ergonomics rula-reba, 2009

Department of Mechanical and Manufacturing EngineeringFaculty of Engineering

KMP 5907Industrial Ergonomics

Lecturer : Assoc. Prof. Dr. Rosnah Mohd. Yusuff

Take home testKMP 5907 : Industrial Ergonomics 27 February 2010Due : 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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Question

A worker sprays cabinet doors at a cabinet manufacturer. Doors are suspended on an overheadconveyor 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 atthe worker’s mid-chest level.The worker sits on a high stool in a completely open room. A hand-held pneumatic spray gun is usedto paint the doors. The worker paints in a irregular sweeping motion. Each door takes approximately45 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 lineweighs 1 kg for 3m of hose. The worker also wears a cartridge respirator which weighs 0.6kg madefrom 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 wouldyou 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 yourconcerns that will likely effectively address the problem.

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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 overviewand visualize every features. Secondly, work activities that showed evidence onMusculoskeletal Disorder injury risk are identified. And the last thing is using the Awarenessworksheet. In this identification, commitment from subordinate is needed such as managementrecords / 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 1.0me. Workers sits on high stoolf. 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 topaint.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 theworker at a rate of one door every 90 seconds.

In open room (no booth)



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Sketch :

Worker paints in a irregular sweeping motion.

Spray gun has pistol grip handle, and two paint lines (hoses) feeding into thebottom of the handle from a pressurized, master paint reservoir. Each paintline weighs 1kg for 3m of hose.



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To identify work activities that showed evidence on MSD injury risk, Steps to be taken areuse the injury records, a musculoskeletal discomfort questionnaire, front-line supervisorinterviews, and a list of management concerns to identify work groups and work activities thathave significant evidence of MSD risk factors. To identify the tasks problems the Elements toErgonomics 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 aboveshoulder 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? Sufficientpauses?

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-heldpneumatic spray gun/ cartridge respirator?



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From the interview, past records and the questionnaire, the details are used to describe theelements to ergonomics by a worksheet which is named Ergonomics Awareness Worksheet.The purpose of the worksheet is to increase basic awareness of potential problems associatedwith jobs and tasks. This awareness can help provide clues on how to make effectiveimprovements.

ERGONOMICS AWARENESS SHEET

Risk FactorsRisk

Reason for Problems or ×

Situation 1 :MSD : Repetition, Contact stress, gripforce. Similar motions every fewseconds. 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 mayhave problem while sitting and reaching.Sitting on high stool and spray at aheight mid-chest level could bedangerous. Holding 2kg tools for hoursmay cause MSD issue.

a. The doors pass by at a height such that thebottom 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. Theworkers need to complete every taskaccording to time rate, 90 seconds. Needlots movement and motions.

a.Doors are suspended on an overheadconveyor and pass by the worker at a rate ofone door every 90 seconds.

b.Each door is 0.67 X 1.0mc. 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 ofthe handle from a pressurized, master paintreservoir.

c.Each paint line weighs 1kg for 3m of hose.d. Worker wears a cartridge respirator which

weighs 0.6kg made from vulcanized rubberwith two cartridge filters.

Situation 5 : MSD: Toxic vapours. Hazardouschemicals in coatings and solvents canenter the body several ways.a. In open room (no booth)



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ANSWERS - QUESTION B

b. What are (is) important parameters to quantify, measure or evaluate. What method wouldyou use to quantify these parameters?

Quantify, measure or evaluate is the process of estimating the risk levels for the ergonomicproblem and their acceptability. This is used as a base for prioritizing actions to control theseergonomic problems and minimise safety and ergonomics risks. The important parameters toquantify, measure or evaluate are the ergonomics risks associated with spray painting. The MSDconcern are includes :

i. RSI - Repetitive Strain Injuryii. RMI - Repetitive Motion Injuryiii. UECTD - Upper Extremity Cumulative Trauma Disordersiv. WRULD - Work Related Upper Limb Disorder

The method would be used to quantify these parameters are by using the Ergonomics MSDAssessment. 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 thework environment and the performance of work contribute significantly orMusculoskeletal disorders that are aggravated or prolonged by work conditions. The Assessment isused to estimate the risk level of the work tasks identified. From the checklist also we can identifiedthe 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 toindicate RisklevelBody Part Physical Risk Factor Duration Visual Aid

Hands Using the hand (heel/base of palm) tohold the spray handle in hours.

> 5 hours totalper day.

Potential High

Finger Using the finger to trigger the spray gunin hours.

> 5 hours totalper day.

Potential High

REPETITION :

NeckShouldersElbowsWristsHands

Using the same motion with little or novariation every few seconds in sittingposition (sit on high stool);

> 6 hours totalper day

Potential High



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WristsHands

Using the same motion with little or novariation every few secondsWrists bent in; awkward wrist posture;= 30° flexion, or= 45° extension, or= 30° ulnar deviationand High forceful hand(s) exertions


Potential High

Triggerfinger

Repeated pressure on a finger whenusing the trigger on a spray gun maystrain the tendon running to that finger,as well as the tendon covering. Intensivetriggering with the fingers in a rapid,steady motion with little opportunitiesfor temporary work pauses.


Potential High

GRIP FORCE : Mark toindicate RisklevelBody Part Physical Risk Factor Duration Visual Aid

ArmsWristsHands

Gripping spray gun weighing 2kg ormore per hand;-Highly repetitive motion-Wrists bent in; = 30° flexion, or = 45° extension, or = 30° ulnar deviation.


Potential High

Power gripping an unsupported spraygun. Power gripping with a force ofspray activity. Potential

High

AWKWARD POSTURE : Mark toindicate RisklevelBody Part Physical Risk Factor Duration Visual Aid

Shoulder

Working with the hand above thehead or the elbow above the shoulder.


Potential High

Repetitively raising the hand abovethe head or the elbow above theshoulder more than once per minute.

> 3 hours totalper day Potential

High



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Neck

Working with variations neck bentand movements, without support orthe ability to vary posture.


Potential High

Back

Working with the back bent forwardmore than 30° without support, or theability to vary posture.


High

Working with the back bent forwardmore than 45° without support or theability to vary posture.


High

LIFT / LOWER FORCE : Mark toindicate RisklevelBody Part Physical Risk Factor Duration Visual Aid

Body

-Holding spray guns weighs 2kg

-Two paint lines (hoses); each lineweighs 1kg, 2 x 1kg = 2kg,

-cartridge respirator 0.6kg


Potential High



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RESPIRATORY AND SKIN SENSITISATION : Mark toindicate RisklevelBody Part Physical Risk Factor Duration Visual Aid

Body

Expose to hazardous substances (poorventilation)Short term effects : nausea, skinirritation, rashesLong term effects : asthma, lung cancer


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 theiracceptability. Once a potential risk has been identified, the purpose of the Ergonomics Assessment isto determine if a high risk or potential risk exists.

Refer to the Ergonomic Musculoskeletal Disorder (MSD) Assessment , the box (þ) is checkedto indicate “High Risk” and “Potential Risk” factors.

RISK FACTOR SUMMARY TABLE

Risk Factor Body Part “High Risk” “Potential Risk”

Contact StressHandsFinger

RepetitionNeck, shoulder, elbowWrists, handsTrigger finger

Grip force Arm, wrists, handsAwkward posture Shoulder

NeckBack

Lift / lower force BodyRespiratory and skinsensitisation Body

From the completed Risk factor summary table,

Ø “High Risk” task requires that controls be implemented without delay. Controls should beeliminated, 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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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 theergonomics process to appropriatemanagers, supervisors and employees;

§ Committing adequate resources to theergonomics process;

§ Integrating production processes andproduction improvements with safety andhealth concerns;

§ Ensuring that managers and employees areaccountable for carrying out theirresponsibilities under the ergonomicsprocess.

Involving Employees§ Implement a procedure that encourages

prompt and accurate reporting of MSDs aswell as of their early indications;

§ Develop a system to engage employees inthe design of work, equipment andprocedures, the reporting of workplacehazards and training;

§ Establish an employee complaint orsuggestion procedure designed to allowemployees to raise ergonomic issueswithout fear of reprisal;

§ Request employee feedback on workplacemodifications;

§ Form employee groups to identifyproblems, analyze tasks and recommendsolutions.

Providing TrainingThis training are on ergonomic issues andshould include:§ The procedures for reporting work-related

illnesses as required by OSHA’sregulation.

§ The company’s ergonomics process;§ How to identify ergonomic risk factors;§ The policies and procedures for avoiding

injury, including proper work practices anduse of equipment;

§ How to recognize MSDs and their earlyindications;

The advantages of addressing earlyindications of MSDs .

The handle should allow to comfortablyand safely grip. This enables the fingersand palm to control the handle without theneed for excessive compression and"contact stress" to the palm. The shape ofthe handle should be designed for a"power grip". This means the wrist is in aneutral position, with all the fingersgrasping the handle. In this position, themuscles used for gripping are able to workmost efficiently and are less prone tofatigue and injury.

Repetition Use automated machines to carry outspray painting.

Grip force

Power tools should be about 1.5kg (nomore than 2.3kg). Tools applied with ahorizontal force should have a benthandle, so that unnecessary to excessivelybend the wrist. Tools applied with avertical force should have a straight ("in-line") handle.

Awkward posture

High stool or angled seat should provide asurface on which the employee can lean,shift weight, and change trunk angle. Thebackrest should be height adjustable andlarge enough to support the upper andlower back. The shape of the backrestshould provide support for the inwardcurve of the low back.

Lift / lower force

Precision hand tools should be as light aspossible (no more than 1.75kg). Thecentre of gravity of tool should be alignedwith the centre of gripping hand.

Respiratory and skinsensitisation

Substitute a product with a less toxicalternative. Enclose the work site to bespray-painted (booth).



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