Leak Testing (LT) Requirements Under ASME Section V

The technique must demonstrate a specified minimum detectable leak rate, verified against a calibrated leak standard rather than asserted. ASME Section V, enforced by American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Standards Committee,.: Employer-based, not central.

An auditor examining LT asks for gauges, detectors, tracer gas equipment and the calibrated leak standards used to set sensitivity. Section V certifies no company and no person. It tells an NDE provider how to run a method, and three obligations follow you into every audit. First, a written procedure for each method and technique, demonstrated capable of producing meaningful results to the satisfaction of the Authorized Inspector — Article 1, T-150. Second, examination equipment calibrated and that calibration recorded and available to the Inspector. Third, certification records for NDE personnel whose required contents are fixed by Article 1, T-190. Personnel qualification itself sits at Article 1, T-120, which routes out to the employer's written practice and to whichever editions of ASNT SNT-TC-1A, ANSI/ASNT CP-189 or ACCP the referencing Code Section accepts. Article numbers and records, not company certificates, are what a supplier audit asks you to produce.

Source: ASME BPVC Section V product page, asme.org, 2025 edition current (BPVC editions listed as 2025, 2023, 2021). The National Board & ASME Guide (nationalboard.org / asme.org), sections 2.11, 3.10 and 6.2.10 — verified for Article 1 T-120 (personnel qualification, cited alongside SNT-TC-1A and AWS QC1), T-150 (procedures demonstrated capable of producing meaningful results to the satisfaction of the Inspector) and T-190 (contents of NDE personnel certification records); for the rule that RT and UT examiners must be certified to the Employer's written practice or a central certification programme; for MT/PT/VT certification on proficiency plus annual eye examination against SNT-TC-1A, CP-189 or ACCP in the current Code-accepted edition; and for the subcontracted Level III acceptance requirement quoted above. Article numbering cross-checked against the API 653 Publications Effectivity Sheet for March–November 2025 exams (Section V Articles 1, 2, 6, 7 and 23/SE-797, ASME BPVC 2023 edition) and the API 570 Body of Knowledge for February/June/October 2026 exams (Articles 1, 2, 6, 7, 9, 10 and 23/SE-797). ASNT SNT-TC-1A 2024 edition with addendum effective May 2025 per ASNT. Accessed 21 August 2026. Specific T-paragraph numbers beyond T-120, T-150 and T-190 were not independently verifiable and are not stated.

Leak Testing under ASME Section V — procedure, personnel and evidence
Item	What applies	Why it matters
Regime	ASME Boiler and Pressure Vessel Code, Section V — Nondestructive Examination	Enforced by American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Standards Committee, Subcommittee on Nondestructive Examination; enforced in practice by the referencing Code Section, the Authorized Inspector, and the state or provincial boiler and pressure vessel jurisdiction that has adopted the BPVC
Method	Leak Testing (LT)	Needs its own procedure and its own qualified personnel
Procedure approval	The employer's Level III, qualified in this method	The signature an auditor traces
Other methods in scope	RT, UT, PT, MT, VT, ET	Each needs separate qualification
Renewal	No certificate and no expiry — Section V is a code, not an accreditation. ASME publishes BPVC editions on a two-year cycle; the 2025 edition follows 2023 and 2021. Written practices and procedures must be re-reviewed against the edition the referencing Code Section and the adopting jurisdiction have accepted, since the Code-accepted editions of SNT-TC-1A, CP-189 and ACCP change between BPVC editions. Personnel recertification intervals are set by the employer's own written practice, not by Section V.	Applies to the personnel certification behind this method

Does ASME Section V require a separate procedure for LT?

Yes. Every method in scope needs its own written procedure, approved by someone qualified in that method, describing technique, equipment, calibration, scanning or coverage, acceptance criteria and reporting. A single combined "NDT procedure" covering several methods is a finding under every regime that names procedures individually.

Who can approve a LT procedure under ASME Section V?

A Level III qualified in LT. Because ASME Section V accepts employer-based certification, that Level III may be contracted rather than employed — but their own qualification must cover LT, and an auditor will check that before accepting the signature.

What LT records does a ASME Section V audit sample?

The approved procedure, the technician's LT certification on the date of work, and the equipment evidence — gauges, detectors, tracer gas equipment and the calibrated leak standards used to set sensitivity. The auditor works backwards from a finished job, so every item has to reconcile with the report and its stated acceptance criteria.

What is the most common LT finding at audit?

Sensitivity never demonstrated against a calibrated leak standard. It is a records failure rather than a technique failure — the examination was performed correctly and the evidence supporting it cannot be produced, which under ASME Section V is recorded the same way as not having done the work.

Can a technician certified elsewhere perform LT under ASME Section V?

Not automatically. Employer-based certification ends when the holder leaves, so the new employer must certify them under its own written practice. Prior training and documented experience transfer as evidence; the certificate itself does not.

What equipment evidence does LT need under ASME Section V?

Calibration status traceable to the day of use, covering the instrument and its accessories — probes, cables, blocks and reference standards for ultrasonics; sources and densitometers for radiography. An in-calibration instrument with an out-of-calibration reference block fails the same way as an uncalibrated one.

How do LT requirements differ from the other methods in ASME Section V?

Scope, qualification and evidence are method-specific, so the differences are real rather than administrative. ASME Section V also covers RT, UT, PT, MT, VT, and each carries its own procedure, its own personnel qualification and its own equipment evidence.

Personnel certification for LT

Employer-based, not central. Section V leaves certification to the employer's written practice, built on ASNT SNT-TC-1A, ANSI/ASNT CP-189 or ACCP in the edition the referencing Code Section accepts. Radiographic and ultrasonic examiners must be qualified and certified to that written practice or to a central certification programme; magnetic particle, liquid penetrant and visual examiners may be certified by the Certificate Holder on the basis of proficiency in the techniques employed plus an annual eye examination. The joint National Board and ASME Guide states that the Level III examiner may be an employee of the Certificate Holder or of a subcontractor, and that where he is subcontracted, documented evidence must be on file accepting the subcontractor's Level III examiner as the Certificate Holder's Level III examiner. An outsourced Level III is expressly contemplated by the audit guidance.