Method of acceptance sampling
This proven method is widely used to decide whether or not to accept or reject a production lot without checking every single item of the lot. Performed on randomly-selected sample items, once the production lot has been completed and packed, this standard is recognized by every industrial company.
Acceptance sampling is not an alternative to process improvement. Instead it should complement improvement efforts by providing incentives. It also serves as a temporary measure for ensuring quality until successful improvements are made.

Alternatives

There are five possible alternatives to acceptance sampling:

• Release all lots without any inspection,
• Discard all lots without any inspection,
• 100% inspection of all lots,
• Accept sample, reject discarded lots,
• Accept sample with 100% inspection of rejected lots.

Focus on Acceptable Quality Levels
Bridgenova quality inspectors throughout BN use the ISO 2859 tables (also known as AQL tables) to measure acceptable levels of quality of the Asian products they inspect. These tables are a US standard with equivalents in all national and international standardization organizations (ANSI/ASQC Z1.4, ISO 2859, NF06-022, BS 6001, DIN 40080).

How do I determine the right sample size and acceptance number?
For a hypothetical inspection of a 4,000-unit lot, with an Acceptable Quality Level of II, Table B indicates that the sampling size should be 200 units. For an AQL of 2.5, the corresponding acceptance number is 10.

TABLE A

Lot batch size			Special inspection levels				General inspection
			S-1	S-2	S-3	S-4	Ⅰ	Ⅱ	Ⅲ
2	to	8	A	A	A	A	A	A	B
9	to	15	A	A	A	A	A	B	C
16	to	15	A	A	B	B	B	C	D
26	to	50	A	B	B	C	C	D	E
51	to	90	B	B	C	C	C	E	F
91	to	150	B	B	C	D	D	F	G
151	to	280	B	C	D	E	E	G	H
281	to	500	B	C	D	E	F	H	J
501	to	1200	C	C	E	F	G	J	K
1201	to	3200	C	D	E	G	H	K	L
3201	to	10000	C	D	F	G	J	L	M
10001	to	35000	C	D	F	H	K	M	N
35001	to	150000	D	E	G	J	L	N	P
150001	to	500000	D	E	G	J	M	P	Q
500001	and	over	D	E	H	K	N	Q	R

TABLE B

Sample size code letter	Sample size
		0.40	0.65	1.0	1.5	2.5	4.0	6.5
		Ac　Re	Ac　Re	Ac　Re	Ac　Re	Ac　Re	Ac　Re	Ac　Re
A B C	2 3 5		0　1	0　1		0　1	0　1	0　1
D E F	8 13 20				0　1	1　2	1　2 2　3	1　2 2　3 3　4
G H J	32 50 80	0　1	1　2	1　2 2　3	1　2 2　3 3　4	2　3 3　4 5　6	1　2 2　3 3　4	1　2 2　3 3　4
K L M	125 200 315	1　2 2　3 3　4	2　3 3　4 5　6	3　4 5　6 7　8	5　6 7　8 10　11	7　8 10　15 14　15	10　11 14　15 21　22	14　15 21　22
N P Q	500 800 1250	5　6 7　8 10　11	7　8 10　11 14　15	10　11 14　15 21　22	14　15 21　22	21　22
R	2000	14　15	21　22

Social accountability standards
Much like ISO 9000 for quality management and IS0 14000 for environmental management, the SA 8000 provides a set of standards for evaluating social accountability in the following areas:
Child labor: Companies may not support the use of child labor. The Social Accountability International (SAI) standard defines child labor as the work of "any person under 15 years of age, unless local minimum age law stipulates a higher age for work." Forced labor: Companies may not support the use of "forced labor."
Health and safety: Companies must provide a safe and healthy working environment for their employees.
Freedom of association and right to collective bargaining: Companies must respect the right of all employees to form and join trade unions of their choice and to bargain collectively.
Discrimination: Companies may not engage in or support discrimination in hiring, compensation, access to training, promotion, termination or retirement based on race, caste, national origin, religion, disability, gender, sexual orientation, union membership, or political affiliation.
Disciplinary practices: Companies may not engage in or support the use of corporal punishment, mental or physical coercion or verbal abuse. Working hours: Companies must comply with applicable laws and industry standards on working hours.
Compensation: Companies must ensure that wages paid for a standard working week meet at least legal or industry minimum standards.
Management systems: Top management must define the company's policy for social accountability and labor conditions to ensure that it includes a commitment to conform to all requirements of this standard and national and other applicable laws.

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.

Learn more about Acceptance Sampling Methods.
AQL (Acceptable Quality Levels)
As a quality control company in BN, Bridgenova 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.
Learn more about Acceptable Quality Levels.
Batch/Lot
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. Bridgenova’s default Critical Defect AQL is 0.
Defect classification
Defects detected during inspections are generally classified in 3 categories:

• Critical defect
• Major defect
• Minor defect

During Production Inspection (DUPRO)
The production is inspected when at least 20% of the order has been completed so as to ensure that contractual obligations regarding specifications, packaging, packing and marking are met. If improvement and rectification recommendations have been given during an Initial Production Check, the During Production Inspection determines whether or not this advice has been successfully heeded. More generally, the During Production Inspection makes it possible to provide recommendations on site, so that the quality is maintained throughout the entire production phase.
Factory Audit (FA)
With reference to ISO 9000, SA 8000, or the customer’s specific requirements, an Bridgenova auditor will perform the factory assessment. All the important elements, such as quality system procedures, production capacity, child labor, staff facilities, hygiene, etc. are audited. A Factory Assessment Report is issued by the auditor. It enables customers to efficiently select a high-qualified vendor base.
Pre Shipment Inspection (PSI)
This is carried out when at least 80% of the goods ordered are export packed. Samples are selected at random, according to sampling standards and procedures. The inspection ensures that the production is in accordance with the specifications, purchase orders or letters of credit.
Learn more about sampling methods and inspection procedures..
Initial Production Check (IPC)
This process is carried out at the beginning of the production line and is based on the customer's specifications and reference sample. The Initial Production Check focuses mainly on the quality of the components and materials used in the production process. It also includes a visual check on the quality of packing materials and accessories. The inspector will also monitor the assembly process and check the first production run. The Initial Production Check allows an early (and thus cost-saving) prevention of defective components as well as timely corrections if needed.
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
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.
Container Loading Check (CLC)
This is carried out in the manufacturer's warehouse or at the forwarder's premises. The inspector first checks the quality and quantity of the goods to be shipped to make sure that the right products will be delivered. The inspector then monitors the entire loading phase to ensure good container(s) condition and appropriate loading.
Lot size
The lot size is the total number of units available for random sampling. The lot size only includes packed products.
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. Bridgenova’s default Major Defect AQL is 2.5.
MIL-STD 105E/ ABC-STD 105
Bridgenova 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 or reject a production lot by inspecting a randomly selected number of products.
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. Bridgenova’s default Minor Defect AQL is 4.0.
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.
Learn more about SA 8000.
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. Bridgenova’s default Quality Level is II.
Learn more about the Sampling Level
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.