NBIC

Covers — post-construction activities for pressure-retaining items. The code is organized in four parts:

• Part 1 — Installation — proper installation of boilers, pressure vessels, piping, and related equipment.
• Part 2 — Inspection — in-service inspection methods and documentation for pressure-retaining items.
• Part 3 — Repairs and Alterations — the "R"-stamp rules for welded and mechanical repairs and for alterations requiring re-rating.
• Part 4 — Pressure Relief Devices — installation, inspection, and the "VR"-stamp repair of relief valves.

Does NOT cover (exclusions) — the following are governed elsewhere:

• Original design and new construction of boilers/vessels → ASME BPVC (Sections I, IV, VIII, etc.).
• In-service inspection programs specific to refinery piping and vessels → API 570 / API 510 (which may be used alongside NBIC where adopted).
• Transportation pipelines → ASME B31.4 / B31.8 and pipeline safety regulations.

NBIC is a jurisdictional code; the enforceable edition is the one adopted by the state/province, not necessarily the newest.

NBIC sets minimum requirements for post-construction integrity:

• Installation — pressure-retaining items must be installed with correct supports, relief protection, and controls per Part 1 before being placed in service.
• Inspection — periodic in-service inspection by an authorized inspector, with documentation, per Part 2; findings drive repair/alteration decisions.
• Repairs — welded and mechanical repairs performed by an organization holding a National Board "R" Certificate of Authorization, following qualified procedures (ASME Section IX) and stamped/registered accordingly.
• Alterations — any change beyond the original design requires engineering re-rating, inspector concurrence, and documentation.
• Pressure Relief Devices — set-pressure testing, repair, and the "VR" program ensure relief capacity is maintained (Part 4).

The technical evaluations below determine how an in-service pressure item is legally kept safe after construction.

Repair vs. Alteration

The pivotal distinction: a repair returns an item to a safe operating condition without changing its design; an alteration changes the design (e.g., increased pressure, added nozzle) and requires re-rating calculations and inspector approval. Misclassifying an alteration as a repair is a serious compliance failure.

The "R" and "VR" Stamp Programs

Only organizations accredited by the National Board may apply the "R" stamp (repairs/alterations) or "VR" stamp (pressure-relief-valve repair). Work is documented on National Board report forms and, where required, registered.

Weld Repair Qualification

Welded repairs use procedures and welders qualified to ASME Section IX; NDE and, where needed, post-weld heat treatment follow the construction code of record.

Where to find it in the code: installation → Part 1 · inspection → Part 2 · repairs & alterations → Part 3 · relief devices → Part 4.

Engineering Note: NBIC picks up where the ASME BPVC construction code leaves off; the two are complementary, and the construction code of record still governs the technical basis of any repair.