Kill switch

Vehicles

On railways,{{cite news |newspaper=BizJournals.com (Pittsburgh)

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.

NASCAR requires all their stock cars to be equipped with a steering wheel–mounted kill switch, in case the accelerator pedal sticks and the driver needs to shut down the engine.

A related concept is the dead man's switch, where the operator must be holding a button or lever any time the vehicle is operating. A common example of this is the kill switches used by boaters and jetskiers wherein a cord connects the kill switch to the operator (usually by the operator's life jacket or clothing), and if the operator is thrown overboard in an accident, the cord will pull the switch and immediately shut down the vessel's engine. This prevents it from becoming a runaway vessel that could impose a danger to other vessels or swimmers at sea, and allows the operator to swim back to the vessel and re-board it without the risk of being injured by the boat's propeller. A similar device is featured on most lawnmowers: a lever on the handle either disables the ignition system and applies a brake to the flywheel (on a gasoline lawnmower), or cuts the power to the motor (on an electric lawnmower), as long as it is not held down.

Monster Truck Racing Association requires all of their monster trucks to be equipped with kill switches (either remote or in cab), in case the monster truck loses control and the driver needs to shut off the engine. Monster trucks' kill switches are tested before races.

Pioneer-era planes and World War I aircraft

Early aviators using rotary engine–powered aircraft from the beginnings of their use in 1908, up through the end of World War I in 1918 had what could be called a reversed functionality version of the "dead man's switch" for cutting the ignition voltage to the spark plugs on such a power-plant, to give a degree of in-flight speed control for a rotary engine. This was often called a "blip switch" or "coupe switch" (from the French term coupez, or "cut") and when not being pressed, allowed the high voltage from the engine's magnetos to operate the ignition with normal engine operation in flight—pressing the "blip switch" cut the flow of high voltage from the magnetos, stopping the combustion process in the cylinders. When such a "blip switch" was intermittently used on landing approach, this allowed a limited degree of engine speed control, as rotary engines generally did not have a conventional throttle in their carburettors to regulate engine speed, but only for governing the fuel-air ratio for start-up and full-speed operation.

Anti-theft

Kill switches are also used on land vehicles as an anti-theft system and as an emergency power off. Such devices are often placed in bait cars and configured so that observing police can trigger the switch remotely.{{cite news |newspaper=The New York Times

Smartphones

Main article: Smartphone kill switch

In smartphones, a kill switch is a security feature that allows the phone's owner to remotely render the smartphone inoperable if it is lost or stolen. From 2015 this feature is legally required in California for smartphones.{{cite news

Software

By analogy to physical kill switches, kill switch can be used to refer to a mechanism incorporated in software that can be activated by its manufacturer or licensor, 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 is a debate about implementing kill switches in robots{{cite news

In AI

Google started to work on a hardware kill switch for AI in 2016.

Industrial machinery

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.{{cite web |archive-url=https://web.archive.org/web/20130417042555/http://machinedesign.com/article/designing-with-e-stop-switches-0622 |archive-date=2013-04-17

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.

Nuclear power plants

Main article: Scram

A kill switch in a nuclear reactor plant is called SCRAM. It is usually characterized as an acronym for "safety control rod axe man", though this is probably a backronym.

Early computers

Early computers were large electrical devices and typically had an emergency off switch located on or near the operator's console.

Machine tools

Emergency stop functions are frequently used on machine tools, including equipment like wood and metal sawing machines, grinding machines, drilling machines, milling machines and machining centres and lathes. The emergency stop safety function, and general requirements for emergency stop devices are set out in ISO 13850. Machine specific (type-C) standards often include specific requirements for the emergency stop functions, but in the absence of a relevant type-C standard, the risk assessment should be used to determine whether or not an emergency stop function would be useful in avoiding or limiting harm. The ISO machinery safety standard types are defined in ISO 12100, and this nomenclature is used by other standards development organizations, like ANSI in the US, and CSA in Canada.

Complementary protective measure

A machinery's emergency stop control is considered a complementary protective measure because it is intended to complement the primary safeguarding measures like fixed guards, movable interlocked guards or safeguarding devices. The primary safeguarding measures prevent injury automatically, either by enforcing distance between a hazard and a person, or by eliminating the hazard by stopping hazardous motion or switching off a source of hazardous energy.

By contrast, an emergency stop requires a deliberate action on the part of a person who must first recognize that some hazardous condition is about to arise or is arising, and who then must activate the emergency stop function by pressing the emergency stop button or activating another emergency stop device such as a pull-cord switch.

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{{cite news |newspaper=The New York Times

Exercise machines

Treadmills{{cite news |newspaper=The New York Times

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, or an accident involving a passenger or ride employee has happened.{{cite news |publisher=WWAYTV3 (CBS)

Spaceflight

Range safety systems can automatically destroy errant vehicles in-flight. Range-safety officers may also manually destroy vehicles; this method was used to destroy errant solid rocket boosters in the Space Shuttle Challenger disaster.

References

References

1. Davies, Chris. (19 Sep 2009). "Microsoft remote software "kill switch" confirmed".
2. Williams, Martyn. (24 Jun 2014). "10 things to know about the smartphone kill switch".
3. (14 May 2017). "Cyberattack's Impact Could Worsen in 'Second Wave' of Ransomware". The New York Times.
4. "Warning: Blockbuster 'WannaCry' malware could just be getting started". NBC News.
5. (2016-06-08). "Google developing kill switch for AI". BBC News.
6. "ISO 13850:2015 Safety of machinery — Emergency stop function — Principles for design". International Organization for Standardization.
7. "ISO 12100:2010 Safety of machinery — General principles for design — Risk assessment and risk reduction". International Organization for Standardization.
8. "ANSI B11.0-2020 Safety Of Machinery". American National Standards Institute.
9. "Z432-16 (R2021) Safeguarding of machinery". Canadian Standards Organization.