Design Validation Test – Closing the gap: API 6D Annex F vs. ISO 23632
Design Validation Testing( DVT) remains one of the most debated subjects in the valve industry, and one that is still evolving toward greater standardisation. As end users raise the bar for integrity assurance, DVT has become a key gatekeeper separating a valve design that merely meets paper requirements from one whose performance under design conditions has actually been proven.
By Ir. Tengku Syahdilan ST.
API 6D 25th Edition, Section 3.1.14, defines design validation as the process of proving a design through testing, to demonstrate that a product conforms to its design requirements. The same section notes that validation may take several forms: prototype testing, functional or operational testing of production units, testing specified by industry standards or regulatory bodies, and field performance reviews. Section 5.10.4 further requires that validation follow the manufacturer’ s own procedure, with results documented, and adds that Annex F offers one accepted method for valves in the as-shipped condition— applicable only when invoked by the manufacturer or purchaser. In practice, end users consider that functional or operational testing of production units alone is not sufficient. Consequently, many end users have developed a patchwork of proprietary procedures to validate valve designs more rigorously, variously branded as Prototype
Testing, Type Acceptance Testing, or Product Acceptance Testing. For end users, DVT functions as an early screening criterion, confirming that a design meets its stated requirements before entering production or service, thereby reducing the risk of integrity failures later in the asset’ s lifecycle. API 6D Annex F( 25th Edition) and ISO 23632:2021 both attempts to bring order to this patchwork, but they do so from different starting points and with different scopes. Gaps remain, most notably in scaling logic and in the triggers for requiring a new validation test. This article compares the two protocols and outlines where the industry still needs to close the gap.
Two standards, two philosophies
API 6D Annex F sits inside API 6D, Specification for Valves, published by the American Petroleum Institute in its 25th edition in November 2021. Annex F is an informative annex that applies only when called up by the purchaser. It follows the
14 Valve World November 2026 www. valve-world. net