In May of 2019, a new version of IEC 61482-1-1 (2.0) is expected be published. It will include a new, more conservative, type of arc rating for materials called the Incident Energy Limit Value (ELIM). Arc Ratings are calculated using at least 20 data points and a logistic regression to determine the incident energy level of a 50% probability that there is enough heat transfer to cross the Stoll Curve (ATPV), or for the material to breakopen and create exposure (EBT). The ELIM value will be even more conservative; it is defined by the anticipated new standard as “the numerical value of incident energy attributed to a product (material or clothing), below which all product responses are below the Stoll Curve and without breakopen”.
ELIM is calculated by averaging the three incident energy levels below the mix zone (all 20 data points are still required). As a reminder, the “mix zone” is known as the range in testing between the lowest incident energy level that crossed the Stoll Curve, and the highest incident energy level that did not cross the Stoll Curve.
The mix zone and the data points used to calculate ELIM are simply demonstrated using the image below:
You won’t see this value in reports now since it is not a part of the current test method, but the value is currently obtainable upon request in testing in anticipation of the release of the new IEC 61482-1-1 Standard. You can expect to hear more about ELIM in the near future and we will continue to publish updates about version 2.0–reach out if you have questions.