Module 3-3 V1.2-2011 1 of 21

Mechanical vibration Overview

Terminology

Classification according to effect

Classification according to vibration type

Characteristics

Effect of vibration

Damage caused by vibrationLimit values

Technical solutions for protection against vibration

Module 3-3 V1.2-2011 2 of 21

Terminology

Mechanical vibration is caused (emitted) above all during the use of mechanical tools and vehicles. Vibration is frequently coupled with noise . This is due to vibration and noise frequently sharing the same physical causes, such as unbalanced mass forces, shocks, and the interaction between workpiece and tool.

Module 3-3 V1.2-2011 3 of 21

Classification according to effect

Whole-body vibration Hand-arm vibration

Stationary machines Presses Motors/

generators Turbines Installations

Transport machinery Earthmoving machinery Trains Ships Aircraft

Hand-operated machines Percussive drilling machines Chainsaws Sickle-bar mowers Pneumatic drills

Emissions caused by

lead to exposure

Module 3-3 V1.2-2011 4 of 21

Classification according to vibration type

Periodic vibratione.g. motors, generators, presses

Stochastic vibratione.g. vehicles

Module 3-3 V1.2-2011 5 of 21

Examples of vibration emissions

Examples of machines that emit mechanical vibration

Spiral conveyor(the emitted vibration acts upon the entire body)

Rotary hammer (causes hand-arm vibration)

Module 3-3 V1.2-2011 6 of 21

Characteristics

Variables influencing the vibrational acceleration

Frequency-weighted acceleration (whole-body vibration)Vibration total value (hand-arm vibration)

Frequency of the vibration

Acceleration amplitude(intensity) of the vibration

Vibration type(whole-body vibration, hand-arm vibration)

Direction of vibration(in accordance with the system of co-ordinates in relation to the body)

Module 3-3 V1.2-2011 7 of 21

System of co-ordinates for vibration

Physiological system of co-ordinates for vibration(in accordance with VDI Guideline 2057)

Handle position

Flat rest for palm of hand

Module 3-3 V1.2-2011 8 of 21

Impact upon the human being

The impact of vibration is dependent upon its amplitude and frequency.

Low-frequency vibration in particular has a harmful effect upon human organ systems, since their resonant frequencies lie within this range.

Vibration of high amplitude and low frequency causes damage above all to the locomotor apparatus.

Vibration at high frequencies (for example on hand-operated machines)may lead to circulatory disturbances in the fingers.

In addition, vibration impairs reaction and dexterity, and can therefore lead to an increased accident hazard.

Module 3-3 V1.2-2011 9 of 21

Resonant frequencies of the human body

Part of the body Posture Frequency range (Hz)

Whole body Lying 1-2

Spine Sitting 3-6

Stomach Sitting 4-7

Stomach Lying 4-8

Thorax Sitting 4-6

Thorax Lying 6-12

Hand-arm system Forearm horizontal 8-20

Eyeball Head upright 20-25

Cranial bone Lying 50-70

Module 3-3 V1.2-2011 10 of 21

Reaction to strong vibration

Source: Schnauber, H.; Herterich, J.: Auswirkung mechanischer Schwingungen auf den Menschen: Haufe Verlag 1989

Dyspnea (shortness of breath)Difficulty breathingForced expirationPain in the thoraxVoluntary muscle contractionJaw resonancePain in the lower abdomenMuscle tensionBackacheHeadacheThroat complaintsInfluence upon speechRectal irritationBladder irritationGeneral feeling of unease

Moderate complaints

Serious complaints

Module 3-3 V1.2-2011 11 of 21

Vascular disordersDisorders caused by temporary circulatory disturbances during exposure to hand-harm vibration, e.g. formally recognized occupational disease (BK) 2104, vibration white finger

Neurological disordersTingling and numbness in the fingers, caused for example by crushing of nerves as in carpal tunnel syndrome

Disorders of the skeletal systemDegenerative changes in bones and joints of the hand-arm system caused by shocks, e.g. formally recognized occupational disease (BK) 2103

Muscular disordersMuscular asthenia, pain in the hands and arms caused by mechanical injury or damage to nerves

To EN ISO 5349-1:2001

Damage

Module 3-3 V1.2-2011 12 of 21

Raynaud's syndrome = "vibration white finger"

Example of vibration white finger

Module 3-3 V1.2-2011 13 of 21

Limit values

German Ordinance on noise and vibration protection

Action values HAV WBV

2.5 m/s0.5 m/s

Exposure limits HAV WBV 5.0 m/s

z-axis 0.8 m/s x-y-axis 1.15 m/s

Take immediate measures and prevent the values from being exceeded

Organize regular occupational medical examinations

Inform workers and provide instruction on the hazards

Draw up and implement a vibration abatement programme

Offer occupational medical examinations to the workers

Module 3-3 V1.2-2011 14 of 21

Rotating instead of oscillating machine components Belt drives instead of chain drives Drilling instead of punching or hammer forging Casting instead of forging Pressing instead of impact forming Electric drive instead of internal combustion engine Optimum speeds Avoid unbalances in rotating machine parts Additional masses for reduction of the normal frequencies Achieve low production tolerances

Technical solutions for protection against vibratio n

Module 3-3 V1.2-2011 15 of 21

Example of a technical solution for protection agai nst vibration

Excitation system(forging hammer)

Object to be protected(PC workplace)

Insulation close to the source Insulation remote from the source

Principle of insulation close to the source

Insulation of the vibration exciter

Principle of insulation remote from the source

Screening of the workplace to be protected

Module 3-3 V1.2-2011 16 of 21

Example of a technical solution for protection agai nst vibration

Impact screwdriver

Technical solutionInvolving special vibration-damping design of the handle and support against the reaction moment

Source: ITH GmbH, www.ith.de

Module 3-3 V1.2-2011 17 of 21

Examples: Institute for Occupational Safety and Hea lth of the DGUV

Fork-lift truck

Hand-operated machines

Module 3-3 V1.2-2011 18 of 21

Important literature for Module 3-3

German Ordinance on noise and vibration protection, 2007 EU Vibration Directive 2002/44/EC , 25 June 2002 NALS: Acoustics, Noise Control and Vibration Engine ering Standards

Committee in DIN and VDI, www.nals.din.de www.nora.kan.de (OSH standards search) VDI 2057:2002, Part 1: Human exposure to mechanical vibrations

Whole-body vibration VDI 2057:2006, Part 2: Hand-arm vibration VDI 2057:2006, Part 3: Whole-body vibration at workplaces in buildings VDI 3831:2006 Protective measures against vibration effects on man EN ISO 8041:2008 Human response to vibration Measuring instrumentation EN ISO 5349-1:2001 Mechanical vibration Measurement and evaluation of

human exposure to hand-transmitted vibration Part 1: General requirements EN ISO 5349-2:2001 Practical guidance for measurement at the workplace EN ISO 14253:2008 Mechanical vibration Measurement and calculation of

occupational exposure to whole-body vibration with reference to health

Module 3-3 V1.2-2011 19 of 21

Important literature for Module 3-3

BGIA Report 6/2006 Vibrationseinwirkung an Arbeitspltzen Kennwerte der Hand-Arm und Ganzkrper-Schwingungsbelastung: Sankt Augustin, Hauptverband der Berufsgenossenschaften 2006

CEN Report CR 12349 Mechanical vibration Guide to the health effects of vibration upon the human body: Berlin, Beuth 1996

Dresig, H. : Schwingungen und mechanische Antriebssysteme: Berlin Heidelberg, Springer Verlag 2006

Dupuis, H.; Hartung, E:; Schfer, N .: Schwingungsminderung am Arbeitsplatz (research report No 305): Dortmund. Bundesanstalt fr Arbeitsschutz und Unfallforschung 1982

Kaulbars, U .: Messung, Bewertung und Beurteilung der Hand-Arm-Vibrationsbelastung an Arbeitspltzen. In: BGIA-Handbuch Sicherheit und Gesundheit am Arbeitsplatz. 48. Published by: Berufsgenossenschaftliches Institut fr Arbeitsschutz BGIA, Sankt Augustin. Berlin: Erich Schmidt loose-leaf. 2nd edition, 2003 www.bgia-handbuchdigital.de/210520

Module 3-3 V1.2-2011 20 of 21

Important literature for Module 3-3

Riedel, S.; Kinne, J. : Prfung von Schwingungsisolierten Fahrzeugsitzen mit mechanischen Mensch-Modellen - Laborversuche: Dortmund, GfA-Press 2002

Schnauber, H.; Herterich, J .: Auswirkung mechanischer Schwingungen auf den Menschen: Haufe Verlag 1989

Module 3-3 V1.2-2011 21 of 21

Important literature for Module 3-3

http://www.dguv.de/bgia/de/pra/softwa/kennwertrechner/index.jsp

http://bb.osha.de/de/gfx/good_practice/gefaehrdungskategorien.php

Whole-body vibration calculator etc.European Agency for Safety and Health at Work

Hand-arm vibration calculator