Layer Management for Multi-Clearance Facilities

Abstract

Designing a secure facility involves multiple stakeholders, many of whom do not hold Top Secret (TS) clearance. This creates a documentation hazard: how to produce construction drawings that give the General Contractor (GC) enough info to build the walls, without revealing the location of classified sensors or red-cabling routes? This guide proposes a rigorous AutoCAD Layer State system for "Sanitized" vs. "Classified" plot sets.

1. The Clearance Dilemma

A standard "Electrical Plan" usually shows lights, outlets, and data ports.

• Risk: If the data ports for the "Red Network" are shown on the same sheet as the light switches, an uncleared electrician might see the layout of the secure network.
• Requirement: We need to generate two sets of drawings from the same CAD file:
  1. Unclassified Set: Walls, Lights, HVAC, Black Data.
  2. Classified Set: Red Data, Intrusion Detection Sensors, SCIF shielding details.

2. The Layering Standard (NCS Modified)

We adopt the National CAD Standard (NCS) but append a "Security Level" suffix.

2.1 Suffix Logic

• _U: Unclassified (Visible to all)
• _C: Confidential (Need to Know)
• _S: Secret/Top Secret (Cleared personnel only)

2.2 Example Layer List

• E-POWR-WALL_U (Power outlets - Unclassified)
• E-DATA-JACK_U (NIPR/Black Data jacks - Unclassified)
• E-DATA-JACK_S (SIPR/Red Data jacks - SECRET)
• T-SENS-MOTN_S (Motion Sensors - SECRET)
• A-WALL-FULL_U (Architectural Walls - Unclassified)

3. Layer States Manager

Manually freezing/thawing layers for every plot is a recipe for a security breach. We use Layer States.

3.1 State: "PLOT_UNCLASS"

• Action:
  • Thaw: *_U
  • Freeze: *_C, *_S
• Result: A clean floor plan showing walls and standard power. The Red network jacks simply vanish.

3.2 State: "PLOT_CLASSIFIED"

• Action:
  • Thaw: *_U, *_C, *_S
• Result: The full picture. The Red jacks appear next to the Black jacks.

4. Operational Security (OPSEC) in CAD

4.1 The "0" Layer Trap

Never draw classified geometry on Layer 0. If a block is inserted on an Unclassified layer but contains geometry on Layer 0, it might show up unexpectedly.

4.2 XREF Management

Ideally, keep the Classified data in a separate .dwg file XREF'd into the sheet.

• Workflow:
  • Sheet_A101.dwg (The Sheet file)
  • XREF: Floor_Plan_Base.dwg (Walls)
  • XREF: Security_Overlay.dwg (The Secret stuff)
• Distribution: When sending files to the uncleared GC, you simply do not send the Security_Overlay.dwg. Even if they have the sheet file, the XREF will be "Not Found," preventing accidental data spills.

5. Conclusion

Layer management is not just about drafting hygiene; in secure facility design, it is a matter of national security. A robust Layer State or XREF segregation strategy ensures that "need to know" applies to the blueprints just as strictly as it applies to the people.