign stating "24-Hour Video Surveillance." What control types does this represent?

Q3.Which sensor type might generate false alarms due to HVAC air movement?

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