How to Read Security Drawings

Access Control Card Reader

Often shown as a rectangle with a slot symbol or CR notation. Located at doors. Requires power (24VDC) and data connection (RS-485 or Ethernet). Must be on the correct side of the door and coordinated with door hardware.

CCTV Camera

Shown as a small circle, square, or dome symbol with a viewing angle arrow indicating the camera's field of view. PTZ cameras (pan-tilt-zoom) are marked differently. Requires PoE (Power over Ethernet) or dedicated power and network connection.

Motion Sensor/PIR Detector

Often a circle with radiating lines or a motion wave symbol. Must have clear line-of-sight into the space it protects. Placement near vents, heat sources, or moving objects causes false alarms.

Door Contact/Sensor

Shown as a small rectangle or triangle on the door frame and door. When the door opens, the contact signal is sent to the control panel. Used for alarm zones and automation (closing security gates when a door opens).

Electric Strike

Shown on the door hardware schedule and sometimes on the security plan with a bolt symbol. Electronically releases the latch when access is granted. Requires 24VDC power and coordination with the card reader and control panel.

Magnetic Lock (Mag Lock)

Shown on the door frame or in the control diagram. Holds the door closed via electromagnetic force. Requires sustained 24VDC power; if power fails, the door releases. Must be coordinated with door hardware and fire code requirements.

Control Panel/Processor

Shown as a large rectangle in the security room or equipment room. All field devices (readers, cameras, sensors) connect back to the panel. Requires dedicated power, network connectivity, and adequate physical space for mounting and cable terminations.

Intercom/Video Callstation

Shown at lobbies and entry points. Allows visitors to call apartments or offices. Requires network connection and often auxiliary speaker wiring. Must be weatherproofed if at exterior doors.

Card Reader Location

Is the reader on the outside (exit side) or inside (entry side)? A reader on the wrong side of the door defeats security and creates a usability nightmare. The hardware schedule should specify reader location as part of the door detail.

Electric Strike vs. Mag Lock

Different doors use different hardware. A restroom door might have a badge reader with an electric strike. A secure equipment room might have a mag lock. The hardware schedule lists which doors get what.

Fire Ratings and Emergency Release

Fire-rated doors with mag locks must have battery backup and manual release mechanisms for emergency egress. The hardware schedule must specify these requirements; the security plan must account for the power and release infrastructure.

PoE (Power over Ethernet)

A single Ethernet cable provides both network connection and 48VDC power to PoE devices (cameras, readers, etc.). Requires an Ethernet switch with PoE support and adequate power budget. A single PoE+ port provides ~30W; multiple PoE devices may require a dedicated PoE switch with high total power budget.

24VDC Power Supplies

For non-PoE devices (magnetic locks, readers, sensors), dedicated 24VDC supplies are required. The specification sheet lists amperage; a typical card reader draws 0.5A, a mag lock draws 1–2A. Calculate total load and size the supply accordingly. Undersizing causes voltage drop and device malfunction.

Backup Power (UPS/Battery)

Access control must remain operational during power loss (emergency egress). A UPS (uninterruptible power supply) is required to keep electric strikes and mag locks powered during an outage. Capacity must support the system for at least 15–30 minutes (code-dependent). Size the UPS based on total load and required runtime.

Network Connectivity

Security systems require Ethernet connectivity (often separate from building network for security reasons). The plan should show network closet locations, cable routes, and switch placement. Modern systems often use dedicated security networks isolated from IT.

1. Cameras Pointing at Walls or Obstructed by Structural Elements

A camera location on the security plan is obstructed by a column, beam, or wall on the architectural plan. Result: camera installed in a location where it can't see anything. Verify field of view against architectural sections.

2. Card Readers on Wrong Side of Door

Reader installed on the entry side instead of exit side. Creates a security breach and requires hardware relocation mid-construction. Verify reader location against door schedules.

3. Missing Conduit Homerun from Device to Panel

A reader is shown on the plan but no conduit route is specified. Electricians improvise, running cable through spaces where it gets damaged or where it violates code. Always verify that every device has a defined pathway back to the control panel.

4. Motion Sensors in Locations with Blind Spots

A motion sensor is positioned behind or near a large structure, creating areas not covered by the detector. Intruder can move through the uncovered space. Verify coverage against architectural sections and layouts.

5. Inadequate Power Capacity or Wrong Power Type

24VDC supply sized for 5A but actual load is 8A. Devices malfunction due to voltage drop. Verify power supply sizing against device specifications and total load calculations.

6. No UPS or Backup Power for Door Locks

Mag locks and electric strikes lose power during an outage, preventing emergency egress. Fails fire code inspection. Verify UPS capacity and verify mag locks are on the backup circuit.