API 1104 — Welding of Pipelines and Related Facilities

Welding code for cross-country pipeline construction — qualifies WPS/welders for oil and gas pipelines, sets RT/UT acceptance for girth welds.

Scope

API 1104 — Welding of Pipelines and Related Facilities — is the welding code for cross-country pipeline construction. It is the dominant code for oil and gas transmission pipelines in North America and is widely referenced internationally for pipelines transporting crude petroleum, petroleum products, fuel gases, carbon dioxide, nitrogen, and other gases. API 1104 covers welding procedure qualification (WPS/PQR), welder qualification, production welding requirements, examination (visual, radiographic, ultrasonic), and acceptance criteria for girth welds and other field welds. API 1104 differs from ASME Section IX in welder qualification details and from ASME B31.4/B31.8 in acceptance criteria — it is specifically tuned to the high-volume, field-erection environment of cross-country pipeline construction. The current edition is the 22nd Edition (October 2021) with Errata.

NDT methods it governs

{"label":"Pipeline Integrity Inspection","href":"/blog/ndt-pipeline-integrity-inspection-guide"}
{"label":"Weld Inspection Methods","href":"/blog/weld-inspection-ndt-methods-guide"}
{"label":"Radiographic Testing (RT)","href":"/blog/radiographic-testing"}
{"label":"Phased Array UT","href":"/blog/phased-array-ultrasonic-testing-paut-guide"}

Certifications that reference it

{"label":"ASNT Certification (RT, UT)","href":"/asnt-certification"}
{"label":"API 570 Certification","href":"/api-570-certification"}

Issuing body

API

Revision history

2021 —
2018 —
2013 —
2010 —

Related standards

api-570 · aws-d1-1 · asme-b31-3 · asme-section-v-article-2 · asme-section-v-article-4 · iso-17636 · iso-17640

Applying this in an inspection programme

Code compliance is only demonstrable if the evidence behind it is: the procedure revision in force, the inspector's certification state and the instrument's calibration status at the time of test. Atlantis NDT provides ASNT Level III consulting for procedure and written-practice work against this code, training toward the certifications that reference it, and inspection management software that keeps that evidence recoverable years later. Request a consultation.

How a standard like this is applied in an inspection programme

A standard is only half of the requirement. It defines how an examination is performed and, in some cases, how results are classified — but the acceptance criteria that decide whether a component stays in service normally come from the construction or in-service code governing the item, not from the examination standard itself. Confusing the two is one of the more common findings in a procedure review: a procedure that correctly cites the examination standard but applies acceptance criteria from the wrong code or the wrong edition.

What has to be in place for compliance to be demonstrable

A written procedure qualified against this standard for the specific materials, thickness ranges and geometries in scope — not a generic procedure covering everything
Personnel certified for the method and level under ASNT SNT-TC-1A, ANSI/ASNT CP-189, NAS 410 or ISO 9712, current on the date the examination was performed
Equipment, probes and reference standards in calibration on that date, with traceability to a national standard under ISO 17025
The applicable edition of the standard recorded against the examination, so historical work stays assessed under the edition then in force
Technique sheets under the same revision control as the procedure above them — the most frequently uncontrolled document in an otherwise compliant quality system

Edition changes

When a new edition is issued, new work moves to it from a defined effective date that you set and record; work already performed stays assessed under the edition in force at the time. Retrospectively applying a new edition to historical dispositions invalidates the original acceptance decision and creates a substantially larger problem than the one being solved.

Where this usually goes wrong

Not in the technical content, but in reconstruction. An auditor picks an issued report and asks which procedure revision applied, who performed the work and whether they were qualified on that date, and whether the instrument and reference blocks were in calibration. Programmes that hold only current state can answer none of those. Binding the document revision, the qualification state and the calibration state to each inspection record as it is created turns that from an investigation into a lookup.