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Back to: Advanced Physical Security Integration (APSI)

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Lesson 9.2: System Design & Bill of Materials (BOM)

Module: 9 – Project Management & Lifecycle Prerequisites: Lesson 9.1 (Site Survey) Estimated Time: 45–60 Minutes

1. Learning Objectives

By the end of this lesson, you will be able to:

  • Construct a complete Bill of Materials (BOM) that includes “Hidden” items like licenses, mounts, and patch cables.
  • Calculate storage requirements (HDD size) based on retention time, resolution, and H.265 compression.
  • Audit a PoE Power Budget to ensure the switch can actually power all the devices.
  • Estimate labor hours accurately by applying “Difficulty Factors” (e.g., high ceilings vs. drop ceilings).

2. The Anatomy of a BOM

A rookie quotes a camera. A professional quotes a System. If you forget one bracket or license, that money comes out of your profit margin.

The “Camera Kit” Checklist: For every single camera location, you need:

  1. The Device: (e.g., 5MP IP Dome).
  2. The Lens: (If not built-in, usually for box cameras).
  3. The Mount:
    • Wall Arm?
    • Pendant Cap? (The adapter that connects the camera to the arm).
    • Corner/Pole Adapter? (If mounting to a corner or pole).
    • Back Box? (To hide the pigtail connectors).
  4. The License: VMS Channel License (e.g., Milestone Device License).
  5. The SD Card: (Optional, for Edge Recording backup).

The Infrastructure Checklist:

  1. Cabling: Cat6 (1000ft box). Estimate average run length + 15% slack.
  2. Connectors: RJ45 Jacks / Patch Panels.
  3. Switching: PoE Switch (Check port count AND power budget).
  4. Storage: NVR or Server + Hard Drives (HDD).
  5. Consumables: Zip ties, electrical tape, screws, anchors, conduit.

3. The Math: Storage & Bandwidth

You cannot guess hard drive size. You must calculate it.

The Formula Factors:

  1. Resolution: 4MP takes 2x space of 1080p.
  2. Frame Rate (FPS): 30fps takes 2x space of 15fps. (Standard security is 15fps).
  3. Compression: H.265 saves 40-50% space compared to H.264.
  4. Retention: How long to keep video? (Standard is 30 Days).
  5. Activity: Motion Only (recording 40% of the day) vs. Continuous (100%).

The Calculator:

  • Scenario: 10 Cameras, 4MP, 15fps, H.265, 30 Days, 50% Motion.
  • Result: You need approx. 4 TB of usable storage.
  • Purchase: Buy 6 TB or 8 TB (Hard drives are formatted; a 6TB drive only gives you ~5.4TB usable, plus you need RAID redundancy).

4. The Math: PoE Budget

Just because a switch has 24 ports doesn’t mean it can power 24 cameras.

PoE Classes:

  • Class 2 (7W): Fixed Domes (No IR).
  • Class 3 (15.4W): Standard Bullet with IR.
  • Class 4 (30W / PoE+): PTZ or Heated Camera.
  • Class 8 (60W-90W / PoE++): Big PTZ with wipers/lasers.

The Trap:

  • Switch: 24-Port Switch with a 180W Total Budget.
  • Devices: 20 Cameras @ 10W each = 200W required.
  • Result: The switch will power up the first 18 cameras. Camera 19 and 20 will stay dead.
  • Fix: Check the datasheet for “Total PoE Budget” and ensure it > Total Device Wattage.

5. Estimating Labor (The “Difficulty Factor”)

Labor is the biggest risk.

Baseline:

  • Simple Drop Ceiling Install: 2 Hours/Device (Run wire, mount, aim, focus).

Multipliers:

  • High Ceiling (Lift Required): x 2.0 (4 Hours).
  • Hard Lid (Drywall/Concrete): x 2.5 (5 Hours – requires conduit).
  • Exterior Penetration: x 1.5 (3 Hours – requires drilling/sealing).
  • Programming: Add 15 mins per camera for IP addressing, naming, and VMS setup.

Example Quote:

  • 10 Cameras (Standard Office): 20 Hours.
  • 2 PTZs (Exterior Warehouse): 8 Hours.
  • Server Setup: 4 Hours.
  • Total: 32 Man-Hours.

6. The “Exclusions” (Protecting Yourself)

In your design document, explicitly state what you are NOT doing.

  • Example: “Quote excludes 110V electrical work. Client must provide power outlet at the rack location.”
  • Example: “Quote excludes patching and painting of drywall.”
  • Example: “Quote excludes scissor lift rental.”