Document 82Eod97ROpBKQ3oDKVJ0mYGQm
UCC 022793
USE DUST COLLECTION
WHEN MACHINING
UCC 022794
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PMENT
INTRODUCTION
A i 732*
The purpose of this booklet is to provide practical guidelines for brake and clutch service mechanics in the handling and process ing of asbestos containing friction materials and in the maintenance and repair of brake and clutch assemblies on which the materials are installed.
Adherence to the recommended work practices will reduce
employee exposure to airborne concentrations of asbestos dust
and wilt assist employers in complying with government
regulations.
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This area is regulated by federal, state and local authorities. We
caution that you may not rely on strict adherence to the work
practices recommended herein as assuring compliance with
these regulations, because (a) they are subject to amendment; (b)
there are on-going administrative interpretations of these
regulations; and (c) particular field conditions may vary. You
should direct all questions relating to compliance with regulations
to the appropriate regulatory agencies.
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ASBESTOS AND FRICTION MATERIALS
Most molded friction, materials contain about 50% asbestos -
some woven materials over 90%. In molded materials, resin
binders prevent the release of asbestos fibers during normal
handling. Woven friction materials, normally used only in con
struction and industrial applications, must be handled with care to
avoid Creating dust as the asbestos fibers are less firmly bound
into the product.
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Potentially hazardous airborne concentrations of asbestos dust
can be created by improper cleaning and handling of worn brake
and clutch assemblies, uncontrolled machining operations and
poor housekeeping.
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Breathing excessive quantities of asbestos fiber , can cause ;
respiratory disease and cancer. Smoking greatly increases therisk
of lung cancer among asbestos workers. Prevention of asbestos T:
dust exposure is the only known method of eliminating asbestos-
related disease among those.working with asbestos containing i
products
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(Proper work'" practices' offer ithe best assurance of providing '
'exposure safeguards forworkersVemoving, installing and machin-
.ing asbestos containing friction materials,
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UCC 022795
UCC 022796
OT USE R HOSE
A<7326
SUMMARY OF OSHA ASBESTOS STANDARD EFFECTIVE JULY 1, 1976
Under the current standard, it is the employer's responsibility to assure that exposure of employees does not exceed the following permissible exposure levels.
a. Eight-hour time-weighted average: Two fibers, longer than
five micrometers, per cubic centimeter. . : \ .:
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b. Ceiling (Peak) concentrations: Ten fibers,, longer than five
; micrometers, per cubic centimeter.
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Engineering controls such as isolation, enclosure, exhaustventila-- tion and dust collection are the preferred methods for meeting the prescribed exposure limits. All external surfaces must be main
tained free of asbestos fiber accumulation.t
Respiratory protection is required whenever airborne fiber con
centrations exceed either the permissible time weighted average
level or the permissible ceiling concentration. Protective clothing
is required whenever airborne fiber concentrations exceed the
permissible Veiling level. Caution signs, change rooms and
employee notification are required where asbestos fiber concen
trations exceed permissible exposure limits. The standard re
quires that all workplaces where asbestos fibers may be released
shall be monitored to determine exposure levels, and regular
monitoringusTreqLiired, where' exposure levels are expected to ' .
exceed permissible fiihits.' tmployers must maintain records-of
monitoring required byl.the standard.;?They. must aiso provide or^
make available medical examinations for employees exposed to
airborne concentrations of asbestos fibers.'
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UCC 022797
UCC 022798
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HANDLING NEW FRICTION MATERIALS
Handling new disc brake assemblies, lined brake shoes, clutch
facings and brake blocks purchased in individual boxed sets is
unlikely to create significant airborne concentrations of asbestos
dust. If the parts are purchased in buik quantities, abrasion during
shipment .may result in the accumulation of dust in shipping
containers. Dust should be removed by vacuuming or cleaning
with a damp cloth. :
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Whenever possible, purchase friction materials preground and
ready for installation. This may keep dust levels below OSHA
maximums and eliminate the need for respiratory protection,
restricted areas, regular monitoring, special clothing, change
rooms and employee notification.
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REMOVING WORN FRICTION MATERIALS
Asbestos fibers in disc brake linings, drum brake linings, blocks yd'
and dry clutch facings are locked into the product with resin
binders which prevent the release of asbestos fiber during normal -
installation. Heat and abrasion during normal use may generate
dust containing asbestos. Some dustwiilaccumuiatein brakeand
clutch assemblies.
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When removing worn friction materials, remove the accumulated y'
dust in the assemblies with an industrial vacuum cleaner
equipped with a high efficiency filter system. If such equipment is :
not available, dust can be removed with a damp cloth. Do not use y T .
compressed air or dry brushingfor cleaning. y yy-.
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Use a NIOSH approved respirator when removing worn friction ,
materials, or cleaning brake or clutch assemblies, y
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MACHINING FRICTION MATERIALS
There is an increasing trend for manufacturers and rebuilders to
provide brake linmgand clutch facings pre-drilled and pre-ground
in final assembly form. In the case of truck brake blocks, various
oversize thicknesses are available. However, there are some
-instances where field machining is necessary. This is particularly
; true for construction and industrial equipment applications which
: may require machining of blocks, slab stock or roll lining.
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Dust generation car. he minimized or eliminated during arcing of y brake blocks by lathe turning at low speed rather than grinding. Whenever possible friction materials should be cut to length with a V , .shear rather than,a saw or abrasive cut-off wheel. *
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UCC 022799
UCC 022800
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DO NOT EEP IN
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DUST COLLECTION METHODS
! When asbestos-containing friction materials are machined, i.e., drilled, ground, grooved, cut or beveled, the dust created contains asbestos fibers which may become airborne unless adequatedust controls are employed. The preferred method for minimizing airborne dust from machining operations is local exhaust ventila tion. A local exhaust ventilation system consists of dust collection hoods or enclosures connected by duct work or piping to a dust
collection filter and a suction source.
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The two operations that offer the greatest potential for generation of excessive amounts of airborne asbestos fiber are arc grinding and beveling of lined brake shoes and linings or brake blocks.
Grinding, machines-used for these operations must be provided
with, exhaust, ventilation, to maintain worker exposures within
permissible levels.
If a-central exhaust system is not available, NIOSH (National Institute for Occupational Safety and Health) has stated that, at a miminum, the dust bag of the arcing machine shall be removed and replaced with the hose from a high efficiency industrial vacuum. " . ; . : \ . . :
For large volume machining operations that operate on a con tinuous basis, the preferred dust collection device is a fabric filter
or baghouse, with a heavy-duty exhaust fan as the suction source. : The dust collector must meet the air-cleaning requirements of the
Federal Environmental Protection Agency Emission Standard for Asbestos. Approval must be obtained from EPA for installation and operation of each system.
OTHER METHODS OF MINIMIZING DUST EXPOSURE
: Whenever possible machining and repair operations should be
isolated from other work areas in a restricted area to prevent
: unnecessary exposure of other workers. Entrances to restricted
areas shall be posted with asbestos exposure warning signs as
; follows:
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. Asbestos ',
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Dust Hazard . .
, - Avoid Breathing Dust '*
. > Wear Assigned Protective Equipment '
Do Not Remain in Area Unless Your Work Requires it
'' Breathing Asbestos Dusl
J May Be Hazardous To Your Health ,, ,
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UCC 022801
UCC 022802
WEAR PROVED IRATOR ABLE TO D DUST
A 57332
Good housekeeping is essential in a workplace where asbestos containing materials are handled. Industrial vacuum cleaners equipped with multiple stage high efficiency filters should be used for removing accumulations of asbestos dust and waste.
Never use compressed air or dry sweeping for cleaning. Water or other dust suppressants should be applied if brooms are used.
Good personal hygiene practices are important in minimizing
asbestos dust exposure. Do not smoke. Wash before eating.
Shower after work. Change to work clothes upon arrival at work and
change from work clothes at conclusion of work. Work clothing
should not be taken home. Laundering of asbestos contaminated
clothing shall be done so as to prevent the release of airborne
asbestos fibers in excess of the exposure limits.
DISPOSAL OF FRICTION MATERIAL DUST AND
WASTE
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Dispose of vacuum cleaner waste and asbestos containing cleaning materials in plastic bags or other sealed containers, with the following warning label printed on the container:
i:-:-G/L ;/ '' Caution
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: 'V'.?' .. Contains Asbestos Fibers
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<; Avoid Creating Dust
Breathing Asbestos Dust May Cause Serious Bodily Harm
Use a NIOSH approved respirator when servicing vacuum
cleaners, dust collectors, or handling any asbestos-containing
waste materials.
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Asbestos-containing waste materials must be collected, process-;
ed. packaged, transported and deposited in such fashion that no
'visible `emissions are generated to the atmosphere. All wastes
must be disposed of at sites operated in. accordance with
^applicable laws and regulations.
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UCC 022803
A '733
V:."O'
SOURCES OF ADDITIONAUNFORMATION
"Standard for Exposure to Asbestos Dust" (Code of Federal Regulations, Title 29,
1910.1001)--OSHA
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"National Emissions Standards for Hazardous Air Pollutants--Asbestos and
Mercury'1 (Code of Federal Regulations Title 40, Chapter 1, Subchapter C, Part 61,'
Subparts A, B}--EPA \
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"Fundamentals Governing the Design and Operation of Local Exhaust Systems,"
ANSI Z9.2-1971 ($7.00) and "Practices for Respiratory Protection," ANSI Z88.2-
1969 ($5.50)--ANSI i .
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"Industrial Ventilation Manual" ($8.00)--ACGIH
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For other information, a user may contact the manufacturer supplying his friction
materials, the Asbestos Information Association or the Friction Materials Stand
ards Institute. - . . ,
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ACGIH
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American Conference of Governmental
Industrial Hygienists
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Committee on industrial Ventilation
P.O. Box 16153 ,;:v i i
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Lansing, Ml 48901 , . :
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ANSI
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American National Standards Institute 1430 Broadway : , ,
New York, NY 10018 . - . i
AIA
i-Asbestos Information Association
;1745 Jefferson Davis Highway
Arlington, VA 22202
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October 1978 31^% ' ,
EPA
Environmental Protection Agency
Public Information Center
401 M Street SW ;
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Washington, DC 20460
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FMSI
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. Friction Materials Standards
Institute
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East 210 Route 4
Pa ram us, NJ 07652
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OSHA
Occupational Safety and Health . Administration . , ,
Office of Information
Washington, DC 20210
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UCC 022804