Mistake proofing is a technique used to prevent human errors by improving systems, machines, and methods. Examples of mistake proofing include fingerprint door locks, gas pumps with automatic shutoffs, submarines that surface if power is lost, and car locks that activate when driving. Different types of human errors like errors in memory, perception, or motion can be addressed through mistake proofing to reduce defects.

1. Mistake proofing

2. FICCI CE
Mistake proofing
Mistake proofing is a scientific technique for improvement of
operating systems including materials, machines and methods with
an aim of preventing problems due to human error. The term “error”
means a sporadic deviation from standard procedures resulting from
loss of memory, perception or motion.

3. FICCI CE
Examples of
mistake proofing
Finger print ID lock is an excellent example of mistake proofing.
There's no need to fumble for your keys in the dark any more. The
Fingerprint ID Door Lock is a cylindrical lock combined with a
security bolt that will let you into the house using just your finger. It
reads your unique fingerprint and only allows entry to prints it
recognizes.

4. FICCI CE
Examples of mistake proofing
Gas pumps are equipped with hose couplings that break away
and quickly shutoff the flow of gasoline.

5. FICCI CE
Examples of
mistake proofing
The bathyscaph is a deep water submarine used to explore the very
lowest parts of the ocean.It is electrically powered.Once at the
bottom,if the batteries or electrical system fail the best outcome
would be for the submarine to return to the surface.The designers
made this outcome occur by holding the ballast in place with
electromagnets.When power is lost,the ballast drops off
automatically and sub starts it ascent.

6. FICCI CE
Examples of mistake proofing
Automobiles controls have a mistake proofing device to ensure
that the key in the on position before allowing the driver to shift
out of park.The keys can not be removed until the car is in park.

7. FICCI CE
Examples of mistake
proofing
3.5 inch diskette can not be inserted unless diskette is oriented
correctly.This is as far as diskette can be inserted upside-down.
The beveled corner of the diskette pushes a stop in the disk drive out
of the way allowing diskette to be inserted.This feature,along with the
fact that the diskette is not square,prohibit incorrect orientation.

8. FICCI CE
Examples of mistake proofing
Electronic car locks can have three mistake
proofing devices:
• Ensures that no door is left unlocked.
• Door automatically locks when car exceeds the
speed of 18mile an hour.
• Lock won’t operate when door is open and engine
is running.

9. FICCI CE
Examples of mistake proofing
New lawn mowers are required to have a safety
bar on the handle that must be pulled back in order
to start the engine.If you let go of the safety bar,the
mowers blade stops in 3 seconds or less.This is an
adaptation of the”dead man switch” from railroad
locomotives.

10. FICCI CE
Examples of mistake proofing
Retail stores use electronic article
surveillance to ensure that no one walks
away without making payment.

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Defect Vs errors
It is important to understand that defects and errors are not the
same thing. A defect is the result of an error, or an error is the
cause of defects as explained below.
Cause Result
Error Defect

12. FICCI CE
Prevention of defects
Cause Intermediate result End result
Machine Take
Work zero
or Detect error corrective
Procedure defect
human error action
Modify work Analyze for
procedure to preventive action
prevent such errors

13. FICCI CE
Types of error
• Error in memory of PLAN : Error of forgetting the sequence/
contents operations required or restricted in standard procedures.
• Error in memory of EXECUTION : Errors of forgetting the
sequence/contents of operations having been finished.
• Error in PERCEPTION of type : Error of selecting the wrong object
in type or quantity.

14. FICCI CE
Types of error
• Error in perception of MOVEMENT : Error of
misunderstanding/misjudging the shape, position, direction or other
characteristics of the objects.
• Error in motion of HOLDING : Error in failing to hold objects.
• Error in motion of CHANGING : Errors of failing to change the shape ,
position , direction , or other characteristics of object according to the
standard.

15. FICCI CE
Human error provoking
situations
• Complex design
• Inadequate written standards
• Too many parts
• Mix up
• Too many steps
• Specifications or critical conditions
• Too many adjustments
• Frequent repetition

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