Sets out the process to be completed before the French NF mark can be affixed to a breathalyser. An NF-approved breathalyser must demonstrate that it can provide an accurate result of the alcohol content in a breath sample, remain unaffected by the temperature or volume of the sample and not give a distorted reading due to other substances such as medication or sweets. The NF symbol is a mark of quality, and Terpan Laboratories has chosen to sell only products that are NF certified.