Document BR7JzKxZwpre0r30rnv8ej58J
FILE NAME Ford FD DATE 1968 July
DOC FD036
DOCUMENT DESCRIPTION Internal Report - Exposure to Asbestos During the Servicing of Brakes of Passenger Cars
Report 41/68 Exposure to Asbestos during the Servicing of Brakes of Passenger
Cars
M
July 1968
Fridhishal
Dr D E Hickish > 1/163 Industrial Hygiene
Specialist -
8006 1202
INTRODUCTION
This investigation was undertaken in view of the
increased national concern regarding
and of the impending revision of the
exposure
Asbestos
to asbestos
Regulations
of the Ministry of Labour
could
One involve
of the operations within the exposure to asbestos dust is
motor industry which the cleaning of
brake drums and clutch assemblies
routine servicing by blowing blowing
normally carried out during with compressed air jets
The brake linings in current use
may contain
40 to 60 asbestos when manufactured - the asbestos being
normally in the chrysotile form and occasionally in the
amosite form
Crocidolite asbestos is said not to be used
II
FIELD INVESTIGATION
It was considered that any hazard to health from
exposure to brake or clutch dust
within the Dealer Repair Organisation
would be more widespread
than within Ford of
Britain so the initial investigation was carried out at
a large Main Dealer service bay
At this garage the number
of cars per day given a routine service varies between 10 and 20
but not all servicing involves brake cleaning
Air sampling was carried out
initially on two
T.Ps occasions A and B using thermal precipitators
as the
sampling instruments On the second occasion samples were
also collected on membrane filters
'
This latter technique
has been developed in recent years and is likely to become
the preferred method of sampling for asbestos in Great Britain
and the U.S.A.
eee
In
8006 1203
2
In each case measurements were made
a By the side of cars being given a service which included
brake cleaning and
b In the cloud during brake cleaning and then near
to the car for the remainder of the service period
As the mechanic normally blows the dust away from
himself the sampler at b would be exposed during blow
to dust concentrations greater than those
actually pertaining
at the breathing zone
It was considered however that to
factor sample in this way would provide an additional
of safety
Details of the sampling are given in Table 1
when
zone
A further period of air sampling
membrane filter samples were collected of the brake operative by means
C was carried out
from the breathing
of a personal
sampler with suitably modified flow rate approx 250 min )
The sampling covered an entire work shift during which
brake blow was carried out on the following vehicles
5 Corsairs 1 Zodiac 4 Cortinas 1 Prefect
The thermal precipitator slides were subsequently
incinerated and examined by projection using- using-
a 4 mm objective and X.17 eyepiece The membrane filter
samples were rendered translucent by the addition of
triacetin and examined in a
similar manner
contrast microscopy was not used |
Phase
The results of the T.P. counts for occasions A and B are given in Table 2 and for the membrane counts on the
eee
occasions
8006 1204
III IV
occasions B and C in Table 3.
The counts are expressed in
terms of particles with diameter greater than l and of
fibres i.e. particles with aspect ratio greater than 1
and length greater than 5
LABORATORY INVESTIGATI
In view of the relatively few fibres present in the
air samples a laboratory investigation was undertaken
comprising microscopic examination of samples from brake lining material which was filed to produce dust and brake drum dust
collected by spatula from brake drums immediately prior to
blowing
The samples were sieved through mesh
screens and then examined before and after incineration
The results are shown as fibre proportions in Table 4
Samples of material collected from the brake drums
of a an Anglia van b a Mark II Cortina and c an Anglia
car were analysed by Dr S Holmes of Turner Brothers Asbestos Co.Ltd and his findings are shown in Table 5
DISCUSSION OF RESULTS
a Standards of dustiness
In June 1968 the British Occupational Hygiene Society
published Hygiene Standard for Chrysotile Asbestos Dust
suggested that in order to reduce the risk of
contracting
which
asbestosis to % of those with a lifetime's exposure to the
dust the accumulated exposure should not exceed
100 years i.e. 2 fibres for 50 years or
4 fibres for 25 years
In this standard fibres are
eos defined defined
8006 1205
Table 2.
Results of Thermal Precipitator Samples
Sample
Sample Sample
NoNo..
Sample details
Sample time
mins
Static - by car
Al
30
A4
45
A6
30
weighted average
B1
45
B5
35
weighted average
Dust concentration
Particles
1n
Fibres > 5
99 134
62 , 103 124 102 115
2 1 2 1.57 0.5 0 0.28
b In dust cloud
then static
223
30
223
45
223
35
weighted average
B3
45
B7
35
weighted average
71 141
92
106
103 181 137
3 2 0 1.64 0.5 0.2 0.37
8006 1210
Table 3.
Results of Membrane Filter Counts
Sample
Details
1. General atmosphere samples
a Static by car
B2 B6
weighted average
b In dust cloud then static
B4 B8
weighted average
Sample
time
mine
Fibres
45
1.12
35
1.42
1.25
45
1.71
35
3.62
2.55
II Personal samples
C1
C2
C3
C4
C5
Sample lost
C6
33
weighted average
60
0.63
56
1.12
59
0.21
56
0.96
64
0.38
70
0.79
'
0.68
8006 1211
Table 4.
Fibres - as percentage of total particles
observed
Sample
Brake lining material
Brake drum dust borne dust
Fibre proportion %
Incinerated | Incinerated
28 0.6
12.3 1.6
-
1.3
Table 5
Analysis of Brake drum dust
SaSmapmlpele
Anglia Van
Electron diffraction
microscopy
Chrysotile present
Cortina Mk.II
3.Anglia car
ray
diffraction
normal specimen
~
ray
diffraction
extracted
specimen)
Iron & quartz | Less than %
present No | chrysotile
chrysotile
possibly 0.1
detected
to %
Less than
specimen 1
As specimen 1
8006 1212
Report 52/68 Exposure to Asbestos Dust during
Brake Maintenance Operations on Commercial Vehicles Fleet Repair
Garage Dagenham
October 1968
a 1
Dr D E Hickish - 1/163
Industrial Hygiene Specialist
8006 1213
INTRODUCTION
This study was undertaken to assess the degree of exposure to fibrous dust in brake maintenance procedures on commercial vehicles and to provide comparative data relating to a previous study on operators working on
passenger cars
II
INVESTIGATION
Air sampling took place in the garage on the
19th September 1968.
Membrane filters in conjunction with
Casella personal samplers suitably modified to provide
a flow rate of 200 cmmin were used and the following
sampling procedure adopted
a
Personal samples were collected from the brake
blow off operator Mr Crone and the mechanic working in the adjacent bay Mr Hillman during the blowing
operation
The filters were then changed and replaced
to run for the rest of the shift
b Static samplers were positioned at three points
A. and C. about 20-25 from the source of dust
generation and separate samples were collected for the
morning and afternoon shifts
.
The sampling positions are shown in Fig.1 The collected samples were subsequently removed to
the laboratory and after preparation examined by
projection microscopy for the presence of fibres greater
than 5u equal to
A fibre is defined as having or greater than 3
an aspect
ratio
eee III RESULTS
8006 1214
III IV
RESULTS
Table 1 shows the fibre counts per cm for each
sample collected
DISCUSSION OF RESULTS
i Standards of dustiness
In a previous Report 41/68 Exposure to Asbestos
during the servicing of brakes of passenger cars
reference was made to the Hygiene Standard for Chrysotile Asbestos Dust proposed by the British Occupational Hygiene
Society
This standard suggested a Threshold Limit Value
of 2 fibres for an exposure period of 50 years
Categories of dustiness were proposed as follows
Dust Category
Negligible
Low Medium
High
Concentration fibres cm
averaged over 3 months
0 - 0.4
0.5 -
.
1.9
2.010.0 2.010.0 2.010.0
10
ii Field Investigation
Static Samples
As the blowing operation took place in the early
part of the morning shift the concentrations obtained at
the static positions during the afternoon shift
samples 8 9 10 probably represent the background
contamination Thus it can be seen that the generation of
a dust cloud by blowing off dust from commercial vehicle brakes results in increased background contamination of
3 to 4 times the background level at any point within
a radius of 20-25 ft
The concentrations are all well below the TLV and
with one exception come within the Negligible dust category
... Personal
Personal samples
The fibre concentrations for the mechanic engaged
on the blowing task taken for the duration of the
operation shows an exposure of nearly 4 times the TLV
while the concentration measured in the breathing zone
of the mechanic working in the adjacent bay during the same period just exceeded the TLV
The personal samples from the two mechanics taken over the remainder of the shift give similar results When the samples for the two mechanics are calculated on
the basis of weighted concentrations the exposures
are below the TLV and come within the Low dust category
CONCLUSIONS
In the light of the environmental data and of the
irregular intervals at which cleaning is carried
out it is not a daily procedure it does not appear . that a significant hazard to health should occur in the
|
case studied
Nevertheless the conditions which obtain during
the blowing operation are extremely unpleasant and
alternative methods of cleaning should be investigated
or
measures
adopted
to
minimise
personal
exposure
e.g. local ventilation or use of suitable respirator
8006 1216
Table 1. Results of Membrane Filter Counts
Sample
No.
DescriDepscription tion
1
Personal Mr Crone Brake maintenance
Front brakes blown out in this period
2 ,| Personal Mr Hillman Clutch repair
procedure at adjacent vehicle bay
Flow Duration
mins
Concentration
min fibres
Dust
Category
99
193
7.09
Medium
127
207
2.25
Medium
:
3
Static Position A.
190
232
4
Static Position B.
185
133
S
Static Position C._
180 206
| ~|~
6
Personal Mr Crone.One rear brake assembly 317 180
blown off at beginning of sampling period
:
T
Personal Mr Hillman Clutch repair
~
| procedure at adjacent vehicle bay
278 148
8
Static Fosition ^
806
9
Static Position 3
1217 10 Static Position C.
186
211
186 170
135 172
0.17 0.49 0.28 0.08
0.11
0.07 0.11 0.07
Neg
Nag
Neg Neg
Neg
Neg Neg Neg
weighted average concentrations
average
Mr Crone
Mr Hillman
1.75
Low
0.79
Low
SKETCH OF INIRANGEMENT OF
N
SAMPLING SCHEME AT REPAIR
19. SEPTEMBER 1968
GARAGE
Fig1
WELDING _s3
TYRES
1
1 |
| | 1
|.
| @
| 1
|
1
-
ad
a
i
8006 1218
. ote
os 8
"
.
8006 1219
June 5 1973
oct
Mr W. Hombach Mr N. Gordon
3GK3
1/431
een
-
Subject EXPOSURE EXPOSURE TO ASDESTOS DURING BRAKE CLEANING
The Port of Europe Service department are considering approved
equipment for European Dealers including items for the control of the dust produced when brake drums are blown out
In Ford of Britain there has bom some use of items like the Drumolene unit shown on the attached leaflet and we are about
to conduct some further tests of their efficiency and of their ability to comply with National legislation I should be interested to know whether in Ford of Germany you have legislation which applies to brake cleaning and whether there are any pieces of equipment for dust control which are approved by Government Agencies
ent
Pither
Or D. Hiokish
Industrial Hygiene Specialist
1/163 94-3330
PHIC
8006 1220 PQ
July 5 1978
Dr D E Hickish cc R Gordon
1/163
Subject Exposure to Asbestos during Brake Cleaning
A demonstration of the Drumclene brake dust extraction system has
been arranged with BT Sales and Services Ltd the manufacturer of
the equipment
It is scheduled for 10.30 on Tuesday July 11
in the Warley Basement Garage Please advise the name and
extension of the Industrial Hygiene representative who will be
attending the meeting
In addition we have a prototype equipment from another supplier that can be studied after the Drumclene representative has left
Nemlen Nemlen
P J Hinton
European Service
1/451 84 3121
-
.
*
8006 1221
July 17 1973
co
Mr P.J. Hinton Nr Goribon
1/451 1/431
Subject
EXPOSURE TO ASBESTOS DUST DURING BRAKE CLEANING
As requested the demonstration of the Drunclene brake dust extraction
systes by the B.T. Sales engineer was attended on July 11 1978
While the engineer weg demonstrating the olarning ability of the exdgment on the rear brake nogembly of a Cortina a high intensity light beam as described in the Schedule of the Certificate of Approval No. AP 1 2363 of the Asbestos Regulations 1969 was used to assess the containment of the dust by the equipment No dust es seen to escape from the equipment during the cleaning
indicating that there should be no hazard to health if this
equipment goes into service in the dealerships
.
s
a
t
. '
|
t- 2
A..J Croc'ten
Intustrial Hygiene Analyst
1/163 34-2452
8006 1222 .PQ .PQ
S ELTD
SHEFFIELD
oe
to
e
8006 1223
we
The B.T. DRUMCLENE
Drumclene enables the effective method of Air Blast
be employed in total safety
Cleaning to
The Drumclene is a weight steel cylinder spigot
mounted on to a detachable frame which is fitted with fully rotating castors
The spigot attached to the base of the cylinder is 1 diameter which enables the Drumclene to be mounted on a standard Trolley Jack for height adjustment if required Trolley Jack adaptors are available which when fitted increase the spigot diameter to 1~ The vehicle end of the Drumclene is partially enclosed by a segmented diaphragm which forms a dust seal behind the backplate of the exposed brake mechanism when the unit is in position
A fabric sleeve with elastic wrist band enables the operator to handle the button air gun inside the unit
Large shatterproof viewing panels are incorporated in
both models
particles Whilst the unit is complete within itself it is
connect to a standard line supply via tnheeces"sarByStPo
Socket mounted towards the rear end of the unit
The blast of air on to the exposed brake mechanism within
the Drumclene is sufficient to dislodge the
dusts etc. but in
majority of
extreme cases it may be necessary to
dislodge any solidified matter with a stiff brush All dust
and solids are then drawn through the bottom outlet of
the unit which is designed to accept most
Suction Cleaner hoses up to 23 bore
Industrial
by use of the
push reducing adaptor supplied
Suction Cleaner specifications are noted on the
page but whatever their capacity we recommendoptphoesu itn e
of a type having bag collection and additional filtrati
suitable for handling dust and asbestos
8006 1224
This model is designed to accommodate a wide range of vehicles with drum brakes
in the 7 to 12 diameter range
A single sleeve situated in the rear end of the cylinder enables the operator to complete the cleaning process with efficiency and safety
In some cases drum brakes are serviced and cleaned whilst the vehicle is in an
elevated position i.e. on a vehicle lift
in these cases we recommend the use
ofa high stand Part No. BT200
as illustrated on the opposite page Whilst the general requirement of a
suction cleaner is outlined in the intro
ductory paragraph it is essential that for use with the BT200 the cleaner must have in addition to filtration etc. a
minimum airflow of 50 CFM with its
hose connected
Designed for use on the larger diameter drum brakes found on commercial vehicles etc. with back plates in the 12 to 19
diameter range Two access sleeves are fitted as standard to this model but if necessary a third sleeve can be fitted to the centre of the circular rear window If ordered with this sleeve fitted the model number becomes BT 416
This third sleeve affords additional access
when the Drumclene is used on drum brakes of greater depth than standard e.g. Double Wheel Assemblies In some cases it has been found that
Fleet users only handle a specific drum size for example 17 diameter In these instances we are able to offer special size diaphragms solely for Fleet use It will be appreciated that a suction
cleaner for use with the BT400 has to
have a larger flow than that used on the smaller model therefore we recommend a cleaner capacity of 95/100 CFM in addition to the filtration requirements mentioned previously
7
B.T.
Cra 400
8006 1225
Spare Parts List
Description
Top Window Sealing Strip Top Window Rear Circular Window Sealing Strip Rear Circular Window Rear Window W 3rd Sleeve Fabric Sleeve
Sleeve Retaining Clip
Castor
Thumb Screw 5/16 W Diaphragm Complete Air Line Assembly Outlet Reducer
Diaphragm Elastic W Clip
BT 200 BT200
_
BT200 BT200 BT200 BT200 BT200 BT200
DG271 BT200
Spare Part Code Number
BT 400
BT 200 MKII
BT200
-
BT400
BT200 BT200
_
=
BT400 BT200 BT400 BT200 BT200 BT400 BT400
DG271
BT400
_ _
BT200 BT200 BT200 BT200 BT200 BT200
DG271
BT200
When ordering spares please quote Description and Part Number
BT 400 MKII
BT200 BT200 BT400 BT400 BT400 BT200 BT400 BT200 BT200 BT400 BT400 DG271 BT400
SERVICE LTD
A
B.T.SALES 2
B.T.SALES
B.T.SALES
SHEFFIELD
B.T. Sales & Service Limited
Huntingtower Road Sheffield 7GR
Telephone 685021 & 661424 STD 0742
Agent's Name and Address
?
8006 1226