A kill switch, also known as an emergency stop (e-stop) and as an emergency power off (EPO), is a safety mechanism used to shut off machinery in an emergency, when it cannot be shut down in the usual manner. Unlike a normal shut-down switch or shut-down procedure, which shuts down all systems in order and turns off the machine without damage, a kill switch is designed and configured to abort the operation as quickly as possible (even if it damages the equipment) and to be operated simply and quickly (so that even a panicked operator with impaired executive functions or a by-stander can activate it). Kill switches are usually designed to be noticeable, even to an untrained operator or a bystander. Most kill switches feature a Mollyguard, a removable, protective barrier against accidental activation (e.g. a plastic cover that must be lifted or glass that must be broken). Kill switches are features of mechanisms whose normal operation or foreseeable misuse might cause injury or death; industrial designers include kill switches because damage to or the destruction of the machinery is less important than preventing workplace injuries and deaths.
1.1 Nuclear power plants 1.2 Vehicles
1.2.1 Pioneer era planes and World War I aircraft
1.3 Industrial machinery 1.4 Machine tools 1.5 Fuel stations and road vehicles 1.6 Elevators and escalators 1.7 Gym 1.8 Amusement rides 1.9 Software 1.10 Military
2 See also 3 References
Applications A similar system, usually called a dead man's switch (for other names, see alternative names), as its name suggests, is a device intended to stop a machine (or activate one) if the human operator becomes incapacitated, and is a form of fail-safe. They are commonly used in industrial applications (e.g., locomotives, tower cranes, freight elevators) and consumer applications (e.g., lawn mowers, tractors, jet skis, outboard motors, snowblowers, motorcycles and snowmobiles). The switch in these cases is held by the user, and turns off the machine if they let go. Some riding lawnmowers have a kill switch in the seat which stops the engine and blade if the operator's weight is no longer on the seat. Nuclear power plants Main article: Scram A kill switch in a nuclear reactor plant is called SCRAM. It is usually cited as being an acronym for safety control rod axe man. Vehicles
An emergency switch in Japan
On railways, an emergency stop is a full application of the brakes in
order to bring a train to a stop as quickly as possible. This occurs
either by a manual emergency stop activation, such as a button being
pushed on the train to start the emergency stop, or on some trains
automatically, when the train has passed a red signal or the driver
has failed to respond to warnings to check that he/she is still alert,
which is known as a dead man's switch. A similar mechanism is the
In large ships, an emergency stop button pulls the countershaft for
the fuel pumps to the stop position, cutting off the fuel supply and
stopping the engines. With a controllable-pitch propeller, the stop
button may declutch the engine from the propeller.
The arrows indicate that the stop button must be turned to reset the switch before the equipment can be restarted.
On large industrial machines, an emergency stop button is typically located on the panel, and possibly in several other areas of the machine. Often, an emergency stop is made wireless using a remote control. This provides a rapid means to disconnect the energy source of the device to protect workers. For fail-safe operation, the emergency stop button is a normally closed switch, which ensures that a broken wire will not prevent it from being activated, but may accidentally activate the emergency stop. In some contexts, such as nuclear reactors or data centers, the emergency stop is known as a scram switch. In the European Union, most types of machinery are required to be equipped with an emergency stop according to the Directive 2006/42/EC. Exceptions apply for machinery in which an emergency stop would not lessen the risk as well as for portable hand-held/hand-guided machinery. Machine tools The kill switch is also used on such things as band saws and static belt sanders, pillar drills and lathes. Fuel stations and road vehicles A kill switch is also used for gasoline pumps or any other device that pumps large amounts of explosive or flammable chemicals. There is commonly a single kill switch for all pumps at a pumping station. Elevators and escalators Elevators often have a red two-way button on the control panel which is either marked "Emergency Stop" or "Run/Stop". Normally, the button is in the "up" or unpushed position, allowing the elevator to "run" in normal service. When the button is pushed, the elevator comes to an immediate stop. When the button is pulled back out, it resumes normal service, thus the reason for the use of the phrase "Run/Stop". Escalators will typically have a key-operated control that will turn the escalator off, or change its direction to up or down. Next to the key switch will be a red "Emergency Stop" button, which is used in the event of equipment failure, or where there is a potential for injury, such as when someone's shoe gets stuck in the "comb" at the top or bottom of the escalator and there is a risk of serious injury. The key switch is used to return the escalator to service after it has been stopped. Gym Treadmills often use a safety key with one end magnetically attached to the machine and the other end clipped to the user's waist. If the safety key is pulled out, such as in the event of a fall, the treadmill stops immediately. In other cases, some other treadmills have a more traditional kill switch, often mounted towards the rear of one of the hand railings. Amusement rides The emergency stop on an amusement ride is similar to that on industrial equipment. Typically brakes on a ride are designed to be disengaged when power is applied; disconnecting power will cause all brakes to engage. Most amusement rides have a computer that can, similar to the rail example provided above, engage the emergency stop when such a ride is determined to be out of operating specification. Software By analogy to physical kill switches, "kill switch" can be used to refer to a mechanism incorporated in software. By such its manufacturer or licensor may be able to disable it, for example if the product is withdrawn, or a maintenance fee has not been paid, or a device has been lost or stolen. It can also refer to kill switches for the stopping of malware such as in the WannaCry ransomware attack. There also is a debate about implementing kill switches in robots and advanced artificial intelligence systems. Military French and Israeli electronic warfare units use kill switches to disable opponents' military systems. See also
Internet kill switch
Blue Light Station
^ Repas, Robert (June 22, 2010) "Designing with E-stop switches". machinedesign.com ^ Davies, Chris (19 Sep 2009). "Microsoft remote software "kill switch" confirmed". SlashGear. Retrieved 10 May 2017. ^ Williams, Martyn (24 Jun 2014). "10 things to know about the smartphone kill switch". PCWorld. Retrieved 10 May 2017. ^ Chan, Sewell; Scott, Mark (14 May 2017). "Cyberattack's Impact Could Worsen in 'Second Wave' of Ransomware". The New York Times. Retrieved 14 May 2017. ^ "Warning: Blockbuster 'WannaCry' malware could just be getting started". NBC News. Retrieved 14 May 2017. ^ Kottasova, Ivana (12 January 2017). "Europe calls for mandatory 'kill switches' on robots". CNNMoney. Retrieved 14 May 2017. ^ Larson, Selena (26 January 2017). "Killing the immortal: Why scientists are debating the life span of robots". CNNMoney. Retrieved 14 May 2017. ^ "The Hunt for the Kill Switch". IEEE Spectrum: Technology, Engineering, and Science News. Retrieved 2017-07-13. ^ Markoff, John (2010-09-26). "Stuxnet Worm Is Remarkable for Its Lack of Subtlety". The New York Times. ISSN 0362-4331. Retrieved 2017-07-13.
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