Contents 1) Purpose... 3 2) Policy... 3 3) Definitions... 3 4) Procedure... 4 a) Requirements... 4 b) Noise standard... 4 c) Responsibilites... 5 d) Exposure Monitoring and Assessments... 6 e) Employee Training... 7 f) Audiometric Testing... 7 g) Equipment Purchases... 9 h) Program Administration... 9 i) Hearing Protection Selection... 10 j) Determining Hearing Protection Attenuation... 11 5) REFERENCES/RELATED LINKS... 11 6) ATTACHMENTS... 11 a) None... 11 Safety Policy and Procedures 2 OF 11 Revised 01/27/09
Orange County Sanitation District Section Number: SAFETY SOP-106 Effective / Revised Date: 06/18/08 Supersedes: New Subject: Hearing Conservation Program Approved by: 1) PURPOSE a) The purpose of this policy is to establish guidelines for use by OCSD staff in preventing employees from developing noise induced hearing loss on the job. This is done through equipment selection, exposure assessments, training, and annual hearing tests. 2) POLICY a) It is Orange County Sanitation District s (OCSD) policy to establish procedures and guidelines to identify preferred, standard methods for controlling employee noise exposures and to ensure that all staff and temporary workers at all sites comply with these standards. 3) DEFINITIONS Action Level: An 8-hour time weighted average of 85 decibels measured on the A-scale, slow response, or equivalently, a dose of 50 percent. Audiogram: A chart, graph, or table resulting from an audiometric test showing an individual s hearing threshold levels as a function of frequency. Audiologist: A professional specializing in the study and rehabilitation of hearing, who is certified by the American Speech, Hearing and Language Association or licensed by a state board of examiners. Baseline Audiogram: The audiogram against which future audiograms are compared. Continuous Noise: Noise with negligibly small fluctuations of level within the period of observation. Decibel (db): The unit of measure of sound level. dba (decibels-a-weighted): A unit of measurement of sound level corrected to the A-weighted scale, as defined in ANSI S1.4-1971, using a reference level of 20 micropascals (0.00002 Newton per square meter.) Hertz (Hz): A unit of measurement of frequency, numerically equal to cycles per second. High Noise Area: An area where equipment operates in excess of 85 dba. Impulsive Noise: Noise that is characterized by a sharp rise and rapid decay in sound levels and is less than 1 second in duration. Intermittent Noise: Noise levels that are interrupted by intervals of relatively low sound levels. Medical Pathology: A disorder or disease affecting the ear, which should be treated by a physician. Noise Dosimeter: An instrument used to measure sound level over the course of a work shift. Safety Policy and Procedures 3 OF 11 Revised 01/27/09
4) PROCEDURE Noise reduction rating (NNR): Measure of the estimated attenuation capacity of a hearing protector to represent the approximate noise reduction, in dba Otolaryngologist: A physician specializing in the diagnosis and treatment of disorders of the ears, nose and throat. Representative Exposure: Measurements of an employee s noise dose or 8-hour time weighted average sound level that Safety deems to be representative of exposures of other employees in the workplace. Similar Exposure Group: Group of workers having the same general exposure profile for the agent(s) being studied because of the similarity and frequency of the tasks performed, the materials and processes with which they work, and the similarity of the way they perform tasks. Sound Level: A measurement derived from the mathematical derivation of the measured A- weighted average sound level when compared to a standard reference pressure of 20 micropascals. Sound Level Meter: An instrument used for the measurement of sound level. Standard Threshold Shift (STS): A change in hearing threshold relative to the baseline audiogram of an average of 10 db or more at 2000, 3000 and 4000 Hz in either ear. Time Weighted Average (TWA): The average time, over a given work period (e.g. 8-hour workday) of a person's exposure to a chemical or an agent. The average is determined by sampling for the contaminant throughout the time period. a) Requirements i) The district shall conduct noise monitoring and implement this Hearing Conservation Program when it is determined that employee exposure to noise meets or exceeds the action level of an 8- hour TWA of 85 dba. The Hearing Conservation Program shall include the elements listed below. ii) Employees shall be required to wear hearing protection where noise monitoring results are over 90 dba. b) NOISE STANDARDS i) The Cal OSHA Noise Standard, CCR Title 8 Article 105 Control of Noise Exposure established 90 dba as the 8-hour TWA permissible exposure limit (PEL) for continuous noise, with allowable increases of 5 dba for each halving of exposure duration, up to a maximum of 115 dba (Table 1). The standard specifies that feasible engineering or administrative controls shall be utilized to reduce sound levels within the PEL's shown, and, if such controls fail to accomplish that reduction, personal protective equipment (PPE) shall be provided and a continuing effective Hearing Conservation Program administered. The principal components are exposure monitoring, audiometric testing, hearing protection, employee training, and recordkeeping. ii) The District has set the 8-hour time-weighted average at 90 dba. As with the Cal-OSHA Noise Standard, audiometric testing and training is required. The District has also established a Sound Pressure Level not exceeding 140 db Linear Peak. Safety Policy and Procedures 4 OF 11 Revised 01/27/09
TABLE 1 PERMISSIBLE EXPOSURE LIMITS Duration Per Day Sound Level (Hours) (dba Slow Scale) 8 90 6 92 4 95 3 97 2 100 1.5 102 1 105 30 min 110 15 min or less 115 *NOTE: c) RESPONSIBILITIES i) The Occupational Clinic shall: Exposure to impulse or impact noise should not exceed140-db peak sound pressure level. (1) Provide guidance and consultation on matters pertaining to hearing conservation for the Sanitation District. (2) Conduct baseline audiometric testing in accordance with the pre-placement physical and provide results to the Safety & Health Division. ii) The Safety and Health Supervisor shall: (1) Receive and review employee reports of occupational noise hazards and coordinate a response with the Occupational Clinic and Safety Staff according to established procedures. (2) Coordinate with the Occupational Clinic and Safety Staff in evaluating the results of routine occupational noise surveys and specialized noise hazards evaluations and help in determining the appropriate corrective action where needed. (3) Represent the District in liaison with Governmental and private organizations on matters related to occupational noise and hearing conservation. (4) Establish and maintain a hearing protection and audiometric testing program for all employees whose noise exposures equal or exceed an 8-hour TWA of 85 dba per Cal/OSHA regulations. Safety Policy and Procedures 5 OF 11 Revised 01/27/09
iii) Safety & Health Division shall: (1) Administer the Hearing Conservation Program including noise monitoring, coordination of audiometric testing, and employee training. (2) Receive and review employee reports of occupational noise hazards and coordinate a response (3) Post high noise areas based upon a TWA. (4) Perform specialized noise hazards evaluations, recommending corrective action where needed, and providing training for employees included in the Hearing Conservation Program. (5) Perform routine occupational noise surveys to identify and monitor hazardous noise areas and operations and assist in determining those occupations or employees to be included in the Hearing Conservation Program. (6) Provide training for employees included in the Hearing Conservation Program. (7) Coordinate with Engineering to ensure that appropriate noise controls are specified for new equipment. iv) Managers and Supervisors shall: (1) Ensure that all employees working in potentially hazardous noise areas (as defined herein) are familiar with the contents of this program. (2) Ensure that when employees are in the Hearing Conservation Program, the mandatory aspects of the hearing protection and employee training sections of this program are adhered to. (3) Request occupational noise evaluations when in their judgment they are needed. They may be guided by reports of noise that causes excessive interference in conversing (face to face, or via radio, or telephone) or by repeated complaints about loud and intrusive noise, ringing in the ears following noise exposure, etc. d) Exposure Monitoring and Assessments i) The Safety and Health Division shall conduct noise surveys and dosimetry to determine areas where hearing protection is required and determine which employees must be included in this hearing conservation program. (1) General Requirements (a) Exposure assessment equipment (sound level meters and noise dosimeters) shall be properly calibrated. (b) Only personnel properly trained in the evaluation of noise exposure data shall interpret the data. (2) Initial Exposure Assessments (a) A noise survey shall be conducted in all areas of the worksite and noisy tasks to determine if noise exposures may exceed 85dBA. (b) In areas where noise exposures exceed 85 dba, a noise dosimeter shall be used to determine if employees noise exposure exceed an 8-hour TWA of 85 dba. (c) If employees move around frequently, Safety shall develop Similar Exposure Group (SEG) to accurately determine noise exposures. Safety Policy and Procedures 6 OF 11 Revised 01/27/09
(3) Periodic Exposure Assessments (a) If an employee s noise exposure exceeds an 8-hour TWA of 85 dba, monitoring shall be repeated every 2 years. (b) Monitoring shall be repeated within 3 months when there is a change in equipment, production processes or maintenance routines. (c) Monitoring may be repeated at shorter frequencies if employees are developing significant threshold shifts. ii) Areas of Exposure (1) The following areas have been found to be 90 dba or over: (a) Plant 1 - Central Generation excluding the control room and break area. (b) Plant 1 MSP motors (c) Plant 1 Gas Compressor Building - inside (d) Plant 1 - Building 4 Welding/Cutting Area (e) Plant 2 - Power Building D Generator Room (f) Plant 2 - Digester M-L Pump Room (g) Plant 2 Primary Effluent Pump Station (PEPS) Air Compressor Room (h) Plant 2 Central Generation excluding the control room and break areas. (i) Plant 2 - Headworks A&B Generator Rooms 1 and 2 (j) Plant 2 - Emergency Power Building excluding data room (k) Plant 2 - Headworks B lower level at pump 9 (l) Plant 2 - West Return Activated Sludge (RAS) lower level at pumps (m) Plant 2 - Lindstrom Dewatering Building - Basement e) Employee Training i) The success of this Hearing Conservation Program depends largely on effective employee education regarding all aspects of the program. The primary focus of the training must be on the workers and they must be informed about the reasons for and the requirements of the Hearing Conservation Program. ii) Annual training is provided to all employees who are in the Hearing Conservation Program. Employees in the Hearing Conservation Program are employees who are exposed to 85 dba or greater on an 8-hour time weighted average for 12 or more days per year and/or exceed a peak noise level of 140 db linear peak. iii) The training shall cover hazards and effects of noise; the purpose, advantages, and disadvantages of various types of hearing protectors; the selection, fitting, and care of protectors; the purpose and procedures of audiometric testing and noise exposure data. f) Audiometric Testing i) All audiograms obtained shall meet the requirements of Cal-OSHA requirements found in 8 CCR 5097, Appendix B: Audiometric Measuring Instruments. Safety Policy and Procedures 7 OF 11 Revised 01/27/09
ii) The audiometric testing program shall include baseline and annual audiometry for all employees in the Hearing Conservation Program. Testing shall be performed by a qualified audiometric technician or by a consultant who specializes in audiometric examinations. (1) The test shall be made available within one year of an employee's first exposure at or above the action level. iii) Baseline audiogram (1) The reference against which future audiograms are compared, should be obtained prior to an employee's first exposure to noise that equals or exceeds the action level. It shall be obtained as soon as possible, but no longer than 6 months, after it becomes known that the employee will be or is exposed to noise that equals or exceeds the action level. Testing to establish a baseline audiogram for employees shall be preceded by at least 14 hours without exposure to workplace noise. (2) This requirement may be met by wearing hearing protectors which will reduce the employee's exposure to a sound level of 85 dba or below. (3) The SAFETY AND HEALTH DIVISION shall notify employees of the need to avoid high levels of non-occupational noise exposure during the 14-hour period immediately preceding the audiometric examination. iv) Annual audiograms (1) They are given to all employees exposed to 85 dba, as an 8-hour time-weighted average, for 12 or more days per year and/or exceed a noise level of 140 db linear peak. The results are compared to the baseline audiogram to determine if an employee's audiogram is valid and if a standard threshold shift (STS) has occurred. The STS is either a change in hearing threshold relative to the baseline audiogram of an average of 10 db or more at 2000, 3000, and 4,000 Hertz (Hz) in either ear, after applying the standard age correction methodology shift of 25 db HL or more in the same ear and frequency on two consecutive tests at frequencies between 1000 and 6000 hertz. The Offsite Occupational Clinic shall review problem audiograms to determine whether there is a need for further evaluation or referral. If an STS is identified, the employee shall be informed of this fact in writing within 21 days of the determination and shall be fitted or refitted with adequate hearing protectors and required to wear them. (a) If an STS is indicated as a result of the mobile van audiometric testing, the employee will have a follow-up test to confirm whether the STS is valid. This test shall be conducted at the Offsite Occupational Clinic. (2) At termination of work for the District, an employee who has been exposed to noise is required to have an audiometric test performed as well. (3) Audiometric tests shall be pure tone, air conduction, hearing threshold examinations, with test frequencies including, as a minimum, 500, 1000, 2000, 3000, 4000, and 6000 Hz. Tests of each frequency shall be run separately for each ear. v) Standard Threshold Shift (1) If a comparison of the annual audiogram to the baseline audiogram indicates a standard threshold shift, the employee shall be informed of this fact, in writing, within 21 days of the determination. (2) Unless a physician determines that the standard threshold shift is not work related or aggravated by occupational noise exposure, the Safety & Health Division shall ensure that the following steps are taken when a standard threshold shift occurs: Safety Policy and Procedures 8 OF 11 Revised 01/27/09
(a) An employee not using hearing protectors shall be fitted with hearing protectors, trained in their use and care, and required to use them; and (b) A job restriction stating Must wear hearing protection if exposed to noise levels exceeding 85 dba shall be placed in the employee s medical file. (c) The STS will be recorded on the OSHA 300 log as an injury. (d) The new audiogram will then become the baseline for future comparisons. (3) The employee and his/her supervisor shall be notified of this restriction in writing. (4) The supervisor shall be responsible to ensure the employee properly wears hearing protection. (5) An employee already using hearing protectors shall be refitted and retrained in the use of hearing protectors by the Safety and Health Division and provided with hearing protectors offering greater attenuation if necessary. (6) Refer the employee for a clinical audiological evaluation or an otological examination, as appropriate, if additional testing is necessary or if the district suspects that a medical pathology of the ear is caused or aggravated by the wearing of hearing protectors. (7) Inform the employee of the need for an otological examination if a medical pathology of the ear which is unrelated to the use of hearing protectors is suspected. (8) If subsequent audiometric testing of an employee whose exposure to noise is less than an 8- hour time-weighted average of 85 decibels indicates that a standard threshold shift is not persistent, the Safety and Health Division: (a) Shall inform the employee of the new audiometric interpretation; and (b) May discontinue the required use of hearing protectors for that employee. (9) As used in this section, a standard threshold shift is a change in hearing threshold relative to the baseline audiogram of an average of 10 db or more at 2000, 3000 and 4000 Hz in either ear. (10) In determining whether a standard threshold shift has occurred, allowance may be made for the contribution of aging (presbycusis) to the change in hearing level by correcting the annual audiogram according to the procedure described in 8 CCR Article 105, Appendix F: Determination and Application of Age Correction to Audiograms g) Equipment Purchases i) In an effort to reduce equipment-related noise, attempts shall be made to purchase equipment that meets the following requirements for noise: (1) Equipment shall produce a noise level of less than 85 dba at the operator s workstation or a distance of 5 feet from the equipment. (2) Equipment that is not able to meet the above requirements shall be enclosed, dampened or some other form of control used to minimize the noise level to include posting a warning sign. h) Program Administration i) The Hearing Conservation Program shall be managed and administered by the Safety and Health Division. Safety Policy and Procedures 9 OF 11 Revised 01/27/09
ii) Noise exposure measurement records and audiometric test records shall be retained in the Safety Division office in accordance with District recordkeeping requirements. The audiometric record shall include: (1) Name and job classification of the employee. (2) Date of the audiogram. (3) Examiner's name. (4) Date of the last acoustic or exhaustive calibration of the audiometer. (5) Employee's most recent noise exposure assessment. (6) Date of the last hearing conservation training and the name of the person conducting the training. iii) A confirmed work related average threshold shift in either ear of 10 db HL at 2000, 3000 and 4000 Hertz after applying the standard age correction methodology must be recorded on the OSHA Log within 6 days of identification. iv) All acoustic and audiometric records shall be provided upon request to the employee/former employee requesting the documentation, representatives designated by the employee, and OSHA. v) Audiogram Recordkeeping (1) The Safety & Health Division shall maintain audiometric test records for an employee s length of employment plus 30 years. vi) Program Review and Assessment (1) This Hearing Conservation Program shall be evaluated annually to ensure that it is effective in providing adequate protection against harmful noise. The following steps shall be followed to conduct this program review: (a) The Safety & Health Division shall determine if regulations or national consensus standards have changed since the last annual program review. (b) Review Federal OSHA Standards, interpretations and documents. (c) Review consensus standards. (d) The Safety & Health Division shall review the current Hearing Conservation Program, proposed changes to State and Federal Regulations and national consensus standards and recommend changes to the district s Hearing Conservation Program as required. (e) The Safety Division shall have 30 days to make minor program changes, and 60 days in the case of major program revisions. (f) Hearing Conservation Program reviews shall start by November 15 of each year. i) Hearing Protection Selection i) Prerequisites (1) Noise that cannot be attenuated from the workplace through process control or other engineering methods to reduce the noise. ii) Precautions (1) The improper selection of hearing protection can lead to permanent hearing loss. (2) Ear muffs and ear plugs Noise Reduction Rating (NRR) cannot be added together. So if an ear muff has a 30 NRR and ear plugs have a 32 NRR you do not have a combined NRR of 62. Safety Policy and Procedures 10 OF 11 Revised 01/27/09
iii) Instructions (a) If ear muffs and ear plugs are used together you only add an additional 5 db to the earmuffs NRR. (1) The District shall make hearing protectors available to all employees exposed to an 8-hour time-weighted average of 85 decibels or greater at no cost to the employees. (2) The District shall ensure that hearing protectors are worn by all employees: (a) Who are required to wear personal protective equipment; or (b) Who are exposed to an 8-hour time-weighted average of 85 decibels or greater, and who: (i) Are required to wear hearing protectors because baseline audiograms have not yet been established; or (ii) Have experienced a standard threshold shift. (3) Employees shall be given the opportunity to select their hearing protectors from a variety of suitable hearing protectors provided by the employer. j) Determining Hearing Protection Attenuation i) When using a sound level meter set to the A-weighting network: (1) Obtain the employee's A-weighted TWA. (2) Take the Noise Reduction Rating (NRR) from the hearing protection and subtract 7 db and this will give you the actual NRR on the hearing protector container, and subtract the remainder from the A-weighted TWA to obtain the estimated A-weighted TWA under the ear protector. (a) If the NRR for an ear plug is 32 you would subtract 7 from the 32 and get a true NRR of 25 db. So if the noise level was105 db in an area you would subtract 25 db from 105 db to get 80 db exposure to the employee. 5) REFERENCES/RELATED LINKS a) SAFETY-SOP-102, Personal Protective Equipment b) SAFETY-POL-403, Medical Examinations c) Title 8, California Code of Regulations Article 105, Control of Noise Exposure. d) Title 29, Code of Federal Regulations, Part 1910.95 Occupational Noise Exposure e) American National Standards Institute (ANSI) S1.4-1971 Weighting Networks for Acoustical Measurements, Design Response of 6) ATTACHMENTS a) None Safety Policy and Procedures 11 OF 11 Revised 01/27/09