EIA-585:1991 (R2002)

PURPOSE Conventional attribute sampling plans based upon acceptance numbers that permit acceptance of a lot when some allowable number of nonconformances are encountered during inspection are no longer desirable. In addition, emphasis is now placed on the quality level that is received by the customer. This relates directly to the Lot Tolerance Percent Defective (LTPD) value or the Limiting Quality Protection of MIL-STD-105. Measuring quality levels in percent nonconforming, although not incorrect, has been replaced with quality levels measured in parts per million (PPM). As a result, this standard addresses the need for sampling plans that can augment MIL-STD-105, are based upon a zero acceptance number, and address quality (nonconformance) levels in the parts per million range. This document does not address minor nonconformances, which are defined as nonconformances that are not likely to reduce materially the usability of the unit of product for its intended purpose. APPLICATION The sampling plans based upon a zero acceptance number designated in this standard are applicable, but not limited, to inspection of the following: a. End items. b. Components and raw material. These plans are designed for use with isolated lots,.and the Operating Characteristic curves are located in Appendix A. The manufacturer's risk, which is approximately equal to the AQL values of MIL-STD-105, is of little concern to consumers and users of zero acceptance number sampling plans. What is of interest is the level of nonconformances that will not be exceeded at a given confidence level, in any shipment of material to the consumer. INSPECTION Inspection is the process of measuring, examining, testing, or otherwise comparing the unit of product with the requirements. INSPECTION BY ATTRIBUTES Inspection by attributes is inspection whereby either the unit of product is classified simply as nonconforming or conforming, or else the number of nonconformances in the unit of product is counted and compared to a given requirement or set of requirements. UNIT OF PRODUCT The unit of product is the thing inspected in order to determine its classification as nonconforming or conforming or to count the number of nonconformances. It may be a single article, a pair, a set, a length, an area, an operation, a volume, a component of an end product, or the end product itself. The unit of product may or may not be the same as the unit of purchase, supply, production, or shipment. NONCONFORMANCE A nonconforming unit is one that is likely to result in failure, or to reduce materially the usability of the unit of product for its intended purpose.