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  • Evaluation of workEvaluation of work--related musculoskeletal related musculoskeletal

    disorder risk of forestry workers: a case study disorder risk of forestry workers: a case study

    using OWASusing OWAS

    Angela Calvo Angela Calvo -- ItalyItaly

    15. Arbeitswissenschaftliches Seminar - 15th Seminar of Work Science

  • Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

    The 10 most important emerging physical risks identified by the Risk Observatory of the European Agency for Health and Safety (2002-2006)

    4,57 4,56 4,5 4,43 4,42 4,4 4,38 4,35 4,21 4,17

    0

    1

    2

    3

    4

    5

    Lack

    of ph

    ysica

    l acti

    vity

    Vibrat

    ion&a

    wk. p

    ostur

    e

    Therm

    al ris

    ks x

    low-st

    atus

    MSD&

    psich

    osoc

    ial ris

    k

    Multi-

    factor

    ial ris

    ks

    Therm

    al dis

    comf

    ort

    Vibrat

    ion&m

    uscu

    lar w

    ork

    Huma

    n-mac

    hine i

    nterfa

    ce

    Long

    -stan

    ding e

    rgon.r

    isks

    Expo

    sure

    to UV

    radia

    tion

    Like

    rt s

    cale

    val

    ues

  • RISKS

    MSD disorders

    Thermal discomfort

    Vibration and awkward postures

    Noise

    Long-standingergonomic risks

    Vibration and muscular work

    Dangerous machineries

    Forestry operators main risks

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • MANUAL WORK LOAD

    MSD RISKS

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • MSD risk evaluation

    OWAS Ovako Working-posture Analysis System;

    NIOSH National Institute of Occupational Society and Health;

    OSHA Occupational Safety and Health Administration;

    PATH Posture, Activity, Tools and Handling.

    Some known systems

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • THE NIOSH METHODOLOGY

    NIOSH National Institute of Occupation Society and Health

    RWL: Reccomended Weight Limit

    RWL=CP*A*B*C*D*E*F*G*H (de-multiplicative factors)

    Lifting Index LI

    LI = Weight to be moved

    RWL

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • THE OSHA METHODOLOGY

    OSHA Occupational Safety and Health Administration

    Guidelines

    Integrated system for the work organization

    Risk evaluation

    Procedures to limit the riskexposure

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • PATH METHODOLOGY

    PATH Posture, Activity, Tools and Handling

    Ergonomic risk

    Positions:

    5 for back

    2 for neck

    3 for arms

    10 for legs

    Used tool

    Activitytype

    Manual work load

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • OWAS METHODOLOGY

    252 configurations

    4 for back

    3 for arms

    7 for legs

    3 for the weight

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

    OWAS positions

    Back Arms Legs Load

    Bendingback

    Standing back

    Twistingback

    Twistingand bendingback

    Armsunder the shoulder

    One armover the shoulder

    Both the armsover the shoulder

    Sit

    Standing weighton 2 legs

    Standing weighton 1 leg

    Standing kneesbent

    Standing, weight on 1 leg, knee bent

    Kneeling, 1 or 2 kneestouchingthe ground

    Walking

    Lessthen 10 kg

    Between10 and 20 kg

    More then 10 kg

  • Risk classes

    252 configurations

    Class 1: natural position

    Class 2: positions which may be dangerous

    Class 3: dangerous positions

    Class 4: very dangerous positions

    4 risk classes

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

    Legs-w

    eight

    back

    arms

    3372Walking, 10-20 kg

    load, twistingback,

    both the arms

    over the shoulder

    1141Standing

    kneesbent, 20kg load,

    bendingback, armsunder

    the shoulder

    2313Sitting, >20kg load,

    bendingback,

    both the arms

    over the shoulder

  • OWAS method: the index risk

    ( ) ( ) ( ) ( )[ ] 1004321 +++= dcbaIa, b, c, d : frequency rates into classes 1, 2, 3 e 4.

    Index risk (I)

    Risk class Frequency

    I = 100, minimum risk

    I = 400, maximum risk

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • Forestry yards location: Buthier (Gran S. Bernard) Ozein (Cogne)1500 meters over the sea level, in a very sloped area (>30), slippery and uneven ground

    Analized works cut of the tree; manual tree extraction; skidding and stacking of the logs.

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

    5 operators considered (age:30-50)

  • Cut phase: 1 operator

    Used tools: 6 kg chainsaw, hoe and 1,5 kg peavey

    Position: the operator is standing or with the knees bent, bending and twisting back, the arms always under the shoulder

    Risks: noise, vibration and muscularwork, exhaust gas, position and chainsaw potential danger

    Cut mark realization: 4131posture, class 2

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • Manual tree extraction: 4 operators

    Manual extraction: 4173 posture, class 4

    Used tools: 2 kg short-handled timber hoe to movelogs (3-7m long and 10-30cm diameter)

    Position: the operators workswith the bending or twistingback, standing with the weighton one leg or knee bent, the arms under the shoulder and moved weight > 20 kg

    Risks: awkward postures, thermaldiscomfort, heavy muscular work

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • Skidding and log stacking: 4 operators. Phase 1

    Used tools: hoe, tractor and pulley with chains

    Position: 2 operators works withthe bending back, standing withthe weight on one leg or kneebent, the arms under the shoulder

    Risks for the tractor driver: noise and vibration

    Risk for the operators: awkward postures, thermal discomfort, noise

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • Skidding and log stacking: 4 operators+tractor driver

    Stacking: 2143 posture, class 3

    Used tools: none. 2-3 operatorsstack the logs manually

    Position: bending back at the first time, then standing, knees bendingat the beginning, arms under the shoulder.

    Risks: heavy manual work load, thermal discomfort,

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

    Skidding and log stacking: 4 operators. Phase II

  • Data collection and elaboration

    32123P3G2B1S220,26340,527429

    32143P3G4B1S251,874103,748828

    32143P3G4B1S220,26340,527527

    32143P3G4B1S241,56383,127726

    32143P3G4B1S241,56383,127825

    44143P3G4B1S477,931155,862924

    32142P2G4B1S212,82925,659423

    32143P3G4B1S221,38242,76564

    32141P1G4B1S26,75413,50963

    32143P3G4B1S220,26340,52792

    32143P3G4B1S225,65951,31861

    RiskClass

    Owascode

    Weight

    codeLegsArmsBack

    Movedweight

    (kg)

    Log weight

    (kg)Time (s)Sample

    For each phase and for each operator, all the postures and the movedweight have been evaluated

    825 risk classes values have been calculated

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • THE WINOWAS Software

    The WINOWAS software haas beenused for the data analysis (frequencyrates and risk classes evaluation)

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • Results

    Considering the index risk between 100 and 400 and 4 riskclasses from 1 to 4:

    Cut phase: IR = 287 (frequency rate in class 3+4: 50%)

    Manual extraction: IR = 311 (frequency rate in class 3+4: 77%)

    Skidding+manual log stacking: IR = 300 (frequency in class 3+4: 91%)

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

  • Results: manual extraction

    Evaluation of work-related musculoskeletal disorder risk of forestry workers: a case study using OWAS

    0

    10

    20

    30

    40

    50

    60

    Operator 1 Operator 2 Operator 3 Operator 4

    frequ

    ency

    rate

    (%)

    Class 1Class 2Class 3Class 4

    Class1: 1%. Class2: 22%. Class3: 42%. Class4: 35%

  • CONCLUSIONSAll the operations in both the yards are characterized by anhigh index risk value

    The more critical operation is the manual extraction, with the highest frequency rate in class 4: therefore, the unfavourable environment conditions do not permit the use of machineries

    Index risk values

    287

    311

    300

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