About "European Norm"

For temperature ratings, NANGA uses the uniform standard used in  European countries (European Norm).

EN (European Norm) is the name of the uniform standard that has been established in Europe. It is also called the European Standard. The calculation of temperature ratings for sleeping bags is defined by EN13537. Manufacturers used to calculate temperature ratings by their own methods, but now ratings are displayed based on unified criteria. Tests are conducted by authorized third parties for fairness. This is a big difference from temperature ratings based on manufacturers' own standards.

EN 13537 testing method

A mannequin equipped with temperature sensors is dressed in long sleeves and underwear down to the ankles, then laid inside a sleeping bag on top of a camping mattress. Temperature is measured at 5 locations inside the mannequin, and heat radiation levels are also measured. The measured temperatures and the room temperature in the laboratory are plugged into an equation to produce a value. A sleeping bag's ability to retain warmth is affected not only by the amount of stuffing, but also by the type and thickness of the fabric and accessories like zippers, so all these elements are judged comprehensively in the test.