‘AQL‘ stands for “Acceptance Quality Limit” , and is defined as the “quality level that is the worst tolerable” in ISO 2859-1. It represents the maximum number of defective units, beyond which a batch is rejected. Importers usually set different AQLs for critical, major, and minor defects.
For example: AQL 2.5% meaning “I want no more than 2.5% defective items in the whole order quantity, on average over several production runs with that supplier”.
AQL used as an important tool to taking sample in any product inspection.
It helps us to minimize risk, saving time, labor and money by taking samples wisely and correctly once conduct an inspection.
At VN Inspects, when we conduct a typical product inspection (no special requirement from client), we will use:
- General Inspection level II to select sample size
- Acceptance Quality Limit for Major Defect is 2.5
- Acceptance Quality Limit for Minor Defect is 4.0
- And not allow any Critical Defect (AQL for Critical Defect is 0%)
This is an industry standard. Most buyer/supplier involved in international trade are familiar with it.
Here is how it works…
1. AQL Defects
Defect means any failure to meet customer quality requirements. In actual practice, there are three categories of defects:
- Critical defects: Defects, which could harm users. Critical defects are unacceptable. Critical defects are defined as 0% AQL (Should be for all industry)
- Major defects: Defects usually not acceptable by the end-users, as they are likely to result failure in performance or very bad appearance. The AQL for major defects is 2.5% (In most industry)
- Minor defects: There is some departure from specifications, but most users would not mind it. The AQL for minor defects is 4% (In most industry)
2. Acceptance Quality Limit Table
3. How to understand this table?
Example in an inspection batch of 3456 units. Assuming we have set an General Inspection Level II. Accpetance Quality Limit for Major Defect is 2.5, Minor Defect is 4.0 and and not allow any Critical Defect. Therefore:
- 3456 units at General Inspection level II -> indicates that the sampling size letter of “L” and sample size should be 200 units selected randomly
- The batch is accepted if NO MORE than 10 products with major defects AND NO MORE than 14 products with minor defects are found
- The batch is rejected if we found 11 products with major defects, regardless how many minor defects are
- The batch is still accepted if we found 8 products with major defects and 5 products with minor
What should Buyer/Customer do with the rejected lot/batch?
Buyer/Customer can switch to 100% inspection and discard rejects, require supplier to rework or replace.
Buyer/Customer may also discuss with supplier in order to take a business decision like buying this lot at a discount, require special warranty assurance letter,…
Important
The AQL of a product can vary from industry to industry. For example: Medical products have stringent AQLs because defective products are a health risk.
Special case: The AQL in the Codex standard stan233 (food products) – There is another widely-used standard for food products. It calls for taking a much smaller sample (which makes sense since opening a food product’s packaging means destroying it)
AQL at VN Inpsects
Clients can set their own Acceptable Quality Limit for each inspection and we will follow “the rules of game” when performing an inspection.
In most case, the clients will also have their own classification for defective issue, and we will follow your criteria too.
In case no special requirement, we will apply an industry standard as mentioned above.
Contact us to discuss more on how we work together or booking an inspection service.
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