Editing Compressed-air energy storage (section)

==== Safety ====
As with most technologies, compressed air has safety concerns, mainly catastrophic tank rupture. Safety regulations make this a rare occurrence at the cost of higher weight and additional safety features such as pressure relief valves. Regulations may limit the legal working pressure to less than 40% of the rupture pressure for steel bottles (for a [[safety factor]] of 2.5) and less than 20% for fiber-wound bottles ([[safety factor]] 5). Commercial designs adopt the [[ISO 11439]] standard.<ref>{{cite ISO standard |csnumber=44755 |title=ISO 11439:2013 — Gas cylinders — High pressure cylinders for the on-board storage of natural gas as a fuel for automotive vehicles |date=June 2013}}</ref> High-pressure bottles are fairly strong so that they generally do not rupture in vehicle crashes.