ASME B31.4 Liquid Pipelines

ASME B31.4 is the code for transportation of liquids by pipelines, including crude oil, refined petroleum products, liquid alcohols, ammonia, and CO2, defining weld NDT requirements integrated with API 1104.

Definition

B31.4 governs hazardous-liquid pipelines in the United States and is supplemented by 49 CFR Part 195. It references API 1104 for weld acceptance and API 1163 for in-line inspection.

What this document is

The ASME code for pipeline transportation systems for liquids and slurries — design, construction, examination and testing of liquid pipelines between facilities, the liquid-line counterpart to B31.8 for gas.

How it is applied

Its examination sections invoke girth-weld NDT with acceptance criteria aligned to API 1104 practice; in-service integrity of the same lines is then governed by regulation (in the US, DOT/PHMSA rules) rather than the construction code.

The common misuse

Applying B31.3 process-piping thinking to a transportation pipeline. The codes split at the plant fence for a reason — examination percentages, acceptance criteria and repair rules all differ.

Where ASME B31.4 Liquid Pipelines fits in an inspection programme

A term is only useful when it connects to a decision. ASME B31.4 Liquid Pipelines appears in written procedures, in technique sheets, and in the records an owner or accreditation body reviews afterwards — which means the way it is defined in your documentation has to match the way it is applied on site. Where the two drift apart, audits find it. Atlantis writes and reviews procedures against the governing codes, trains inspection personnel to apply them, and builds the record-keeping that makes the evidence retrievable years later. Procedure development and code consulting · NDT training and certification · Ask us about your programme.

Related terms

ASME B31.8 Gas Transmission and Distribution Piping — ASME B31.8 is the code for gas transmission and distribution piping systems, including pipelines and onshore station piping, defining NDT, hydrostatic testing, and integrity management for natural gas service.
API 1104 Welding of Pipelines and Related Facilities — API 1104 is the welding code for pipelines and related facilities transporting liquids, gases, or slurries, defining procedure and welder qualification, weld inspection (RT, AUT), and acceptance criteria for cross-country and station piping.
API 1163 In-Line Inspection Systems Qualification — API 1163 is the standard for qualifying in-line inspection (ILI) tools and processes for hazardous-liquid and gas pipelines, defining tool performance specifications, dig verification programs, and reporting requirements.

More standard terms

ASME Section V · ASME Section VIII · ASME Section IX · ASME Section XI · ASME B31.1 Power Piping · ASME B31.3 Process Piping · API 510 Pressure Vessel Inspection Code · API 570 Piping Inspection Code · API 571 Damage Mechanisms · API 579-1 / ASME FFS-1 Fitness-for-Service

Where this comes up in practice

Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.

Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A and ISO 9712, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.