Manual materials handling

SC 206 Ergonomics of Manual Materials Handling 7/96 1
Introduction to the Ergonomics of
Manual Materials Handling
OR-OSHA 206
9512

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health services to employers and employees:
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Standards and Technical Resources (Salem Central)
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Give
us
a
call

Section 1. Identify the costs of MMH injuries.
Objectives

Objectives
Section 2. Define the activities involved in MMH.

Objectives
Section 3. Apply MMH modeling to hazard recognition.

Objectives
Section 4. Recognize the factors that influence MMH.

Objectives
Section 5. Understand and apply the guidelines for safe lifting.

Objectives
Section 5. Understand and apply the guidelines for safe lifting.
Section 6. Return to the workplace and conduce a basic survey.

What Is Manual Materials Handling?
Manual Materials Handling (MMH) is an important
application of ergonomic principles that particularly
addreses back injury prevention.

On your own: Your instructor has completed the
demonstration. Make a list of anything that the
instructor did that you believe could result in an
injury to the back.
What did you see?
1. _________________________________________________________________
2. _________________________________________________________________
3. _________________________________________________________________
4. _________________________________________________________________
5. _________________________________________________________________
6. (bonus)___________________________________________________________

How well did you do? Rate your observation skill level on the following chart.
0 1 2 3 4 5 6
I didn’t
see anything
wrong
I identified
the instructor’s
five plus a
sixth risk
for a bonus
Excellent
Bonus

$600,000,000 in three years, 1990 - 1992
Section 1. Costs
$ 6.00 per second

$600,000,000 in three years, 1990 - 1992
30,741 accepted disabling claims in 1993
Section 1. Costs
$ 6.00 per second

$600,000,000 in three years, 1990 - 1992
55 % were filed for sprains and strains.
Section 1. Costs
$ 6.00 per second

$600,000,000 in three years, 1990 - 1992
7,789 (40.9%) were the trunk area.
Section 1. Costs
$ 6.00 per second
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5

$600,000,000 in three years, 1990 - 1992
7,789 (40.9%) were the trunk area.
Section 1. Costs
$ 6.00 per second
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
Boxes and containers second.

Section 1. Costs
Form a Group
1. Introduce yourself to those at your table
2. Pick a Leader for your group
3. Name your group
4. Write the group name in bold letters on the back
of the name tent provided
5. Everyone in your group should take notes

Section 1. Costs
As a group: Make a list of all of the possible costs to the
employer, supervisor, and the injured worker. Include
those that may be secondary and away from the work site.
1. _________________________________________________________________
2. _________________________________________________________________
3. _________________________________________________________________

Manual Materials Handling involves five
types of activities:
Section 2. Five Activities

Lifting / Lowering

Lifting / Lowering
Pushing / Pulling

Lifting / Lowering
Pushing / Pulling
Twisting

Lifting / Lowering
Pushing / Pulling
Twisting
Carrying

Lifting / Lowering
Pushing / Pulling
Twisting
Carrying
Holding

As a group and from your experiences: List as many of these activities as you can in
the next five minutes.
Lifting/Lowering:
Pushing/Pulling:
Twisting:
Carrying:
Holding:

Lifting / Lowering : Lifting is to raise from a
lower to a higher level. The range of a lift can
be from the ground to as high as you can reach
your hands. Lowering is the opposite activity
from lifting.

Pushing / Pulling : Pushing is to press against
with force in order to move the object. The
opposite is to pull.

Twisting : As applied to MMH is the act of
moving the upper body to one side or the other
while the lower body remains in a relatively
fixed position. ( Twisting can take place while
the entire body is in a state of motion. )

Carrying : Having an object in ones grasp or
attached while in the act of moving. The weight
of the object becomes a part of the total weight
of the person doing the work.

Holding : Having an object in ones grasp while
in a static body position.

Anything used to compare one thing with
another is considered to be a model.
Section 3. Modeling

Anything used to compare one thing with
another is considered to be a model.
Section 3. Modeling
Hi Y’ all,
They tell me that I’m a
“CRASH DUMMY” but I
perfer to think of myself as
a “MODEL” for “SAFETY”.
What do you think?

Section 3. Modeling
Three Scientific Models

Section 3. Modeling
The Biomechanical Models

Section 3. Modeling
The Physiological Approach

Section 3. Modeling
The NIOSH Lifting Guidelines

Section 3. Modeling
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
L5 / S1 disc.
A Biomechanical model attempts to
establish the physical stresses imposed
on the musculoskeletal system while
working.

Section 3. Modeling
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
L5 / S1 disc.
Sprains and strains have consistently
been the major nature of injury,
accounting for more than half of all
disabling claims. Back sprains and
strains were the single most frequent
work injury, responsible for 25.3
percent of total claims in 1993.

Section 3. Modeling
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
L5 / S1 disc.
Lower back stress
L5 / S1 disc.
The numbers C1 through C7, T1
through T12, and L1 through L5 are the
designations assigned to vertebra.

Section 3. Modeling
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
L5 / S1 disc.
A vertebra is one of the bony segments
composing the spinal column.
Compressive force.

Section 3. Modeling
The discs allow flexibility in your spine and act
as shock absorbers. The center of the dis is jelly-
like. It is surrounded by tough rubber-like
bands that are attached to the bones (vertebral
bodies).
(Adapted from: The Saunders Group inc., 4250 Norex Drive, Chaska, MN 55318)

Section 3. Modeling
The nerves provide the
energy to make the
muscles work. Please
note the nerve locations
with regards to the
locations of the discs.

Section 3. Modeling
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
L5 / S1 disc.
The compressive forces on L5 / S1 are a function of
the following:
* The length and weight of the upper extremities.

Section 3. Modeling
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
L5 / S1 disc.
the following:
* Angles from vertical of these body parts. How
far the object to be handled is from the arch of the
foot.)

Section 3. Modeling
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
L5 / S1 disc.
the following:
* Angles from vertical of these body parts. How
far the object to be handled is from the arch of the
foot.)
* The weight of the load. (How much the object to
be handled weighs.)

Section 3. Modeling
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
L5 / S1 disc.
Twisting in the middle of a lift amplifies
the negative results of forces on the lower
back. For purposes of illustration
consider the follow:

Section 3. Modeling
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
L5 / S1 disc.
Twisting in the middle of a lift amplifies
the negative results of forces on the lower
back. For purposes of illustration
consider the follow:
The Great Herniated
Tomato Experiment

Section 3. Modeling
What about
“Cumulative Trauma”?

Section 3. Modeling
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
C
The following model
shows the sources of
force on L5 / S1 disc.
It does not reflect the added forces during twist / bend lifting.

Section 3. Modeling
Angle from upper
vertical of trunk =
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
C
“A”
The following model

Section 3. Modeling
Angle from lower
vertical of upper
arm =
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
C
“B”
The following model

Section 3. Modeling
Angle from upper
vertical of lower
arm =
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
C
“C”
The following model

Section 3. Modeling
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
C
Factors to consider :
* Factor 1 = Subject weight, subject height, and Angle A

Section 3. Modeling
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
C
* Factor 2 = Subject weight, subject height, Angle A, and Angle B

Section 3. Modeling
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
C
* Factor 3 = Subject weight, subject height, Angle A, Angle B, and Angle C

Section 3. Modeling
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
C
* Factor 3 = Subject weight, subject height, Angle A, Angle B, and Angle C
* Factor 4 = Object weight, subject height, Angle A, Angle B, and Angle C

Section 3. Modeling
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
CAngles A B C Object
F1

Section 3. Modeling
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
F1
F2

Section 3. Modeling
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
F1
F2
F3

Section 3. Modeling
A
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
B
F1
F2
F3
F4
4 3 2 1

Section 3. Modeling
When a task requires more than 3 lifts per minute.

Section 3. Modeling
The Physiological Approach = ( 3 + lifts per min. )
9
10
11
12
13
14
A person’s endurance is primarily limited by the
capacity of the oxygen transport system.

Section 3. Modeling
0 1 2 3 4 5 6 7 8 9
9
10
11
12
13
14
Increased metabolism demands an increase in the
delivery of oxygen and nutrients to the
tissue.

Section 3. Modeling
0 1 2 3 4 5 6 7 8 9
9
10
11
12
13
14
Increased metabolism demands an increase in the
delivery of oxygen and nutrients to the
tissue.
Energy cost, heart rate, blood
pressure and blood lactate
are measured.

Section 3. Modeling
Frequency of Lifts (lifts/minute)
Weight
Lifted
0 1 2 3 4 5 6 7 8 9
9
10
11
12
13
14
The frequency is marked on the line at
the bottom of the chart.
The Relationship of Frequency to Weight.

Section 3. Modeling
Weight
Lifted
0 1 2 3 4 5 6 7 8 9
9
10
11
12
13
14
The weight that can be lifted can now
be marked on the left of the chart.

Section 3. Modeling
Weight
Lifted
0 1 2 3 4 5 6 7 8 9
9
10
11
12
13
14
As the frequency of lifts per
minute increases, the weight
of the objects to be lifted must
be decreased.

Section 3. Modeling
Weight
Lifted
0 1 2 3 4 5 6 7 8 9
9
10
11
12
13
14
be decreased.

Section 3. Modeling
Aerobic capacity is defined as the
maximum level of metabolism of
which a person is capable. An
individuals aerobic capacity depends
on the capacity to deliver oxygen to
the working muscles.
Aerobic Capacity

Section 3. Modeling
It is advantageous to design / select
the task load wich maximizes
efficiency.
Effective Use of Muscles

Section 3. Modeling
It is advantageous to design / select the task
load which maximizes efficiency.
For dynamic effort (work) the optimal
load is approx. 30% of maximum.

Section 3. Modeling
For dynamic effort (work) the optimal load is
approx. 30% of maximum.
Overloading or underloading the
muscular system is not efficient.

Section 3. Modeling
For dynamic effort (work) the optimal load is
approx. 30% of maximum.
Overloading or underloading the muscular
system is not efficient.
For static effort (work) the optimal
load is approx. 10% of maximum.

Section 3. Modeling
NIOSH Lifting Guidelines
National Institute of Occupational Safety & Health (NIOSH)
Work Practices Guide for Manual Lifting 1982
V2
V1
H1
H2

Section 3. Modeling
The NIOSH guidelines determine what
the maximum load should be, given the
following characteristics:
V2
V1
H1
H2

Section 3. Modeling
* Weight of the object lifted.
V2
V1
H1
H2

Section 3. Modeling
* Position of load with respect to
the body; starting and ending point
of horizontal and vertical distance.
V2
V1
H1
H2

Section 3. Modeling
* Frequency of lift.
V2
V1
H1
H2

Section 3. Modeling
* Frequency of lift.
* Duration of lift.
V2
V1
H1
H2

Section 3. Modeling
H1 = horizontal location from the
midpoint between ankles to the center of
the load at origin of lift (in inches)
V2
V1
H1
H2

Section 3. Modeling
V1 = vertical location of the hands at the
beginning of lift measured from floor to
hands (in inches)
V2
V1
H1
H2

Section 3. Modeling
hands (in inches)
D = vertical travel distance from
origin to destination of load
(in inches)
V2
V1
H1
H2

Section 3. Modeling
hands (in inches)
D = vertical travel distance from
origin to destination of load
(in inches)
F = average frequency of lift
(lifts / minute)
V2
V1
H1
H2

Section 3. Modeling
This range is acceptable.Body Interference
Limit
Functional Reach
Limit
Action
Limit
(cm)
(in.)
Acceptable
HORIZONTAL LOCATION OF LOAD
WEIGHTLIFTED
(lb.) (Kg)
200
150
100
50
0
80
40
20
0
0
60
20 40 60 80
0 10 20 30

Section 3. Modeling
Body Interference
Limit
Functional Reach
Limit Maximum
Permissible
Limit
Action
Limit
(cm)
(in.)
Acceptable
WEIGHTLIFTED
(lb.) (Kg)
200
150
100
50
0
80
40
20
0
0
60
20 40 60 80
0 10 20 30
Administrative
Controls
“Administrative Controls” are
required in this range.

Section 3. Modeling
Body Interference
Limit
Hazardous
Lifting
Conditions
Functional Reach
Limit Maximum
Permissible
Limit
Action
Limit
(cm)
(in.)
Administrative
Controls
Required
Acceptable
WEIGHTLIFTED
(lb.) (Kg)
200
150
100
50
0
80
40
20
0
0
60
20 40 60 80
0 10 20 30
The lift should be eliminated
by using “Engineering
Controls.”

Section 3. Modeling
Design the horizontal distance to be
as close to 7 inches as possible.

Section 3. Modeling
Design the vertical location of the
origin of the lift to be at least 30
inches from the floor.

Section 3. Modeling
Design the vertical location of the
origin of the lift to be at least 30
inches from the floor.
The vertical travel distance should
be no greater than 10 inches.

Section 4. Factors that Influence MMH
Manual Materials Handling is influenced by
the following factors:

Worker Characteristics

Task Characteristics / Work Practices

Material / Container Characteristics

Material / Container Characteristics
Worker characteristics are different in
each of us and affect the kind and amount
of work that we can perform.

The following five general rules should be
applied at every opportunity.
Section 5. Safe Lifting Guidelines

Plan the lift

Plan the lift
Both squat and stoop lifting is now considered acceptable
for jobs requiring repeditive lifting. The term used to
describe this is free form lifting. No matter what type of lift
is used, it is never permissable to exceed the maximum
acceptable load of the worker.

Plan the lift
Keep the load as close to the body as possible.

Plan the lift
Lift the load with a smooth body motion. (Avoid jerking)

Plan the lift
Lift the load with a smooth body motion. (Avoid jerking)
When turning, do not twist. Turn with the feet.

(Adapted from: The Saunders Group inc.,
4250 Norex Drive, Chaska, MN 55318)

Body Mechanicics
Keep back arched when lifting.
Keep head and shoulders up.

Body Mechanicics
Plan ahead. Test the load before lifting.

Keep the weight close to the body.
10 lbs. 100 lbs. 10 lbs. 10 lbs.
10 lbs.
100 lbs.
10
lbs.
10 lbs.

The Diagonal Lift
Squat. Head up. Back arched. Feet spread. One foot ahead.

The Power Lift
Partial squat. Head up. Back arched. Feet spread. One foot ahead.

Section 6. The MMH Survey
Surveys are tools that can remind us of
conditions and practices that when present in
the workplace can lead to injury or illness.
Surveys should ask critical questions about
the operation.

The Manual Materials Handling Survey
Costs Yes No
Are we experiencing costly accidents relative to this task?
Activities
Are any of the following activities required in this task?
Lifting / Lowering . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pushing / Pulling . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Twisting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Carrying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Holding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Models
Do any of the following models apply to this task?
Biomechanical (compression forces at L5) . . . . . . .
Physiological (frequency vs. weight). . . . . . . . . . . .
Aerobic Capacity (conditioning) . . . . . . . . . . . . . . .
Effective use of muscles . . . . . . . . . . . . . . . . . . . . . .
NIOSH lifting guidelines . . . . . . . . . . . . . . . . . . . . .
Factors
Are any of the following influencing the task?
Worker Characteristics . . . . . . . . . . . . . . . . . . . . . . . .
Task Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . .
Material / Container Characteristics . . . . . . . . . . . .

Training
Is the employee in need of training in safe lifting? . . . . . . .
Is the employee in need of training in body mechanics? . .
Note: Any one “Yes” answer can be serious
enough to cause serious injury or illness. The
more “Yes” answers the higher the risk, even
when the single “Yes” is determined to be
minor. This is due to the cumulative effect
of multiple negative factors.

The Golfer’s Lift

Kneel When Working In A Low Position

Straight Leg Lift, Bend At The Hips, Not The Back

Partial Squat Lift

Reaching With a Heavy Load

Back Unsupported

Working Surface Too Low and Far Away

Appendices
* Definitions
* Equipment, Materials, Container Characteristics
* Biomechanical Model
* NIOSH Lifting Summary
* Manual Materials Handling Survey
* Task Evaluation Guide
* Action Plan Flow Diagram

Thank You !

Manual materials handling

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