Webbing is categorized into 4 different types with different MBS, abrasion resistance and lifetime. Lifetime is counted as days exposed to the elements. Leaving your line rigged for a week costs 7 days of lifetime (regardless of use, because UV is the main culprit). Webbing will come with a small tag to help you keep track of how many days of highlining it has seen. Webbing lifetime is finite – once the days run out it is no longer safe for highlining. Webbing can become unsafe much earlier for other reasons – abrasion, excessive use and harsh conditions can all lead to an early retirement (consider making a slack rag).
Type A+ is the super webbing with more than 40 kN MBS and a very long lifetime. Recommended for permarigs.
Type A webbing can be used in all kinds of highline situations. It has an MBS of 30 kN or more.
Type B webbing is for alpine missions and those of you who don’t like heavy backpacks. With a 26 kN MBS it can be used (with caution) on most highlines.
Type C has significantly shorter lifetime and abrasion resistance. With an even lower MBS of 22 kN, it should only be used by experienced riggers and in controlled circumstances (competitions, shows, birthday parties, etc.).
All types of sewn loops are also tested. They have to retain 80% of the MBS of their category. (E.g. Type A: 30kN minimum → All Type A loops have min. 80% x 30kN = 24kN)
Every webbing will have a standardized stretch curve, measured at the same speed, and the stretch % at 5 kN has to be stated in the manual. Why 5 kN? Because the traditional 10 kN does not reflect the forces in real life usage.