Transcript DPI uditivi / Tipologie

The implementation of the noise
directives in a Member State
Renata Sisto
Department of Occupational Hygiene
Monte Porzio Catone (Roma), ITALY
[email protected]
OSH Seminar, Bucharest, October 20-21, 2005
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SUMMARY
• Hearing loss as the first occupational disease in
Italy
• Early effects on hearing of noise exposure
• An evaluation of current law efficacy in risk
control
• Perspectives and outlooks
OSH Seminar, Bucharest, October 20-21, 2005
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Noise / Hearing Loss
Industry, services and agriculture - years 1999÷2004. (data from Italian National
Institute of Public Accident Insurance INAIL )
Notification
year
Hearing impairment in
listed occupational fields
Hearing impairment
in non listed occupational
fields
N.
R.
N.
1999
5843
2015
6640
12483
2000
5379
879
6374
11753
2001
4816
549
5943
10759
2002
3641
465
3698
7339
2003
2631
357
3663
6294
2004
2178
209
3725
5903
N: Notified on suspicion
R: recognized and refunded
R.
TOTAL Noise induced
Hearing impairment
OSH Seminar, Bucharest, October 20-21, 2005
N.
R.
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Noise / Hearing Loss
Occupational hearing impairment cases notified on suspicion to INAIL
(industry, services, agriculture)
Occupational Hearing
impairment
14000
12000
10000
8000
6000
4000
2000
0
1999
2000
2001
2002
2003
2004
Notification year
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Noise / Hearing Loss
Occupational hearing impairment cases recognized and refunded by INAIL
(industry and services)
Occupational hearing
impairment cases
recognized by INAIL
2500
2000
1500
1000
500
0
1999
2000
2001
2002
2003
2004
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Noise / Hearing loss
Noise induced hearing loss is at day the first
occupational disease
 Between 1999 and 2004 the Italian National Institute
of Public Accident Insurance (INAIL) recognized and
refunded in industry, and services occupational fields
about 4470 new cases of occupational noise induced
hearing loss.
 During the years 1999-2004 the percentage incidence
of noise induced hearing impairment results to be
near 50% of the total number of notified cases of
occupational disease
OSH Seminar, Bucharest, October 20-21, 2005
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Noise / Hearing loss
Occupational
noise-induced
hearing
impairment is still a major phenomenon, even
if its general evolution shows an important
and constant decrease, from 12483 cases
notified on suspicion in 1999 to 5903 cases
notified on suspicion in 2004, and from 2015
cases recognized and refunded in 1999 to
209 cases recognized and refunded in 2004.
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Aging-induced hearing loss
20 years
Hearing threshold dB
30 years
50 years
60 years
65 years
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Exposure
duration (years)
Hearing threshold dB
Noise-induced hearing loss
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The ISO 1999 (1990) standard
The ISO 1999 standard provides the algorithms to calculate the
NIPTS (Noise Induced Permanent Threshold Shift)
at different percentiles as a function of frequency, of personal
daily exposure level LEX, 8h and of exposure duration, in years.
The NIPTS which corresponds to the median of the distribution
(50° percentile) can be calculated with the use of the following
formula:
N0,50 = [u + v log(q/q0)](Lex, 8h – L0)2
where u, v and L0 are functions of frequency and q is the
duration in years of the exposure
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The ISO 1999 (1990) standard
NIPTS relative to fiftieth percentile at 4000 Hz
Permanent Threshold Shift (dB)
45
NIPTS Lexp 80
NIPTS Lexp 87
NIPTS Lexp 95,7
NIPTS Lexp 100
40
35
30
25
20
15
10
5
0
0
5
10
15
20
Exposure time (years)
25
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The ISO 1999: 1990 standard
It is the standard currently used to estimate the dose-effect relation
also by the Italian National Institute of Public Accident Insurance (INAIL)
The ISO standard gives the predicted hearing threshold H’,
expressed in decibel, as function of the age and of the
noise exposure:
H’ = H + N – (HN/120)
where:
H is the predicted hearing threshold, in decibel, as function of the
age (HTLA);
N is the noise induced permanent threshold shift (NIPTS)
The H and N values are given in different percentile ranges
OSH Seminar, Bucharest, October 20-21, 2005
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Cochlear gain and feedback
• The outer hair cells (OHCs) are the heart of an active
feedback mechanism that permits to obtain high sensitivity
to low amplitude signals and a good frequency
discrimination capability.
• The amplification gain associated with this system can be
estimated of order 40 dB.
• Noise induced damage initially affects OHCs, with a
reduction of this gain resulting in a corresponding increase
of the hearing threshold.
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Outer hair cells (OHCs) schematics
TM
IHC=mechanoelectrical
transduction
OHC=electromechanical
transduction
BM
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Noise exposure and early hearing
impairment
• Experimental data show that even in the cases in which
there has not been observed yet a hearing threshold increase
corresponding to the clinical definition of hearing impairment
(threshold higher than 20 dB at one or more audiometric
frequency), the hearing threshold undergoes a statistically
significant increase in the populations of subjects exposed to
noise.
• In the next figure a comparison is shown between the average
hearing threshold of non exposed (normal) and exposed
subjects. Even if for the exposed population there is not yet any
clinically defined hearing loss (for the MHL class,
10dB<HT≤20dB), the degradation of the threshold (with the
characteristic frequency dependence of noise induced hearing
loss) is already visible with respect to the non exposed
subjects of the same age.
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Comparison of average audiometric thresholds between a
population of young (mean age=30 years) exposed (MHL,
HL) and non exposed subjects (Normal)
0
Normal
non exposed
MHL
Hearing Loss (dB HTL)
-5
HL
-10
exposed
-15
exposed
-20
-25
-30
0
2000
4000 f (Hz) 6000
8000
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10000
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A new diagnostic technique based on otoacoustic emissions
can be used to detect the early effects of noise exposure
Comparison of TEOAE SNR between a population of young (mean age=30
years) exposed (MHL, HL) and non exposed subjects
TEOAE SNR in third of octave bands
20
HL
MHL
TEOAE SNR (dB)
15
exposed
not exposed
10
exposed
5
0
-5
0
1000
2000
3000
4000
5000
6000
f (Hz)
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Noise / State of the Art
Actual evaluation and control of risk from
occupational noise exposure
 The risk evaluation reports in some productive fields
are either absent or unsatisfactory from a qualitative point of
view.
 The technical reports often lack fundamental information
 The
level
of
performance
of
the
law
against
noise
implementations is not sufficient.
 In particular, the implementations relative to the technical,
organizational and procedural participations are disregarded.
OSH Seminar, Bucharest, October 20-21, 2005
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Noise / State of the Art
Actual evaluation and control of risk from
occupational noise exposure
 There is no territorial uniformity in the risk evaluation
reports and also in the regional regulations
 Official statistical studies are absent relative to occupational
noise exposure in Italy.
 A national data base is absent containing the personal daily
exposure level in the different occupational fields.
OSH Seminar, Bucharest, October 20-21, 2005
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Noise / State of the Art
Actual evaluation and control of risk from occupational noise exposure
 According to the data communicated to Italian National
Institute for Prevention and Safety at Working Places
(ISPESL), the workers officially exposed to personal noise
levels above 90dB(A) are 41000, and the workers exposed
to levels in the range
80dB(A) < LEX, 8h < 90dB(A) are about 12000.
These data are evidently underestimated, if one thinks
that there are in Italy more than three millions of
companies
OSH Seminar, Bucharest, October 20-21, 2005
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Noise / Risk evaluation
 The risk evaluation reports in some particular
occupational field are totally absent or they are
insufficient from a qualitative point of view.
 Transports: in many public or private transport
companies a noise risk evaluation is still absent due to
an incorrect interpretation of the Italian law.
 Schools: the noise risk evaluation is totally absent
although occurrence of hearing impairment pathologies
is growing among the teachers.
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Noise / Risk evaluation in schools
 ISPESL is promoting a national project research about
noise risk at school. High noise levels were found, especially in
maternal and elementary schools.
The high levels of noise cause hearing impairment and
insurgence of laryngopathologies in teaching staff and they
cause learning difficulties and loss of attention in pupils.
The high levels of noise are principally due to the architectural
characteristic of scholastic buildings. For example:
-the insufficient insulation of the classrooms cause high levels of
disturbances produced by external sources
-reverberating effects from the walls produce
sound distortion and loss of speech intelligibility
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Noise / Risk evaluation in schools
Maternal school
Teachers (a.m. turn)
LEX,8h= 85.3 ± 1.8 dB(A)
(dosimetric methodology)
LEX,8h= 84.3 ± 2.9 dB(A)
(phonometric methodology)
Lpeak= 123.5 dB
Maternal school
Teachers (p.m. turn)
LEX,8h= 85.8 ± 1.4 dB(A)
(dosimetric methodology)
LEX,8h= 84.3 ± 2.3 dB(A)
(phonometric methodology)
Lpeak= 123.5 dB
Non teaching staff
LEX,8h= 80.9 ± 1.4 dB(A)
(phonometric methodology)
Lpeak= 110.7 dB
Nataletti P., Pieroni A. in Acustica and Scholastic Environments.
Venezia, 5 maggio, 2005
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Noise / Technical reports
 The technical reports are often incomplete and not
exhaustive.
Hearing protectors: it is very rare to find in the reports
the effective degree of protection given by the personal
protective equipments calculated in agreement with the
standard EN 458 (2001)
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Hearing protectors
Attenuation is a statistical variable characterized at each
octave frequency band by a mean value and by a standard
deviation
APV ( f )  m( f )  s( f )
This statistical aspect is often neglected in technical reports so
leading to an underestimate of the actual noise exposure.
OSH Seminar, Bucharest, October 20-21, 2005
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density(%)
Probability
densità
di probabilità
Gaussian probability distribution
10
8
6
m-s
4
m+s
34% 34%
2
0
15
20
25
30
35
40
45
attenuazione
Attenuation (dB)
Population in the interval between m-s and m+s
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Probability density
densità di probabilità (%)
Gaussian probability distribution
10
8
6
m-s
4
84%
2
0
15
20
25
30
35
40
45
attenuazione(dB)
Attenuation
(dB)
The mean attenuation m(f) minus 1 standard deviation, (m-s), is
the minimum attenuation for 84 % of the population of exposed
subjects
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m - s
The choice  = 1 is currently done without considering that
16% of workers have an attenuation lower than the assumed
minimum value.
The attenuation data reported by manufacturers are referred to
the minimum attenuation for the 84% of the population.
The italian regulations do not sufficiently stress this statistical
aspect.
Neglecting the statistical nature of the attenuation given by
hearing protectors could produce mistakes in the risk
evaluation.
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Hearing protectors / Real attenuation
The attenuation data reported by manufacturers are referred to
the maximum attenuation evaluated in standardized conditions.
In working places the conditions are very different
1)
2)
3)
4)
5)
6)
7)
8)
workers are not formed to the use of hearing protectors
the wearing conditions are not optimized
the size is often not optimized
there are anthropometric differences in the external ear
the hearing protectors have to be worn for a long time
there are uncontrolled movements (mandibular, etc.)
the wearing conditions are affected by physical activity
discomfort
 The attenuation of hearing protectors in working places are
lower than those declared by manufacturer
OSH Seminar, Bucharest, October 20-21, 2005
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Hearing protectors / Real attenuation
Work di
ambiente
enviroment(min)
lavoro
(min)
Work di
ambiente
enviroment(max)
lavoro
(max)
Declared by
produttore
attenuazione (dB)
0
10
20
manufacturer
30
40
50
60
125
250
500
1000
2000
4000
8000
(Hz)
frequenza
Frequency
(Hz)
Muffle
Mean attenuations and their standard deviations declared by
manufacturer compared to those measured in a real work environment
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Hearing protectors / Formation effect
attenuazione (dB)
0
No instructions
nessuna
istruzione
With ainstructions
istruzioni
corredo
Practical demonstration
dimostrazion
e pratica
Declared by manufacturer
produttore
10
20
30
40
50
60
125
250
500 1000
2000
4000
8000
frequenza (Hz)
0
10
nessuna
No instructions
istruzione
20
istruzioni
Witha
corredo
demonstration
30
Practical
dimostrazione
pratica
Declared
produttore
by manufacturer
40
50
attenuazione (dB)
attenuazione (dB)
0
10
instructions
20
30
40
50
60
60
125
250
500
2000
4000 8000
1000Bucharest,
Seminar,
October
OSH
frequenza (Hz)
20-21, 2005
125
250
31500
1000
2
frequenza (H
Risk evaluation in call centers
Call centers: This is a case in which the methodology given by
the current law to perform risk assessment is totally inadequate.
The incorrect risk evaluation standard methodology
(phonometric measurements with a microphone at 10 cm from
the ear) causes an underestimate of exposure levels, and
consequently, an insufficient level of protection.
The solution is a new methodology based on an artificial manikin
and/or a miniaturized microphone inserted into the ear canal. The
first methodology is being standardized in Italy.
OSH Seminar, Bucharest, October 20-21, 2005
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Methodology and instrumentation for the inside and outside
evaluation of noise
 Manikin method (ISO/DIS 11904-2 (2000). “Acoustics Determination of sound immissions from sound sources
placed close to the ears - Part 2: Technique using a manikin
(manikin-technique)” )
1. Noise is measured at tympanic height with the manikin microphones;
2. A correction is performed using the transfer function (provided by the
manufacturer, by the ISO 11904-2 or experimental)
3. Elaboration of the recorded spectrum provides an estimate of the
noise outside the ear that would produce inside it the measured noise
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Manikin used for the measurements
Manikin: B&K 4128
Right Ear: B&K 4158
Left Ear: B&K 4159
Outer Ear: B&K DZ 9752
OSH Seminar, Bucharest, October 20-21, 2005
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Frequency response provided by Bruel & Kjaer for the manikin 4128 C, valid in
conditions of diffuse field and free field
18
B&K campoFree
liberofield
16
B&K campoDiffused
diffuso
field
14
(dB) (dB)
Gain
Guadagno
12
10
8
6
4
2
0
20
40
80
160
315
630
1.25k
2.5k
5k
10k
20k
Frequenza(Hz)
(Hz)
Frequency
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Equivalent sound levels outside the operator ear, estimated
using the frequency response provided by B&K for diffuse field.
Amplification
volume
Sound level (dB(A))
Mean
dev.
Call center
Standard
min
max
Level I
71.8
1.9
69.7
73.5
Level II
77.8
1.7
75.9
80.7
Level III
81.8
1.7
79.9
84.1
Level I
77.3
1.3
75.9
78.5
Level II
80.3
2.3
76.7
83.0
Level III
84.2
1.7
82.4
87.0
Data from Peretti et al., 2002
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The noise directive 2003/10/CE
News
 The new directive applies to all occupational fields. This is a
clear improvement with respect to the old one.
 It introduces new action and limit value based on LEX,8h
and/or to Lpeak
limit value: 87 dB(A) LEX,8h and/or 140 dB(C) Lpeak
upper action value: 85 dB(A) LEX,8h and/or 137 dB(C) Lpeak
lower action value: 80 dB(A) LEX,8h and/or 135 dB(C) Lpeak
 Decrease by 5 dB in the main requirements (formation, DPI, …)
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The noise directive 2003/10/CE
Critical points
The limit value of 87 dB(A) proposed by the new noise directive includes
the hearing protectors. In other words, the attenuation given by hearing
protectors has to be taken into account when assessing if the limit is being
adhered to.
Consequently, the limit value is not well defined.
The real protection given by personal protective equipments is dependent on
several variables such as real environmental conditions, wearing procedures
and workers formation.
The average attenuation given by hearing protectors is about 20 dB: so the
limit value is adhered to also if the environmental levels rise to 110 dB(A)
So the serious risk exists that the employees will continue to be exposed to
high environmental noise level. The employee protection could result to be
based less on technical and procedural measures to reduce noise emission and
exposure, and more on checking the behaviour of employees.
OSH Seminar, Bucharest, October 20-21, 2005
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The noise directive 2003/10/CE
Critical points
Another critical point is related to the fact that in the new noise
directive there are no technical enclosures providing methodologic
and metrologic instructions for the measure of noise exposure and
of hearing function in exposed workers.
The lack of technical enclosures requires detailed national
guidelines to help the operators in the field of occupational
prevention and safety.
In Italy, ISPESL has promoted the development of such guidelines,
also providing widespread diffusion of this information, which is
freely available online on the web page:
http://www.ispesl.it/linee_guida/fattore_di_rischio/rumore_eng.
htm
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Italian national guidelines on noise
National guidelines for evaluation of risk from
noise exposure in working places
OSH Seminar, Bucharest, October 20-21, 2005
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Conclusions and outlooks
The aim of the new directive was to introduce more
protective standards for the noise exposure, by shifting
the requested countermeasures to the immediately lower
threshold level, and by setting at 87 dB a threshold that
must not be exceeded in any case.
On the other hand, the introduction of DPI attenuation in
the evaluation of the effective noise level could lead to
confusion and metrological difficulties in practical
applications.
The challenge that must be faced by national institutions is
that of explaining how to apply the new criteria without the
risk of lowering the effective level of protection of workers
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