Fail-safe - Revision history

Michel Lamontagne at 16:15, 24 October 2022

2022-10-24T16:15:11Z

Michel Lamontagne at 16:11, 24 October 2022

2022-10-24T16:11:24Z

Michel Lamontagne at 18:26, 25 September 2020

2020-09-25T18:26:46Z

Michel Lamontagne: /* Redundancy */

2020-09-25T18:25:27Z

Redundancy

Michel Lamontagne: /* Systems to be considered */

2020-09-25T18:00:57Z

Systems to be considered

Jburk at 08:51, 18 December 2018

2018-12-18T08:51:17Z

Farred: Undo revision 8025 by 85.43.254.202 (Talk) undo vandalism

2013-01-22T16:08:23Z

Undo revision 8025 by 85.43.254.202 (Talk) undo vandalism

85.43.254.202: /* Interconnectivity */

2013-01-22T15:26:44Z

Interconnectivity

Farred: Capitalization

2012-11-29T15:31:38Z

Capitalization

Rfc: link to failure of the colony

2012-11-28T19:40:00Z

link to failure of the colony

← Older revision		Revision as of 16:15, 24 October 2022
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	The basic premise of fail-safe behavior is to ensure that if a system or subsystem fails, it should do so in a "safe" manner; that is, no single failure should be able to place those who use or maintain it in danger. Even if parts of the system fail, the system as a whole must continue working. A full breakdown of a vital system would be catastrophic for the colony and can mean a complete [[failure of the colony]]. In this case all settlers would die. Fail-safe design must avoid [[w:Single_point_of_failure\|single points of failure]].		The basic premise of fail-safe behavior is to ensure that if a system or subsystem fails, it should do so in a "safe" manner; that is, no single failure should be able to place those who use or maintain it in danger. Even if parts of the system fail, the system as a whole must continue working. A full breakdown of a vital system would be catastrophic for the colony and can mean a complete [[failure of the colony]]. In this case all settlers would die. Fail-safe design must avoid [[w:Single_point_of_failure\|single points of failure]].
		+
		+	However, even in the case of a complete system wide failure of the settlement, there may be ways of rescuing the settlers, if the transportation system is adequate or if more than one settlement is built.

	==Systems to be considered==		==Systems to be considered==

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-Due to the hostile [[environmental conditions]] on [[Mars]], human visitors to the planet would have to rely heavily on artificial environments in order to survive.  Their [[habitat]]s' [[life support]] equipment must therefore run 100% reliably. This article describes the principles of '''fail-safe''' engineering.
+Due to the hostile [[environmental conditions]] on [[Mars]], human visitors to the planet would have to rely entirely on artificial environments in order to survive.  Their [[habitat]]s' [[life support]] equipment must therefore run 100% reliably. This article describes the principles of '''fail-safe''' engineering.
 The basic premise of fail-safe behavior is to ensure that if a system or subsystem fails, it should do so in a "safe" manner; that is, no single failure should be able to place those who use or maintain it in danger. Even if parts of the system fail, the system as a whole must continue working. A full breakdown of a vital system would be catastrophic for the colony and can mean a complete [[failure of the colony]]. In this case all settlers would die.  Fail-safe design must avoid [[w:Single_point_of_failure|single points of failure]].
@@ Line 14: / Line 14: @@
 Every system is built twice or more, where each can work independent from the other. The capacity of each system is high enough to support the full service in case of failure of one system.
 In another example the number and size of [[solar panel]]s could be at least twice as large as actually needed for vital system operation. In normal operation mode the surplus energy generated could be used for additional production with energy storage systems.
-Redundancy requirements can be reduced using modular systems.  For example, rather than doubling the number of solar panels, we can design the system so that redundancy is at the component level.  In an extreme case, where each solar panel has redundant connections, a single extra solar panel would provide the required redundancy.
+Redundancy requirements can be reduced using modular systems.  For example, rather than doubling the number of solar panels, we can design the system so that redundancy is at the component level.  In an extreme case, where each solar panel has redundant connections, a single extra solar panel would provide the required redundancy (n+1).
 If losing solar power is a possibility, for example during a dust storm, the redundancy at a system level would require a separate power source, such as nuclear reactors, or stored power in various forms.
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 Services must also be available in the case of local failure. Therefore, the service providing systems should be interconnected.
-<strong>Example:</strong> If system A and system B have their own air supply system, then people in building A can get air from building B in case of a failure in the air supply system of their own building.
+<strong>Example:</strong> If habitat A and habitat B have their own air supply system, then people in building A can get air from building B in case of a failure in the air supply system of their own building.  To be able to provide this, the air systems of A and B must be significantly overbuilt.
 ==Grid instead of chain==
-The whole system must be available independent from the failure location, even in catastrophic situations. The interconnection must allow normal functioning of the whole system even if one system part is completely destroyed. For the connection of more than two systems a grid is better than a chain.
+Fow power systems, the whole system must be available independent from the failure location, even in catastrophic situations. The interconnection must allow normal functioning of the whole system even if one system part is completely destroyed. For the connection of more than two systems a grid is better than a chain.
 [[Image:mesh.gif]]

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 Due to the hostile [[environmental conditions]] on [[Mars]], human visitors to the planet would have to rely heavily on artificial environments in order to survive.  Their [[habitat]]s' [[life support]] equipment must therefore run 100% reliably. This article describes the principles of '''fail-safe''' engineering.
-The basic premise of fail-safe behavior is to ensure that if a system or subsystem fails, it should do so in a "safe" manner; that is, no single failure should be able to place those who use or maintain it in danger. Even if parts of the system fail, the system as a whole must continue working. A full breakdown of a vital system would be catastrophic for the colony and can mean a complete [[failure of the colony]]. In this case all settlers would die.  Design must avoid [[w:Single_point_of_failure|single points of failure]].
+The basic premise of fail-safe behavior is to ensure that if a system or subsystem fails, it should do so in a "safe" manner; that is, no single failure should be able to place those who use or maintain it in danger. Even if parts of the system fail, the system as a whole must continue working. A full breakdown of a vital system would be catastrophic for the colony and can mean a complete [[failure of the colony]]. In this case all settlers would die.  Fail-safe design must avoid [[w:Single_point_of_failure|single points of failure]].
 ==Systems to be considered==

@@ Line 1: / Line 1: @@
 Due to the hostile [[environmental conditions]] on [[Mars]], human visitors to the planet would have to rely heavily on artificial environments in order to survive.  Their [[habitat]]s' [[life support]] equipment must therefore run 100% reliably. This article describes the principles of '''fail-safe''' engineering.
-The basic premise of fail-safe behaviour is to ensure that if a system or subsystem fails, it should do so in a "safe" manner; that is, no single failure should be able to place those who use or maintain it in danger. Even if parts of the system fail, the system as a whole must continue working. A full breakdown of a vital system would be catastrophic for the colony and can mean a complete [[failure of the colony]]. In this case all settlers would die.  Design must avoid [[w:Single_point_of_failure|single points of failure]]
+The basic premise of fail-safe behavior is to ensure that if a system or subsystem fails, it should do so in a "safe" manner; that is, no single failure should be able to place those who use or maintain it in danger. Even if parts of the system fail, the system as a whole must continue working. A full breakdown of a vital system would be catastrophic for the colony and can mean a complete [[failure of the colony]]. In this case all settlers would die.  Design must avoid [[w:Single_point_of_failure|single points of failure]].
 ==Systems to be considered==
@@ Line 12: / Line 12: @@
 ==Redundancy==
-Every system is built twice or more, where each can work independent from the other. The capacity of each system is big enough to support the full service in case of failure of one system. In normal operation both systems are running in parallel with half load. This principle provides the best reliability for the whole function.
+Every system is built twice or more, where each can work independent from the other. The capacity of each system is high enough to support the full service in case of failure of one system.
-<strong>Example:</strong> The number and size of [[solar panel]]s could be at least twice as large as actually needed for vital system operation. In normal operation mode the surplus energy generated could be used for additional production with energy storage systems.
+In another example the number and size of [[solar panel]]s could be at least twice as large as actually needed for vital system operation. In normal operation mode the surplus energy generated could be used for additional production with energy storage systems.
 Redundancy requirements can be reduced using modular systems.  For example, rather than doubling the number of solar panels, we can design the system so that redundancy is at the component level.  In an extreme case, where each solar panel has redundant connections, a single extra solar panel would provide the required redundancy.
 ==Interconnectivity==
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 <strong>Example:</strong> The [[Internet]] is (partially) constructed in a grid architecture. Despite the fact that it is the most complex artificial thing men have ever constructed it has never failed as a whole.
-==Backup systems==
+==Standby systems (back-up)==
 A standby system is automatically powered up, or can be manually brought into operation shortly. Advantage: The system is not subject to full maintenance effort during standby mode. Risk: If not checked in regular intervals the backup system may not be able to work if needed.
-For example, during a solar storm the solar panels might not provide enough energy.  Then a nuclear reactor could be used as backup.  Alternatively, the solar panels could have excess capacity to produce methane and oxygen for energy storage.  The energy could be returned to the grid using combustion generator sets or fuel cells.
+A typical application is diesel generators in standby mode, that are activated if grid power fails.  However, the switch between the generator set and the grid may be the failing component  Therefore a second diesel generator, with a second switch, may be added for full redundancy.
 [[category:Health and Safety]]

@@ Line 1: / Line 1: @@
 Due to the hostile [[environmental conditions]] on [[Mars]], human visitors to the planet would have to rely heavily on artificial environments in order to survive.  Their [[habitat]]s' [[life support]] equipment must therefore run 100% reliably. This article describes the principles of '''fail-safe''' engineering.
-The basic premise of fail-safe behaviour is to ensure that if a system or subsystem fails, it should do so in a "safe" manner; that is, no single failure should be able to place those who use or maintain it in danger. Even if parts of the system fail, the system as a whole must continue working. A full breakdown of a vital system would be catastrophic for the colony and can mean a complete [[failure of the colony]]. In this case all settlers would die.
+The basic premise of fail-safe behaviour is to ensure that if a system or subsystem fails, it should do so in a "safe" manner; that is, no single failure should be able to place those who use or maintain it in danger. Even if parts of the system fail, the system as a whole must continue working. A full breakdown of a vital system would be catastrophic for the colony and can mean a complete [[failure of the colony]]. In this case all settlers would die.  Design must avoid [[w:Single_point_of_failure|single points of failure]]
 ==Systems to be considered==
 * Life support systems ([[oxygen]], [[temperature]])
-* Production and [[food preservation|storage]] of [[food]]
+*Life support systems ([[oxygen]], [[temperature]])
-* Production, distribution and storage of [[energy]]
+*Production and [[food preservation|storage]] of [[food]]
-* Telecommunication network
+*Production, distribution and storage of [[energy]]
-* [[building]]s
+*Telecommunication network
 ==Redundancy==
 Every system is built twice or more, where each can work independent from the other. The capacity of each system is big enough to support the full service in case of failure of one system. In normal operation both systems are running in parallel with half load. This principle provides the best reliability for the whole function.
-<strong>Example:</strong> The number and size of [[solar panel]]s is at least twice as big as actually needed for vital system operation. In normal operation mode the surplus energy can be used for additional convenience.
+<strong>Example:</strong> The number and size of [[solar panel]]s could be at least twice as large as actually needed for vital system operation. In normal operation mode the surplus energy generated could be used for additional production with energy storage systems.
 ==Interconnectivity==
-Services must be available, also in case of local failure. Therefore, the service providing systems are interconnected.
+Services must also be available in the case of local failure. Therefore, the service providing systems should be interconnected.
-<strong>Example:</strong> If system A and system B have their own air supply system then people in building A can get air from building B in case of a failure in the air supply system of their own building.
+<strong>Example:</strong> If system A and system B have their own air supply system, then people in building A can get air from building B in case of a failure in the air supply system of their own building.
 ==Grid instead of chain==
@@ Line 34: / Line 37: @@
 A standby system is automatically powered up, or can be manually brought into operation shortly. Advantage: The system is not subject to full maintenance effort during standby mode. Risk: If not checked in regular intervals the backup system may not be able to work if needed.
 [[category:Health and Safety]]

← Older revision		Revision as of 08:51, 18 December 2018
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−	[[category:~~concepts]]~~	+	[[category:Health and Safety]]
−	~~[[category:technology]]~~
−	~~[[category:safety~~]]