Design Error

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What is Ergonomics?

The study of man's relationship with his workplace.

Fitting the task to the man rather than forcing him/her to adapt to his working environment.

Designing the workplace to prevent occupational injury and illness.

Discovering the capabilities and limitations of the human body.

Balance for Optimization

Ergonomics

WorkerCapabilities

JobDemands

CUMULATIVE TRAUMA DISORDERS (CTDs)

Term assigned to identify a group of injuries that classically result from

long-term and repeated “wear and tear” on the musculoskeletal system.

• CUMULATIVE indicates injuries that develop gradually over time, and result from many repeated stresses on a particular body part.

• TRAUMA signifies bodily insult or injury from mechanical stresses.

• DISORDERS describes the adverse health effects that arise from chronic exposure to repeated trauma.

Ergonomics

Cumulative Trauma DisordersYour Job

Your Body

Trauma

Healing Valve

Your Job

Your Body

Trauma

Healing Valve

CTD

Cumulative Trauma Disorders

Win - WinProduction

Quality

Compliance

Compensation Costs

Healthy Workforce

Careers/Employment

Safety Working Conditions

Ergonomics

OSHAct 1970"General Duty

Clause"

Section 5. (a) Each employer -

(1) shall furnish to each of his employeesemployment and a place of employment whichare free from recognized hazards that arecausing or are likely to cause death orserious physical harm to his employees;

DUTIES

Ergonomics

Voluntary Guidelines

o OSHA Meatpacking Guidelines

o General Industry Guidelines (dropped in lieu of standard)

o Food Distribution Warehouses

o ANSI HFS-100/1988; VDTs

o ANSI Z-365; Control of CTDs

Ergonomics

Nature of Injury

Strains/Sprains 43%

CTDs 5%

Occ Illness 4%

Laceration/Puncture11%

Fractures 9%

F.B. in Eye 3%Dislocations 2%

Contusions 9%Burns 3%

Amputations 1%

1990 Ohio Injury/Illness Claims Information1990 Ohio Injury/Illness Claims Information

Ergonomics

Part of Body

Back 20%

Face/Neck 3%

Trunk/Internal 11%

Arms 12%Hands 5%

Fingers 11%

Legs 13%

Feet/Toes 5%

Mult/Major 13%

Other 15% Eyes 4%Head 2%

1990 Ohio Injury/Illness Claims Information1990 Ohio Injury/Illness Claims Information

Ergonomics

CTD Recognition Rising

0

2000

4000

6000

8000

10000

12000

14000

1985 1986 1987 1988 1989 1990

Occ Illness CTD

In 1990, 59% of all Occupational IllnessClaims are logged asCTDs

In 1990, 59% of all Occupational IllnessClaims are logged asCTDs

One half of all CTD claims are logged asCarpal Tunnel Syndrome (CTS)

One half of all CTD claims are logged asCarpal Tunnel Syndrome (CTS)

Ergonomics

Ohio Back Injury Claims

0

5000

10000

15000

20000

25000

30000

79 80 81 82 83 84 85 86 87 88 89 90

Low Back Back General Back w/Disc

In 1990, $513 Mwas paid out bythe BWC for back injuries alone

In 1990, $513 Mwas paid out bythe BWC for back injuries alone

Ergonomics

Average Total Claim Cost

$0 $2 $4 $6 $8 $10 $12 $14 $16 $18 $20

Eyes

Head

Face & Neck

Back

Trunk +

Arms

Hands

Fingers

Legs

Feet/Toes

$5

$18

$8

$18

$12

$7

$5

$4

$9

$5

(Thousands)

Direct Costs = Medical + Comp + Reserve

Direct Costs = Medical + Comp + Reserve

Indirect costs are estimatedanywhere from 4 up to 20 times direct costs

Indirect costs are estimatedanywhere from 4 up to 20 times direct costs

1980-1983BWC data

1980-1983BWC data

Ergonomics

Iceberg Analogy

Accident Cost

•Medical Payments•Compensation

Supervisor time to investigate

Breaking in substitute

Efficiency due tobreak-up of crew

Damaged tools/equipment

Down-timeOverhead $ while work disrupted

Failure to meet deadline/fill orders

Loss of production

Loss of good will

Overtime to make up production

Hiring costs

Lost time by fellow workers

Direct Costs

Indirect or HiddenCosts

Worksite AnalysisKey Elements

I. Records Analysis I. Records Analysis

Worksite Analysis

Records Analyses help identify & prioritize jobs to evaluate.Records Analyses help identify & prioritize jobs to evaluate.

Accident Production Personnel Employer/Employee Records Records Records Survey

OSHA log 200 Seasonal Trends Turn-over Rate Symptoms surveyIncidence Rate Quality Control Absenteeism Early reporting mechanismPrevalence Rate Model Changes Suggestion award programFirst-aid logs BottlenecksAccident Invest.Workers’ Comp.

Worksite AnalysisKey Elements

I. Records Analysis

II. Risk Factor RecognitionII. Risk Factor Recognition

OCCUPATIONAL

RISK FACTORS

OCCUPATIONAL

RISK FACTORS Attributes of a job or task that we know increase the probability of developing a musculoskeletal cumulative trauma disorder (CTD)

• FORCE (Internal & External)

• POSTURE

• REPETITION

• INSUFFICIENT REST

Worksite Analysis

OCCUPATIONAL

RISK FACTORS

OCCUPATIONAL

RISK FACTORS Attributes of a job or task that we know increase the probability of developing a musculoskeletal cumulative trauma disorder (CTD)

• FORCE (Internal & External)

• POSTURE

• REPETITION

• INSUFFICIENT REST

Worksite Analysis

Synovial Sheaths

Carpal Ligament(Extensor Retinaculum)

Extensor Tendons

TWO KINDS OF BACK INJURIES

MUSCULAR SPINAL

Resting Dynamic Static

bloodflow

needed

bloodflow

supplied

bloodflow

needed

bloodflow

needed

bloodflow

supplied

bloodflow

supplied

Vertebrae

Top View

Side View

Micro-fractures in Vertebral Endplate

Scar tissue from healing fractureshinders passage of nutrients to disc resulting in gradual weakeningand de-generation.

Disc Degeneration

Hierarchy of Controls

Ergonomics

Engineering ControlsWorkstation DesignTool DesignProcess ModificationMechanical Assist Administrative Controls

TrainingJob RotationPacingPolicyJob Enlargement

Personal Protective EquipmentGlovesWrapsShields

FIRST CHOICE

SecondChoice

Last & Least

BACK INJURIES

MAN VS. MACHINE

•DECISION MAKING•LOW REPETITION ACTIVITIES•LOW FORCE APPLICATION•DELICATE FORCE APPLICATION

•TAKING INSTRUCTION•HIGH REPETITION ACTIVITIES•HIGH FORCE APPLICATION•HAZARDOUS ENVIRONMENTS

STATURE

EYE

SHOULDER

ELBOW

HIP

KNEE

21.67”21.5”19.3”20.0”

N.A.E.A.

L.A.

36.0”36.4”32.7”34.0”

N.A.E.A.

L.A.

43.5”43.3”40.8”40.9”

N.A.E.A.

L.A.

N.A.E.A.

L.A.

69.1”68.6”65.2”65.1”

N.A.E.A.

L.A.

64.6”64.4”60.7”60.9”

N.A.E.A.

L.A.

56.7”56.5”52.8”53.2”

N.A.= NORTH AMERICA E.= EUROPE A.= ASIA L.A.= LATIN AMERICA

50thPERCENTILE

MALE

D

E

C

B

A

Horizontal Work Envelope

A-Normal reach radiusB-Sitting/Standing distanceC-Extended reach radiusD-Beginning work distanceE-Optimum work area

Max = 15”Max = 9”Max = 22”Ideal = 4”10” x 10”

SIT OR STAND?Type of Task

Lifting more than 11lbs

Work below elbow height

(e.g. packaging or assembly)

Extended horizontal reaching

Light assembly with repetitive movements

Fine manipulation and precision tasks

visual inspection and monitoring

Frequent moving around

First Choice

Standing

Standing

Standing

Sitting

Sitting

Sitting

Sit-Standing

Second Choice

Sit-Standing

Sit-Standing

Sit-Standing

Sit-Standing

Sit-Standing

Sit-Standing

Standing

A > 4” B = (for power grips) 1.5” C = 3” to 3.5” (for precision operations) .45”

Manual Tool Dimensions