Top 10 AQL Terms That Importers Succeed in AQL Inspection

AQL Terms

As an importer going about your business, often you’ll come across such AQL terms as AQL Inspection, AQL standard, ANSI certification, AQL 4.0, AQL 2.5, AQL 1.5, and many others. But what exactly do they mean?

Typically, your manufacturer may locates over 1000s of kilometers away from you. You may not be able to travel to China and inspect your products personally all the time because of the huge cost involved or other good reasons. This means that you can’t be in charge of every small detail in the manufacturing procedure because you aren’t at the factory when your goods in production.

So, how do you ensure the highest quality standards for your shipment from far away?

This is where 3rd party quality control (QC) inspection companies come in. An third party inspection company ensures that the manufacturer follows your requirements to meet the expectations. They’ll make sure that the required quality specifications are maintained between pre-shipment quality checking and the final products that reach you. Obviously, you don’t want to hurt the integrity of your business by selling your customers products that are defective or of quality that’s below par.

The AQL table helps you set the highest tolerance levels for any manufacturer’s faults in your shipped goods. The table sets out the guidelines for sampling and inspection of the sampled products out of your whole shipment.

Below we discuss the Top 10 AQL terms that are critical for any importer wanting to succeed in this business:

1) Acceptance Sampling

The AQL table guides you on the sampling process. In most cases, inspecting the entire shipment is too costly and time-consuming, however much you want to maintain quality. The only way out is the use of sampling. Let’s look at the reasons for sampling in detail below:

● Time & Energy: Inspecting every single unit of your delivery would be time-consuming and demands too much energy for those involved in the process.

● Destructive Product Sampling: For some products like bullets, testing also results in the wastage, or destruction or expiry of the units used.

Statistically, the fundamental inferences behind the concept of the AQL table function in a manner that even when the lot size goes up, a relatively tiny sample pick would still result in figures large enough to represent all items. Therefore, you may choose to inspect about 10% to 20% of the AQL sample size. This will not just lower the cost of the inspection; it allows you to save time.

2) Acceptable Quality Level or Acceptance Quality Level (AQL)

The AQL implies to the least acceptable quality requirements for goods in delivery. They must pass this threshold during AQL inspection to qualify for clearance and onward delivery to the last consumer. Typically, the AQL chart scale ranges between 0 and 15. However, it isn’t very common to see values beyond 6.5. A high acceptable quality level implies that you are more lenient to faults discovered in the delivery hence more defects.

The AQL table is a quality control tool used by many professionals across the world to ensure the same quality assurance measures are observed.

Here’s what the AQL table tells you:

  • The suitable number of items to use in the AQL inspection;
  • The appropriate AQL sample size;
  • The number of defective items that are tolerable in a particular sample.

Because no factory can produce perfect goods all the time, a few defects once in a while are a normal thing. But this doesn’t mean that you accept low-quality products in your shipments. Additionally, each item in your shipment holds unique importance when it comes to quality assurance. As a result, it is important that you use different AQLs to measure the varied quality defects.


What If Your Shipment Fails the AQL Inspection?

The manufacturer should ensure they supply goods that meet your specific quality standards. If they fail, you can:

  • ● Ask for the fixing of the defects by the supplier;
  • ● Request for replacement of defective products;
  • ● Requesting the manufacturer/supplier to compensate for the unusable items;
  • ● Ensure you destroy any goods the supplier may consider selling in the counterfeit market at lower prices.

Any of these measures you take will depend on the severity of the poor-quality issues encountered.

3) ANSI/ASQ Z1.4-2003 (R2018)

Established by the US-based ANSI institute in collaboration with the ASQ organization, the ANSI-ASQ Z1.4 standard is the most commonly used quality threshold for AQL sample selection globally.

  • ● The US FDA accepts this quality standard as a relevant measure for all kinds of sampling plans; single, double and multiple AQL levels.
  • ● If the sampling plan is single-level, the quality inspector will select only a single sample randomly and go on to draft a QC report according to the quality threshold as assessed on that one sample item.
  • ● The standard here is based on inspecting quality attributes falling under two categories; either conforming or not conforming to required standards.
  • ● Sample standard deviation is used to measure the level of non-conformance to the minimum standards, typically AQL 1.5 or better.

Learn more about the ASQ Z1.4 standard and Quality Control Standards

4) General Inspection Level

Levels of inspection are applied when determining the sample size to examine from a shipment. The AQL table comes in determining:

  • ● Lot size;
  • ● Total order quantity;
  • ● Overall inspection levels when checking for appearance, functionality, assembly, etc. The overall inspection level is often categorized into three AQL levels according to the range of the quality inspection being targeted:
  • ● G-I costs the least in terms of money and time, using the lowest sample size;
  • ● G-II is the mid-level option balancing money and time costs vis-à-vis transparency, and is the inspection level used by most importers;
  • ● G-III is the biggest sample size and gives the most dependent transparency while also consuming the highest amounts of time.

aql table, aql inspection and general inspection levels

5) Special Inspection Level

In contrast to general inspection levels, special inspection levels are conducted on much smaller AQL sample sizes. They’re used in cases that:

  • ● Prove destructive to those items being inspected, for instance, in fabric GSM tests that involves the cutting out of a small portion of fabric from the sample used;
  • ● Are costly or take a lot of time to perform, for instance, a test on battery charging in the case of electronic devices;
  • ● Tend to have similar outcomes across all pieces, for instance, when taking the measurements of injection-molded items that vary slightly size-wise from each other.

6) Critical Defect

Defect classification is an important step because it determines if the goods pass or fail the test.

Most importers usually set an AQL of 0.0 for critical defects that implies nil tolerance. In simple terms, if they find a single critical defect then the inspectors should reject the whole sample. This is because a critical defect will affect the operation of the item. For this reason, a defect here can’t be tolerated.

Critical defects typically fall where:

  • The good exposes the final user to risks;
  • The defect renders the affected item unusable;
  • It causes the goods to be repeatedly recalled.

Learn more: 3 Defect Classification In Product Inspection

7) Major Defect

aql 2.5 damaged edge major defect classification from aql inspectionWhile not as severe as critical defects are, a major defect can still have a huge impact on the product’s functionality. However, unlike critical defects, major defects still allow some imperfection to pass. Here, the AQL value of about 2.5 is commonly used for major defects. Here are some of the faults that make major defects:

  • ● Adversely impacting on the overall performance of the product;
  • ● Varying significantly from original product quality specifications;
  • ● That would likely trigger the return of the product by the end-user.

Since they don’t often lead to serious dangers to the final consumer, major defects could be tolerable but just for very trace sample amounts. But they still hurt user satisfaction and approval.

8) Minor Defects

While these defects are the least severe among the 3 categorizations, they can still harm the reputation your trade enjoys with customers. Here, the AQL levels range from about AQL 2.5 to AQL 4.0.

Typically, minor defects encompass items:

  • Not directly affecting the functionality of the product;
  • Being unnoticeable to the user during the unpackaging of the items;
  • That doesn’t result in the rejection/returning of an item by the final consumer.

NB: Other defects can be considered as either major or minor depending on their seriousness. For instance, a scratch less than 1 mm on the surface of a vase will be considered a slight defect while it becomes a severe defect if bigger than that.

9) Acceptance Point

This refers to the upper limit in the total number of defective parts/pieces allowable in any given AQL sample size on a specified AQL so as an order can be accepted after AQL inspection. Importers can choose what acceptance point they prefer depending on the type of service and AQL level they want to provide their customers, just like they choose the most appropriate AQL for each defect class. Typically, they go for higher acceptance points when dealing with minor defects, much diminished for major defects, and finally lowest for a critical defect.

10) Rejection Point

Represented by ‘Re’ in an AQL table, this marker indicates the least count of defects a particular sample size can contain at a certain AQL for the order to be rejected. Usually, the rejection point is set at a single value over the tolerance point. In case the total count of defects discovered is equal to or more than the rejection region level, the order won’t pass as fit for use. That means rejection and typically a request for either replacement or repair.


It’s important to note that any sampling method, however random sampling inspection, will carry its own risk of defects whatever methodical method is used to draw the sample. That’s why using acceptable sampling standard such as an AQL table and its accompanying AQL chart enables you to leverage on the use of limited resources and time in inspecting shipments that normally gives the same outcome like in performing inspection of the samples separately.

Author: AQI Service as a professional quality control service company in China specialized in providing a complete range of quality inspection and testing and certification services in China & Asia for global importers, buyers, retailers, and sellers.

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