1.1 Purpose This European standard establishes requirements when implementing statistical product acceptance methods to meet defined risk requirements. This standard also establishes the minimum content required to be covered in an organization’s documented procedures that govern their application of statistical product acceptance methods. These general requirements and documented procedures apply the requirements of the EN 9100/EN 9110/EN 9120 quality management system standards, in addition to establishing requirements for retrievability, safety/critical characteristics, and quality parameters that protect the customer. 1.2 Application This standard is applicable when invoked in a purchasing contract or specification, contractual document, customer agreement, or adopted by the organization. The purchase contract/agreement may or may not identify the appropriate EN 9138 clause(s) to be applied by the organization. All statistical methods of product acceptance require the use of Clause 4 and Clause 5. To accept product produced: - by individual lots, see Clause 6; - under switching rules, see Clause 7; - under process controls, see Clause 8; and - by continuous sampling or special case methods, see Clause 9.