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Mine Health and Safety Act, 1996 (Act No. 29 of 1996)

Guideline for a Mandatory Code of Practice

Occupational Health Programme (Occupational Hygiene and Medical Surveillance) for Noise

Part A. The Guideline

4. Definitiions and Acronyms

 

4.1 "A-weighted sound pressure level or sound level (LpA)"

means the sound pressure level in decibels, of A-weighted sound pressure given by the following  equation (SANS  10083):

 

LpA = 10 log ( PA )2

p0

Where:

 

(a) LpA is the A-weighted sound pressure level.
(b) PA is the A-weighted pressure in pascal.
(c) p0 is the reference sound pressure (20 µPa).

 

4.2 "Baseline audiogram"

means an audiogram conducted for purposes of regulation 11.4 (4) of the MHSA to establish a reference against which subsequent audiograms can be compared.

 

4.3 "CIOM"

means Chief Inspector of Mines

 

4.4 "COIDA"

means the Compensation for Occupational Injuries and Diseases Act (Act 130 of 1993).

 

4.5        "Cl"

means confidence interval.

 

4.6 "COP"

means Code of Practice.

 

4.7        "DMRE"

means the Department of Mineral Resources and Energy.

 

4.8 "Decibel (dB)"

means the logarithmic unit for quantifying the level of a sound, where the base of the logarithm is the 1oth root of 10 and the quantity concerned is proportional to power, relative to a reference level of 20 micro Pa.

 

4.9 "Decibel, A-weighted (dBA)"

means the logarithmic unit for the level of a sound, as measured using a sound level meter's A-weighting network, which network applies weighting to the values for constituent frequencies of a sound in accordance with the human ear's sensitivity to it.

 

4.10 "ENT specialist"

means ear, nose and throat specialist.

 

4.11 "Equivalent continuous A-weighted sound pressure level ( LAeq, T)"

means the value of the A-weighted sound pressure level in decibels, of a continuous steady sound that, during a specified time interval ( 1), has the same mean square sound pressure as a sound under consideration, the level of which varies with time, and it is defined by the following equation (SANS 10083):

N1755 Definition 4.11 formula

Where:

LAeq, T is the equivalent continuous A-weighted sound pressure level, in decibels, determined over a time interval T that starts at t1 and ends at  t2.
p0 is the reference sound pressure level (p0 = 20 µPa).
pA(t) is the instantaneous A-weighted sound pressure of the sound signal, in pascal.

 

4.12 "Hearing conservation"

means the prevention or minimisation of noise-induced hearing impairment by the implementation of hearing conservation procedures.

 

4.13 "Hearing conservation programme"

means the process aimed at the prevention of hearing impairment, involving the implementation of the following measures:

(a) Assessment and prediction of noise exposure in all working places which may be accessed by any person.
(b) The reduction of the 8-hour rating level where this is expected to exceed the noise rating limit for hearing conservation.
(c) The introduction of a prohibition to persons entering such a working place unless such person is adequately protected.
(d) The introduction of a medical surveillance programme for all employees working in such working places.
(e) The introduction of a follow-up assessment programme as contemplated in (a) and (b) above.

 

4.14 "Hz (Hertz)"

means the derived unit of frequency  and is defined as one cycle per second.

 

4.15 "Homogeneous exposure group (HEG)"

means a group of employees whose exposures to noise has been determined to be statistically similar enough that, by monitoring a representative number of individuals in the group, the exposures of the remaining workers can be defined.

 

4.16 "ISLM"

means integrating sound level meter.

 

4.17 "kHz  (kilohertz)"

means  a  measure  of  frequency  equivalent  to  1 000 cycles  per second.

 

4.18 "L Aeq, 8h"

means the 8-hour equivalent continuous A-weighted sound pressure level in decibels and is the steady sound pressure level which would in the course of an 8-hour period deliver the same A-weighted sound energy as that due to the actual

noise on any particular representative working day.

 

4.19 "MOHAC"

means the Mining Occupational Health Advisory Committee.

 

4.20        "Monitoring"

means the repetitive and continued observation, measurement and evaluation of health, and/or environmental or technical data, according to prearranged schedules, using nationally or internationally acceptable methodologies.

 

4.21 "MHSA"

means Mine Health and Safety Act, 1996 (Act 29 of 1996) as amended.

 

4.22 "MHSC"

means the Mine Health and Safety Council.

 

4.23 "NIHL"

means noise-induced hearing loss.

 

4.24 "Noise"

means unwanted sound that could adversely affect health.

 

4.25 "Noise zone"

means an area within which the noise equals or exceeds the OEL.

 

4.26 "Occupational exposure  limit (OEL) for  noise"

means the value of the 8-hour rating level (LAeq, 8h), at or above 85 dBA Which hearing impairment is likely to result.

 

4.27 "OMP"

means Occupational Medical Practitioner.

 

4.28 "Percentile"

means the value of a variable below which a certain percent of observations fall. For example, the 20th percentile is the value (or score) below which 20 percent of the observations may be found. The term percentile and the related term percentile rank are often used in the reporting of scores from norm-referenced tests.

 

The 25th percentile is also known as the first quartile (Q1), the 50th percentile as the median or second quartile (Q2), and the 75th percentile as the third quartile (Q3).

 

4.29 "PPE"

means personal protective equipment.

 

4.30 "PLH"

means percentage loss of hearing.

 

4.31 "RMS"

means root-mean-square.

 

4.32 "Sampling cycle"

means the planned sampling programme for the year, which must terminate at the end of each calendar year.

 

4.33 "SANS 1451"

means:

(a) SANS 1451-1 (Ed. 1.02): Hearing protectors part 1: ear-muffs.
(b) SANS 1451-2 (Ed. 1.01): Hearing protectors part 2: ear-plugs.
(c) SANS 1451-3 (Ed. 1.03): Hearing protectors part 3: ear-muffs attached to an industrial safety helmet, or as amended from time to time.

 

4.34 "SANS 10083"

means the measurement and assessment of occupational noise for hearing conservation purposes, or as amended from time to time.

 

4.35 "SD"

means standard deviation.

 

4.36 "SLM"

means sound level meter.

 

4.37 "Standard threshold shift (STS)"

means an average change in hearing of 10 dB or more at the frequencies of 2 OOO Hz, 3 000 Hz and 4 000 Hz in one or both ears, as compared to the employee's STS  baseline audiogram .

 

4.38 "STS baseline"

means the initial audiometric value determined at the first STS testing, and it is the better of the employee's two audiograms performed by an audiometrist on the same day that do not differ from each other by more than 10 dB for any of the frequencies in the 2 000 Hz, 3 3 000 Hz and 4 000 Hz test ranges.