Safeguarding the hands of workers is an increasingly technical process given the development and inclusion of advanced fibers and materials engineered into safety gloves today.
For safety managers, a range of EN standards exist to help them identify and specify the right gloves for workers.
Whilst some of these standards are more commonly understood – including EN 374 and EN 388 – the EN455-1 AQL certification often goes under the radar with many people not aware of the test or the significance of the results.
What is an AQL and how does it meet EN455-1?
The Acceptable Quality Level (AQL) is an internationally recognized quality standard designed to assess the statistical quality control of products such as medical protective gloves. In particular measuring for the % likelihood of pinhole defects in a batch of disposable gloves.
How did AQL develop?
The advent of mass production manufacturing following the industrial revolution created challenges when it came to ensuring the consistent quality of products produced on such a large scale.
The challenge was, how do you ensure that your customers receive the quality of product that they expect without inspecting every item manufactured? For a while. no solution was available and the industry continued to manufacture millions of products without any agreed and systematic way of checking their quality.
Eventually, statisticians working for the US Army between the Great War and Second World War devised a series of statistical tests enabling a small proportion of randomly chosen samples from each batch of ammunition to be tested. From these tests, they could accurately predict the behaviour of all of the untested ammunition. This test method proved so successful in predicting the performance of ammunition, that the military started using it to control the testing of their other bulk purchases.
By the 1970’s, the UK recognised the effectiveness of this approach, adopted the tables and re-published them as British Standard BS6001. The international community then followed suit, re-publishing them as International Standard ISO 2859. Today almost every statistically controlled mass production process uses these tables to sample and test its output. When it comes to measuring the effectiveness of gloves in protecting workers' hands against hazards, ensuring quality and safety is essential.
How are gloves tested to create an AQL score?
A defined number of gloves from a production batch are selected and tested for water-tightness (detection of holes) which is determined by a leak test. In the test, the gloves are filled with 1000 ml of water and then observed for a defined time period. The test is considered passed when no water leaks from the glove, proving that it has no holes.
An AQL result of 1.5 accepts the statistical probability that there are less than 1.5% of the products with defects in the batch of gloves. An AQL of 0.65 assumes a more stringent quality acceptance level, allowing the wearer to have a higher degree of personal protection.
How does the AQL apply to gloves and what do I need to look out for?
The most important thing to remember when it comes to AQL is that the lower the AQL number rating, the greater the quality of barrier protection the wearer will have. European Standards EN 455 states that medical examination gloves for example shall have an AQL score of 1.5. The most common AQL numbers in the UK and Europe are 1.5 and 4.0. However, you can also get 1.0 and 0.65 AQL-rated gloves which are often used in some specialist areas such as microbiology labs and surgery.
As an example of this, Globus has worked with global manufacturer Showa to launch a new range of premium single-use nitrile gloves combining comfort, dexterity and chemical protection.
Silicone-free and powder-free for safer use, the new range of single-use nitrile gloves includes accelerator-free, antistatic and hi-visibility versions. They also feature AQL ratings ranging from 0.65 to 1.5.
Still not sure?
To find out more about AQL, please contact us to speak to one of our safety specialists.