T15; FAILURE MODES AND EFFECTS
ANALYSIS (FMEA) QUESTIONS AND
ANSWERS
FM - ANSWER What could go wrong? and how?
E - ANSWER What are the consequences?
A - ANSWER Probability of occurrences and severity of the consequences
Failure - ANSWER Departure of an item from its required or intended
operation,
function, or behavior;
The inability of a system, subsystem, or component to perform its
required function.
The inability of an item to perform within previously prescribed
limits.
Failure Mode - ANSWER Manner by which an item fails; the mode or state
the items is in
after it fails.
The way in which the failure of an item occurs.
FMEA - ANSWER a tool for evaluating the effect(s) of potential failure
modes of subsystems, assemblies, components, or functions.
Equipment oriented and not hazards oriented
Answers the following questions: - ANSWER What can fail?
, How does it fail?
How frequently will it fail?
What are the effects of the failure?
What is the reliability/ safety consequence of the failure?
FMEA Worksheet - ANSWER 1. system
2. subsystem
3. mode/phase
4. item
5. failure mode
6. failure rate
7. causal factors
8. immediate effect
9. system effect
10. method of dectection
11. current controls
12. hazard
13. risk
14. recommended action
Typical general failure modes - ANSWER • Failure to operate
• Premature operation
• Intermittent operation
• Failure to cease operation
at a prescribed time
• Loss of output
• Degraded output
example of failure mode for valves - ANSWER open, partially open, closed,
partially closed, wobble
Functional failure modes are a little more abstract than hardware failure modes -
ANSWER 1. function fails to perform
2. function performs incorrectly
ANALYSIS (FMEA) QUESTIONS AND
ANSWERS
FM - ANSWER What could go wrong? and how?
E - ANSWER What are the consequences?
A - ANSWER Probability of occurrences and severity of the consequences
Failure - ANSWER Departure of an item from its required or intended
operation,
function, or behavior;
The inability of a system, subsystem, or component to perform its
required function.
The inability of an item to perform within previously prescribed
limits.
Failure Mode - ANSWER Manner by which an item fails; the mode or state
the items is in
after it fails.
The way in which the failure of an item occurs.
FMEA - ANSWER a tool for evaluating the effect(s) of potential failure
modes of subsystems, assemblies, components, or functions.
Equipment oriented and not hazards oriented
Answers the following questions: - ANSWER What can fail?
, How does it fail?
How frequently will it fail?
What are the effects of the failure?
What is the reliability/ safety consequence of the failure?
FMEA Worksheet - ANSWER 1. system
2. subsystem
3. mode/phase
4. item
5. failure mode
6. failure rate
7. causal factors
8. immediate effect
9. system effect
10. method of dectection
11. current controls
12. hazard
13. risk
14. recommended action
Typical general failure modes - ANSWER • Failure to operate
• Premature operation
• Intermittent operation
• Failure to cease operation
at a prescribed time
• Loss of output
• Degraded output
example of failure mode for valves - ANSWER open, partially open, closed,
partially closed, wobble
Functional failure modes are a little more abstract than hardware failure modes -
ANSWER 1. function fails to perform
2. function performs incorrectly
