Physical QC Traveler

Example: Physical QC Traveler on Module W-042

A physical Quality Control (QC) traveler attached directly to a module is a valid and inspector-credible method for demonstrating process compliance. This approach is widely used in regulated manufacturing and is appropriate for early-stage and low-tech deployment in construction systems.

What This Artifact Is

The pinned drawing and checklist constitute a process traveler. It records execution of an approved process step-by-step and provides auditable evidence that required constraints were applied. It is not an inspection result and does not replace the inspector’s authority.

Requirements for a Valid Traveler

The traveler must be a compiled, frozen artifact that includes:

• Module ID (e.g., W-042)
• Approved drawing version or schema reference
• Revision identifier or date

The traveler must correspond exactly to the approved design. Sketches or informal notes are not acceptable.

Structure of the Checklist

Each check mark corresponds to a specific, binary requirement that is enforced mechanically or structurally. Examples include:

• Box height class: H18
• Stud spacing class: S16
• Fire blocking present
• Fastener schedule A applied
• Wire routing path R-02 applied

Checklist items must be objective and falsifiable. Vague assessments such as “looks good” are not permitted.

When Checks Are Applied

Each check is applied:

• Immediately after the corresponding build step
• By the worker performing the step
• Before the module advances to the next operation

This ensures process control rather than post-hoc review.

Traveler Handling

The traveler:

• Remains physically attached to the module during assembly
• Is visible until the module is closed
• Is removed only at final close-out
• Is scanned or photographed for the permanent record

This prevents skipped steps and preserves traceability.

Inspector Interaction

On site, the inspector may:

• Verify the module ID
• Confirm visible compliance markers (e.g., H18 embossing)
• Reference the traveler on file if needed

The inspector is not required to review the traveler unless an anomaly or audit condition exists.

Language Constraints

The traveler must never state “inspected and approved.” It documents execution of the approved process, not a compliance judgment.

Rationale

A physical traveler is trusted because deviation would require deliberate bypass or falsification. This provides sufficient evidence of process fidelity while preserving inspector authority.

Deployment Guidance

Early-stage OSE implementations should prefer physical travelers due to:

• Zero software dependency
• Minimal training overhead
• High acceptance by Authorities Having Jurisdiction
• Clear alignment with established industrial practice