some jurisdictions, when automatic doors are used on the primary exit route, these doors are equipped with crash bars. In the event the automatic door does not function, it becomes an outward swinging rather than sliding door. Crash bars are one of many emergency release mechanisms that can be used with automatic doors. Depending on available space, a common alternative is to install an emergency exit door beside the automatic doors. Installation of a secondary crash bar equipped exit is often required in large buildings with revolving doors, since these are too slow for a crowd to move through. Around the world European Union In the European Union, panic bars are governed by the standard EN 1125, Panic exit devices operated by a horizontal bar. As with other EN family standards, the English language version is produced by the British Standards Institution and utilises the call sign BS EN 1125. Panic bars are required to conform to this standard in order to carry CE marking and thus be sold in the European Economic Area. In 2008, the standard was updated to include an alpha-numeric labelling scheme. In this system, products are tested to various benchmarks and assigned a letter or number accordingly. Products must achieve minimum quality scores in order to receive general CE approval. The nine rating categories are: Category of Use Number of Test Cycles Test Door Mass Fire Resistance Safety Corrosion Resistance Security Projection of device Type of device EN 1125 is one of two standards which govern exit devices in the EU. The other standard, EN 179, governs door handles, push pads, and other exit devices with emergency release functionality. However, EN 179 devices shall only be used at locations where people "are familiar with the emergency exit and its hardware and therefore a panic situation is unlikely to appear". Examples of places where EN 179 hardware may be used in place of EN 1125 panic bars include small apartment buildings and offices. United States The first panic bar, made by Von Duprin, was available by 1908 in many models and configurations. In the US, building exit requirements are generally controlled by model codes such as the International Building Code and the NFPA Life Safety Code. Adoption of regulations varies by location and may occur at the city, county, or state level. Model codes are usually supplemented with amendments adopted locally. Additional requirements may be imposed