GBZ 49-2002 Occupational Hearing Impairment Diagnostic Standard GBZ49-2002 Standard download decompression password: www.bzxz.net

ICS 13.100
National Occupational Health Standard of the People's Republic of China GBZ49—2002
Diagnostic Criteria of Occupational Noise-induced Hearing Loss
Diagnostic Criteria of Occupational Noise-induced Hearing LossPublished on April 8, 2002
Implemented on June 1, 2002
Ministry of Health of the People's Republic of China
Article 6.1 of this standard is recommended, and the rest are mandatory. This standard is formulated in accordance with the "Law of the People's Republic of China on the Prevention and Control of Occupational Diseases". From the date of implementation of this standard, if there is any inconsistency between the original standard GB16152-1996 and this standard, this standard shall prevail. In occupational activities, hearing loss caused by noise is a prominent occupational hazard in industrialized society. In order to protect the health of workers and effectively prevent noise hazards, this standard is specially formulated. Appendix A of this standard is a normative appendix, and Appendix B is an informative appendix. This standard is proposed and managed by the Ministry of Health of the People's Republic of China. This standard was drafted by Beijing Institute of Otolaryngology. The participating organizations include Shanghai Institute of Labor Health and Occupational Diseases, Sichuan University Affiliated Occupational Disease Prevention and Treatment Institute, and Beijing Hospital. This standard is interpreted by the Ministry of Health of the People's Republic of China. Occupational Hearing Loss Diagnosis Standard
GBZ49-2002
Occupational noise-induced hearing loss is a progressive sensorineural hearing loss caused by long-term exposure to noise during work.
1 Scope
This standard specifies the diagnostic standards and treatment principles for occupational hearing loss. It is applicable to the diagnosis and treatment of various degrees of hearing loss caused by exposure to occupational noise.
2 Normative References
The clauses in the following documents become clauses of this standard through reference in this standard. For dated referenced documents, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For undated referenced documents, the latest versions shall apply to this standard.
GB4854
GB7341
GB7582
GB7583
GB/T16180
3 Diagnostic principles
Standard zero level for calibration of pure tone audiometer
Audiometer
Acoustics Otology Relationship between normal air conduction hearing threshold and age and gender Acoustics Pure tone air conduction hearing threshold measurement Hearing protection Identification of disability degree of workers caused by work-related injuries and occupational diseases Based on a clear history of occupational noise exposure, symptoms of conscious hearing loss or tinnitus, pure tone audiometry for sensorineural hearing loss combined with dynamic observation data, on-site hygiene investigation, and exclusion of hearing loss caused by other reasons, a diagnosis can be made. Normal hearing range and observation objects
4.1 Normal hearing range
Hearing loss at each frequency is ≤25dB, according to B.1 of Appendix B in Ni and N areas. 4.2
Observation subjects
Hearing loss at all frequencies is ≤25dB. According to B.1 of Appendix B, hearing loss is judged to be in zone I to IV (grade). Those within the range of zone I to IV (grade) are all observation subjects. For those whose hearing loss reaches grade V, after calculating the average hearing of both ears according to B.2 of Appendix B, there is no hearing loss.
a) Grade I: N+A
Grade IⅡI: Ni+B or D+A
Grade II: Ni+C or D+B
d) Grade IV: D+C
Grade V: E+B or E+C
5 Hearing impairment classification
a) If the hearing loss in any ear reaches Grade V, the average hearing threshold of both ears shall be calculated according to B.2 of Appendix B to assess hearing impairment and noise-induced deafness;
b) If the hearing loss at any high frequency (3000, 4000, 6000HZ) is ≥30dB, the average hearing threshold of both ears can be directly calculated according to B.2 of Appendix B to assess hearing impairment. 5.1
Mild hearing loss
Moderate hearing loss
Severe hearing loss
Noise-induced hearing loss
Treatment principles
Treatment principles
26~40dB
41~55dB
56~70dB
7190dB
Observation subjects, hearing loss and noise-induced hearing loss should strengthen personal hearing protection. Those with other symptoms can receive symptomatic treatment.
6.1.2 Hearing loss with a hearing loss of more than 56dB should wear hearing aids. 6.2 Other treatments
6.2.1 For observation subjects and those with mild hearing loss, protective measures should be strengthened, and generally there is no need to move away from the noisy working environment. For those with moderate hearing loss, it may be considered to arrange jobs that do not require high hearing. For those with severe hearing loss and noise-induced hearing loss, they should be transferred away from the noisy environment.
6.2.2 Those who are sensitive to noise (i.e. those whose hearing loss observation subjects reach level IⅢ and level III or above within one year of working in a noisy environment) should consider being transferred away from the noisy working environment. Instructions for the correct use of this standard
See Appendix A (Informative Appendix).
Appendix A
(Informative Appendix)
Instructions for the correct use of this standard
A.1 The hearing assessment of occupational noise-induced hearing loss is based on the air conduction results of pure tone audiometry, and the results of pure tone audiometry are sensorineural hearing loss.
A.2 In view of the temporary shift of occupational noise-induced hearing loss, the screening time for hearing measurement should be 12 to 48 hours after the subjects leave the noise environment. If the results of the screening audiometry have reached the level of hearing loss and noise-induced hearing loss, a re-examination should be conducted, and the re-examination time is set to be one week after leaving the noise environment. The test personnel should be specially trained and qualified. A.3 Age correction value of pure tone air conduction threshold: When determining occupational noise-induced hearing loss, the age factor should be considered and the correction should be made according to the median (50%) of the hearing level deviation of normal otologists (18 to 70 years old) in GB7582. Table AI gives the median value of the hearing threshold level deviation of frequencies from 500 to 6000 Hz relative to the age of 18 years old (rounded to the nearest whole decibel number). This value is the expected statistical distribution of 50% of the normal otologists in males and females aged from 20 to 60 years old.
A.4 If the pure tone air conduction hearing loss of a certain frequency is increased to 100dB or the subject still has no reaction to the maximum sound output of the audiometer, it is calculated as 100dB. Www.bzxZ.net
A.5 Excluding other causes of deafness as described in the diagnostic principles mainly includes: pseudo-deafness, traumatic deafness, drug-induced deafness, infectious-induced deafness, familial deafness, presbycusis, Meniere's disease, sudden deafness, labyrinthitis, auditory neuralgia, various middle ear diseases, etc.
A.6 If speech frequency hearing loss is greater than high frequency hearing loss or the difference in hearing loss between the two ears is 3 or more levels, an otolaryngologist should be consulted to exclude other causes of deafness. If the cause of deafness in the poorer hearing ear is not related to occupational noise, it will not be included, and only the hearing value of the better ear can be used to grade hearing loss. A.7 When one ear is mixed deafness, if the bone conduction hearing threshold is increased in accordance with the characteristics of occupational noise-induced deafness and is not the same cause as conductive deafness, it can be assessed according to bone conduction hearing threshold; if the bone conduction hearing threshold may be the same cause as conductive deafness, it should be graded according to the contralateral ear. At the same time, a comprehensive analysis should be conducted in combination with the results of previous regular physical examinations. A.8 Personal hearing protection refers to wearing soundproof earplugs, earmuffs or soundproof caps. A.9 Assessment steps:
Step 1: Determine whether noise causes sensorineural hearing loss (medical history, physical examination, hearing test). Step 2: Make age corrections to the pure tone audiometry results (air conduction) according to GB7582. Step 3: Classify occupational noise hearing loss according to 4.2 of this standard. If the hearing loss of any ear reaches Grade V: Assess the degree of hearing damage and noise-induced hearing loss according to Chapter B.2 of Appendix B. Step 4: If the conditions are not met, any frequency of the high frequency (3000, 4000, 6000Hz) is ≥30dB, and the average hearing threshold of both ears can be directly calculated according to Chapter B2 of Appendix B to assess the degree of hearing damage and noise-induced hearing loss. Step 5: Assess the degree of hearing loss and noise-induced hearing loss: a. Calculate the average hearing threshold of one ear (B1):
HL500Hz+HL1000Hz+HL2000Hz
Average hearing threshold of one ear=
b. Calculate the average hearing threshold of both ears (B2)
Average hearing threshold of both ears=
Average hearing threshold of better ear (dB)
)×4+Average hearing threshold of worse ear (dB)×15
Step 6: Handling principles: Handle in accordance with relevant provisions. Only the diagnosis certificate issued by the professional institution designated by the health authority is valid. A.10
Table A. Median rate of hearing threshold level deviation of 1500-6000Hz frequency relative to the age of 18, Hz
58--60
New rate+H
Deviation value, dH
Continued Table A.1
Appendix B
(Normative Appendix)
Classification of occupational noise hearing loss, degree of hearing damage and calculation of noise-induced hearing loss B.1 When using the hearing loss classification chart, speech frequency (500, 1000, 2000Hz) and high frequency (3000, 4000, 6000Hz) refer to the range of hearing loss reached at any frequency in one ear, not the average value of a group of frequencies. "Ten" indicates the combination of speech frequency and high frequency.
5001000True2000Cat3000Heavy400010
6000Hz
Chengye
Occupational noise hearing loss classification chart
Occupational noise hearing loss classification table
Note: The combination with slashes should exclude other hearing loss. Business Electronics
>25dBHL
Xitian Industry Products
>45dBHL
→65dBHL
B.2 The calculation method for occupational noise hearing loss and noise-induced deafness is as follows (when calculating the average hearing value, the decimal point is rounded to an integer). The first step is to correct the hearing threshold of each frequency for age, see Chapter A3 of Appendix A. The second step is to calculate the average hearing threshold of one ear:
Average hearing threshold of one ear (dB)=
HL500Hz+HL1000Hz+HL2000Hz
The third step is to calculate the average hearing threshold of both ears:
Average hearing threshold of both ears (db)=
Average hearing threshold of better ear (dB)×4+Average hearing threshold of worse ear (dB)×15
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