Original research

O-RING INSPECTION AND ACCEPTANCE CRITERIA IN FACTORY ACCEPTANCE TESTS

Pages 457-468

10.61552/JIBI.2026.04.009

Marcelo Predes

• View Article
• PDF 746 K

Abstract: Factory Acceptance Tests (FAT) are commonly performed to verify the conformity and functional performance of equipment before delivery and installation at the customer’s site. Although functional tests can demonstrate the performance of assembled equipment, they do not necessarily provide evidence of the conformity of critical physical components involved in its operation. This issue is particularly relevant for sealing systems, in which O-rings may directly influence equipment tightness and reliability. Existing FAT approaches generally emphasize equipment-level functional verification, while O-ring studies predominantly address component characteristics, failure mechanisms, and inspection methods. This study proposes a risk-based framework that integrates O-ring component conformity verification into the equipment-level FAT acceptance process, establishing explicit links between operational context, component criticality, verification requirements, conformity evidence, installation condition, and equipment performance. The framework distinguishes three complementary levels of evidence: component conformity, installation conformity, and equipment performance. Its application is demonstrated using a commercial Parker E1549-70 O-ring under three clearly defined FAT scenarios with different operational contexts and consequences of sealing failure. The results demonstrate that the same O-ring may require different levels of verification depending on its function and criticality within the equipment. The framework also establishes a logical relationship between earlier detection of component nonconformities and potential impacts on leakage failures, rework, downtime, and quality-related costs. The proposed approach does not establish universal acceptance limits for O-rings; instead, it provides a risk-proportionate structure for integrating component-level evidence into equipment acceptance and complements, rather than replaces, conventional functional FAT testing.

Keywords: Factory Acceptance Test, FAT, O-Ring, Sealing, Acceptance Criteria, Quality Inspection, Component Conformity.

Received: 27.06.2026. Revised: 15.08.2026. Accepted: 08.09.2026.