Document 06D65L59pL9XxGYvR2XMnndBk
FILE NAME: Z/ZZZ/Ed
DATE:
DOC#: /Ed
DOCUMENT DESCRIPTION:W^Z/Z ZZZDd^ EZDZZZZZ Z
I ~ -
I I .-
I ~ I -~
WJllRTSCJHIAJFTSVJEJRlBANlD ASJBlESTZJENllJENT lE. V.
Arbeits- und Umweltschutz
I I ~
J
j
J -
i I -
I -
J
I I -
J I I -
I INTERNATIONAL COLLOQUIUM ON
DUST MEASURING TECHNIQUE AND STRATEGY
I
AT WARMENSTEINACH GERMANY
ON AUGUST 29 AND 30, 1977
III ADDRESS: GORLITZER STRASSE 1, D-4040 NEUSS, TELEFON 02101/13051-53 I TELEX 8517402 au d
.,..
I' .,
)
7"'!
-J
1
J
1
1
' noi
!__J
.--'
l
_j
-l '
~
..,
i _J
-i
--
i '
_.
....,
l ___ _;
1
I.
L I S T 0 F PART I C I PANT S
==========================================
AUSTRALIA
Mr. G. Major,
Mr. G.C. Pickford, Mr. J.W. Winters,
School of Public Health & Medicine
The University of Sydney Building A 27 New South Wales 2006
Tropical
Wunderlich Limited o'connel Sydney
James Hardie & Coy.Pty.Ltd. 65 York St. Sydney
AUSTRIA
Mr. Bigga,
Osterreichische Staub(Silikose)Bekampfungsstelle
I Technische Abteilung
Postfach 72 8700 Loeben
Mr. Schmiedlnger,
Eternit-Werke L. Hatschek 4840 Vocklabruck
BELGIUM
Mr. van Herle,
Eternit S.A. 2920 Kapelle-op-den-Bos
CANADA
I
Mr. G. Gibbs, M.Sc.Ph.D.,Occupational Health and Safety
Institute for Mineral Industry Research McGill University, Gault Estate
Mount St. Hilaire,
Montreal, Que.
SWITZERLAND
Mr. Kunzler,
SWEDEN
Mr. F. Danstrand, Mr. N. Hallin,
~Mr. s. Skyllberg,
UNITED KINGDOM
Mr. A.A. Cross, Dr. G. Leguen,
Mr. R.M. Wagg, Ur. W.H. Walton,
4
Schweizerische
anstal t Fluhmattstr. 6002 Luzern
Unfallversicherungs-
C.A. Clase AB Ruskvadersgatan 8 417 Goteborg
Organisation for Industrial Safety and Health in the Construction Industry Burgghalsan Fack 10041 Stockholm
Swedish National Board of Industrial Safety Fack 10026 Stockholm 39
Asbestos International Association 68, Gloucester Place London WlH 3HL
Research & Service Laboratory Division Health & Safety Executive 403/405 Edgware Rd. Cricklewood London NW 2
Health & Safety 403/405 Edgware Cricklewood London NW2
Executive Rd.
Institute of Occupational Roxburgh Place Edinburgh EHB 9SU
Medicine
1
~__1
]
- ___,i
.... ' ;
. - _J
___ ] 1-~
1
_J
1
I I
I
.. -J
1- _,
1- _j 1__J
1_J
J
USA Dr. G. Chase,
Mr. F.A. Madsen,
Dr. Rhodes, Dr. Y. Hammad,
5
Johns-Manville Corporation Health, Safety & Environment Department Greenwood Plaza Denver, Colorado 80217 OSHA Occupational Safety and Health Administration 390 Wakara Way Salt Lake City Utah 84108
Union Carbide Corporation P.O. Box 579 Niagara Falls, N.Y. 14302 Tulane University School of Medicine Pulmonary Disease Section New Orleans, La 70112
].
6
]
]
]
I I.
s uMMA Ry
=========================
I
1_j
J
~J
According to an agreement of the Executive Committee of the Asbestos International Association Dr. Robock organized a colloquium on
J
DUST MEASURING TECHNIQUE AND STRATEGY
1
with cooperation of Professor Gibbs and Mr. Walton.
J The aim of this colloquium was . to establish the differences of dust
J
measuring technique and strategy within the different countries
..,.
. to achieve an international standardization
!
which enables us to compare the situations
_J
in the plants within the asbestos industry
and which gives us the basis for epidemiological
., studies (retrospective and prospective)
The colloqium took place at Warmensteinach, a small town in the National Park Fichtelqebirge (Bavaria), on August 29 and 30, 1977.
Invited were representatives of the and the controlling authorities. 39 countries participated.
asbestos industry experts from 15
7
After an introduction by Dr. Roback in which he illustrated the necessity of a standardization the following topics were discussed:
- Techniques and strategies applied
- Results from scientific and practical dust measurements
- Presentation of dust measuring data
- Automation of fibre counting
A convention for the standardization of method and strategy could not be reached in the shortness of time because of numerous different opinions. Dr. Roback was asked to convene a Dust Working Group to prepare such convention.
In the following a summary of the presentations and individual contributions:
TECHNIQUES AND STRATEGIES APPLIED
MR. TEICHERT reported in his presentation
EQUIPMENT AND STRATEGY OF DUST MEASUREMENTS WITHIN THE GERMAN A/G INDUSTRY
about the functions of the German asbestos cement (A/C) industry, the measuring instruments applied and their principles and limits, kind of sampling, selection of measuring points and measuring procedures as well as about preparation, counting and calculation of average values based on individual results.
8
Those measuring series were reported about which demonstrate the problems connected with each complex and the measures taken (e.g. way of handling equipments) were explained on the basis of results.
-.-.-.-.-.-.-.-.-
MR, WALTON mainly referred in his. presentation
PROBLEMS IN THE STANDARDIZATION OF ASBESTOS DUST MEASUREMENTS
to the membrane filter method. He pointed out that it is the purpose of standardization
i
- to enable information from different sources to
j
J
be compared and collated into one general pool
J ,
of knowledge;
' I
~
- to ensure that specified limits (TLV's, MAK's)
can be uniformly implemented to provide the
__J
intended levels of safety.
J
To be effective, standardization must cover not only
the evaluation (counting) of samples, but also the
method and strategy of sampling, e.g. the shape and
orientation of the filter holder, the sampling air
velocity, when and where samples are taken, whether
over a short period or over the whole shift, whether
in the breathing zone or in the general environment,
etc.
The hygiene standard for asbestos in Britain (2 F/ml)
J was derived from epidemiological evidence in an asbestos factory where environmental measurements have
9
been regularly made since 1953. At first sampling was by thermal precipitator and all particles (not restricted to fibres) were counted. Then a new improved form of thermal precipitator was used, and finally there was a change to membrane filter methods when fibres >S m were counted. All the counting of fibres on the membrane filters was by the so-called "full-field-method", i.e. with no graticule in the microscope eyepiece to define the counting area.
Methods have since changed further. The standard is applied to personal sampling whereas it was derived for fixed position sampling, and to counti~g with a graticule which gives much higher values than fullfield counting, and to single shifts whereas the derivation was based on long-term average levels. Thus, it seems probable that the standard now being enforced is appreciably more stringent than was intended.
Mr. Walton reported about experience regarding comparative countings.
The influence of the graticule on the counting result was pointed out and a graticule specially concipated
. for the fibre counting was presented. This graticule
allows an exact determination of countable fibres.
The relatively great divergencies in comparative countings can substantially be influenced by different detection limits of thin fibres. The limitation not only to a maximum diameter of fibres but also to a minimum diameter could be helpful.
(_!
(J
[J
rJ
rl
10
, "'I
I
_j
tf the ratio length to diameter would be increased
from 3 1 to 5 1 the number of asbestos fibres
]
would not be affected but all elongated mineral
fibres could be excluded.
A standardization should not only be an agreement
between the evaluating people but also the biologists
should be,consulted to examine if the right respon-
] sible parameters are measured. Concerning this matter the biologists have still to answer a lot of open
questions about relevant parameters for the different
types of reaction
I - fibrosis
,.., I - mesothelioma
J
- lung cancer
- other tumors
- .- .- .- .- .- .- .- .-
'1 i
_j
The two presentations and the contributed papers have de-
monstrated that the membrane filter method is handled in
very different ways with regard to important details. This
1 can lead to different and not comparable results.
__J
TECHNIQUE
- SAMPLING
velocity at the suction aperture (mm/sec. - m/sec.)
flow rate c:heck
. pressure constancy (pulsation)
-
time (overloaded filter)
-f
I
11
- FILTER . type of material (nitrocellulose, celluloseacetate) . pore width . diameter surface (with and without grid)
- PREPARATION embedding medium (refractive index) e.g. triacetine, US-mixture, cyclohexanone, acetone vapour and thus influence on detection limit background thickness of the layer of dust permanency . way of handling the medium, the filter and the cover slip and storing of the prepared slides
- COUNTING microscopic equipment phase contrast device illumination filter magnification graticule thus influence on detection limit and size determination
- COUNTABLE FIBRES length diameter ratio length diameter agglomerates splitted fibres
]
,]_,
. __ _jl
J J J
J
,
J
l
__ _j
..., __ J ]
- ]__
1
- _j
12
- STATISTICAL PRECISION
consideration of fibres overstepping field of counting
total number of fibres to count number of fields of counting to overloaded filter
evaluate
STRATEGY
- FUNCTION . engineering control . exposure control
- SELECTION OF MEASURING POINTS some points distributed over the hall all workplaces all workplaces with dust exposure
- POSITION stationary
. personal on the person following the person
consideration of influencing factors (draught, working conditions)
- DURATION short-time long-time
- STATISTICAL PRECESION numb0r of samples repetition working cycle
13
- CALCULATION peak concentration
. arithmetic average . time-weighted average
- .- .- .-.- .- .- .-
RESULTS FROM SCIENTIFIC AND PRACTICAL DUST MEASUREMENTS
PROFESSOR GIBBS pointed out in his presentation
RESULTS FROM SCIENTIFIC AND PRACTICAL DUST MEASUREMENTS
that dust measurements should serve - to prove the compliance with standards - to identify dust sources - to test the effectiveness of control measures - to improve our knowledge of the relationships
between asbestos dust exposure and its health
eff~cts.
Given that a standard is set, it is the responsibility of the government or agency promulgating this standard to set it out in clear terms, to describe and designate the appropriate instrumentation for collecting the sample, the calibration, its operation location and frequency of sampling: tolerances on the measurement and the way in which measurements are to,interpret. To identify dust sourcas in recent years a number of instruments based on light scattering, piezoelectric effect, ~-ray absorption etc. have been deviced for the rapid measurement of airborne concentrations of dust. Such methods cannot distinguish between asbestos fibres and other dust, but as relative measurements they can be very helpful, for example to test the
, ...
"'"'
, .,.
I
'
'""l'I
"" ' ... , ...
~ ,. , ..
....
14
effectiveness of control measures by checking before and after modification at a site.
Although the exposure to asbestos is related to 4 main
diseases very little is known about the risks dependent on the level of exposure.
The available data on dust concentrations in was determined by methods which deviate from currently applied membr~ne filter method. It essential
the past the is therefore
- to find methods to convert past environmental data to the equivalent fibre concentrations to determine whether standards which have been set, based on the membrane filter method, have validity in scientific terms,
- to consider carefully and determine whether this measure of airborne fibre concentration is an adequate index of environmental quality for the control of each of the diseases associated with asbestos exposure,
- to conduct more studies of exposure-response.
-.- .-.-.-.-.-.-
The participants contributed data from the past and present for the various branches of the asbestos industry. Since
in many countries they have only just began with measurements in the last few years a very limited amount of data was
presented. In most of the cases values could only be indicated to some striking workplaces. This does not enable us to derive a representative cross-section for the whole industrial branch but it gives a rough idea of the order of magnitude of the
15
I
fibre concentrations in the past and at present in the different industrial branches:
FIBRE CONCENTRATIONS (F/CM 3 )
MINES
former
I
I minimum
0. 1
maximum
1
majority
0.5
MILLS
minimum maximum majority
f-o-r-m- -e-r
10 200
20 - 100
!~'.:'!~x
1. 5 100
5 - 10
INSULATION INDUSTRY (production and application) former
minimum maximum majority
5
1000 40 - 100
2 200 5 - 50
TEXTILE INDUSTRY
minimum maximum majority
-fo-r-m--e-r
5 300
50 - 200
~~5!~l
0. 5
18
1
-
!: .J
.1 ] ]
J
] ]
J
J
]
J
l__J
J
..,
l
_J
J
I l
_l
J J J
16
!Y.s- INDT,JSTRY
minimum maximum majority
-fo-r-m--e-r
4
150
10 - 50
-. -.-.-.-.- .-
~~~~~
0. 1 5
0.5 - 2
PRESENTATION OF DUST MEASURING DATA
MR THIELE reported in his presentation
PRESENTATION OF DUST MEASURING DATA
about the way of proceeding in the Danks EternitFabrik A/S.
The results of measurements serve to inform the worker and the management. In order to be able to discuss the situation with the worker the results must quickly be available, i.e. as long as the worker can still clearly remember the working situation in question.
For the management a general survey is provided cating the number of employees exposed to dust. with different exposure levels are formed
indi4 groups
> 1 f /cm 3 > 2 f /cm 3
> 3 f /cm 3
> 5 f /cm3
The remaining employees are exposed to a dust concentration of ( 1 f/cm 3 If this survey is k8pt over a longer period the positive development of the dust situation can be realized at once.
81
MR. A.A. CROSS (10)
Example of group of factories and operations comprising
Asbestos Cement Manufacture (sheets, pipes, fabrications - not pressure pipes)
Asbestos Insulating Board Friction Materials
Thermal Insulation Materials Application of Asbestos and other Insulating
Materials (including spray)
I Stripping and repair of Insulation
1. Programme of Asbestos Dust Concentration Measurement.
1. 1. Method - Membrane filter method in accordance with ARC Technical Notes 1 and 2.
1. 2.
Sampling
Period - 10 minute periods covering
period of maximum dust emission. Multiple samples (usually two) when significant variation from expected (from previous records).
Longer periods (representative of continuous shift operators) up to 4 hours are carried out when 10 min. samples indicate concentration ( 2 f/ml.
1. 3.
Sampling
Locations -
Operator's breathing zone (OBZ). Normally by lapel mounted sampling head. Alternatively, with sampling head on probe, held in OBZ by sampler following operator's movements. Machine counts(MC). ~easurements at point of emission (dust emission source) by static sampler. Background Counts (BG). Measurement at predetermined locations in workshop area to determine condition of general working environment.
2. Responsibility. (1) Continuous programme of monitoring carried out by local technical staff of
I
82
' .
operating company, often associated also with quality control. Reports monthly to local mangement and to headquarters service chief. All measurements exceeding 2 f/ml subject of immediate special report to plant management for investigation and remedy. Monthly summary of such reports presented to senior mangernent (board of directors) by director responsible, with information on action taken or planned. In cases of sustained excess dust level, sampler has authority (through workshop management) to stop the offending process.
1 (2) Central Environmental Service (re-
sponsible to parent company board) makes twice yearly visit to carry out parallel dust measurement. This ensures continuous correlation of sampling.and evaluation techniques, and confirms reliability and consistency of reports. It also provides opportunity for advice and communication on control techniques.
I (3) Central Environmental Service is re-
sponsible for establishing techniques of sampling, for specifying equipment, for training, and for supplying emergency and investigatory facilities within and outside the organisation.
(4) By liaison with associated members of ARC and with the technical branch of the Factory Inspectorate, the Central Environmental Service endeavouring to maintain consistency of measurement with other experts.
Results.
The effect of constant and planned moni~oring in reduction of excessive dust concentration is demonstrated by the following comparison. Percentage of Measurements in different
Levels of Concentration
1971
1976
< 2 f/ml
2-4 f/ml
4-12 f/ml
> 12 f/ml
52.3 2 2. 1 18.9
6.7
88.3 9.5 2.2