NBBI Authorized Inspector (AI) key terms

A National Board-commissioned individual employed by an authorized inspection agency who performs Code inspections and signs manufacturer's data reports for boilers, pressure vessels, and pressure relief devices.

A National Board-commissioned supervisor who directs and reviews Authorized Inspectors' work, holds supervisory authority, and may perform inspections when an inspector is unavailable.

An organization that employs National Board-commissioned inspectors and is authorized by ASME and the jurisdiction to provide third-party Code inspection services to manufacturers and users.

A credential issued by the National Board of Boiler and Pressure Vessel Inspectors that authorizes an individual to perform inspections under the NBIC and ASME Code after passing examinations and meeting experience requirements.

A document issued by ASME that permits a manufacturer or assembler to use a specific Code symbol stamp and to certify that items conform to the applicable ASME Code section.

The ASME stamp, such as U, S, or H, applied to a nameplate or item to certify that it was constructed in accordance with the applicable ASME Code section under an authorized inspection agency's inspection.

A certified form, such as the U-1 or U-1A, on which the manufacturer records design, material, inspection, and test details and which the Authorized Inspector signs to attest Code compliance.

A permanent marking attached to a boiler, pressure vessel, or relief device that shows the manufacturer, serial number, Code stamp, design pressure, capacity, and other required data for identification and traceability.

The state, provincial, or municipal government body that regulates boiler and pressure vessel safety, adopts the ASME Code and NBIC, and may impose additional inspection, registration, or operating requirements.

The National Board's code for inservice inspection, repairs, alterations, and rerating of boilers and pressure vessels, used with ASME construction rules and adopted by many jurisdictions.

An examination performed on an operating boiler or pressure vessel to verify its condition and continued suitability for service, often required by the jurisdiction and conducted under NBIC rules.

Work that restores a boiler or pressure vessel to a safe condition without changing its design pressure, temperature, or other essential design parameters, performed under NBIC rules and often with an R stamp.

A change to a boiler or pressure vessel that affects its pressure-retaining capability, design pressure or temperature, or essential design features, requiring reanalysis and usually an R stamp and jurisdiction notification.

The National Board repair symbol stamp that a qualified organization applies after completing a repair or alteration under NBIC rules, signifying that the work was inspected and documented.

The National Board symbol stamp for organizations that repair or remanufacture pressure relief valves, certifying that the work and testing comply with NBIC and National Board requirements.

An automatic device that opens to discharge fluid when inlet pressure exceeds a set value and recloses after pressure falls, protecting boilers and pressure vessels from overpressure.

The inlet pressure at which a pressure relief valve is adjusted to begin opening under specified conditions, marked on the valve and used to establish the vessel's overpressure protection limit.

The pressure increase above the maximum allowable working pressure permitted while a pressure relief device discharges at its rated capacity, typically limited by Code to a stated percentage.

The difference between the set pressure at which a relief valve opens and the lower pressure at which it reseats, usually expressed as a percentage of set pressure.

The National Board or ASME process by which a pressure relief device's flow capacity is tested and rated, allowing the device to be marked with a certified capacity for sizing and overpressure protection.

The highest pressure at which a boiler or pressure vessel is designed to operate under its design temperature and allowable stress, established by Code calculations and marked on the nameplate.

The pressure used in the Code design calculations for a boiler or pressure vessel, often equal to or above the maximum allowable working pressure, and used to establish minimum thickness.

A pressure test using water to verify the strength and leak tightness of a boiler or pressure vessel, usually conducted at a specified multiple of design pressure before the item is stamped and released.

A factor used in Code calculations that reflects the strength of a welded joint relative to the base material, depending on joint type and the extent of nondestructive examination performed.

A written document that specifies the welding variables, such as process, filler metal, preheat, and PWHT, that a welder must follow to produce a weld meeting Code requirements.

A record of the test welds and destructive test results used to prove that a welding procedure specification can produce welds with the required mechanical properties under Section IX.

A test that demonstrates an individual welder's ability to produce sound welds using a qualified procedure, with results recorded and valid for specified conditions and time limits under Section IX.

A controlled heating and cooling process applied after welding to relieve residual stresses, soften the heat-affected zone, or reduce hardness, as required by the applicable Code section and material specification.

A nondestructive method that uses X-rays or gamma rays to produce images of internal weld flaws such as porosity, slag, or lack of fusion, evaluated against Code acceptance criteria.

A nondestructive method that directs high-frequency sound waves into material to detect internal discontinuities and measure thickness, with acceptance criteria defined by the applicable Code section.

A document supplied by the material manufacturer that reports chemical composition and mechanical properties of a heat of material, used by the fabricator to verify compliance with the Code specification.

The maximum stress value permitted by the Code for a material at a given temperature, derived from tensile strength, yield strength, and other criteria, and used in design thickness calculations.

A test that measures a material's resistance to brittle fracture by striking a notched specimen, required by the Code for certain materials, thicknesses, or low-temperature service conditions.

Extra material thickness added to a pressure part during design to compensate for metal loss expected from corrosion or erosion over the intended service life.

The ASME Code section that sets construction requirements for power boilers, including materials, design, fabrication, inspection, testing, and stamping, with specific rules for drums, tubes, and piping.

The ASME Code section covering construction of heating boilers, including cast iron and steel boilers, with rules for design, materials, fabrication, inspection, and testing intended for low-pressure heating service.

The ASME Code section that provides rules for constructing unfired pressure vessels, covering design, materials, fabrication, inspection, testing, and certification for a wide range of pressure service.

A stage in fabrication or inspection at which work must stop until the Authorized Inspector or jurisdiction performs the required inspection and documents acceptance, preventing concealment of nonconforming work.

A document that records a departure from Code, specification, or drawing requirements, describes the disposition such as repair or accept-as-is, and tracks corrective action until closure.

The ASME Code section that establishes requirements for qualifying welding procedures, welders, brazers, and brazing procedures, including essential variables and test specimen requirements.