they did not play a role in the Space Shuttle Columbia disaster of 2003. Future An O-ring is one of the simplest, yet highly critical, precision mechanical components ever developed. However, there are new advances that may take some of the burden of critical sealing away from the O-ring. There are cottage industries of elastomer consultants assisting in designing O-ring-less pressure vessels. Nano-technology-rubber is one such new frontier. Presently, these advancements are increasing the importance of O-rings. Since O-rings encompass the areas of chemistry and material science, any advancement in nano-rubber will affect O-ring production companies. Already, there are elastomers filled with nano-carbon and nano-PTFE and molded into O-rings used in high-performance applications. For example, carbon nanotubes are used in electrostatic dissipative applications and nano-PTFE is used in ultra pure semiconductor applications. The use of nano-PTFE in fluoroelastomers and perfluoroelastomers improves abrasion resistance, lowers friction, lowers permeation, and can act as clean filler. Using conductive carbon black or other fillers can exhibit the useful properties of conductive rubber, namely preventing electrical arcing, static sparks, and the overall build-up of charge within rubber that may cause it to behave like a capacitor (electrostatic dissipative). By dissipating these charges, these materials, which include doped carbon-black and rubber with metal filling additives, reduce the risk of ignition, which can be useful for fuel lines. Standards ISO 3601 Fluid power systems — O-rings ISO 3601-1:2012 Inside diameters, cross-sections, tolerances and designation codes ISO 3601-2:2016 Housing dimensions for general applications ISO 3601-4:2008 Anti-extrusion rings (back-up rings) See also Cooper Ring Diaphragm seal Gasket Labyrinth seal O-ring theory of economic development Ozone cracking Polymer degradation Obturating ring References External links O-ring basics from C. Otto Gehrckens Seal rings ISO standards