ISO 5349-1:2001

INTERNATIONAL ISO
STANDARD 5349-1
First edition
2001-05-01
Mechanical vibration — Measurement
and evaluation of human exposure
to hand-transmitted vibration —
Part 1:
General requirements
Vibrations mécaniques — Mesurage et évaluation de l'exposition des
individus aux vibrations transmises par la main —
Partie 1: Exigences générales
Reference number
©
ISO 2001
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ii © ISO 2001 – All rights reserved

Contents Page
Foreword.iv
Introduction.vi
1 Scope .1
2 Normative references .1
3 Terms, definitions and symbols.2
3.1 Terms and definitions .2
3.2 Symbols .2
4 Characterization of hand-transmitted vibration .2
4.1 General considerations.2
4.2 Measuring equipment for hand-transmitted vibration.3
4.3 Coupling of the hand to the vibration source.5
4.4 Quantity to be measured.5
4.5 Multi-axis vibration .5
5 Characterization of hand-transmitted vibration exposure .6
5.1 General.6
5.2 Daily exposure duration.6
5.3 Daily vibration exposure .6
6 Information to be reported.7
Annex A (normative) Frequency-weighting and band-limiting filters.8
Annex B (informative) Guidance on health effects of hand-transmitted vibration.11
Annex C (informative) Relationship between vibration exposure and effects on health .15
Annex D (informative) Factors likely to influence the effects of human exposure to hand-transmitted
vibration in working conditions .18
Annex E (informative) Preventive measures to be adopted by those responsible for occupational
health and safety.19
Annex F (informative) Guidelines for reporting additional information .21
Bibliography.24
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this part of ISO 5349 may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 5349-1 was prepared by Technical Committee ISO/TC 108, Mechanical vibration and
shock, Subcommittee SC 4, Human exposure to mechanical vibration and shock.
This first edition of ISO 5349-1 cancels and replaces ISO 5349:1986, of which it constitutes a technical revision. It
is, in most respects, compatible with its predecessor, but differs from it technically in several important respects.
In the previous version, the evaluation of vibration exposure was based on the directional component with the
greatest frequency-weighted root-mean-square acceleration. In the present version, the evaluation is based on the
“vibration total value”, i.e. the root-sum-of-squares of the three frequency-weighted root-mean-square component
values. This change recognizes the fact that the vibration characteristics of some power tool types are not
dominated by a single directional component.
Vibration exposures based on the root-sum-of-squares method will have values greater than those reported for a
single direction of vibration. Measurement of vibration in three axes will result in a vibration total value of up to
1,7 times (typically between 1,2 and 1,5 times) the magnitude of the greatest component. For data obtained in
accordance with ISO 5349:1986, the vibration total value can be calculated from the three component values as
shown in 4.5 of this part of ISO 5349. Where only the greatest single-axis value is available, the vibration total
value shall be estimated from this value using a suitable multiplying factor as discussed in 4.5.
The daily vibration exposure in accordance with this part of ISO 5349 is based on the 8-h energy-equivalent
acceleration value. The previous version used a reference duration of 4 h. The change to the more conventional
8-h reference duration brings the evaluation of vibration exposure into line with the “time-weighted average”
procedures commonly used for the evaluation of human exposures to noise and to chemical substances. The use
of the 8-h reference duration is purely a matter of convention and does not imply that a “typical” daily exposure
duration is 8 h. Conversion of 4-h equivalent magnitudes to 8-h values is achieved easily, by applying a multiplying
factor of 0,7.
The frequency weighting previously had a slope of zero at frequencies below 16 Hz and –6 dB per octave at higher
frequencies and applied over the frequency range covered by the octave bands from 8 Hz to 1 000 Hz. It is now
defined mathematically in annex A as a realizable filter characteristic, designated W . Band-limiting filters are also
h
defined with cut-off frequencies of 6,3 Hz and 1 250 Hz. The one-third-octave band weighting factors, also given in
annex A, differ slightly from those in the previous version in that they describe the W curve with band-limiting
h
included.
iv © ISO 2001 – All rights reserved

The guidance in annex C on the relationship between vibration exposure and the development of vascular
symptoms, is broadly compatible with that in annex A of the previous version, but is restricted to consideration of a
prevalence of 10 % in order to limit the potential for inappropriate use of the relationship. Compared to the previous
version, daily vibration exposures are now expressed as 8-h energy-equivalent values and the values quoted have
been multiplied by a factor of 1,4 to estimate the increase resulting from the change from evaluation using the
greatest single-axis value to evaluation using the vibration total value.
International Standard ISO 5349 consists of the following parts, under the general title Mechanical vibration —
Measurement and evaluation of human exposure to hand-transmitted vibration:
Part 1: General requirements
Part 2: Practical guidance for measurement at the workplace
Annex A forms a normative part of this part of ISO 5349. Annexes B to F are for information only.
Introduction
Intensive vibration can be transmitted to the hands and arms of operators from vibrating tools, vibrating machinery
or vibrating workpieces. Such situations occur, for example, when a person handles tools such as pneumatic,
electric, hydraulic or internal combustion engine-driven chain saws, percussive tools or grinders.
Depending on the type and place of work, vibration can enter one arm only, or both arms simultaneously, and may
be transmitted through the hand and arm to the shoulder. The vibration of body parts and the perceived vibration
are frequently a source of discomfort and possibly reduced proficiency. Continued, habitual use of many vibrating
power tools has been found to be connected with various patterns of diseases affecting the blood vessels, nerves,
bones, joints, muscles or connective tissues of the hand and forearm.
The vibration exposures required to cause these disorders are not known precisely, neither with respect to vibration
magnitude and frequency spectrum, nor with respect to daily and cumulative exposure duration. The guidance
given in this part of ISO 5349 is derived from limited quantitative data available from both practical experience and
laboratory experimentation concerning human response to hand-transmitted vibration, and on limited information
regarding current exposure conditions. It is thus difficult to propose a comprehensive method for the evaluation of
vibration exposure. However, the use of the information given in this part of ISO 5349 should protect the majority of
workers against serious health impairment associated with hand-transmitted vibration. It may also assist in the
development of new hand-operated power tools to reduce the risk of vibration-related health effects. It does not
define safe exposure ranges in which vibration diseases cannot occur.
The use of this part of ISO 5349 will contribute to the gathering of consistent data in order to improve occupational
safety. In particular, it is hoped that such data will serve to extend the present knowledge of dose-effect
relationships.
This part of ISO 5349 specifies the general requirements for the measurement and evaluation of human exposure
to hand-transmitted vibration. It is supplemented by the information given in ISO 5349-2, which gives practical
guidance for the implementation of appropriate measurement and evaluation techniques at the workplace.
Instrumentation to be used for measurements made in accordance with ISO 5349 is fully specified in ISO 8041.
Annex A contains definitions for the frequency weighting W and for band-limiting filters, required for measurement
h
of frequency-weighted acceleration in accordance with ISO 5349.
Annex B contains information on the health effects of hand-transmitted vibration, while annex C gives guidance
which may assist competent authorities responsible for the definition of exposure limits or action levels as required.
Annex D contains information on other factors which can affect human response to hand-transmitted vibration and
annex E contains guidance on preventive measures for those responsible for occupational health and safety.
To facilitate further progress in this field and to allow the quantitative comparison of exposure data, uniform
methods for measuring and reporting exposure of human beings to hand-transmitted vibration are desirable.
Further information is contained in annex F.
vi © ISO 2001 – All rights reserved

INTERNATIONAL STANDARD ISO 5349-1:2001(E)
Mechanical vibration — Measurement and evaluation of human
exposure to hand-transmitted vibration —
Part 1:
General requirements
1 Scope
This part of ISO 5349 specifies general requirements for measuring and reporting hand-transmitted vibration
exposure in three orthogonal axes. It defines a frequency weighting and band-limiting filters to allow uniform
comparison of measurements. The values obtained can be used to predict adverse effects of hand-transmitted
vibration over the frequency range covered by the octave bands from 8 Hz to 1 000 Hz.
This part of ISO 5349 is applicable to periodic and to random or non-periodic vibration. Provisionally, this part of
ISO 5349 is also applicable to repeated shock type excitation (impact).
NOTE 1 The time dependency for human response to repeated shocks is not fully known. Application of this part of
ISO 5349 for such vibration is to be made with caution.
This part of ISO 5349 provides guidance for the evaluation of hand-transmitted vibration exposure, specified in
terms of a frequency-weighted vibration acceleration and daily exposure time. It does not define limits of safe
vibration exposure.
NOTE 2 Annex C is concerned with the approximate relative importance of various characteristics of the vibration exposure
which are believed to produce health effects.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 5349. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 5349 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 2041, Vibration and shock — Vocabulary.
ISO 5349-2, Mechanical vibration — Measurement and evaluation of human exposure to hand-transmitted
vibration — Part 2: Practical guidance for measurement at the workplace.
ISO 8041,Humanresponsetovibration — Measuring instrumentation.
IEC 61260, Electroacoustics — Octave-band and fractional-octave-band filters.
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this part of ISO 5349, the terms and definitions given in ISO 2041 apply.
NOTE For the convenience of users of this part of ISO 5349, a glossary of terms relating to medical conditions is given in
annex B.
3.2 Symbols
In this part of ISO 5349, the following symbols are used.
a (t) instantaneous single-axis acceleration value of the frequency-weighted hand-transmitted vibration
hw
at time t, in metres per second squared (m/s );
a root-mean-square (r.m.s.) single-axis acceleration value of the frequency-weighted hand-
hw
transmitted vibration, in metres per second squared (m/s );
a , a , a values of a , in metres per second squared (m/s ), for the axes denoted x, y and z respectively;
hwx hwy hwz hw
a vibration total value of frequency-weighted r.m.s. acceleration (sometimes known as the vector
hv
sum or the frequency-weighted acceleration sum); it is the root-sum-of-squares of the a values
hw
for the three measured axes of vibration, in metres per second squared (m/s );
a daily vibration exposure (8-h energy-equivalent vibration total value), in metres per second
hv(eq,8h)
squared (m/s );
A(8) a convenient alternative term for the daily vibration exposure a ;
hv(eq,8h)
D group mean total (lifetime) exposure duration, in years;
y
T total daily duration of exposure to the vibration a ;
hv
T reference duration of 8 h (28 800 s);
W frequency-weighting characteristic for hand-transmitted vibration.
h
4 Characterization of hand-transmitted vibration
4.1 General considerations
The method specified in this part of ISO 5349 takes account of the following factors which are known to influence
the effects of human exposure to hand-transmitted vibration in working conditions:
a) the frequency spectrum of vibration;
b) the magnitude of vibration;
c) the duration of exposure per working day;
d) the cumulative exposure to date.
Other factors which may influence the effects of vibration exposure, but for which standardized methods for
reporting do not yet exist, are listed in annex D.
2 © ISO 2001 – All rights reserved

4.2 Measuring equipment for hand-transmitted vibration
4.2.1 General
Measurement of hand-transmitted vibration shall be undertaken using instrumentation conforming to the
requirements of ISO 8041. This equipment shall be checked for correct operation before and after use. The
calibration shall be traceable to a recognized standard maintained by an accredited laboratory.
4.2.2 Vibration transducers
The vibration transducer may be an accelerometer which may be designed to make general vibration
measurements (for non-percussive tools) or may be specifically designed for large peak accelerations such as
those produced by percussive tools.
The vibration transducers shall be able to withstand the range of vibration magnitudes and shall have stable
characteristics. The dimensions of the transducers shall be such that they do not interfere with the operation of the
machine and such that the location of the point of measurement can be identified.
ISO 5349-2 contains further guidance on the selection of transducers.
4.2.3 Location and orientation of transducers
The vibration transmitted to the hand shall be measured and reported for three directions of an orthogonal
coordinate system such as defined in Figure 1.
For practical vibration measurements, the orientation of the coordinate system may be defined with reference to an
appropriate basicentric coordinate system (see Figure 1) originating, for example, in a vibrating appliance,
workpiece, handle or control device gripped by the hand (see ISO 8727 for further information).
The vibration in the three directions should preferably be measured simultaneously. Measurements made
sequentially along each of the three axes are acceptable, provided the operating conditions are similar for all three
measurements. The measurements shall be made on the vibrating surface as close as possible to the centre of the
gripping zone of the machine, tool or workpiece. The location of the transducers shall be reported.
NOTE The vibration magnitude can vary considerably with position on the vibrating surface.
Further guidance on transducer positioning is given in ISO 5349-2.
4.2.4 Mounting of transducers
The transducers should be mounted rigidly. Further information on accelerometer mounting is given in ISO 5348
and ISO 5349-2. Practical guidance on mounting transducers in difficult situations (such as on resilient surfaces or
where the vibration is impulsive), and on the use of hand-held adaptors, is also given in ISO 5349-2.
a) “Handgrip” position (In this position, the hand adopts a standardized grip on a cylindrical bar)
Key
����� Biodynamic coordinate system
--------------- Basicentric coordinate system
b) “Flat palm” position (In this position, the hand presses down onto a sphere)
NOTE The origin of the biodynamic coordinate system is the head of the third metacarpal (distal extremity). The z -axis
h
(i.e. hand axis) is defined as the longitudinal axis of the third metacarpal bone and is oriented positively towards the distal end of
the finger. The x -axis passes through the origin, is perpendicular to the z -axis, and is positive in the forwards direction when
h h
the hand is in the normal anatomical position (palm facing forwards). The y -axis is perpendicular to the other two axes and is
h
positive in the direction towards the fifth finger (thumb). In practice, the basicentric coordinate system is used: the system is
generally rotated in the y-z plane so that the y -axis is parallel to the handle axis.
h
Figure 1 — Coordinate systems for the hand
4 © ISO 2001 – All rights reserved

4.3 Coupling of the hand to the vibration source
Although characterization of the vibration exposure currently uses the acceleration of the surface in contact with the
hand as the primary quantity, it is reasonable to assume that the biological effects depend to a large extent on the
coupling of the hand to the vibration source. It should also be noted that the coupling can affect considerably the
vibration magnitudes measured.
The vibration measurements shall be made with forces which are representative of the coupling of the hand to the
vibrating power tool, handle or workpiece in typical operation of the tool or process.
1)
Forces between the hand and gripping zone should be measured and reported. It is also recommended that a
description of the operator's posture be reported for individual conditions and/or operating procedures (see
annexes D and F).
4.4 Quantity to be measured
The primary quantity used to describe the magnitude of the vibration shall be the root-mean-square (r.m.s.)
frequency-weighted acceleration expressed in metres per second squared (m/s ).
The measurement of frequency-weighted acceleration requires the application of a frequency weighting and band-
limiting filters. The frequency weighting W reflects the assumed importance of different frequencies in causing
h
injury to the hand. The characteristics of the W frequency weighting and methods for band-limiting are given in
h
annex A.
The r.m.s. value shall be measured using a linear integration method. The integration time shall be chosen such
that a representative sample of the vibration signal is used (see ISO 5349-2).
For additional purposes (research, prevention, technical reduction of vibration) it is strongly recommended that
frequency spectra be obtained (see annex F for further information).
4.5 Multi-axis vibration
It is known that on most power tools the vibration entering the hand contains contributions from all three
measurement directions. It is assumed that vibration in each of the three directions is equally detrimental.
Measurements should therefore be made for all three directions. The frequency-weighted r.m.s. acceleration
values for the x-, y- and z-axes, a , a and a , shall be reported separately (see annex F).
hwx hwy hwz
The evaluation of vibration exposure (see clause 5), however, is based on a quantity that combines all three axes.
This is the vibration total value, a , and is defined as the root-sum-of-squares of the three component values:
hv
22 2
aa� ++a a (1)
hv hwxyzhw hw
In some cases it may not be possible to make vibration measurements in three axes. If measurements are made
only in one or two axes, the axis of greatest vibration shall be included (where this can be identified). The vibration
total value shall be estimated using the measured values available and a carefully considered multiplying factor.
The vibration magnitude in the axis of greatest vibration requires a multiplying factor in the range 1,0 to 1,7 to give
the vibration total value (for further advice, see ISO 5349-2). Where a multiplying factor is used to estimate the
vibration total value, the multiplying factor and a justification for the choice of value shall be reported, together with
the component value(s) measured.
1) An International Standard on the measurement of gripping and pushing forces is in course of preparation.
5 Characterization of hand-transmitted vibration exposure
5.1 General
Vibration exposure is dependent on the magnitude of the vibration and on the duration of the exposure. In order to
apply the guidance on health effects given in annex C, the vibration magnitude is represented by the vibration total
value a .
hv
5.2 Daily exposure duration
Daily exposure duration is the total time for which the hand(s) is(are) exposed to vibration during the working day.
The vibration exposure time may be shorter than the time for which the person is working with the power tools or
workpieces. It is important to base estimates of total daily exposure duration on appropriate representative samples
for the various operating conditions and durations and their intermittency (see ISO 5349-2 for further guidance).
5.3 Daily vibration exposure
Daily vibration exposure is derived from the magnitude of the vibration (vibration total value) and the daily exposure
duration.
In order to facilitate comparisons between daily exposures of different durations, the daily vibration exposure shall
be expressed in terms of the 8-h energy-equivalent frequency-weighted vibration total value, a ,as shown in
hv(eq,8h)
equation (2). For convenience, a is denoted A(8):
hv(eq,8h)
T
Aa()8 � (2)
hv
T
where
T is the total daily duration of exposure to the vibration a ;
hv
T is the reference duration of 8 h (28 800 s).
If the work is such that the total daily vibration exposure consists of several operations with different vibration
magnitudes, then the daily vibration exposure, A(8), shall be obtained using equation (3):
n
A()8=aT (3)
� hvii
T
i=1
where
a is the vibration total value for the i th operation;
hvi
n is the number of individual vibration exposures;
T is the duration of the i th operation.
i
The individual contributions to A(8) shall be reported separately.
EXAMPLE If the vibration total values for exposure times of 1 h, 3 h and 0,5 h (within the same working day) are 2 m/s ,
2 2
3,5 m/s and 10 m/s respectively, then:
22 2
1��
22 2 2
A(8)= 2m/s��1h+ 3,5 m/s 3 h+ 10m/s� 0,5h =3,4m/s
�� � � � �
��
8h
��
6 © ISO 2001 – All rights reserved

NOTE The result of the calculation in the above example is quoted to two significant figures. This does not imply an
equivalent accuracy of measurement but arises from the computation. In normal measuring situations it would require great care
to obtain an accuracy better than 10 % in the value of A(8).
It is recommended that, where criteria for acceptable vibration exposures are to be defined, these should be
specified as A(8) values.
6 Information to be reported
When an evaluation of exposure to hand-transmitted vibration is carried out in accordance with this part of
ISO 5349, the following information shall be reported:
� the subject of the exposure evaluation;
� the operations causing exposures to vibration;
� the power tools, inserted tools and/or workpieces involved;
� the location and orientation of the transducers;
� the individual root-mean-square, single-axis frequency-weighted accelerations measured;
� the vibration total value for each operation;
� the total daily duration for each operation;
� the daily vibration exposure.
Where measurements have not been made in all three axes, the multiplying factor used to estimate the vibration
total value, and the justification for its selection, shall also be reported.
NOTE In ISO 5349-2, a more exhaustive list of recommended information to be reported is given (see also annexes D
and F).
Annex A
(normative)
Frequency-weighting and band-limiting filters
A.1 Frequency-weighting and band-limiting filter characteristics
The measurement of a requires the application of frequency-weighting and band-limiting filters. The frequency
hw
weighting W reflects the assumed importance of different frequencies in causing injury to the hand. The range of
h
application of the measured values to the prediction of vibration injury (see annex C) is restricted to the working
frequency range covered by the octave bands from 8 Hz to 1 000 Hz (i.e. a nominal frequency range from 5,6 Hz to
1 400 Hz). Band-limiting high-pass and low-pass filters restrict the effect on the measured value of vibration
frequencies outside this range where the frequency dependence is not yet agreed.
NOTE The frequency dependencies of responses to vibration are unlikely to be the same in all axes. However, it is not yet
thought appropriate to recommend different frequency weightings for different axes.
The frequency-weighting and band-limiting filters may be realized by analog or digital methods. They are defined in
Table A.1 in a mathematical form familiar to filter designers and the curve is shown graphically in Figure A.1 in a
schematic way. Further details and tolerances for filter characteristics are given in ISO 8041.
Table A.1 — Characteristics of band-limiting and weighting filters for the frequency weighting W
h
a a
Band limiting Frequency weighting
f f Q f f Q K
1 2 1 3 4 2
6,310 1258,9 0,71 15,915 15,915 0,64 1
The band-limiting filter is defined by the transfer function of the filter, H (s):
b
22 2
sf4�
Hs()�
b
222 2
(/sf�24�sQ��f)(s �2�fs/Q��4f)
11 1 2 1 2
where s=j2�f is the variable of the Laplace transform.
The band-limiting filter can be realized by a two-pole filter.
The frequency-weighting filter is defined by the transfer function of the filter, H (s):
w
()sf��22�Kf
Hs()�
w
22 2
(/sf��24sQ � �f)f
42 4 3
where s=j2�f is the variable of the Laplace transform.
The frequency-weighting filter can be realized by a two-pole filter.
The total frequency-weighting function is H(s)= H (s) � H (s).
b w
a
Values of f designate resonance frequencies (n=1to4); Q designate selectivity (n = 1 or 2); K is a constant gain.
n n
8 © ISO 2001 – All rights reserved

Figure A.1 — Frequency-weighting curve W for hand-transmitted vibration, band-limiting included
h
(schematic)
A.2 Conversion of one-third-octave band data to frequency-weighted acceleration
As an alternative to the use of the W filter, the r.m.s. acceleration values from one-third-octave band analysis can
h
be used to obtain the corresponding frequency-weighted acceleration.
The r.m.s. frequency-weighted acceleration a canbecalculatedas follows:
hw
= ( ) (A.1)
aWa
hw � hiih
i
where
W is the weighting factor for the i th one-third-octave band as shown in Table A.2;
hi
a is the r.m.s. acceleration measured in the i th one-third-octave band, in metres per second squared
hi
(m/s ).
The one-third-octave band frequencies from 6,3 Hz to 1 250 Hz constitute the primary frequency range and the
calculation of a using equation (A.1) shall include all one-third-octave bands within this range. Frequencies
hw
outside this primary range (i.e. those shown in the grey areas of Table A.2) do not generally make an important
contribution to the value of a and may be excluded from the calculation, provided it is known that there is no
hw
significant vibration energy at the high and low ends of the frequency range.
If the frequency-weighted acceleration value is influenced by significant components at the high and low ends of
the frequency range, the guidance in annex C for the prediction of finger blanching from vibration exposure data
should be treated with caution.
NOTE If the spectrum contains dominant single-frequency components, the procedure outlined above may cause
differences between the computed and directly measured values of the frequency-weighted acceleration. Discrepancies occur if
these components are at frequencies which differ from the centre frequency of a one-third-octave band. For this reason, the use
of the weighting filter W or calculations based on narrower band measurements are preferred. When, in the latter case, for a
h
certain frequency f or a narrow frequency band with the mid-frequency f the unweighted vibration acceleration a(f) is given, the
corresponding weighted acceleration a (f)iscalculatedtobe a (f)= a(f) �H(j2�f)�.
h h
a
Table A.2 — Frequency weighting factors W for hand-transmitted vibration with band limiting for
hi
conversion of one-third-octave band magnitudes to frequency-weighted magnitudes
b
Nominal mid frequency Weighting factor
Frequency band number
Hz W
i
hi
6 4 0,375
7 5 0,545
8 6,3 0,727
9 8 0,873
10 10 0,951
11 12,5 0,958
12 16 0,896
13 20 0,782
14 25 0,647
15 31,5 0,519
16 40 0,411
17 50 0,324
18 63 0,256
19 80 0,202
20 100 0,160
21 125 0,127
22 160 0,101
23 200 0,0799
24 250 0,0634
25 315 0,0503
26 400 0,0398
27 500 0,0314
28 630 0,0245
29 800 0,0186
30 1 000 0,0135
31 1 250 0,00894
32 1 600 0,00536
33 2 000 0,00295
a
For filter responses and tolerances, see ISO 8041.
b
Index i is the frequency band number in accordance with IEC 61260.
10 © ISO 2001 – All rights reserved

Annex B
(informative)
Guidance on health effects of hand-transmitted vibration
B.1 General
Powered processes and tools which expose operators’ hands to vibration are widespread in several industrial
activities. Occupational exposure to hand-transmitted vibration can arise from rotating and/or percussive hand-held
power tools used in the manufacturing industry, quarrying, mining and construction, forestry and agriculture, public
utilities and other work activities. Exposure to hand-transmitted vibration can also occur from vibrating workpieces
held in the hands of the operator, and from hand-held vibrating controls such as motorcycle handlebars or vehicle
steering wheels.
Excessive exposure to hand-transmitted vibration can induce disturbances in finger blood flow, and in neurological
and motor functions of the hand and arm. It has been estimated that 1,7 % to 3,6 % of the workers in the European
countries and the USA are exposed to potentially harmful hand-transmitted vibration. The term "hand-arm vibration
syndrome" (HAVS) is commonly used to refer to the complex of peripheral vascular, neurological and
musculoskeletal disorders associated with exposure to hand-transmitted vibration. Workers exposed to hand-
transmitted vibration may be affected with neurological and/or vascular disorders separately or simultaneously.
Vascular disorders and bone and joint abnormalities caused by hand-transmitted vibration are compensated
occupational diseases in several countries. These disorders are also included in an European list of recognized
occupational diseases.
B.2 Vascular disorders
Workers exposed to hand-transmitted vibration may complain of episodes of pale or white finger, usually triggered
by cold exposure. This disorder, due to temporary abolition of blood circulation to the fingers, is called Raynaud's
phenomenon (after Maurice Raynaud, a French physician who first described it in 1862). It is believed that vibration
can disturb the digital circulation making it more sensitive to the vasoconstrictive action of cold. To explain cold-
induced Raynaud's phenomenon in vibration-exposed workers, some investigators invoke an exaggerated central
vasoconstrictor reflex caused by prolonged exposure to harmful vibration, while others tend to emphasize the role
of vibration-induced local changes in the digital vessels. Various synonyms have been used to describe vibration-
induced vascular disorders: dead or white finger, Raynaud's phenomenon of occupational origin, traumatic
vasospastic disease, and, more recently, vibration-induced white finger (VWF). VWF is a prescribed occupational
disease in many countries.
Initially attacks of blanching involve the tips of one or more fingers but, with continued exposure to vibration, the
blanching can extend to the base of the fingers. Sometimes, an attack of blanching is followed by cyanosis, i.e. a
bluish discoloration of the affected fingers due to increased extraction of oxygen from the sluggish digital
circulation. In the recovery phase, commonly accelerated by warmth or local massage, redness, eventually
associated with tingling and/or pain, may appear in the affected fingers as a result of a reactive increase of blood
flow in the cutaneous vessels. The blanching attacks are more common in winter than in summer and last from a
few minutes to more than one hour. The duration varies with the intensity of the triggering stimuli and the severity
of the vasospasm, the attack usually ending when the whole body is warmed. If vibration exposure continues, the
blanching attacks become more frequent and may occur all year around. In the rare advanced cases, repeated and
severe finger blanching attacks can lead to trophic changes (ulceration or gangrene) in the skin of the fingertips.
During the attack the affected workers can experience a complete loss of touch sensation and manipulative
dexterity, which can interfere with work activity, thus increasing the risk for acute injuries due to accidents.
In occupational medicine, various staging systems for the classification of VWF have been developed. The
Stockholm Workshop Scale (1986) is an internationally recognized grading system for classifying cold-induced
Raynaud's phenomenon in the hand-arm vibration syndrome. This scale consists of four stages according to the
extent, frequency and severity of finger blanching attacks and is described in Table B.1. A scale based on scores
for the blanching of different phalanges has also been proposed (see reference [13]).
Several laboratory tests are used to diagnose white finger objectively. Most of these tests are based on cold
provocation and the measurement of finger skin temperature or digital blood flow and pressure before, during and
after cooling of the fingers and hands.
Epidemiological studies have demonstrated that the prevalence of VWF varies widely, from 0 % to 100 % of
individuals in a group of vibration-exposed workers. It appears that the probability and severity of white-finger
symptoms is influenced by several factors, such as the characteristics of vibration exposure (frequency, magnitude,
direction, impulsiveness, duration), the type of tool and work process, the environmental conditions (temperature,
air flow, humidity, noise), some biodynamic and ergonomic factors (grip force, feed force, arm posture), and various
individual characteristics (susceptibility, diseases and agents, e.g. nicotine and certain medicines, affecting the
peripheral circulation). Thus, there is a complex relationship between vibration exposure and the development of
white finger symptoms. Epidemiological studies suggest that the occurrence of VWF increases with increasing
duration of vibration exposure. There is some evidence that the cumulative exposure before the appearance of
finger blanching is approximately inversely proportional to the magnitude of the vibration exposure (i.e. if vibration
magnitudes are doubled, a halving of the years of exposure is required to produce the same effect).
Since the late 1970s a decrease in the incidence of VWF has been reported among active forestry workers in both
Europe and Japan after the introduction of anti-vibration chain saws and administrative measures curtailing the saw
usage time together with endeavours to reduce exposure to other harmful work environment factors (e.g. cold and
physical stress). Recovery from VWF has also been reported among retired forestry workers. Similar findings are
not yet available for other tool types.
Table B.1 — Stockholm Workshop Scale (1986)
Vascular component
Stage Grade Description
0 — No attacks
1 Mild Occasional attacks affecting only the tips of one or more fingers
V
Moderate Occasional attacks affecting distal and middle (rarely also proximal) phalanges
V
of one or more fingers
Severe Frequent attacks affecting all phalanges of most fingers
V
Very severe As in stage 3 with trophic changes in the fingertips
V
Sensorineural component
Stage Description
0 Exposed to vibration but no symptoms
SN
Intermittent numbness with or without tingling
SN
Intermittent or persistent numbness, reduced sensory perception
SN
Intermittent or persistent numbness, reduced tactile discrimination and/or manipulative
SN
dexterity
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B.3 Neurological disorders
Workers exposed to hand-transmitted vibration may experience tingling and numbness in their fingers and hands. If
vibration exposure continues, these symptoms tend to worsen and can interfere with work capacity and life
activities. Vibration-exposed workers may exhibit a reduction in the normal sense of touch and temperature as well
as an impairment of manual dexterity at the clinical examination. As an other effect of hand-transmitted vibration, a
reduction of the vibration sensitivity of the skin of the fingertips may also be found. Epidemiological surveys of
vibration-exposed workers show that the prevalence of peripheral neurological disorders varies from a few percent
to more than 80 % of individuals in a group of vibration-exposed workers, and that sensory loss affects users of a
wide range of tool types.
It seems that sensorineural disturbances may develop independently of other vibration-induced disorders, probably
reflecting different pathological mechanisms. A classification for the neurological component of the HAVS was
proposed at the Stockholm Workshop 1986, consisting of three stages according to the symptoms complained and
the results of clinical neurological examination and psychophysical testing methods such as tactile discrimination,
vibrotactile perception and precision manipulation (see Table B.1).
Vibration-exposed workers may sometimes show signs and symptoms of entrapment neuropathies, such as carpal
tunnel syndrome (CTS), a disorder due to compression of the median nerv
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