Document Z4GwwNgB08VkZL1b9n52Ezjop

FILE NAME Brakes BRK DATE 0000 DOC BRK306 DOCUMENT DESCRIPTION AIA - Recommended Work Practices - Fabrication and Use of Asbestos Friction Materials ae S, BS Speer Street USPHS Membrane Airborne Asbestos Fibers Vacuum Cleaning Stations Filter Method For Page 1 Page 2 Page 3 Page 5 Page 7 Page 8 Appendix A Appendix B Appendix C Introduction The Occupational Safety and Health Act was signed into and became effective on April 28 1971. The Act has the every American worker a safe and healthy workplace law on December stated objective of 29 1970 assuring On December 7 1971 the Secretary of Labor issued an emergency standard for exposure to asbestos dust As required by the Act a permanent standard for asbestos exposure was promulgated six months later on June 7 1972. The present OSHA Asbestos Standard discussed in this booklet became effective July 7 1972 Thorough understanding of the standard is important to management of any company utilizing asbestos in its manufacturing or processing operations The work practices on the following pages have been prepared by the Standards and Technical Committee of the Asbestos Information Association America They are intended as general guidance for safe and clean workplace conditions in keeping with the spirit and intent of the OSHA Standard for Occupational Exposure to Asbestos Dust : These practices have been developed through careful study and consultation and are recommended as good procedure It is recognized that manufacturing conditions vary Implementation of the practices contained herein cannot be considered as a guarantee of OSHA compliance Where there may be a question of compliance OSHA personnel should be consulted A proposed revision to the OSHA Asbestos Standard was published in the Federal Register on October 9 1975. This work practice booklet will be revised as necessary to reflect any approved changes to the standard : Products and Operations The types of asbestos friction material products covered by these work practice recom- mendations are Brake eat band 6: Operations to which these work practices may apply are Clutchassemblyandrebuilding operations 4 transmision ex asaembslysembly Automatictaransmission assembly Summary of OSHA Asbestos Standard General Comments OSHA published a Standard for Exposure to Asbestos Dust in the Federal Register Vol 37 No. 110 dated June 7 1972. The standard was recodified from 1910.93a to 1910.1001 in the Federal Register Vol 40 No. 103 dated May 28 1975. The standard is reproduced as Appendix A. The standard applies to any manufacturing fabricating or handling process or operation utilizing asbestos fiber or materials containing asbes- tos fiber The standard is divided into eight major sections 1. 1910.1001 -Permissible Exposure Limits Sets maximum allowable asbestos fiber concentration in the workplace air 2. 1910.1001 -Methods of Compliance Recommends procedures to meet permis- sible exposure limits 3. 1910.1001 PersonaPlrotective Equipment Specifies types of personal protective equipment and defines circumstances under which they are required 4. 1910.1001 -Method of Measurement 1910.1001 -Monitoring Specifies monitoring procedures to determine if work places meet permissible expo- sure limits 5. 1910.1001 -Caution Signs and Labels States when caution signs and labels are required and wording to be used 6. 1910.1001 -Housekeeping Specifies results to be obtained from housekeeping and methods of waste disposal 7. 1910.1001 -Recordkeeping Specifies type and duration of monitoring recordkeeping States requirements for employee notification of monitoring results if exposure is in excess of permissible exposure limits and of corrective action being taken 8. 1910.1001 -Medical Examinations Details requirements for medical examina- tions and duration of medical record- keeping Specific Comments 1. Exposure Limits 1910.1001 b It is the employer's responsibility to assure that exposure of employees to airborne concentrations of asbestos fibers does not exceed the limits prescribed by the stand- ard The OSHA standard maximum permissible ex- posure limits of asbestos fiber in the work- place air are a Eight weighted average 1 At present 5 fibers longer than 5 micrometers per cubic centimeter 2 Effective July 1 1976 2 fibers longer than 5 micrometers per cubic centi- meter b Ceiling concentration 1 At present 10 fibers longer than 5 micrometers per cubic centimeter 2 Effective July 1 1976 No change 2. Methods of Compliance 1910.1001 c Engineering Methods Engineering controls such as isolation en- closure exhaust ventilation and dust collec- tion shall be used to meet the prescribed permissible exposure limits All hand operated and power operated tools which may produce airborne asbestos fibers in excess of permissible exposure limits _ shall be provided with local exhaust sys- tems Wet Methods When practicable asbestos products shall be handled in a wet state sufficient to pre- vent the emission of dust to the atmosphere This procedure is not required where the usefulness of the product might be diminished by wetting The applicability of wet methods is limited In most situations engineering controls provide more efficient pro- cedure 3. Personal Protective Equipment and Clothing 1910.1001 d e Respiratory Protection Respiratory protection is required whenever the airborne concentrations of asbestos fiber exceed either the permissible time weighted average level or permissible ceiling concentration The type of respirator to be used is determined by the fiber concentration in the workplace a Fiber concentrations up to but not ex- ceeding 10 times the allowable limit Air purifying respirator- reusable or single use b Fiber concentrations up to but not ex- ceeding 100 times the allowable limit Powered air purifying respirator c concentrations excee1d00itnimges the allowable limit Type C supplied air respirator Protective Clothing Whenever airborne fiber concentrations ex- ceed the prescribed ceiling level the employer shall provide and require the use of special clothing such as coveralls or similar whole body clothing head coverings gloves and foot coverings When the employer provides and requires the use of special clothing he shall also provide for the laundering or disposal of the special clothing Whenever airborne fiber concentrations ex- ceed either the permissible weighted average concentration or permissible ceil- ing concentration the employer shall provide change rooms for his employees Change rooms shall be equipped with two separate lockers or containers for each employee so separated or isolated as to prevent contamination of the employee's street clothes from his work clothes 4. Measurement and Monitoring 1910.1001 e f The standard requires that all workplaces where asbestos fiber may be released shall be monitored to determine exposure levels After initial determination of airborne con- centrations monitoring shall be of such frequency and pattern as to represent with reasonable accuracy the levels of exposure Monitoring must be repeated at no less than month intervals where exposure to asbestos dust may reasonably be foreseen to exceed permissible exposure limits All monitoring shall be done by the membrane filter method Appendix B provides a description of this procedure Affected employees or their representatives shall be given a reasonable opportunity to observe any required monitoring and shall have access to the monitoring records Any employee found to have been exposed at any time to airborne concentrations of asbestos fibers in excess of the prescribed limits shall be notified in writing of the exposure as soon as practicable but not later than five days of the finding 5. Caution Signs and Labels 1910.1001 g Caution signs shall be displayed at each workplace where asbestos fiber concentrations exceed permissible exposure limits Caution labels shall be applied to all materials and products which during any rea- sonably foreseeable use might release con- centrations of asbestos fibers in excess of permissible exposure limits Signs and labels are described in detail in Appendix A. 6. Housekeeping 1910.1001 h All external surfaces machinery and equip- ment shall be maintained free of asbestos fiber accumulations that might if dispersed create asbestos fiber concentrations above permissible exposure limits For recommendations on housekeeping procedures see Housekeeping section under General Recommendations 7. Recordkeeping 1910.1001 ) Every employer shall maintain records of personal and environmental monitoring required by the standard Records shall be maintained for a period of at least three years 8. Medical Examinations 1910.1001 ) Preplacement annual and termination medical examinations must be provided or made available by the employer for any employee . engaged in occupations exposed to airborne concentrations of asbes- tos fibers These medical records must be kept for 20 years and are available to the employee's physician General Recommendations Exhaust and Dust Collection Systems The OSHA Asbestos Standard requires that exhaust and dust collection systems be designed and maintained in accordance with American National Standard Fundamentals Governing the Design and Operation of Local Exhaust Systems ANSI Z9.2-1971 This publication is available from American National Standards Institute 1430 Broadway New York N.Y. 10018 The National ^ missionsStandards for Haz- ardous Air Pollutants NESHAPS as published by the Environmental Protection Agency in the Federal Register Vol 38 No. 66 dated April 6 1973 and amended Octo- ber 14 1975 state that there must be no visible emissions to the outside air from as- bestos mills or from buildings in which com- mercial asbestos is used in the manufacture of textile materials cement products fireproofing and insulating materials friction products paper millboard and felt floor tile plastics and rubber materials chlorine shotgun shells asphalt concrete paints coatings caulks adhesive and sealants Visible emissions are defined as emissions which contain asbestos and which are visu- ally detectable without the aid of instru- ments Rather than meet the visible- emission requirement air cleaning proce- dures using a fabric filter collector may be employed When the use of fabric filters creates a fire or explosion hazard use of a high energy wet collector may be authorized by EPA For small and intermittent production and fabrication operations major dust collection systems of the high volume low velocity type design described in the references above may not be necessary Instead sys- tems of the low volume high velocity type utilizing as their exhaust air source a high efficiency vacuum cleaner could be suitable For design information on these sys- tems attention is invited to the AIA booklet Recommended Work Practices on Shop and Field Fabrication of Asbestos Sheet Products This booklet is available on request to AIA All exhaust and dust collection systems should be inspected periodically for proper functioning For continuous operations it is recommended that the system operation and the interior of the baghouse be checked daily A scheduled maintenance program that includes bag replacement should be prepared and followed Wherever possible operations involving containing materials should be isolated from other work areas by partitions curtains or other means If central exhaust systemarse utilized the work areas should be gn pres- under maintained maintained maintained as as gn negative negative presnegative negative negative sure sure Housekeeping Housekeeping is an essential part of any manufacturing operation is even more essential in an asbestos plant because airborne dust created by lack of good housekeeping has the potential for harm to employees The OSHA Asbestos Standard stipulates that all external surfaces ainn anyplace of of fiber asbestos asbestos fiber A WAN WAN would be excessive with asbestos dust It is important that both new employees and employees with tenure have information concerning the safe use of asbestos brought to their attention at periodic intervals Each employee should be informed of a Operations which could result in exposure to excessive asbestos fibers b Engineering controls and workplace practices for employee protection c Purpose and proper use of respiratory equipment equipment equipment equipment equipment andMedical examination requirements e Provisions of the OSHA asbestos standard A copy of the OSHA Asbestos Standard should be available to employees The AIA pamphlet What Every Employee Should Know About Asbestos and Health is recommended for distribution to em- ployees The pamphlet is available at mini- mal cost from the Association Posters may an et et 808SIOS et et posters 808SIOS et posters Surface cleaning should be accomplished by a vacuum process Portable vacuum cleaning units should be equipped with internal filtration and disposable dust bags Single or hose stationary vacuum cleaning systems designed for use with | A Oa tian wel TL A record of employee training should be kept The record may appropriately include for each employee name social security number and job title along with the date including and description of training ma- terials distributed Vase Demes No visible emissions to the outside air may result from collection processing packaging transporting or deposition of any ascontaining waste material Alternatively wastes may be mixed with water and sealed in a labeled tight container and deposited at a disposal site or they may be formed into friable forms and deposited at a disposal site Specific Recommendations Normally friction materials should be ob- tained from the manufacturer in finished form cut machined and drilled to fit particular requirements This procedure avoids additional fabricating operations Fabricating equipment such as grinders lathes drill presses working on large capacity operations should be equipped with high volume low velocity exhaust and dust mendations on page & Intermittent short duration machining op- erations might be equipped with hign velocity low volume exhaust and dust collection systems All dust control systems which discharge exhaust air to atmosphere must be equipped with fabric filter collection devices U.S. Environmental Protection Agency National Emission Standards for Hazardous Air Pol- Asbestos Federal Register Vol 38 No. 66 dated April 6 1973 If dust control by means of exhaust ventilation is not feasible or practicable wet machining utilizing fluid cutting lubricants might be a suitable alternate Dust and chips generatedby the machining operations shoC 2 ved aquar preaby ) VETLUT methods ED 3.8- preaby paragraphparagraph tions After fabricating and before shipping all excess dust and chips should be removed from the surfaces of friction material to prevent dust contamination of the fabricator's workplace and no customer's workplace Information and Training Employees assigned to a work area where exposure to airborne concentrations of as- bestos fibers may exceed the maximum permissible permisble permissible permis ible limitslimits should be fully informed of the possible hazards to health associated theNESHAPS amend- ment dated October 14 1975. The OSHA OSHA Asbestos Standard requires that asbestos waste which when handled or transported could generate airborne fibers in excess of the permissible exposure limits be disposed of in sealed bags or closed con- tainers impermeable to asbestos fibers Personal Hygiene In the preparation of containing products unless good procedures are fol- lowed dust conditions can result Employees must be aware that inhalation of asbestos dust may be a serious risk to health Every effort should be made to eliminate dust conditions and avoid exposure to dust Good personal hygiene practices are important in every working situation When working with asbestos workers are urged to observe the following personal hygiene practices for their own health protection their families and those with whom they work Do not smoke Wash before eating Shower after work Respirators and special clothing are provided for worker protection under certain excessive dust level conditions These items of personal protective equipment deserve the highest respect of the worker and should be worn prop- erly when required Change to work clothes upon arrival at work and change from work clothes at conclusion of work Use change rooms for this purpose If work clothing is taken home carry in a bag impermeable to asbestos fibers and wash separately from other clothing Never shake dusty clothing Use a washing machine Appendix A RULES AND REGULATIONS Title LABOR Chapter Occupational Safety and Health Administration Depart- ment of Labor PART OCCUPATIONAL SAFETY AND HEALTH STANDARDS Standard for Exposure to Asbestos Dust On December 7 1971 an emergency _ temporary standard concerning exposure to asbestos fibers was published in the FEDERAL REGISTER 36 F.R. 23207 In ac- cordance with section 6 3 of the WilSteiger Occuptaional Safety and Health Act of 1970 a notice of proposed rulemaking regarding a permanent standard for exposure to asbestos fibers was published in the FEDERAL REGISTER ON January 12 1972 37 F.R. 466 The no- tice invited interested persons to submit both orally and in writing data views and arguments concerning the proposal On or about January 24 1972 the Advisory Committee on Asbestos Dust was established and requested to make written recommendations with regard to the proposed standard on asbestos On or about February 1 1972 the Department of Health Education and Welfare transmitted to the Secretary of Labor a criteria document containing Recommendations for an Occupational Exposure Standard for Asbestos by the National Institute for Occupational Safety and Health NIOSH Public notice was given of the receipt of the recommendations and their availability for inspection and copying On or about February 25 1972 the Advisory Committee on Asbestos Dust submitted its written recommendations to the Assistant Secretary of Labor for Occupational Safety and Health Note Federal Register Vol 40 No. 103 May 28 1975 p 23072 announced that the OSHA standard for Exposure to Asbestos Dust was recodified from 1910.93a to 1910.1001 Pursuant to the notice of rule making a hearing was held on March 14 through 17 1972 for the purpose of receiving oral data views and arguments concerning the proposed standard On or about March 31 1972 the presiding hearing ex- aminer certified to the Assistant Secre- tary of Labor for Occupational Safety and Health the record of the proceeding The record includes prehearing written comments a transcript of the oral presentations made at the hearing and numerous exhibits received during the course of the hearing or within the pe- riod allowed after the close of the hearing The proposed standard dealt with 1 permissible concentrations of asbestos fibers 2 methods of compliance 3 warning signs 4 monitoring 5 medical examinations and 6 recordkeeping Each of these major proposals elicited comments arguments objections and counterproposals They all have been examined and considered 1. Acceptable concentrations of asbestos dust The proposed standard would limit occupational exposure to hour weighted average TWA airborne concentrations of asbestos dust not exceeding five fibers longer than five micrometers per milliliter Concentrations above five fibers but not to exceed 10 fibers ceiling concentration would be permitted up to 15 minutes in an hour but for not more than 5 hours in any one hour day NIOSH in effect has recommended that the fiber TWA and fiber peak concentrations be permitted only for 2 years thereafter TWA concentra- tions should be not more than 2 fibers per cubic centimeter cm.of air and peak concentrations should not exceed 10 fibers with no time restriction Numerous objections and counterproposals have been made with regard to both the limits of asbestos fiber concentrations and the time periods to comply with them Some for example have recommended return to a fiber standard of an earlier day i.e. a level adopted under the Healey Public Contracts Act in 1969. Others have recommended a fiber standard to become effective in 6 months then a fiber standard for 2 years and finally a zerofiber standard after 3 years These recommendations give a fair indication of the wide spread of the counterproposals No one has disputed that exposure to asbestos of high enough intensity and long enough duration is causally related to asbestosis and cancers The dispute is as to the determination of a specific level below which exposure is safe Various studies attempting to establish quantitative relations between specific levels of exposure to asbestos fibers and the appearance of adverse biological manifestations such as asbestosis lung cancers and mesothelioma have given rise to controversy as to the validity of the measuring techniques used and the reliability of the relations attempted to be established Because of the long lapse of time between onset of exposure and biological manifestations we have now evidence of the consequences of exposure but we do not have in general accurate measures of the levels of exposure occurring 20 or 30 years ago which have given rise to these consequences There are also controversies concerning the relative toxicity of the various kinds of asbestos and varying hazards in different workplaces It is fair to say that the controversy has centered in the area between a twofiber TWA concentration and fiber TWA concentration with variations on the time needed for compliance Many employers support a fiber TWA Most medical opinion is divided between a fiber standard and a fiber standard In view of the undisputed grave con- sequences from exposure to asbestos fibers it is essential that the exposure be regulated now on the basis of the best evidence available now even though it may not be as good as scientifically de- sirable An asbestos standard can be re- evaluated in the light of the results of ongoing studies and future studies but cannot wait for them Lives of employees are at stake It is concluded that there should be one minimum standard of exposure to asbestos applicable to all workplaces exposed to any kind or mixture of kinds of asbestos Reasons of practical administration preclude a variety of stand- ards for different kinds of asbestos and of workplaces Also while the evidence tends to show that crocidolite for instance is more harmful than chrysotile the evidence is not sufficient to establish separate standards for varieties of asbestos Because there must be one standard governing exposure to all varieties of asbestos and in workplaces apparently more hazardous than others because some present employees with regular exposure to asbestos have probably already accumulated great doses of asbestos fibers due to higher levels of exposure in the past because it appears that levels of exposure which may be safe with regard to asbestosis are not safe with regard to mesothelioma because the statute requires the protection of every employee even of one who may have regular exposure to asbestos during a working life which may reach or even exceed 40 years and because of several other considerations which have been urged and are reflected in the record of the proceeding the conflict in the medical evidence is resolved in favor of the health of employees As of July 1 1976 TWA concentrations of asbestos fibers longer than 5 micrometers will not be allowed to exceed two fibers with a ceiling value of 10 fibers The current TWA concentrations of five fibers and ceiling concentrations of 10 fibers will be permitted until July 1 1976 during what will be a transitional period deemed necessary to allow employers to make the needed changes for coming into compliance with the more stringent standard The record shows that the many work operations subject to the single asbestos standard textile manufacturing industrial and marine installation etc. will meet varying degrees of difficulty in complying with the standard In some plants extensive redesign and relocation of equipment may be needed It appears however the delay in the effective date of the fiber standard will provide all employers a reasonable time to comply At the same time so long as the celling limit is complied with no harm is reasonably expected to result from exposures during the transitional period 2. Methods of compliance It has been pointed out by many persons that protection against asbestos fibers is best obtained by controlling the generation of fibers first and secondly by controlling the dispersion of released fibers into the ambient air of the workplaces Therefore the standard requires feasible technological controls and appropriate work practices as the primary means of compliance Rotation of employees as a way of meeting the TWA concentration requirement is allowed only in stated exceptional circumstances because as a general rule it would be difficult to implement Personal protective equipment such as respirators cannot be relied upon because among other reasons they may be so uncomfortable as to be bur- also many helpful comments The recom- densome except for short periods of mendations of NIOSH and of the Advi- time Therefore it is expected that respirators and shift rotation will be used during the period necessary to install en- sory Committee on Asbestos Dust were much more specific with respect to both frequency and type of medical examina- gineering controls and to train employees in sound work practices but after tions to be required The comments vary as to the class of employees to be ex- technological compliance has been achieved their use must be limited to amined and as to the frequency of the examinations special work situations and emergencies Where both are practicable shift rota- The adopted standard requires medical examinations both at the beginning and _ tion is required the termination of employments exposed 3. Labeling The proposed standard to concentrations of asbestos fibers and stopped short of requiring labeling as- also requires annual medical examina- bestos and containing products tions of every employee exposed to air- The proposed standard would have re- borne concentrations of asbestos It has quired only warning signs at locations been pointed out that in certain indus- where asbestos hazards are present tries such as construction an employee However labeling rather than warning may work for several employers during signs has proved to be a point of con- the same year Accordingly the standard troversy Both NIOSH and the Advisory does not require either preemployment Committee on Asbestos Dust recom- or termination or periodic examinaton mended labels for asbestos products and of any employee who has been examined containers and these recommendations in accordance with the standard within became very controversial in the course the past year of the proceeding Many counterpro- One question which has been raised proposals have been made as to the language of the warning as well as to the goes to whether the employer or the employee should be allowed to choose the products to be subject to the labeling examining physician The standard requirements Employers in general gives the option to the employer Since strongly contend that 1 finished prod- some employers already have a medical ucts which effectively entrap asbestos fibers so that these would not be released in the normal use of the products should examination program in operation and also have medical departments with some expertise in the diagnosis of abes- not be required to be labeled and 2 related diseases it seems more words such as danger and cancer are reasonable to permit them to utilize the unwarrantedly alarming Both contentions have merit and the standard has been changed accordingly present programs and expertise than to permit an employee to choose a private general practitioner 4. Monitoring The proposed standard would have required personal monitoring and environmental monitoring Many issues have been raised concerning the availability and reliability of measuring instruments frequency of monitoring and conditions in which monitor- 6. Records The standard as proposed and as adopted requires maintenance of records of monitoring and of medical examinations Most of the controversy in this area has revolved around the question whether an employer should be allowed to have access to the results of ing should be required The adopted standard takes the objections into consideration It requires periodic monitoring at intervals no longer than 6 months thus allowing considerable time and dis- the required medical examinations The apprehension of those who have argued against employer access is based on the expectation that some employers will use the medical examinations as a means of cretion and prescribes the use of the screening employment applicants and er? membrane filter method which is an ac- worse as grounds for discharging current ceptable method for determination of employees who show signs of being af- asbestos fibers fected by exposure to asbestos Since the It has also been recommended that purpose of the medical examinations is employees or their representatives should to monitor the health of employees ex- have an opportunity to observe the posed to the hazards of abestos em- monitoring The recommendation has been accepted 5. Medical examinations The pro- ployees cannot in reason be granted the privilege of refusing to disclose to their employers results of occupational expo- posed standard would only require an sure It does not make sense to require appropriate medical examination on a employers to provide medical examina- periodic basis The generality of the pro- tions if they cannot know and use the posal has attracted many objections and results of the examinations For these reasons the standard provides that employers may have a restricted access to some medical information On the other hand there is no intention to allow employers to abuse medical information obtained pursuant to the Act to the detriment of employees Therefore the administration of the medical records requirement will be closely watched and in cases of abuse appropriate action will be considered The issues discussed above are believed to be the major ones Numerous other issues have been raised in the rulemaking proceedings Some have been referred to incidentally Many recommendations for instance about work practices are so obviously meritorious that their adoption needs no exposition here Other recommendations and many objections have not been adopted for a variety of reasons which should be manifest Several for instance have recommended the use of respirators only pursuant to a variance or in cases of emergency and occasional short exposures The recommendation with respect to vari- ances undoubtedly has many merits but is considered administratively im- practical Accordingly after consideration of the whole record of the proceeding and pursuant to sections 6 b and c and c of the Williams Occupa- tional Safety and Health Act of 1970 84 Stat 1593 1596 1599 29 U.S.C. 655 657 29 CFR 1910.4 and to Secretary of Labor's Order No. 12-71 36 F.R. 8754 Part 1910 of Title 29 of the Code of Fed- eral Regulations is amended as set forth below 1910.1001 Asbestos a Definitions For the purpose of this section 1 Asbestos includes chrysotile amosite crocidolite tremolite anthophyllite and actinolite 2 Asbestos fibers means asbestos fibers longer than 5 micrometers b Permissible exposure to airborne concentrations of asbestos fibers Standard effective July 7 1972. The hour weighted average airborne concentrations of asbestos fibers to which any employee may be exposed shall not exceed five fibers longer than 5 micrometers per cubic centimeter of air as determined by the method prescribed in paragraph e of this section 2 Standard effective July 1 1976 The hour weighted average airborne concentrations of asbestos flhers to which any employee may be exposed shall not exceed two fibers longer than 5 micrometers per cubic centimeter of air as determined by the method prescribed in paragraph e of this section 3 Ceiling concentration No employee shall be exposed at any time to airborne cencentrations of asbestos fibers in excess of 10 fibers longer than 5 micrometers per cubic centimeter of air as determined by the method pre- scribed in paragraph e of this section c Methods of compliance Engineering methods 1 Engineering con- - trols Engineering controls such as but not limited to isolation enclosure exhaust ventilation and dust collection shall be used to meet the exposure limits prescribed in paragraph b of this section ii Local exhaust ventilation a Local exhaust ventilation and dust col- lection systems shall be designed constructed installed and maintained in accordance with the American National Standard Fundamentals Governing the Design and Operation of Local Exhaust Systems ANSI Z9.2 1971which is incorporated by reference herein b See 1910.6 concerning the availability of ANSI Z9.2 1971and the maintenance of a historic file in connec- tion therewith The address of the American National Standards Institute is given in 1910.100 iii Particular tools All hand erated and operated tools which may produce or release asbestos fibers in excess of the exposure limits pre- scribed in paragraph b of this section such as but not limited to saws scorers abrasive wheels and drills shall be pro- vided with local exhaust ventilation systems in accordance with subdivision ii of this subparagraph - 2 Work practices- Wet methods Insofar as practicable asbestos shall be handled mixed applied removed cut scored or otherwise worked in a wet state sufficient to prevent the emission of airborne fibers in excess of the ex- posure limits prescribed in paragraph b of this section unless the usefulness of the product would be diminished thereby ii Particular products and operations No asbestos cement mortar coating grout plaster or similar material containing asbestos shall be removed from bags cartons or other containers in which they are shipped without being either wetted or enclosed or ventilated so as to prevent effectively the release of airborne asbestos ^...bersin excess of the limits prescribed in paragraph b of this section iii Spraying demolition or removal Employees engaged in the spraying of asbestos the removal or demolition of pipes structures or equipment covered or insulated with asbestos and in the removal or demolition of asbestos insulation or coverings shall be provided with respiratory equipment in accordance with paragraph d 2 iii of this section and with special clothing in accordance with paragraph d 3 of this section d Personal protective equipment1 Compliance with the exposure limits prescribed by paragraph b of this section may not be achieved by the use of respirators or shift rotation of em- ployees except i During the time period necessary to install the engineering controls and to institute the work practices required by paragraph c of this section ii In work situations in which the methods prescribed in paragraph c of this section are either technically not feasible or feasible to an extent insufficient to reduce the airborne concentrations of asbestos fibers below the limits prescribed by paragraph b of this section or iii In emergencies iv Where both respirators and personnel rotation are allowed by subdivisions i ii or iii of this subparagraph and both are practicable personn^'lrotation shall be preferred and used 2 Where a respirator is permitted by subparagraph 1 of this paragraph it shall be selected from among those ap- proved by the Bureau of Mines Department of the Interior or the National Institute for Occupational Safety and Health Department of Health Education and Welfare under the provisions of 30 CFR Part 11 37 F.R. 6244 Mar. 25 1972 and shall be used in accordance with subdivisions i ii iii and iv of this subparagraph i Air purifying respirators A reusable or single use air purifying respirator or a respirator described in subdivision ii or iii of this subparagraph shall be used to reduce the concentrations of airborne asbestos fibers in the respirator below the exposure limits prescribed in paragraph h of this section when the ceiling or the hour weighted average airborne concentrations of asbestos fibers are reasonably expected to exceed no more than 10 times those limits ii Powered air purifying respirators A full facepiece powered air purifying respirator or a powered air purifying respirator or a respirator described in subdivision iii of this subparagraph shall be used to reduce the concentrations of airborne asbestos fibers in the respirator below the exposure limits prescribed in paragraph b of this section when the ceiling or the hour timeweighted average concentrations of asbestos fibers are reasonably expected to exceed 10 times but not 100 times those limits iii Type C supplied respirators continuous flow or pressure class A type C continuous flow or presdemand supplied respirator shall be used to reduce the concentrations of airborne asbestos fibers in the respirator below the exposure limits prescribed in paragraph b of this section when the ceiling or the hour timeweighted average airborne concentrations of asbestos fibers are reasonably expected to exceed 100 times those limits iv Establishment of a respirator pro- gram a The employer shall establish a respirator program in accordance with the requirements of the American National Standards Practices for Respiratory Protection ANSI Z88.2 196w9hich is incorporated by reference herein b See $ 1910.6 concerning the availability of ANSI Z88.2 196a9nd the maintenance of an historic file in connection therewith The address of the American National Standards Institute is given in 1910.100 c No employee shall be assigned to tasks requiring the use of respirators if based upon his most recent examination an examining physician determines that the employee will be unable to function normally wearing a respirator or that the safety or health of the employee or other employees will be impaired by his use of a respirator Such employee shall be rotated to another job or given the opportunity to transfer to a different position whose duties he is able to perform with the same employer in the same geographical area and with the same seniority status and rate of pay he had just prior to such transfer if such a different position is available 3 Special clothing The employer shall provide and require the use special clothing such as coveralls or similar whole body clothing head coverings gloves and foot coverings for any employee exposed to airborne concentrations of asbestos fibers which exceed the ceiling level prescribed in paragraph b of this section 4 Change rooms i At any fixed place of employment exposed to airborne concentrations of asbestos fibers in excess of the exposure limits prescribed in paragraph b of this section the employer shall provide change rooms for employees working regularly at the place ii Clothes lockers The employer shall provide two separate lockers or containers for each employee so separated or isolated as to prevent contamination of the employce's street clothes from his work clothes iii Laundering a Laundering of asbestos contaminated clothing shall be done so as to prevent the release of air- borne asbestos fibers in excess of the ex- posure limits prescribed in paragraph b of this section b Any employer who gives asbestoscontaminated clothing to another person for laundering shall inform such person of the requirement in a of this subdivision to effectively prevent the release of airborne asbestos fibers in excess of the exposure limits prescribed in paragraph b of this section c Contaminated clothing shall be : transported in sealed impermeable bags or other closed impermeable containers and labeled in accordance with paragraph g of this section e Method of measurement All de- terminations of airborne concentrations of asbestos fibers shall be made by the membrane filter method at 400-450 X magnification 4 millimeter objective with phase contrast illumination f Monitoring- Initial determi- nations Within 6 months of the publi- cation of this section every employer shall cause every place of employment where asbestos fibers are released to be monitored in such a way as to determine whether every employee's exposure to asbestos fibers is below the limits prescribed in paragraph b of this section If the limits are exceeded the employer shall immediately undertake a compliance program in accordance with paragraph c of this section 2 Personal monitoring Sam- ples shall be collected from within the breathing zone of the employees on membrane filters of 0.8 micrometer porossity mounted in an open filter holder Samples shall be taken for the determination of the hour timeweighted average airborne concentrations and of the ceiling concentrations of asbestos fibers ii Sampling frequency and patterns After the initial determinations required by subparagraph 1 of this paragraph samples shall be of such frequency and pattern as to represent with reasonable accuracy the levels of exposure of employees In no case shall the sampling be done at intervals greater than 6 months for employees whose exposure to asbestos may reasonably be foreseen to exceed the limits prescribed by paragraph b of this section 3 Environmental monitoring samples shall be collected from areas of a work environment which are represent- ative of the airborne concentrations of asbestos fibers which may reach the breathing zone of employees Samples shall be collected on a membrane filter of 0.8 micrometer porosity mounted in an open filter holder Samples shall be taken for the determination of the 8- hour weighted average airborne concentrations and of the ceiling concentrations of asbestos fibers ii Sampling frequency and patterns After the initial determinations required by subparagraph 1 of this paragraph samples shall be of such frequency and pattern as to represent with reasonable accuracy the levels of exposure of the employees In no case shall sampling be at intervals greater than 6 months for employees whose exposures to asbestos may reasonably be foreseen to exceed the exposure limits prescribed in paragraph b of this section 4 Employee observation of monitoring Affected employees or their representatives shall be given a reasonable opportunity to observe any monitoring required by this paragraph and shall have access to the records thereof g Caution signs and labels 1 Caution signs i Posting Caution signs shall be provided and displayed at each location where airborne concentrations of asbestos fibers may be in excess of the exposure limits prescribed in paragraph b of this section Signs shall be posted at such a distance from such a location so that an employee may read the signs and take necessary protective steps before entering the area marked by the signs Signs shall be posted at all approaches to areas containing excessive concentrations of airborne asbestos fibers ii Sign specifications The warning signs required by subdivision i of this subparagraph shall conform to the requirements of 20 x 14 vertical format signs specified in 1910.145 4 and to this subdivision The signs shall display the following legend in the lower panel with letter sizes and styles of a visibility at least equal to that specified in this subdivision Legend Asbestos 2a ..2---n~ e. e Notation " Sans Serif Gothic or Block Dust Hazard " Sans Serif Gothic or Block Avold Breathing Dust Wear Assigned Protective Equipment Do Not Remain In Area Unless Your Work Re- 1/4 Gothic ...Gothic ...Gothic quires It Breathing Asbestos Dust May Be Hazardous To Your Health 14 point Gothic Spacing between lines shall be at least equal to the height of the upper of any two lines 2 Caution labels Labeling Caution labels shall be affixed to all raw materials mixtures scrap waste debris and other products containing asbestos fibers or to their containers except that no label is required where asbestos fibers have been modified by a bonding agent coating binder or other material so that during any reasonably foreseeable use handling storage disposal processing or transportation no airborne concentrations of asbestos fibers in excess of the exposure limits prescribed in paragraph b of this section will be released ii Label specifications The caution labels required by subdivision i of this subparagraph shall be printed in letters of sufficient size and contrast as to be readily visible and legible The label shall state CAUTION Contains Asbestos Fibers Avoid Creating Dust Breathing Asbestos Dust May Cause Serious Bodily Harm h Housekeeping- Cleaning All external surfaces in any place of employ- ment shall be maintained free of accu- mulations of asbestos fibers if with their dispersion there would be an excessive concentration 2 Waste disposal Asbestos waste scrap debris bags containers equipment and contaminated clothing consigned for disposal which may produce in any reasonably foreseeable use handling storage processing disposal or transportation airborne concen- trations of asbestos fibers in excess of the exposure limits prescribed in paragraph b of this section shall be collected and disposed of in sealed impermeable bags or other closed impermeable containers ) Recordkeeping Exposure records Every employer shall maintain records of any personal or environmental monitoring required by this section Records shall be maintained for a period of at least 3 years and shall be made available upon request to the Assistant Secre- tary of Labor for Occupational Safety and Health the Director of the National Institute for Occupational Safety and Health and to authorized representa- tives of either 2 Employee access Every employee and former employee shall have reasonable access to any record required to be maintained by subparagraph 1 of this paragraph which indicates the employee's own exposure to asbestos fibers 3 Employee notification Any employee found to have been exposed at any time to airborne concentrations of asbes- tos fibers in excess of the limits pre- scribed in paragraph b of this section shall be notified in writing of the exposure as soon as practicable but not later than 5 days of the finding The employee shall also be timely notified of the corrective action being taken j Medical examinations- General The employer shall provide or make available at his cost medical examinations relative to exposure to asbestos required by this paragraph 2 Preplacement The employer shall provide or make available to each of his employees within 30 calendar days following his first employment in an occupation exposed to airborne concentrations of asbestos fibers a compre- hensive medical examination which shall include as a minimum a chest roent- genogram posterior 14 ^ 17 inches a history to elicit symptomatology of respiratory disease and pulmonary function tests to include forced vital capacity FVC and forced expiratory volume at 1 second FEV ) 3 Annual examinations On or be- fore January 31 1973 and at least 1nually thereafter every employer shall provide or make available comprehensive medical examinations to each of his employees engaged in occupations exposed to airborne concentrations of asbestos fibers Such annual examination shall include as a minimum a chest roentgenogram posterior 14 x 17 inches a history to elicit symptomatology of respiratory disease and pulmonary function tests to include forced vital capacity FVC and forced expiratory volume at 1 second FEV ) 4 Termination of employment The employer shall provide or make available within 30 calendar days before or after the termination of employment of any employee engaged in an occupation exposed to airborne concentrations of asbestos fibers a comprehensive medical examination which shall include as a minimum a chest roentgenogram posanterior 14 x 17 inches a history to elicit symptomatology of respiratory disease and pulmonary function tests to include forced vital capacity FVC and forced expiratory volume at 1 second FEV 5 Recent examinations No medical examination is required of any employee if adequate records show that the employee has been examined in accordance with this paragraph within the _ past year period - 6 Medical records- Maintenance Employers of employees examined pursuant to this paragraph shall cause to be maintained complete and accurate records of all such medical examina- tions Records shall be retained by employers for at least 20 years ii Access The contents of the records of the medical examinations required by this paragraph shall be made available for inspection and copying to the Assistant Secretary of Labor for Occupational Safety and Health the Director of NIOSH to authorized physicians and medical consultants of either of them and upon the request of an employee or former employee to his physician Any physician who conducts a medical examination required by this paragraph shall furnish to the employer of the examined employee all the information specifically required by this paragraph and any other medical information related to occupational ex- posure to asbestos fibers 1910.19 Special provisions for air con- taminants a Asbestos dust Section 1910.1001 shall apply to the exposure of every employee to asbestos dust in every employment and place of employment covered by 1910.12 1910.13 1910.14 1910.15 or 1910.16 in lieu of any dif- ferent standard on exposure to asbestos dust which would otherwise be applicable by virtue of any of those sections Note Following defines additional occupational areas affected by sec- tion 1910.19 above 1910.12 - Construction Work construction alteration and repair including painting and decorating 1910.13 . Ship Repairing 1910.14 - Shipbuilding 1910.15 - Shipbreaking 1910.16 - Longshoring Appendix B USPHS Membrane Filter Method For Evaluating Airborne Asbestos Fibers Nelson A. Leidel Stephen G. Bayer Ralph D. Zumwalde U.S. Department of Health Education and Welfare Public Health Service Center for Disease Control National Institute for Occupational Safety and Health Cincinnati Ohio 45202 November 1975 This report describes the equipment and procedures for collecting mounting sizing and counting asbestos fibers on cellulose ester membrane filters for the evaluation of breathing zone samples of airborne asbestos fibers The purpose of the method presented is to determine an employee's exposure to airborne asbestos fibers This is the method of test referenced in the Federal standard on occupational exposure to asbestos 29 CFR 1910.1001 formerly 29 CFR 1910.93a and the MESA Mining Enforcement Safety Administration air quality standards 30 CFR 55.5-1 b It is used by the National Institute for Occupational Safety and Health NIOSH and the Occupational Safety and Health Administration OSHA Preface f f It has been almost seven years since the last detailed information was published by NIOSH concerning an asbestos counting method Edwards and Lynch 1968 In the interim this method passed from a recommended status to one required by federal occupational health standard 29 CFR 1910.1001 formerly 1910.93a This report was prepared to expand on the 1968 paper It incorporates much of the sampling and analytical experience of the last seven years accumulated by counts made by NIOSH laboratories and the OSHA Analytical Services Laboratory The report attempts to answer many of the practical questions concerning the method A draft of this report has been used for the last two years by the NIOSH Division of Training in a course on asbestos sampling and analysis Recently a report prepared by the Joint ACGIH Aerosol Hazards Evaluation Committee was published in the AIHA Journal Recommended Procedures for Sampling and Counting Asbestos Fibers AIHAJ 36 pp 83-90 1975 The ACGIH report was not submitted for technical review to either NIOSH or OSHA personnel responsible for technical procedures of the USPHS asbestos count method The ACGIH report contains conflicting and possibly confusing guidelines This NIOSH report contains the NIOSH technical guidelines and procedures referenced in the Federal asbestos standard 29 CFR 1910.1001 formerly 29 CFR 1910.93a The guidelines of this NIOSH report should be carefully and consistently followed by personnel collecting and evaluating asbestos samples in order to yield accurate results , Table of Contents oT) Scope Summary of Method Significance Definitions Interferences Apparatus Reagents Safety precautions Sampling Calibration and Standardization Procedure XII Calculations of Airborne Concentrations XIII Precision and Accuracy XIV References | SCOPE A. This method describes the equipment and procedures for collecting mounting sizing and counting asbestos fibers on cellulose ester membrane filters in the evaluation of breathing zone samples of airborne asbestos fibers The purpose of the method is to determine an em- ployee's exposure to airborne asbestos fibers The method is primarily a personal monitoring technique but can be used for area monitoring B. The method has been successfully applied using 37 mm Millipore AA filters and small battery operated personal sampling pumps at a flow rate of 1.0 to 2.5 liters per minute Ipm for time periods of a few minutes to 150 minutes at concentrations of 1 to 20 fibers longer than 5 micrometers centimeter Large deviations from these conditions may result in samples with either too few or too many fibers which will yield air concentration estimates of low statistical precision and accuracy C. This method considers only fibers with a length to width ratio of 3 to 1 or greater and a length greater than 5 micrometers || SUMMARY OF METHOD The sample is collected by drawing air through a membrane filter by means of a battery powered personal sampling pump The filter is transformed from an opaque solid membrane to a transparent optically homogeneous gel The fibers are sized and counted by phasecontrast microscope at 400-450X magnification III SIGNIFICANCE This type method was first used by the Asbestosis Research Council in Great Britain ) and later was slightly modified by the U.S. Public Health Service for asbestos dust studies in the United States 2 It has been referenced as the method of test 3 for the Federal standard for asbestos in industrial air 29 CFR Part 1910.1001 formerly 29 CFR 1910.93a and the MESA air quality standard 30 CFR 55.5-1 in the NIOSH Criteria Document on occupational exposure to asbestos 4 in sampling procedures of the Occupational Safety and Health Administration Department of Labor 5 It is the method used by NIOSH and taught in NIOSH Division of Training Course 582 Sampling and Evaluating Airborne Asbestos Dust Finally the procedure has been submitted to the ASTM for consideration as an ASTM Meth- od of Test IV DEFINITIONS Asbestos fibers means asbestos fibers longer than 5 micrometers Asbestos includes chrysotilo amosite crocidolite tromolite anthophyllite and actinolite For definitions of terms used in this report refer to ASTM Definitions D 1356 Terms Relating to Atmospheric Sampling and Analysis V INTERFERENCES All particulates with a length to width ratio of 3 to 1 or greater and length greater than 5 micrometers should in the absence of other information be considered to be asbestos fibers and counted as such VI APPARATUS A. Sampling Equipment The personal sampling equipment train consists of ) personal sampling pump 2 tubing 3 clothing spring clip 4 tubing monitor metal adaptor and 5 field monitor collecting filter and holder 1. Personal sampler pump The pump must be battery powered and weigh less than 2 pounds 0.9 kg The pump must be capable of sampling at 1.0 to 2.5 1pm against a flow resistance of 7.5 inches of water 1.4 cm Hg for 8 continuous hours on a fully charged battery 2. Tubing Laboratory tubing such as rubber or plastic with 6 mm bore ...inch and about 90 cm length 3 feet 3. Clothing spring clip This clip attaches the rubber tubing to the lapel or shirt of the individual being monitored Large spring paperclips will also work 4. Tubin monitor adaptor A short adaptor with ridges on one end to grip the inside of the tubing The other end is designed for a pressure fit into the field monitor 5. Field monitor collecting filter and holder The only field monitor currently considered acceptable by NIOSH is manufactured by the Millipore Corporation The unit consists of 1 a section styrene plastic case designated Millipore aerosol Monitor Case 2 a 37 mm diameter plain white cellulose ester membrane filter designated Millipore AA nominal pore size of 0.8 micrometer 3 a support pad and 4 two plastic sealing caps If a large number of samples are to be taken it will be less expensive to reuse the plastic cases Great care must be taken in the cleaning and reassembly process The outside mating surfaces of the field moni- tors should be covered with shrink sealing bands to seal the units and provide a writing surface for filter identification B. Optical Equipment 1. Microscope body with binocular head 2. 10X Huygenian eyepieces are recommended Other eyepieces can be substituted if necessary 3. Koehler illumination preferably built in and having provisions for adjusting light intensity 4. A Porton reticle is recommended Others such as the Patterson Globe and Circle can be substituted if necessary 5. Mechanical stago 6. Abbe and Zernike condenser fitted with phase ring or Heine with a numerical aperture N.A. equal to or greater than the N.A. of the objective 7. 40-45X N.A. 0.65 to 0.75 positive phase contrast achromatic objective 8. Phase centering telescope or Bert- rand lens 9. Green filter if recommended by micro- scope manufacturer 10. Stage micrometer with 0.01 _mm sub- divisions For general guidance on microscopes consult Needham 6 and Clark 7 under phase contrast microscopes and accessories C. Filter Mounting Equipment Experience has shown that certain equipment is useful for efficient sample mounting The following items are recommended for extracting and mounting a portion of the filter onto the microscope 1. Microscope slides 2.5 by 7.5 cm one inch by three inches glass slides are most commonly used Sample number data initials etc. can be conveniently written on a frosted end slide 2. Cover slips Cover slips are a necessary part of the slide mount and optical system The shape should be appropriate for the size of the filter wedge The appropriate cover slip depends upon the objective to be used Ordinarily objectives are optically corrected for 10.17 millimeter thickness cover slip Improper cover glass thickness 3. Scalpel A scalpel is needed to remove a portion of the filter to be examined A number curved blade scalpel works very well 4. Tweezers A pair of tipped tweezers is used to remove the membrane filter slice from the field monitor and place it upon the slide 5. Lens tissue To insure cleanliness use of a free tissue is recommended This tissue should also be used for wiping mounting tools and for cleaning slides and cover slips 6. Glass rod or spatula A spatula or firepolished glass rod is needed to spread the mounting solution on the slide 7. Wheaton Balsam bottle This special glass container has a glass top which prevents contamination of the mounting solution A glass rod is included for dispensing the solution . VII REAGENTS Chemicals should be reagent grade free from particles and color conforming to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available Chemicals required are A. Dimethyl phthalate B. Diethyl oxalate VIII SAFETY PRECAURONS Avoid getting the mounting solution on the skin Wash skin promptly with soap and water if skin contact occurs IX SAMPLING A. General Information : General guidelines for the monitoring of omployee exposures to industrial atmospheres are given in reference 8 The Federal requirements regarding employee exposure monitoring for airborne asbestos are given in 29 CFR 1910.1001 B. Calibration The personal sampling pump should be recharged prior to calibration and then calibrated 9 against a bubble meter wet test meter spirometer or smillar device at 1.0 to 2.5 1pm The sampling train used in the calibration pump hose filter should be the same as the one used in the field The calibration should be of sufficient accuracy that the 95 confidence limits on the flowrate are 10 ( two standard deviations C. Mounting the Sampling Pump on the Worker Fasten the sampling pump to the worker's belt and fasten the field monitor to the lapel or shirt front as close to the face as is practical Remove the top cover of the plastic monitor then invert the monitor making certain the exposed filter is facing downward Turn on the pump and adjust to the previously calibrated flowrate 1.0 to 2.5 1pm Immediately record the following information in a logbook 1. Filter number 2. Pump start time and date 3. rate Flow 4. Subject's name operation 5. Type of operation ap roved for worker 6. Ventilation controls is wearing a respirator approved for asbestos The pump should be checked periodically dur- ing the sampling period for proper operation and flowrate D. Optimum Sampling Times The requirement for a minimum count of 100 fibers or 20 fields in Section XI below was determined to be the optimum chioce to achieve low variability of the fiber count as approximated by the Poisson distribution and reduced counting times Another way of looking at this requirement is that the optimum fiber density on the filter should be one to five fibers per microscope counting field To estimate optimum sampling times one must know in advance the approximate field area of the counting scope and the pump flow rate folowing equation The following optimum sampling times calculatecan then be plotted on log paper Minutes MFA 1000 where FL == 1 to 5 fibers ECA = effective collecting area of fil- ter 855 mmfor 37 mm filter MFA =: microscope field area gener- ally 0.003 to 0.006 mm FR - Pump flow rate generally 1.0 to 2.5 1pm AC = Air concentration of fibers in fibers Figures 1 and 2 show typical sampling times for a pump flow rate of 1.7 1pm Figure 1 is for a microscope field area of 0.003 mmIn Fig- ure 2 we see that the sampling times which yield optimum fiber density on the filter are in the range 40 to 80 minutes for a 1.7 1pm sampling rate and 0.006 mmfield area Each individual responsible for sampling asbestos should prepare a similar chart for his particular pump flow rate and field area before sampling is performed to avoid filters that are too light for reliable statistics or too heavily loaded to count However note that the upper limit on _ the optimum counting density of 5 fibers is an arbitrary one This upper limit is highly dependent on the background particulate density Under very light background conditions the upper limit for reliable counts may extend to 25-30 fibers From Figures 1 and 2 it can be seen that there are certain sampling times which will yield optimum fiber densities on the filter for almost all airborne fiber concentrations from 1 to 10 cu.cm These optimum times have been calculated and are presented in Figure 3. Note that the optimum times given by Figure 3 are approximate and can be varied by as much as 25 percent The nomogram is intended as a guide to be used where no prior knowledge of the air concentration is available If after sampling for the times recommended by Figure 3 the sample is very heavily loaded greater than 10 fibers then the air concentration probably greatly exceeded the ceiling standard of 10 cu.cm Conversely if the filter fiber density is very low less 1than fiber then concentration standard than the air probably was the 1976 Federal hour average standard standard of 2 cu.cm 29 CFR 1910.1001 b effec- tive July 1 1976 The nomogram gives the sampling times which produce optimum fiber densities on the filter 1 to 5 fibers for air concentrations of 1 to 10 fibers E. End of Sampling Period Remove the field monitor replace the plastic top cover and the small end caps and store the monitor Always shut off the pump when changing monitors to avoid contaminating or damaging the pump Record the pump shutoff time and flowrate in the logbook F. Blanks With each batch 25 to 50 filters of samples submit two unopened filters which have been subjected to the same handling as the samples except that no air has been drawn through them Label these as blanks If the blanks yield fiber counts greater than about 5 fibers fields then the entire sampling procedure should be examined carefully for the cause of contamination Figure 1 - Optimum sampling times for airborne asbestos where microscope field area = 0.003 sq mm 10 t Ceiling std Air Air T 1972 hr.TWA std | heavy heahveyavy ttooo Maybe Maybe ~ Plant Plant of fiber Optimum Optimum fibers / fibers CC field- field- CC field- field- Fibers N _ 1976 hr.TWA std light Fibers Fibers Too , t 10 15 { 100 200 500 1000 Sampling Time in Minutes @ 1.7 Ipm Figure 2 Optimum sampling times for airborne asbestos where microscope field area = 0.006 sq mm 10 i Ceiling std heavy too Air Air Maybe Air 12 l- 1972 hr.TWA std Maybe _ Plant Plant of fiber of fiber Optimum CC field- Optimum field- 1976 field- / Fibers 2 hr.TWA hr.TWA ~ Fibers light Fibers light Too 1' 10 15 ; 100 200 500 1000 Sampling Time in Minutes @ 1.7 Ipm Figure 3 - Nomogram for optimum sampling times for airborne asbestos fibers a 30EXAMPLE = 1.7 1pm 4 A = 0.00302 mm -0.007 4 READ OPTIMUM TIME = 120 min a -25 % 1pm minutes -0.006 1 minutes 50- minutes m TIME RATE TIME AREA SAMPLING 4 -0.005 , FLOW FIELD SAMPLING 4 -0.004 -0.004 SAMPLING 100- SAMPLING 4 OPTIMUM PUM 4 OPTIMUM 4 , FR OPTIMUM 0.003 MICROSPE a OPTIMUM - 7 A 200- 4 NIOSH / Leidel 1.0 300-0.002 G. Shipping The field monitors in which the samples are collected should be shopped in a rigid container with sufficient packing material to prevent crushing H. Numbers of Samples When sampling for the ceiling standard 29 CFR 1910.1001 effective July 7 1972 only one sample minute maximum duration is theoretically necessary However sev- eral samples should be taken during expected periods of peak air concentrations to allow for detection of gross sampling or counting errors When sampling for determination of noncompliance with the hour TWA standard one should continuously sample as large a portion of the work day as is feasible 29 CFR 1910 1001 or b Normally this would mean 6 to 10 consecutive samples on the same man However if this is not feasible the hour TWA air concentration can be estimated from fewer than 6-10 samples Leidel and Busch 10 have shown an optimum number would be 4 to 7 Refer to reference 10 for treatment of the data for the determination on noncompliance See the NIOSH handbook 8 and Jones and Brief 11 for how to treat data taken for an employee exposure monitoring program ^ CALIBRATION AND STANDARDIZATION A. Porton Reticle and the Counting Field The asbestos fiber count procedure consists of comparing fiber length with calibrated circles and counting all fibers greater than 5 micrometers in length within a given counting field area It is recommended that a Porton reticle be used for this purpose The Porton reticle is a glass plate inscribed with a series of circles and rectangles The square on the left divided into six rectangles is defined as the counting field B. Placement in Eyepiece The Porton reticle is placed inside the Huygenian eyepiece where it rests on the fieldlimiting diaphragm The reticle should be kept clean since dirt on the reticle is in focus and will complicate the counting and sizing process For mounting in other eyepieces such as a Ramsden a counting collar must be used C. Stage Micrometer The Porton reticle cannot be used for counting until it has been properly calibrated with a stage micrometer Most stage micrometer scales are approximately two millimeters long and are divided into units of hundredth of a millimeter or ten micrometers D. Microscope Adjustment When adjusting the microscope follow the manufacturer's instructions while observing the following guidelines 1. The light source image must be in focus and centered on the condenser iris or annu- lar diaphragm 2. The object for examination must be in focus 3. The illuminator field iris must be in focus centered on the sample and opened only to the point where the field of view is illumi- nated 4. The phase rings annular diaphragm and shifting elements must be concentric E. Porton Reticle Calibration Procedure Each eyepiece combination on the microscope must be calibrated Should any of the three be changed disassembly replacement zoom adjustment etc. the combination must be recalibrated Calibration may change if interpupillary distance is changed For proper calibration the following procedure should be , followed closely With a 10X objective in place place the stage micrometer on the mechanical stage focus and center the image Change to the 40-45X objective and adjust the first scale division to coincide with the left boundary of the Porton rectangle Count the number of divisions between the left and right boundaries of the long horizontal dimension of the largest rectangle estimating any portion of the final division This measurement represents 200 L units and one divides the measurement by 200 to find L The large rectangle is 100 L units long on the short vertical dimension The calculated L is inserted into the formula = 2N where N is the circle number indicated on the reticle and D is the circle diameter Since the circle diameters vary logarithmically every other circle doubles in diameter For example number three is twice the diameter of number one number four is twice the diameter of number two When the circle sizes have been determined the counting field area consisting of the left six smaller rectangles can be calcu- lated from the relation 10,000 L. This completes the reticle calibration for this specific objective combination XI PROCEDURE A. Preparation of Mounting Solution A very important part of the sample evaluation is the mounting process This process involves a special mounting medium of prescribed viscosity The proper viscosity is important in order to expedite filter clearing and minimize particle migration Once the sample has been mounted an elapsed time of approximately fifteen minutes is needed before the sample is ready for evaluation Combine the dimethyl phthalate and diethyl oxalate in one to one ratio by volume and pour into a Wheaton balsam bottle Add 0.05 gram of new membrane filter per milliliter of solution to reach the necessary viscosity The mixture must be stirred periodically until the filters have dissolved and a homogeneous mixture is formed The normal shelf life of the mounting solution is about six months Twenty milliliters of mounting solution will prepare approximately 300 samples B. Sample Mounting Cleanliness is important A dirty working area may result in sample contamination and erroneous counts The following steps should be followed when mounting a sample 1. Clean the slides and cover slips with lens tissue Lay the slide down on a clean surface with the frosted end up It is a good practice to rest one edge of the cover slip on the slide and the other edge on the working surface By doing this you keep the bottom surface the one which contacts the filter from becoming contaminated 2. Wipe all the mounting tools clean with lens tissue and place them on a clean surface such as lens tissue When mounting a series of filters the scalpel should be wiped clean before cutting each sample 3. Using a glass rod which is supplied with the Wheaton balsam bottle apply a small drop of mounting solution onto the center of the slide It may be necessary to adjust the quantity of solution used or the size of the wedge The correct amount will result in the solution extending only slightly beyond the filter boundary If the quantity is greater than this adverse particle migration will occur 4. With the spatula or a supplemental glass rod spread the mounting media into a tri- count in either direction from circumference to wedge tip Random fields are selected without looking into the eyepieces by slightly advancing the slide in one direction with the mechanical stage control angular shape The size of this triangle should coincide with the dimension of the filter wedge D. Achieving Comparable Results 1. Size only fibers with a length to width ratio greater than or equal to 3 5. Separate the middle and bottom sections of the field monitor case to expose the fragile filter Cut a triangular wedge from the center to the edge of the filter using the scalpel The size of the wedge should ap- proximate eighth of the filter surface 6. Grasp the filter wedge with the tweezers in the outer area of the filter which was clamped between the monitor case sections Do not touch the filter with your fingers Place the wedge sampled side up upon the 2. Count only fibers greater than 5 micrometers in length Be as accurate as possible in accepting or rejecting fibers near this length Measure curved fibers along the curve to estimate the total length 3. Count as many fields as necessary to yield a total count of at least 100 fibers Exceptions a count at least 20 fields even if you count more than 100 fibers and b stop at 100 fields even if you haven't reached 100 fibers mounting medium 4. Select the field of view without looking 7. Pick up the cover slip with the tweezers through the microscope's eyepieces to elimi- a) and carefully place it on the filter wedge nate unconsciously selecting heavy or Once this contact has been made do not light areas a2 PaCS reposition the cover slip mote 5. The fields are selected along the entire 34 Bs. Ge 3. Label the slide with the sample number length of a radial line running between the a d and current date before proceeding to the outside perimeter and the tip of the wedge next filter 6. When an agglomerate mass of material 9. The sample should become transparent covers a significant portion of the field of after about fifteen minutes If the filter ap- view approx 1/6 or greater reject the field pears cloudly it may be necessary to press and select another Do not include it in the very lightly on the cover slip This is rarely number of fields counted However report necessary the fact as it may have meannig to sampling 10. Discard the sample mount after three days if it has not been counted Crystals which appear similar to asbestos fibers may begin to grow at the mounting media interfaces They seldom present any prob- lems if the slide is examined before three days In any case stay away from the filter's edges when counting and sizing C. Counting and Sizing Finding and inspecting counting fields Place the slide on the mechanical stage and positoin the center of the wedge under the objective lens and focus upon the sample Nearly all of the particulates particles and fibers will be found in the upper ten to fifteen micrometers of the filter surface When counting and sizing continual use of the fine focus control is re- quired to insure that nothing is missed Start counting from one end of the wedge and progress along a radial line to the other end or medical personnel 7. Bundles of fibers are counted as one fiber unless both ends of a fiber crossing another can be clearly resolved . 8. For fibers that cross either one or two sides of the counting field the following procedure is used to obtain a representtaive count First arbitrarily select a the left and bottom sides and b the upper and lower left corners and vertical direction as decision aids Then count any fiber greater than 5 micrometers in length but only if the fiber a lies entirely within the counting area or b crosses the left or bottom sides or c crosses the upper or lower left corners or d crosses both the top and bottom sides Reject and do not count all other fibers Refer to Figures 4 through 9 Figure 4. COUNT fiber crosses both top and bottom sides Figure 5. COUNT as one fiber et a Yan, 4 es Nk tad RSgSt take peumeg dee Pe 2 en Be Ar 7 ae oe 3a Gs tet Care a Ks ake yal sea corner Figure 9. COUNT fiber crosses upper left corner Po Nees CN Ee a parasio: (| Bat yh enn AY Ee EY Ge * v; a eae geo ye M4 { G iW ai San EAS ares AE XII CALCULATIONS OF AIRBORNE CONCENTRATIONS Asbestos fiber airborne concentration may be calculated from the following formula C FB A Where C = Airborne fiber concentrations in fibers . > cm F = Average fiber count in fibers > ...m field B = Average fiber count of blank or con- trol filter in fibers > field It is subtracted to eliminate the error or background contamination W _ 855 mmfor 37 mm diameter filter the portion of the Millipore filter which is exposed when mounted in the field monitor case i.e. the effective filter area A = The area of the counting field of a calibrated reticle expressed in field V Total air volume collected through filter expressed in milliliters XIII PRECISION AND ACCURACY A. An accuracy and precision study of the membrane filter counting procedure for asbestos has been conducted by Conway and Holland 12 They conducted an intralaboratory study involving six counters Three of the counters were experienced while the other three had only a short familiarization with the rules for fiber counting The conclusions of the study included 1. The precision of the procedure for filters not containing an abundance of fine fibers can be estimated by a standard deviation of 16.2 This value includes variation among counters and observed interaction effects 2. The accuracy of the procedure for similar filters may be estimated for a fiber count by a standard deviation of 21.4 This assumes that the contribution of the overall variance from the nonuniform fiber distribution is additive 3. The fiber concentration varies significantly between angular sectors on a given filter Where approximately 100 fibers are counted the standard deviation of the fiber count distribution for the whole filter appears to be represented by 1.6 rather than which is a property of the Poisson distribution where n is the total number of fibers counted 4. A high percentage of very fine fibers on the filter can significantly affect the standard deviation and confidence limits for counts by different counters After combining variations in fiber concentrations over the entire filter with those for different counters it was con- cluded . a For filters with a low concentration of the fibers the standard deviation is estimated at 21 and the 95 confidence interval is 43 . b For filters with a high concentration of fine fibers the standard deviation is esti- mated at 25 and the 95 confidence interval is 50 B. Lynch Kronoveter and Leidel 13 have also reported on the precision of the method Their intralaboratory study utilized the data from a large number of dust counts made by different methods by experienced counters over a period of years in an ^'pidemiologic study of the asbestos products industry They concluded that the standard deviation of counts of fibers longer than 5 micrometers on mem- brane filters could be estimated from the rela- tion = 0-591 Thus for counts of about 100 fibers the standard deviation could be esti- mated at about 15.2 and the 95 confidence limits at 30.4 These values are lower than the precision values reported by Conway and Holland 12 C. Systematic inaccuracies can be introduced by the improper choice of microscope or by not checking a particular individual's counts in relation to other counters Leidel and Busch 14 found that one particular microscope tested yielded counts that were approximately 45 higher on the average than counts from four other microscopes in a phase contrast michoscope evaluation Also one particular counter produced counts that were 27 higher on the average Leidel and Busch 14 concluded that a significant difference in asbestos fiber counts can result when the same filters are counted on different makes and models of microscopes Significant differences can also exist between trained counters They concluded that any laboratory counting asbestos on membrane filters should be part of an interlaboratory collaborative quality program This participation will insure that 1 equipment is propertly adjusted and calibrated 2 counters are properly trained and their counting efficiency is continually evaluated and 3 com- parable results are obtained from each labora- tory This type of quality control program is conducted by NIOSH as the Proficiency Analytical Testing PAT program The PAT program is used by the AIHA as part of their Laboratory Accreditation Program which is partially funded by NIOSH XIV REFERENCES 1 Asbestos Research Council The Measure- ment of Airborne Asbestos Dust by the Membrane Filter Method Technical Note Dr. S. Holmes Secretary P.O. Box 40 Rockdale Lancashire Great Britain 1969 Edwards G. H. and J. R. Lynch The Method Used by the U.S. Public Health Service for Enumeration of Asbestos Dust on Membrane Filters Annals of Occupational Hygiene 11 1-6 1968 Federal Register 39 23543-23545 June 27 1974 U.S. Department of Health Education and Welfare Public Health Service National Institute for Occupational Safety and Health Criteria for a Recommended Standard- Occupational Exposure to Asbestos HSM 72-10267 1972 U.S. Department of Labor Occupational Safety and Health Administration OSHA Sampling Data Sheet No. 2- Asbestos Unpublished - Jan. 1972 Needham G. H The Practcial Use of the Microscope Charles C. Thomas Publish- ing Corp. Springfield Illinois 1958 7 Clark G. .: The Encyclopedia of Micros- copy Rheinhold Publishing Corp. N.Y. 1961 ; 8 Handbook for Compliance Determinations of Employee Exposure to Industrial Atmos- pheres USPHS NIOSH Technical Publica- tion to be published 1975 American Conference of Governmental In- dustrial Hygienists Air Sampling Instru- ments for Evaluation of Atmospheric Contaminants Fourth Edition Section K Air Movers and Samplers pp 26 P.O. Box 1937 Cincinnati Ohio 1972 10 Leide N. A. and K. A. Busch Statistical Methods for the Determination of Noncompliance with Occupational Health Standards NIOSH Technical Publication 75-159 1975 11 Jones A. R. and R. S. Brief Evaluating Benzene Exposures AIHA J. 32 610-613 1971 12 Conway R. E. and Holland W. D Statis- tical Evaluation of the Procedure for Count- ing Asbestos Fibers on Membrane Filters LFE Corporation Richmond CA. Prepared for Asbestos Information Assoc./North America New York N.Y. 1973 13 Lynch J. R. K. H. Kronoveter and N. A. Leidel Validity of the Poisson Distribution in Dust Counting USPHS NIOSH unpublished house report TR 14 Leidel N. A. and K. A. Busch An Evaluation of Phase Contrast Microscopes for Asbestos Counting presented at the 1974 American Industrial Hygiene Conference Miami Beach Florida 18 May 1974 NIOSH unpublished house report TR 1 - Notes ; an A. SOURCES OF PERSONAL SAMPLER PUMPS 1. Mine Safety Appliance Company 201 North Braddock Avenue Pittsburgh PA 15208 2 National Environmental Instruments Inc. P.O. Box 590 Warwick RI 02888 3 Willson Products Divsiion ESB Incorporated P.O. Box 622 Reading PA 19603 B. SOURCE OF CLOTHING SPRING CLIP Catalog number 1140 John F. McGuire Company 120 Bacon Street Pawtucket RI 02860 C. SOURCE OF TUBING MONITOR ADAPTOR Catalog number LH Bection Dickinson & Company Rutherford NJ D. SOURCE OF FIELD MONITOR 1 Complete monitor plastic case filter pad and caps catalog number MAWP 037A0 box 2 Filters and pads only catalog number AAWP 03700 box 3 Monitors only catalog number M0000 37A0 box from the Millipore Corporation : Ashby Road Bedford MA 01730 E. SOURCE OF SEALING BANDS Cellulose bands white opaque 41x25 28 minimum order 2500 Walter H. Jelly & Company 2822 Birch Street Franklin Park IL 80131 It is recognized that equipment and services other than those cited in this report may be available Mention of company or product names is not to be considered an endorsement by NIOSH . Appendix C FL FL ABOVE LINE INCREASER LINE INCREASER LINE INCREASER BRANCH INCREASR HEADER HEADER HEADER HEADER BRANCH 2-2 BRANCH 2-2 BRANCH PLAN 2-2 PIPE 2 PLAN 2-2 PIPE 2 PLAN PIPE PLAN 3 2 HEADER Y HEADER FITTING HEADER FITING PIPE FITING PIPE in 3 (@) St STRAIGHT STRAIGHT 50385-4 STRAIGHT is 50385-4 STRAIGHT A DRINGS 101010 OF : DRINGS pig OF DRINGS .. LENGTH DISP LENGTH REFERENCE REFERENCE REFNCE DUST REFERENCE DUST REFERENCE MATERIAL REFRENCE TYP [ ' ath 2 Dat sitdyla SYSTEM VACUUM 4-0 SYSTEM SYSTEM 4-0 SEAMLES TYPICAL SYSTSEYSTMEM SEAMLESS STA TYPICAL SYSTEM VACUMTYPICAL TUBING ELEVATION TYPICAL TUBING TYPICAL ELVATION ELVATION TYPICAL VACUUM ELVATION VACUUM ELEVATION VACUUM ELEVATION VACUUM N".2 N".2 N".2 ALT TO COLECTOR TUBING COLECTOR TUBING COLECTOR 12 TUBING COLLECTOR GAUGE SEAMLES COLECTOR GAUGE SEAMLESS FLEX.CON GAUGE FLEX.CONN / (e) 16 SEAMLES FLEX.CON i ) 6 FLEX.CON J | } = z { =) om@. B.I. B.I. ELEVATION ELEVATION ow SCH.40 SCH.40 ELVATION SCH.40 NOTE PLAN LOCATIONS PLAN DROPS PLAN LOCATIONS PLAN DROPS ALL LOCATIONS ALL BRANCH LOCATION LOCATION ygLOCATION LOCATION & NUMBER NUMBER NUMBER . % DIST / DIST J VALVE y ALTERNATES ALTERNATES ROTARY 1.2.3.4 1.2.3.4 DISPOSAL D pnamene FLON TUBING FLON TUBING ELEVATION ELEVATION ELEVATION FLOOR ELEVATION FLOR ELEVATION - FLO RFLOOR TYP Em FACTORY fa{<| FACTORY fat FACTORY FACTORY FACTORY St Om Oe t For definitions of terms used in this report refer to ASTM Definitions D 1356 Terms Relating to Atmospheric Sampling and Analysis -- -- -- -- -- fl LENGTH \ SEAMLES SEE SEAMLES SEE SEAMLES a? fl fl LH fl . fl | Lt NOTED S418 TOLERANCS DDIIMMEENNSSIIOONNSS VC TOLERANCES CO FRACTIONALTOLERANCES SUTON FRACTIONALUNLES DECIMAL MOWARD - _ SQOHLW0-16 P-SOGE StenF-9OC0S l SNOWLV'sNOG -- SRE L817 . NES T| WIAHIOVA YAL WOMFAS DUCTLSid y ' COLETRNOD ce SECTION i D a W- | {1 9<4 [ C8 OL Ws SY \ LI Ly ee ALTERNATE ALTERNATE vos meme ALTERNERNAT USIKF 4748 A|F~fisy WO 7 KUO.LVS ') yoSs VACUM AYOLVI STAIONS VACUCM STAIONS- OLETR COLETR | Lo) jes Ah 3 ROTARY[siv VALVE 5 LIS TROWEISaot Ol \ / fo t-y 8t1 fo} \ I\ SQHLNTNOILS SEAML __ ar|TEE SEAMLES foriTT STRAIGHT | rytyet cr] IV colpst i} - INTERM J SN CONV ROTAY wus COLETR 47 40 ALTERN INTERM y-SVsO 33ROTARY 42ONG DAN ALTERN OO WOM4F2S SERTNeaeNSOavnLOe ON 90 QGOHLIN503-4 NOlLdiu9s30 MATERIAL 503-4LSI BAREL @i)1sa BARREL o028! ND Bl NO ne - Cv B,D 21) BAREL*X214 e4+ TYPICAL DUST ot & S82 DESCRIPTON AV 'Sry 3S 49 DESCRIPTON ware md DNIGL HLDNT1NOLS.2 JLIVNeSTV FLEX6'0-1FLEX~ 1 || FLEX ALTERN ALTERN ALTERN ANS * WONFas %* ALTERN AQLOITDSCINTES] DRLON SINVOLJSIAM HLO SNO A IG HOBN APO. vet1 ' + SBZINDTYNOUSVEsRIDOeenmmeiers Be D N INSURE ACAINST WARPACE IN WELDING ES TO COVER NO DESCRIPTION BWG 1 [1 | COMBS POKE HOLE INSPECT WINDOW 12545-2 i feTHK STL.P Lit D D TTTTTTT D TTTTTT TTTTTT D 62...DIA B.C. D D 64 DIA TYR 76 STL.BAFFLE 1-2" A DETAIL = 3 i / TYP b00d b0000d b0000d b0000d VF { NL? 43 1-88 He ! >f l U i 4 | rs : - 3 . 10 REMPOLAVTE AREMBOVLABELE IO GA BRACKET TYP SIDES 2 4 STL.PLATE J % f ~~ Hp 7 NY -A 34 7 FS HOLE - 2 PLACES .0 Sy .0 DETAIL Q3 .5 5-0 DETAIL 13 DIST TRAP VACUUM SYSTEM i i sr | . On Sh Pynos TWAT MANOom RATINGS I-SZOG] RATINGS 1OZ-a RATINGS RATINGS ~HOI INH AON PO A STANDR RATINGS RATINGS 150 STANDR STANDR STAIONS WOL SYTEM RATINGSRATINGSRATINGS BERCISED SYTEM STANDR RATINGS RATINGS SYTEM SYTEMS RATINGS RATINGS | RATINGS #2 YO STATIONS BERCISED DISTANCE TWO SYTEM FOUR WNDU EXTND BERCISDTWwiD2GaHL FT SYTEMS 1 G,. SN NVA SYSTEM ZAO SISXIXFOURYO ALS = FT SYTEM SYTEM Eda. FOUROlPRESYTEM EXTNDE EXTENDED % SYTEM TWO "OD 30 300 300 Bdi.&*ONa FOUR SANI ld aa 19 oN FOUR FOUR NVAOH ASNID IWAD HOZ-VS ZO-S " DBASTO FT SIX - FOURAMOW -LORUIG TI. aO Ld "SN QUANTI ES DETERMINED LEFT EXTND MATERIL QUANTIESQUANTIES SUITOPEN T249ST FATW QUANTIESTd 3030 "SN~= SUIT AMIES OPEN IN - ~ LI QUANTIES QUANTIES DETRMIN UENOIW SATdIN DETRMIN DETRMINBIWKTS TO ASOT AOT4 MOST DETRMIND MODS MODTS Losai NVI Tad INI FSO NA NIN LSna Lid MOdTa || | | ||[ on Vit |_ |_ _} 7 - -- | Afi t -IL il6 Ut -}z | p g |? 9 ol [SI [3 VW 5 SWAL[09-4 LSIT .O-NyDE DOYS | , Wa] 406] (lop-wancs] [LOP-N4D0 [o-wg0s}1]|[.Co-Rav TWRIALV T0sT - La 14 = OS! ost] OF 90 NILING | | aos N3dO e ONL wns KIS ONL XS Ld37 | || | DETAIL'S SILNWED Joa 39 WITS AS SWELA ROTARY WELSA 6 W TIN Ta | GSVANI Wad wo) Q3CNILXG a 8 OAL ATC . :: i ~~aasn y4&gz Gu30a al6; &^'a any LSPTSONIVA 264610 2 262461002 2624610002 ' g 2624610260224610r02anHOSEHOSEHOSEHOSE o 394639463 OROROROORREQUALEQUALEQUAEQLUAL EQUALEQUA] L 7) y ELBOWELBOWELBOWELBOW . RADIUS TWIdlvinWAILS THRD. - 202 EQUAL * 0 " NEWFLEXIBLFEXIBLE F5LANCEDFLANCoEFDLtANFCLAENCDEFLANCEDFLANCEDFLANCED agaNaoeO EQUAL EQUAL t Aq N _ CONN'DCONN'CDONN'.D PROF PROF MOTR PROFPROF PROFPROF PROF al MOTOR sa) &Zz U0 a oezof x F ~ rq in {4 4 * 692 MATERIAL one Bet e ea 2?u zoe Shadegar4 0 2 Se T t SYTESMYTEM MATERIL LIST 04 MATERIAL 10 4 MATERIAL | 1 :H MATERIALMATERIAL LIST LIST 1 RATINGS SYSTEM t 2 ^' 2 En re3ono84bchifts. t- < MM Zope/ winaggegKS0% , .e-,1(4ar) EN SYTEM id Rho aeof1 2075 ) ilacialia aa toate ; tw Wd / \ => +\ g ~ DIAGONALDIAGONAL 7 yeita8ytoa Dfig. aef2Gted oe ao=4Ag ) idUb i} \ : tH 7ua 7 \ e a ae 1.D HAL 10 10 ' P 10101010 60 4 = ~ wo zt ~ f ) 2 : gis< x ze a iua e So rSe0g OULON SYS * ieawuanuo sere ie 33;EE?#35 i: BLaiu ErBSBfHay|3+etosBestu Zz AS * :, VOLUME giafei ze5