Master Degree Assignment 2009

1. Department of Mechanical and Manufacturing Engineering
Faculty of Engineering
KMP 5907
Industrial Ergonomics
Lecturer : Assoc. Prof. Dr. Rosnah Mohd. Yusuff
Take home test
KMP 5907 : Industrial Ergonomics 27 February 2010
Due : 27 March 2010
Name Matric No.
1. Rodzidah Mohd Rodzi GS23997
2. Mohammad Jamil Mohamed Ashraf GS23966
3. Firdaus Mohamed Sahid GS23988
4. Mohd Nurhidayat Zahelem GS23991
5. Syahiran Desa GS23980
6. Khairil Inawan Mohammed GS23974
Group A1
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2. 1
Question
A worker sprays cabinet doors at a cabinet manufacturer. Doors are suspended on an overhead
conveyor and pass by the worker at a rate of one door every 90 seconds. Each door is 0.67 X 1.0m,
and of similar design. The doors pass by the worker at a height such that the bottom of the door is at
the worker’s mid-chest level.
The worker sits on a high stool in a completely open room. A hand-held pneumatic spray gun is used
to paint the doors. The worker paints in a irregular sweeping motion. Each door takes approximately
45 seconds to paint. The spray gun weighs 2 kg, has a pistol grip handle, and has two paint lines
(hoses) feeding into bottom of the handle from a pressurized, master paint reservoir. Each paint line
weighs 1 kg for 3m of hose. The worker also wears a cartridge respirator which weighs 0.6kg made
from vulcanized rubber with two cartridge filters.
a. Identify major ergonomic or work design problems and briefly justify.
b. What are (is) important parameters to quantify, measure or evaluate. What method would
you use to quantify these parameters?
c. How would you use the data to evaluate the extent of the problem?
d. Describe one reasonable administrative and one engineering control for each of your
concerns that will likely effectively address the problem.
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3. 2
ANSWERS - QUESTION A
a. Identify major ergonomic or work design problems and briefly justify.
To identify major ergonomic or work design problems, the first thing we need to do, is overview
and visualize every features. Secondly, work activities that showed evidence on
Musculoskeletal Disorder injury risk are identified. And the last thing is using the Awareness
worksheet. In this identification, commitment from subordinate is needed such as management
records / procedure, front-line supervisors, injury records and the site workers.
1. Overview and visualize of every features.
a. Worker sprays cabinet doors.
b. The doors pass by at a height such that the bottom of the door at the mid-chest level.
c. Doors are suspended on an overhead conveyor and pass by the worker at a rate of one
door every 90 seconds.
d. Each door is 0.67 X 1.0m
e. Workers sits on high stool
f. In open room (no booth)
g. Hand-held pneumatic spray gun is used to paint.
h. Worker paints in a irregular sweeping motion.
i. Each door takes approximately 45 seconds.
j. Spray gun weighs 2 kg.
k. Spray gun has pistol grip handle, and two paint lines (hoses) feeding into the bottom of
the handle from a pressurized, master paint reservoir.
l. Each paint line weighs 1kg for 3m of hose.
m. Worker wears a cartridge respirator which weighs 0.6kg made from vulcanized rubber
with two cartridge filters.
Worker sprays cabinet doors. Hand-held pneumatic spray gun is used to
paint.
a.
The doors pass by at a height such that the bottom of the door at the mid-
chest level. Doors are suspended on an overhead conveyor and pass by the
worker at a rate of one door every 90 seconds.
In open room (no booth)
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4. 3
Sketch :
Worker paints in a irregular sweeping motion.
Spray gun has pistol grip handle, and two paint lines (hoses) feeding into the
bottom of the handle from a pressurized, master paint reservoir. Each paint
line weighs 1kg for 3m of hose.
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5. 4
To identify work activities that showed evidence on MSD injury risk, Steps to be taken are
use the injury records, a musculoskeletal discomfort questionnaire, front-line supervisor
interviews, and a list of management concerns to identify work groups and work activities that
have significant evidence of MSD risk factors. To identify the tasks problems the Elements to
Ergonomics been mode into Question Checklist. The answers of the questions are ‘Yes’ or
‘No’.
ELEMENTS TO ERGONOMICS (QUESTIONS MODE)
Questions
Answer
or ×
1. Are the weights of loads to be lifted judged acceptable by the workforce?
2. Are materials moved over minimum distances?
3. Is the distance between the spray object and the body minimized?
4. Are working spaces wide enough? Safe for human body? Clean and dry?
5. Are the spray guns easy to grasp? Stable? Able to handle without slipping?
6. Are there handholds on these objects?
7. Do gloves fit properly?
8. Is the proper PPE worn?
9. Are the door surfaces adjustable to the best handling heights?
10. Does the working situation avoid: Movements below knuckle height and above
shoulder height? Static muscle loading? Sudden movements during handling?
Twisting at the waist? Extended reaching?
11. Are high rates of repetition avoided by job rotation? Self pacing? Sufficient
pauses?
12. Does the employee have an unobstructed view of handling the task?
13. Is there a preventive maintenance program for equipment?
14. Are workers trained in correct handling and lifting the heavy hand-held
pneumatic spray gun/ cartridge respirator?
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6. 5
From the interview, past records and the questionnaire, the details are used to describe the
elements to ergonomics by a worksheet which is named Ergonomics Awareness Worksheet.
The purpose of the worksheet is to increase basic awareness of potential problems associated
with jobs and tasks. This awareness can help provide clues on how to make effective
improvements.
ERGONOMICS AWARENESS SHEET
Risk Factors
Risk
Reason for Problems
or ×
Situation 1 :
MSD : Repetition, Contact stress, grip
force. Similar motions every few
seconds. Observed signs of fatigue.
a. Worker sprays cabinet doors.
b. Worker paints in irregular sweeping motion.
c. Hand-held pneumatic spray gun is used to
paint.
Situation 2 :
MSD: Awkward posture, lift. Work
surface too high or low. Workers may
have problem while sitting and reaching.
Sitting on high stool and spray at a
height mid-chest level could be
dangerous. Holding 2kg tools for hours
may cause MSD issue.
a. The doors pass by at a height such that the
bottom of the door at the mid-chest level.
b. Workers sit on high stool.
c. Spray gun weighs 2 kg.
Situation 3 :
MSD: Contact stress, grip force. The
workers need to complete every task
according to time rate, 90 seconds. Need
lots movement and motions.
a.Doors are suspended on an overhead
conveyor and pass by the worker at a rate of
one door every 90 seconds.
b.Each door is 0.67 X 1.0m
c. Each door takes approximately 45 seconds.
Situation 4 :
MSD: Grip force, Lift/lower force,
vibration. Heavy tools and equipment,
cause body strain and pain.
a.Spray gun weighs 2 kg.
b.Spray gun has pistol grip handle, and two
paint lines (hoses) feeding into the bottom of
the handle from a pressurized, master paint
reservoir.
c.Each paint line weighs 1kg for 3m of hose.
d. Worker wears a cartridge respirator which
weighs 0.6kg made from vulcanized rubber
with two cartridge filters.
Situation 5 :
MSD: Toxic vapours. Hazardous
chemicals in coatings and solvents can
enter the body several ways.a. In open room (no booth)
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7. 6
ANSWERS - QUESTION B
b. What are (is) important parameters to quantify, measure or evaluate. What method would
you use to quantify these parameters?
Quantify, measure or evaluate is the process of estimating the risk levels for the ergonomic
problem and their acceptability. This is used as a base for prioritizing actions to control these
ergonomic problems and minimise safety and ergonomics risks. The important parameters to
quantify, measure or evaluate are the ergonomics risks associated with spray painting. The MSD
concern are includes :
i. RSI - Repetitive Strain Injury
ii. RMI - Repetitive Motion Injury
iii. UECTD - Upper Extremity Cumulative Trauma Disorders
iv. WRULD - Work Related Upper Limb Disorder
The method would be used to quantify these parameters are by using the Ergonomics MSD
Assessment. Musculoskeletal Disorders (MSDs) are injuries and illnesses that affect muscles,
nerves, tendons, ligaments, joints, spinal discs, skin, subcutaneous tissues, blood vessels, and bones.
Work-Related Musculoskeletal Disorders (WMSDs) are: Musculoskeletal disorders to which the
work environment and the performance of work contribute significantly or
Musculoskeletal disorders that are aggravated or prolonged by work conditions. The Assessment is
used to estimate the risk level of the work tasks identified. From the checklist also we can identified
the prioritize of the ergonomics issue to be controlled.
ERGONOMICS MUSCULOSKELETAL DISORDER (MSD) ASSESSMENT
*** Indicator divided into two, Potential Risk and High Risk
CONTACT STRESS : Mark to
indicate Risk
level
Body Part Physical Risk Factor Duration Visual Aid
Hands
Using the hand (heel/base of palm) to
hold the spray handle in hours.
> 5 hours total
per day.
Potential
High
Finger
Using the finger to trigger the spray gun
in hours.
> 5 hours total
per day.
Potential
High
REPETITION :
Neck
Shoulders
Elbows
Wrists
Hands
Using the same motion with little or no
variation every few seconds in sitting
position (sit on high stool);
> 6 hours total
per day
Potential
High
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8. 7
Wrists
Hands
Using the same motion with little or no
variation every few seconds
Wrists bent in; awkward wrist posture;
= 30° flexion, or
= 45° extension, or
= 30° ulnar deviation
and High forceful hand(s) exertions
> 5 hours total
per day
Potential
High
Trigger
finger
Repeated pressure on a finger when
using the trigger on a spray gun may
strain the tendon running to that finger,
as well as the tendon covering. Intensive
triggering with the fingers in a rapid,
steady motion with little opportunities
for temporary work pauses.
> 4 hours total
per day
Potential
High
GRIP FORCE : Mark to
indicate Risk
level
Body Part Physical Risk Factor Duration Visual Aid
Arms
Wrists
Hands
Gripping spray gun weighing 2kg or
more per hand;
-Highly repetitive motion
-Wrists bent in;
= 30° flexion, or
= 45° extension, or
= 30° ulnar deviation.
> 5 hours total
per day
Potential
High
Power gripping an unsupported spray
gun. Power gripping with a force of
spray activity.
Potential
High
AWKWARD POSTURE : Mark to
indicate Risk
level
Body Part Physical Risk Factor Duration Visual Aid
Shoulder
Working with the hand above the
head or the elbow above the shoulder.
> 3 hours total
per day
Potential
High
Repetitively raising the hand above
the head or the elbow above the
shoulder more than once per minute.
> 3 hours total
per day Potential
High
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9. 8
Neck
Working with variations neck bent
and movements, without support or
the ability to vary posture.
> 3 hours total
per day
Potential
High
Back
Working with the back bent forward
more than 30° without support, or the
ability to vary posture.
> 1 hours total
per day Potential
High
Working with the back bent forward
more than 45° without support or the
ability to vary posture.
> 1 hours total
per day Potential
High
LIFT / LOWER FORCE : Mark to
indicate Risk
level
Body Part Physical Risk Factor Duration Visual Aid
Body
-Holding spray guns weighs 2kg
-Two paint lines (hoses); each line
weighs 1kg, 2 x 1kg = 2kg,
-cartridge respirator 0.6kg
> 6 hours total
per day
Potential
High
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10. 9
RESPIRATORY AND SKIN SENSITISATION : Mark to
indicate Risk
levelBody Part Physical Risk Factor Duration Visual Aid
Body
Expose to hazardous substances (poor
ventilation)
Short term effects : nausea, skin
irritation, rashes
Long term effects : asthma, lung cancer
> 7 hours total
per day
Potential
High
ANSWERS – QUESTION C
d. How would you use the data to evaluate the extent of the problem?
Evaluation is the process of estimating the levels for the ergonomics problems and their
acceptability. Once a potential risk has been identified, the purpose of the Ergonomics Assessment is
to determine if a high risk or potential risk exists.
Refer to the Ergonomic Musculoskeletal Disorder (MSD) Assessment , the box (þ) is checked
to indicate “High Risk” and “Potential Risk” factors.
RISK FACTOR SUMMARY TABLE
Risk Factor Body Part “High Risk” “Potential Risk”
Contact Stress
Hands
Finger
Repetition
Neck, shoulder, elbow
Wrists, hands
Trigger finger
Grip force Arm, wrists, hands
Awkward posture Shoulder
Neck
Back
Lift / lower force Body
Respiratory and skin
sensitisation
Body
From the completed Risk factor summary table,
Ø “High Risk” task requires that controls be implemented without delay. Controls should be
eliminated, or if that is not practicable, the risk has to be minimized.
Ø If the risk remains “Potential Risk”, controls should be developed to minimize the risk.
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11. 10
ANSWERS – QUESTION D
d. Describe one reasonable administrative ad one engineering control for each of your
concerns that will likely effectively address the problem.
Risk Factor Administrative Control Engineering Control
Contact Stress
Providing Management Support.
§ Consistently communicate the importance
of employee safety and health;
§ Assigning and communicating
responsibility for the various aspects of the
ergonomics process to appropriate
managers, supervisors and employees;
§ Committing adequate resources to the
ergonomics process;
§ Integrating production processes and
production improvements with safety and
health concerns;
§ Ensuring that managers and employees are
accountable for carrying out their
responsibilities under the ergonomics
process.
Involving Employees
§ Implement a procedure that encourages
prompt and accurate reporting of MSDs as
well as of their early indications;
§ Develop a system to engage employees in
the design of work, equipment and
procedures, the reporting of workplace
hazards and training;
§ Establish an employee complaint or
suggestion procedure designed to allow
employees to raise ergonomic issues
without fear of reprisal;
§ Request employee feedback on workplace
modifications;
§ Form employee groups to identify
problems, analyze tasks and recommend
solutions.
Providing Training
This training are on ergonomic issues and
should include:
§ The procedures for reporting work-related
illnesses as required by OSHA’s
regulation.
§ The company’s ergonomics process;
§ How to identify ergonomic risk factors;
§ The policies and procedures for avoiding
injury, including proper work practices and
use of equipment;
§ How to recognize MSDs and their early
indications;
The advantages of addressing early
indications of MSDs .
The handle should allow to comfortably
and safely grip. This enables the fingers
and palm to control the handle without the
need for excessive compression and
"contact stress" to the palm. The shape of
the handle should be designed for a
"power grip". This means the wrist is in a
neutral position, with all the fingers
grasping the handle. In this position, the
muscles used for gripping are able to work
most efficiently and are less prone to
fatigue and injury.
Repetition
Use automated machines to carry out
spray painting.
Grip force
Power tools should be about 1.5kg (no
more than 2.3kg). Tools applied with a
horizontal force should have a bent
handle, so that unnecessary to excessively
bend the wrist. Tools applied with a
vertical force should have a straight ("in-
line") handle.
Awkward posture
High stool or angled seat should provide a
surface on which the employee can lean,
shift weight, and change trunk angle. The
backrest should be height adjustable and
large enough to support the upper and
lower back. The shape of the backrest
should provide support for the inward
curve of the low back.
Lift / lower force
Precision hand tools should be as light as
possible (no more than 1.75kg). The
centre of gravity of tool should be aligned
with the centre of gripping hand.
Respiratory and skin
sensitisation
Substitute a product with a less toxic
alternative. Enclose the work site to be
spray-painted (booth).
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