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API 598

8 in-depth engineering guides on API 598 — specification, selection, testing and procurement.

Everything on API 598

Vajra's engineering team has published 8 technical guides covering API 598 for industrial valve selection, specification, testing and procurement. Browse the full set below.

Factory Acceptance Testing (FAT) for Industrial Valves - API 598, ISO 5208 and Witness Testing Guide

Factory Acceptance Testing (FAT) verifies that every valve meets its specified pressure-temperature rating and leakage class before leaving the manufacturer's facility. API 598, ISO 5208, and EN 12266 define the test procedures - this guide covers what is tested, acceptable leakage limits, and how third-party witness inspection works.

2026-05-238

Industrial Valve Hydrostatic Testing Procedures - API 598, ISO 5208 & EN 12266

Factory Acceptance Testing (FAT) of industrial valves involves shell pressure testing and seat leakage testing per API 598, ISO 5208, or EN 12266. Understanding the test pressures, durations, and acceptance criteria ensures you specify the right tests and interpret results correctly.

2026-05-228

Valve Documentation Requirements for Oil & Gas - MTCs, Test Certs, TPI & Traceability

Oil and gas valve procurement requires a specific documentation package. This guide explains every document - what it certifies, which standard it references, and when it's required.

2026-05-219

Valve Testing and Inspection: API 598, ISO 5208, Hydrostatic & Seat Tests

Every industrial valve must pass mandatory pressure tests before despatch - but the test pressures, durations, and acceptance criteria differ significantly between API 598 and ISO 5208. This guide explains hydrostatic shell tests, seat leakage tests, backseat tests, TPI (third-party inspection) requirements, and the full documentation package expected for critical service valves.

2026-05-178

BS 6755 Valve Testing Standard: Explained for Engineers and Procurement Teams

BS 6755 is the British Standard specifying production testing requirements for industrial valves - covering shell pressure tests and seat leakage tests. This guide explains the two parts of BS 6755, test pressures, test durations, leakage acceptance criteria, and how the standard compares to the widely used API 598.

2026-04-279

Valve Trim Selection: Soft Seat vs Metal Seat - A Technical Guide

Choosing between soft seat and metal seat trim is one of the most critical decisions in valve specification. Soft seats provide bubble-tight shut-off but are limited by temperature and abrasion; metal seats endure extreme temperatures and erosive service but require tighter machining tolerances. This guide breaks down the key differences.

2026-04-119

Valve Testing and Inspection Standards: API 598, ISO 5208, and BS 6755

Every industrial valve must be pressure-tested before shipment to verify structural integrity and seat leakage. API 598, ISO 5208, and BS 6755 define the test pressures, durations, and acceptance criteria that differentiate a certified valve from a questionable one.

2026-04-1010

Valve Leakage Classes: ANSI FCI 70-2 and API 598 Explained

When a valve specification says 'Class VI shut-off' or 'API 598 tested', what does that actually mean? Leakage class standards define the maximum allowable seat leakage during factory acceptance testing and set the performance benchmark for valve procurement and QC. Understanding these standards prevents over-specification (unnecessary cost) and under-specification (unsafe operation).

2026-03-016

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Reviewed by Engineering Editorial Team, Vajra Industrial SolutionsDiscipline: Industrial Valve Engineering ContentLast reviewed: 20 June 2026

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