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Frequently Asked Questions

Inspection glossary

Acceptance Sampling

Acceptance Sampling is used to decide whether to accept or reject a production lot. It is performed once the production lot has been completed and packed. Basic procedures for Acceptance Sampling:

•        select a sample from a production lot,

•        inspect the units in the sample,

•        use the result to decide whether or not to accept or reject the lot.


AQL (Acceptable Quality Levels)

As a quality control company in Asia, ChinaInspection uses the Acceptable Quality Level (AQL) to establish a maximum allowable error rate or variation from the standard. Acceptance testing will cease immediately if the failure rate of the product being tested exceeds the minimum Acceptable Quality Level.



A batch or lot is a collection of products – all identical in size, type, conditions and time of production – from which a sample will be taken to decide whether or not it conforms to the acceptance inspection.


Critical Defect

The Critical Defect corresponds to a defect likely to result in unsafe conditions for end-users. You can provide your own list of critical defects to be inspected. ChinaInspection’s default Critical Defect AQL is 0.

Major Defect

This AQL corresponds to any defect, excluding Critical Defects, that is likely to result in failure, or reduced usability of the product unit. A product is said to have a Major Defect when it is not dangerous but cannot be sold because of the defect. You can provide your own list of Major Defects to be inspected. ChinaInspection’s default Major Defect AQL is 2.5.

Minor Defect

This AQL corresponds to a defect that is not likely to reduce the usability of the product unit for its intended purpose, or is a departure from established standards having little bearing on the effective use or operation of the unit. A Minor Defect is nevertheless a workmanship defect beyond the defined quality standard. You can provide your own list of Minor Defects to be inspected. ChinaInspection’s default Minor Defect AQL is 4.0.


Defect classification

Defects detected during inspections are generally classified in 3 categories:

•        Critical defect

•        Major defect

•        Minor defect


Inspection Level

This reference determines the relation between the size of the lot and the size of the sample inspected. The Quality Level may be chosen between I, II, or III.


ISO Certification

ISO is the International Organization for Standardization founded in 1946 to promote the development of international standards and related activities, including conformity assessment, to facilitate the exchange of goods and services worldwide. ISO is composed of member bodies from over 90 countries and covers all areas except those related to electrical and electronic engineering, which are covered by the International Electrotechnical Commission (IEC). The results of ISO's technical work are published as International Standards or Guides.


Lot size

The lot size is the total number of units available for random sampling. The lot size only includes packed products.



ChinaInspection inspectors use the ISO 2859 tables for sampling. The tables are recognized by every industrial company. This American standard has equivalents in all national and international standardization organizations. This standard is a proven method to accept , reject a production lot by inspecting a randomly selected number of products.


Rejection number

The Rejection Number is equal to the acceptance number + 1 and represents the number of defective units from which the lot is discarded. If the total number of sampled products presenting this type of defect is equal or superior to the rejection number, the production has failed.


SA 8000

Consumers, customers and other shareholders have become increasingly concerned about whether products have been manufactured in accordance with human rights, child labor laws and non-discriminatory business practices. Released in October 1997, the Social Accountability 8000 (or SA 8000) Standard is the first global ethical standard. Its objective is to ensure fair sourcing and production of goods and services.


Sampling Level

The Sampling Level represents the global accuracy level of the Sampling Method. For a given lot size, increasing the Sampling Level means increasing the Sample Size. This improves accuracy but also increases the time needed to complete the inspection. The Quality Level may be chosen between I, II, or III. ChinaInspection’s default Quality Level is II.


Sampling size

The sampling size is the total number of units to be inspected.


Sample size code letter

The sample size code letter is the link between AQL tables A and B.



Special Inspection Level

The Special Inspection Level is used instead of the general inspection level when the production has to be operationally inspected. The special inspection level can range from S1, S2, S3 or S4.