FATIGUE STUDY
[Illustration: FIG. 1
This is a picture of the pin plan we use, which shows the city
as divided into districts, and which shows the collectors and
contributors, as marked by different coloured pins.]
FATIGUE STUDY
_The Elimination of Humanity’s Greatest
Unnecessary Waste_
A FIRST STEP IN MOTION STUDY
BY
FRANK B. GILBRETH
Member of American Society of Mechanical Engineers
AND
LILLIAN M. GILBRETH, PH. D.
New York
STURGIS & WALTON
COMPANY
1916
_All rights reserved_
Copyright, 1916
BY STURGIS & WALTON COMPANY
Set up and electrotyped. Published February, 1916.
PREFACE
In the final analysis, that organization is best that has the best
quality of workers. No organization can continue to be of first quality
whose workers are over-fatigued. Other things being equal, that country
will be most happy and most successful whose workers have the least
unnecessary fatigue.
Aside from the pleasure one may obtain from it, it is the duty of every
one to eliminate the causes of unnecessary fatigue, and to promote
the dissemination of knowledge of how to recover most quickly from
unnecessary and necessary fatigue.
Fatigue study rests on scientific investigation that requires the
special training of an expert, and laboratory methods and equipment;
but there are elementary methods of studying and eliminating fatigue
that are not only so simple that any one can understand and apply them,
but that are also a definite stage in the preparation of the fatigue
study expert.
It is the aim of this book to outline both these preliminary methods
and the scientific methods of fatigue elimination and to put the
available material for fatigue study into such shape that any one
interested may make immediate, definite, and profitable use of it.
CONTENTS
PAGE
CHAPTER I
A DESCRIPTION AND GENERAL OUTLINE OF FATIGUE STUDY: WHAT MUST BE DONE
FATIGUE STUDY AND WASTE 3
WHAT FATIGUE IS 4
WHAT FATIGUE STUDY IS 7
THE FIELD OF THIS BOOK 7
THE RELATION OF FATIGUE STUDY TO MEASURED FUNCTIONAL MANAGEMENT 9
RELATION OF FATIGUE STUDY TO MOTION STUDY 11
THE CLASSES OF FATIGUE 13
THE PROBLEMS OF FATIGUE STUDY 14
THE METHODS OF FATIGUE STUDY 14
EMPHASIS IN FATIGUE STUDY 15
A WORK FOR EVERY ONE 16
CHAPTER II
THE FATIGUE SURVEY: WHAT IS TO BE DONE
WHAT A SURVEY IS 18
THE GENERAL SURVEY AND THE FATIGUE SURVEY 19
THE AIMS OF THE FATIGUE SURVEY 19
THE TIME AND PLACE OF MAKING THE SURVEY 20
THE QUALIFICATION OF THE SURVEY MAKER 22
WHAT TO LOOK FOR 25
VARIABLES THAT AFFECT FATIGUE 29
THE SURVEY RECORD SHEET 30
SURVEY PHOTOGRAPHS 31
MAKING THE SURVEY SERVICEABLE 32
CHAPTER III
PRELIMINARY PROVISIONS FOR REST FOR OVERCOMING FATIGUE: WHAT CAN BE
DONE NOW
PROVISION FOR REST 38
CHAIRS TO MAKE THE REST MOST EFFECTIVE 42
BETTERMENT WORK 47
RESULTS 49
CHAPTER IV
HOME READING BOX MOVEMENT: A PRACTICAL ILLUSTRATION
WHAT IT IS 54
THE BOX IN THE PLANT 55
THE PLANT AS A SOURCE OF SUPPLY 55
THE HOME ELEMENT 58
ROUTING THE MAGAZINES 61
THE PROBLEM OF MAINTENANCE 63
HOW THE CONDITIONS VARY 67
THE HOME READING BOX AND FATIGUE 69
THE BY-PRODUCTS OF THE HOME READING BOX MOVEMENT 70
HOW TO BEGIN 75
CHAPTER V
PRELIMINARY FATIGUE ELIMINATION: WHAT CAN BE DONE NOW
THE LIGHTING PROBLEM 77
THE HEATING, COOLING, AND VENTILATING PROBLEM 82
FIRE PROTECTION 84
SAFETY PROTECTION 85
THE WORK PLACE 88
THE WORK-BENCH OR TABLE 90
THE CHAIR OR OTHER FATIGUE-ELIMINATING DEVICE 91
PLACING THE MATERIAL WORKED ON 93
THE PLACING OF TOOLS AND DEVICES 94
THE CLOTHING OF THE WORKER 95
CHAPTER VI
THE FATIGUE MUSEUM: AN OBJECT LESSON
WHAT A FATIGUE MUSEUM IS 99
THE PARENT FATIGUE MUSEUM 100
WHAT THE FATIGUE MUSEUM CONTAINS 102
WHAT THE MUSEUM DOES NOT CONTAIN 102
TYPES OF CHAIRS AND THEIR USES 104
OTHER FATIGUE ELIMINATING DEVICES 108
HOW TO USE THE DEVICES 109
STARTING YOUR OWN FATIGUE MUSEUM 111
CHAPTER VII
FATIGUE MEASUREMENT: HOW TO ATTACK THE PROBLEM SCIENTIFICALLY
HISTORY OF FATIGUE MEASUREMENT 114
FATIGUE, A TEST OF EFFICIENT ACTIVITY 116
THE ACTIVITY 117
MOTION STUDY, MICROMOTION STUDY, THE CYCLEGRAPH, AND THE
CHRONOCYCLEGRAPH METHOD AS MEASURES OF ACTIVITY 118
TESTING THE WORK BY MOTIONS REQUIRED 123
TESTING WORKERS BY MOTION CAPABILITIES 124
THE USE OF ACTIVITY RECORDS AS DATA FOR ELIMINATING FATIGUE 124
THE TIME ELEMENT 125
THE STANDARDIZATION OF WORK AND REST 127
CHAPTER VIII
MAKING ADJUSTMENTS: HOW PRESENT PRACTICE IS DEVELOPED INTO STANDARD
PRACTICE
A CONCRETE EXAMPLE OF MAKING ADJUSTMENTS 132
FORMER METHOD OF ASSEMBLY 133
HOW THE NEW PRACTICE WAS DERIVED 134
THE TWO FACTORS TO BE CONSIDERED 134
OUTLINE OF THE CHANGES TO BE MADE 135
THE SOLUTION OF THE PROBLEM 135
FINAL ADJUSTMENT 139
CHANGES IN TYPE OF WORK DEMANDED 140
CHANGE IN MENTAL ATTITUDE 140
VALUE OF THIS EXAMPLE 140
CHAPTER IX
THE OUTCOME: HOW FAR HAVE WE ATTAINED OUR AIM?
THE TESTS OF GENERAL HEALTH 142
THE TEST OF PROLONGED ACTIVITY 143
THE TEST OF POSTURE 144
THE TEST OF BEHAVIOUR AND IMPLIED MENTAL ATTITUDE 146
THE TEST OF TRANSFERENCE OF SKILL 148
TEST OF “HAPPINESS MINUTES,” INDIVIDUAL AND SOCIAL 149
CHAPTER X
THE FUTURE: WHAT EACH ONE OF US CAN DO
THE WORK OF THE COLLEGES 153
THE WORK OF THE MANAGER 155
THE WORK OF THE WORKER 156
THE WORK OF THE PUBLIC 157
FATIGUE STUDY
CHAPTER I
A DESCRIPTION AND GENERAL OUTLINE OF FATIGUE STUDY: WHAT MUST BE DONE
Fatigue Study and Waste.
In “Motion Study” we stated: “There is no waste of any kind in
the world that equals the waste from needless, ill-directed, and
ineffective motions.”[1] It is an aspect of wasted motions that we are
discussing here. Wasted motions mean wasted effort and wasted time.
One of the results of this waste is unnecessary fatigue, caused by
unnecessary effort expended during time that must, as a result, be
wasted. Time, a lifetime, is our principal inheritance. To waste any
of it is to lose part of our principal asset. To waste time and to
suffer from unnecessary fatigue simultaneously can be excused only
by ignorance. Unnecessary fatigue is caused by some one’s ignorance.
This book aims to call the attention of the world to the relationship
between fatigue and waste, with the hope that the knowledge of our
methods of fatigue elimination may be useful to others.
What Fatigue Is.
A crowd of workers come out of the factory after the day’s work. Some
rush home; others walk at a leisurely pace. Some move slowly and with
effort. Some have their heads back and a satisfied expression on their
faces. Others have their heads bent forward, and look as though life
were not worth while. What is the difference between the members of
this group? Mainly a matter of fatigue. Fatigue is the after-effect
of work. It is the condition of the worker’s organism after he has
expended energy in doing something. It is a necessary by-product of
activity. If, as is presumable, every member of our crowd of workers
has been putting in a day full of activity, we might expect to see the
same marks of fatigue on every face and figure,--but we do not.
What, then, are the reasons for the difference? The state of fatigue
has only been systematically studied during the past thirty years.
Even to-day it is not wholly understood. We do know, however, several
things about it, that may explain what we see in the emerging group.
We know that fatigue is marked by a decrease in power to work, a
decrease in pleasure taken in work, and a decrease in the enjoyment
of the hours spent away from work. We know that exertion not only
uses up temporarily the energy of the body, but that it also seems to
generate a sort of poison which “slows one down” for the time being.
In the third place, we know, also, that the effects of fatigue are
more difficult to overcome as the fatigue becomes greater. Careful
observation and records show that a little fatigue is easily overcome
if proper rest is supplied immediately. Twice the amount of fatigue
requires more than twice the amount of rest. Four times the amount of
fatigue demands much more than twice as much rest as the preceding
“more than twice the amount of rest,” until, finally, a state of
excessive fatigue requires a rest period that might have to be
prolonged indefinitely. It is this fact that lies at the basis of the
great unnecessary waste in accumulated fatigue.
The trouble with these tired workers, then, is that their work has
not been arranged in the least fatiguing manner nor in such a way
that they could get the most rest and recovery in the least amount of
idle time during the working hours. The ones whose heads are high and
whose shoulders are thrown back may have been provided in some way
with sufficient rest. The ones whose heads are bowed probably have
not had the recovery time that they needed. It is possible that those
who have had all the rest they needed have not produced as much as
have the others. The remedy for this may not lie in shortening the
rest, but in improving work methods. The waste in work not done, or
in work done with the wrong method, is a serious economic waste. The
waste in unnecessary fatigue is not only an economic waste, it is a
waste of life, and it calls for immediate attention from every one of
us, whether interested in the individual, the group, or the economic
prosperity of our country.
What Fatigue Study Is.
Our fatigue study is an attack upon this unnecessary waste of human
energy. It is a careful consideration of the problem of activity from
the side of its results upon the human organism. It aims:
1. To determine accurately what fatigue results from doing various
types of work.
2. To eliminate all unnecessary fatigue.
3. To reduce the necessary fatigue to the lowest amount possible.
4. To provide all possible means for overcoming fatigue.
5. To put the facts obtained from the study into such form that every
worker can use them for himself to get more out of life.
The Field of This Book.
The reader who will carefully watch the tired crowd of workers will
probably decide that he would like to do something about the fatigue
problem immediately. There are various methods by which he may attack
the problem. He may, and must, ultimately, review the literature
on fatigue. The work of Marey, of Amar, of Imbert, of Offner, of
Thorndike, and of numerous other physiologists and psychologists lies
open to the student of the subject. He may turn immediately to Miss
Josephine Goldmark’s masterly volume on “Fatigue and Efficiency.” This
will give him an insight into the application of fatigue elimination to
the industries. He may decide, however, that such study must wait, and
that he must actually _do something_ to cut down the fatigue the first
thing the next morning, while the driving force of what he has seen
is still strong. Nothing can mean so much to what he is to do as the
strong incentive that drives him to doing it, the desire to help. But
he will do best if he is instructed and directed. He should plan, in
order that he may do the most in the least amount of time, and do the
big, easy, obvious things first.
This book will outline a method of attack, and furnish a working
practice for attacking the fatigue problem in an industrial plant. This
practice is recommended because it rests on the results of measurement.
We have here not simply a collection of illustrations that show what
has been done in eliminating fatigue in the industries. All fatigue
elimination is to be commended, but illustrations that do not embody
well-recognized principles are questionable models. It is easy to
make external changes that never touch the underlying cause of evil.
Worthwhile, permanent fatigue elimination goes at the fundamentals of
the work itself, and studies these in relation to the fatigue. _What_
has been done is worth while when we know _how_ it has been done, and
_why_ it has been done. Given these facts, we can determine how it
may be done again in the same fashion and possibly even better. The
practice that is the result of _accurate measurement_,--this is the
standard to be demanded.
The Relation of Fatigue Study to Measured Functional Management.
Fatigue study is founded on measurement. This makes it an integral
part of measured functional management. This is management that acts
in accordance with standards. These standards are derived by actually
measuring accurately what is happening. Standards contain the results
of the measurement combined into new working methods. These standards
are maintained only until they can be improved, when the new ones are
in turn measured and maintained. Such accurate measurement demands that
the problem of management be divided into measurable units. These units
are made as small as possible, and constantly smaller as time goes on.
It was the great work of Doctor Taylor to divide an operation, that
is, a piece of work to be measured, into units for timing with a stop
watch, and to _separate rest units from work units_.
From its beginning, Scientific Management has recognized the importance
of the part played by fatigue. This recognition helps to obtain
that co-operation and permanent beneficial efficiency that are the
underlying ideas and the maintaining forces in this type of management.
But fatigue study has only recently been acknowledged as fundamental
to the most efficient management. Any one can attack the fatigue
problem in its present condition in the industries successfully. He
has simply to apply measurement. He can do this without regarding
the investigations and results of others, if he chooses, but he will
progress faster and farther if he uses results already at hand, and
improves on “the best that has been known and thought in the world.”
Relation of Fatigue Study to Motion Study.
Motion study has been described as the dividing of the elements of
the work into the most elementary subdivisions possible, studying and
measuring the variables of these fundamental units separately and
in relation to one another, and from these studied, chosen units,
after they have been derived, building up methods of least waste. It
is through the measuring of motions that one comes to realize most
strongly the necessity of fatigue study.
There has come, in the past twenty-five years, a strong general
realization that the important factor in doing work is the human
factor, or the human element. Improvement in working apparatus of any
type is important in its effect upon the human being who is to use the
apparatus. The moment one begins to make man, the worker, the centre of
activity, he appreciates that he has two elements to measure. One is
the activity itself. This includes the motions, seen or unseen, made
by the worker,--_what_ is done and _how_ it is done. The other is the
fatigue. This includes the length and nature of the interval or rest
period required for the worker to recover his original condition of
working power.
Any one who makes real motion study, or analyzes motion study data,
cannot fail to realize constantly the relationship of motion study to
fatigue study. The fatigue is the more interesting element, in that
it is the more difficult to determine exactly. When we recognize this
close relationship between motion study and fatigue study, we see that
we have a body of data already collected and at our disposal. What
is even more desirable, we have a method of measurement ready at our
hand. Every observation of a motion may be used to give information
about fatigue. Is this information of immediate use to the man who is
attacking his fatigue problem for the first time to-day? Yes, and no.
Yes, in that it is at his disposal. No, in that he must determine his
own particular problem before he can start to solve it. The first step
in this direction lies in classifying fatigue.
The Classes of Fatigue.
There are two classes of fatigue:
1. Unnecessary fatigue, which results from unnecessary effort, or work
which does not need to be done at all. A typical example of such work
is that of the bricklayer, who furnished one of the first subjects for
motion study. Any one who has watched a bricklayer lift all of his
body above the waist, together with the bricks and mortar from the
level of his feet to the top of a wall, cannot fail to realize that
bricklaying requires a great amount of energy as well as skill. Yet by
far the most of the energy expended in the method of laying bricks,
that had existed for centuries, was entirely unnecessary.[2]
2. Necessary fatigue, which results from work that must be done. The
new method, which enabled this same bricklayer to lay three hundred
and fifty bricks per hour, where he had laid one hundred and twenty
bricks per hour before, did not eliminate, and did not expect to
eliminate all of the fatigue accumulated in the working day. The
bricklayer at the end of the day, by reason of motion study devices,
laid more brick, but was nevertheless much less tired. Experimental
work in his case was carried to a high degree of perfection, because
he was recognized as a splendid type of efficient brawn.
The Problems of Fatigue Study.
The problems of fatigue study are, then, four, which may be stated in
very simple terms:
1. To determine what fatigue is unnecessary.
2. To determine what fatigue is necessary.
3. To eliminate all unnecessary fatigue possible.
4. To distribute the necessary fatigue properly, and to provide the
best possible means for speedy and complete recovery.
The Methods of Fatigue Study.
The methods used must rest on a scientific basis. These methods are
the same for the expert and for the man making his first attack on the
problem. They are as follows:
1. Record present practice, make an accurate and complete account in
writing of what is actually being done.
2. Decide in what sequence things are to be measured, and put them in
such shape that they can be measured.
3. Apply accurate measurement.
4. Determine standards synthetically from the measurement, and make
such changes in practice as will make it conform to the standard.
5. Compare the new standard practice with the old practice. Determine
exactly what improvements have been made, in order to be able to
predict the line along which new improvements must lie.
This is the standard method of attack of measured functional
management. It can be the more successfully applied to fatigue study in
that the results can be checked at every point by the results of motion
study, which bear a constant relation to them.
Emphasis in Fatigue Study.
Any such study as this demands an emphasis upon accuracy. The man
making the study must have a strong desire for finding and writing
down the facts. He must have willingness to submit every aspect of the
problem he is studying to the test of accurate measurement. Along with
this desire for facts must go a realization of how the facts are to
be used. Fatigue study is a constructive study. It builds up. It uses
such terms as “elimination,” but its fundamental aim is conservation,
and this conservation includes adding to those things which make life
worth while. The desire to act as a force for betterment must be the
incentive that makes the man doing fatigue study ready to record and
face the actual facts.
A Work for Every One.
Recording facts is difficult work, but there is no one who cannot do
some of it. It is the duty of every man to face the facts with which he
works and to record them. You have come from the crowd of tired workers
with an incentive to do this. Here is the method by which it may be
done.
Summary.
Fatigue study is related to motion study in that both are branches
of waste elimination. Fatigue study classifies fatigue, and outlines
methods by which unnecessary fatigue may be eliminated and rest from
necessary fatigue may be provided.
FOOTNOTES:
[1] See “Motion Study,” p. 2.
[2] See “Bricklaying System,” chapter xiv. Myron C. Clark Co., Chicago.