İşitmeAtölyesiOccupational Noise & Protection
Workplace noise exposure, legal limit values and measures to protect hearing — based on Türkiye regulation and international standards.
Information: The information on this page is compiled from official sources (the Occupational Noise Regulation, CSGB, international standards) and is for information only; it is not binding. For exact and current information consult the official regulation; for workplace practice consult your occupational safety specialist / workplace physician.
Overview
Noise is one of the leading causes of preventable occupational hearing loss. In Türkiye, workplace noise exposure is governed — based on Occupational Health and Safety Law No. 6331 and in parallel with EU Directive 2003/10/EC — by the Regulation on the Protection of Workers from Risks Related to Noise . The regulation sets exposure action and limit values and imposes graded obligations on the employer.
Regulation on the Protection of Workers from Risks Related to Noise. Peak values: 135 / 137 / 140 dB(C).
Key concepts
Regulatory definitions and core acoustic concepts.
- Peak sound pressure (Ppeak): the peak value of the C-frequency-weighted instantaneous noise pressure. (Art. 4)
- Daily noise exposure level (LEX,8h) [dB(A)]: the time-weighted average of all A-weighted exposure levels, including peak sound pressure and instantaneous impulsive noise, over an eight-hour working day (TS 2607 ISO 1999). (Art. 4)
- Weekly noise exposure level (LEX,8h): the time-weighted average of the A-weighted daily levels over a week of five eight-hour working days. (Art. 4)
- Equivalence (3 dB): LEX,8h is an energy-based average; under the international standard every +3 dB halves the safe duration for the same dose (EU/TS; 5 dB under OSHA).
Exposure / dose calculator
Approximate, calculated per the 3 dB rule; for information only. Official assessment relies on measurement and risk analysis.
Employer obligations (graded)
Employer obligations tied to the action values under the regulation.
- The employer keeps hearing protectors available for workers' use. (Art. 9)
- Workers are informed and trained about the risks and precautions. (Art. 11)
- If the risk assessment indicates a health risk, hearing tests may be carried out. (Art. 13)
- The employer ensures and enforces the use of hearing protectors. (Art. 9)
- An action plan with technical/organizational measures is drawn up; work areas are marked and, where possible, access is controlled. (Art. 8)
- Hearing tests are carried out by the employer. (Art. 13)
- A worker's exposure must in no case exceed the exposure limit value; when assessing this value, the protective effect of hearing protectors is also taken into account. (Art. 5, Art. 10)
- If it is found to be exceeded, the employer takes immediate action, determines the causes and revises the measures. (Art. 10)
International comparison
Türkiye aligns with the EU directive; the US (OSHA) uses a higher limit and a 5 dB exchange rate.
| Standard | Action / limit | Exchange rate |
|---|---|---|
| OSHA (US) | PEL 90 dBA · action 85 dBA | 5 dB |
| NIOSH (US, recommended) | REL 85 dBA | 3 dB |
| EU (2003/10/EC) | Action 80/85 · limit 87 dBA | 3 dB |
| Türkiye (2013 Reg.) | Action 80/85 · limit 87 dBA | 3 dB |
How loud, how risky?
Approximate values. Above about 85 dB and over long durations the risk rises; every +3 dB halves the safe duration. Hover along the bar to see the safe exposure time at each level.
Hearing conservation program
Exposure monitoring · audiometric testing · protectors · training · records · information.
A hearing conservation program is the sum of the following obligations of the regulation:
- Determination of exposure and, where necessary, measurement. (Art. 6)
- Prevention/reduction of risk at the source; technical and organizational measures. (Art. 8)
- Provision and use of hearing protectors. (Art. 9)
- Information and training of workers. (Art. 11)
- Consultation and participation of workers. (Art. 12)
- Health surveillance and hearing tests. (Art. 13)
Audiometric surveillance & STS
Standard threshold shift (STS): a change of ≥10 dB in the average of 2000-3000-4000 Hz.
- For workers exceeding the upper exposure action value (85 dBA), hearing tests are carried out by the employer. (Art. 13)
- If the risk assessment indicates a health risk, hearing tests may also be carried out for workers exceeding the lower action value (80 dBA). (Art. 13)
- If hearing loss is found to result from workplace noise, the worker is informed, the risk assessment and measures are reviewed, and if necessary the worker is reassigned to other work without noise exposure. (Art. 13)
- In international practice, a worsening of ≥10 dB in the 2000-3000-4000 Hz average relative to the baseline audiogram standard threshold shift (STS) is considered. (OSHA/NIOSH)
How does noise affect the ear? — see and hear
The cochlea is tonotopic: low-frequency (bass) sounds stimulate the apex, high-frequency (treble) sounds the base. Play a sound and watch which region vibrates.
Play a sound: the cochlear region matching that frequency vibrates.
Noise-induced loss affects high frequencies (treble, the basal region) first. Play a sound below; when you choose a loss type both the sound changes and the cells of the relevant region appear damaged. You can also switch while a sound is playing.
⚠ Lower your device volume before listening. These are short, low-level simulations; real hearing loss varies by individual and this demo is not a substitute for a hearing test.
Source: NIDCD (NIH). For information only.
Noise-induced hearing loss (NIHL)
Symptoms, tinnitus and the 4 kHz notch on the audiogram.
- Noise-induced hearing loss is usually insidious, progressive and permanent; it is often accompanied by tinnitus.
- On the audiogram, typically in the 3-6 kHz region and most marked at 4 kHz, a notch is seen.
- The regulation requires workers to be trained on how and why to report signs of noise-induced hearing loss. (Art. 11)
Early symptoms and self-check
When to suspect it, when to see a professional.
- Sounds start to seem muffled/dull; clarity decreases.
- Difficulty distinguishing speech, especially in noisy environments.
- A constant need to turn up the TV, phone or radio.
- Ringing, buzzing or humming in the ear or head (tinnitus).
- Temporary fullness/buzzing after a loud environment — often clearing in 16–48 hours, but it can leave permanent damage.
If one of these symptoms persists, see an audiologist or ENT specialist and have a hearing test (audiometry). Because the hair cells of the inner ear do not regenerate, noise-induced loss is permanent — but entirely preventable. If you are at work, also report the symptom to your workplace physician.
Source: NIDCD (NIH). For information only; consult a healthcare facility for diagnosis and treatment.
Personal protective equipment (PPE)
Earplugs/earmuffs, NRR and SNR, real-world attenuation (derating).
Hearing protectors provided by the employer (Art. 9):
- Comply with the provisions of the PPE Regulation.
- Selected to eliminate or minimize the hearing-related risk.
- Fit the worker properly; used and maintained correctly; provided individually where hygiene requires.
- Attenuation is stated by NRR (US) or SNR (Europe); real-world protection is usually about half the label value (derating). Overprotection is also avoided because it can prevent hearing warning sounds. (international practice)
Approximate guidance; for information only. Appropriate PPE selection relies on measurement and assessment.
NRR real-world protection calculator
See roughly how much of the labelled NRR value actually applies in the field.
OSHA method (A-weighted): protected ≈ TWA − (NRR−7)/2. NIOSH: protected ≈ TWA − (NRR−7)×factor (earmuff 0.75; foam/custom plug 0.50; other plug 0.30). Approximate; real protection depends on individual fit (fit test / PAR). Source: OSHA 1910.95 App. B; NIOSH.
Protector types and selection
Protectors inserted into the ear canal. Simple and economical; correct and hygienic insertion is critical for protection.
- Compressible foam (roll-down): rolled and inserted, then expands to seal.
- Pre-molded (flanged): ready-shaped, push-in design.
- Formable: takes the shape of the ear canal.
- Custom: made from a personal ear impression.
- Simple and economical
- More comfortable in hot/humid environments
- Small and portable
- Requires correct and hygienic insertion
- Hard to tell from outside whether worn
- Not recommended alone above about 105 dBA
Protectors with a hard shell and cushions that fully cover the ear, sealing around it.
- Generally higher protection
- Easy to fit; suits most people
- Durable, with replaceable parts
- Visible when worn (easy to supervise)
- More expensive
- Less comfortable in hot environments
- Bulky, less portable
- Glasses/helmet arms can break the seal
Plugs custom-made to the person's ear impression; produced by taking an impression at an audiology clinic. The most comfortable option for frequent, long-term use.
- High comfort and fit
- Consistent protection over long-term use
- Flat (musician) filtered options available
- More costly
- Requires an impression-taking process
- May need remaking if the ear shape changes
Amplifies low-level ambient sounds (speech, warning signals) while automatically suppressing loud and impulsive sounds above the threshold (typically ~82-85 dB). Suitable for environments needing communication and with impulsive noise.
- Preserves communication and situational awareness
- Automatic protection against impulsive/loud sound
- Adjustable levels
- More costly
- Requires batteries and maintenance
Wearing a plug and an earmuff together. It provides more protection than a single protector; however protections are not additive — due to bone conduction, about +5 dB is added to the higher NRR value.
- Generally recommended when the 8-hour TWA exceeds about 100-105 dBA (NIOSH/MSHA).
- Considered for an extra safety margin in very loud or impulsive-noise environments.
- Protections are not additive; about +5 dB is added to the higher NRR value.
- Bone conduction sets a limit; at frequencies such as 2000 Hz the extra contribution may be negligible.
The attenuation provided by a protector is stated on the label as single number(s):
- NRR (US, ANSI S3.19): average noise reduction under laboratory conditions.
- SNR (Europe): single-number attenuation value; SNR is usually ~3 dB higher than NRR.
- HML (high/medium/low): shows attenuation at different frequencies; helpful when noise is dominant at a specific frequency.
- Derating: real-world protection is usually about half the label value.
- Selection: consider the noise level and spectrum, the need for communication/warning sounds, comfort and a proper fit, and compatibility with glasses/helmet; avoid overprotection.
Sources: CCOHS, NIOSH, 3M, NIDCD. For information only; selection relies on measurement and assessment.
Which protector suits me?
1 · What is the noise level in the environment?
2 · Do you need to hear speech or warning sounds?
3 · Is the environment hot, humid or dirty; do you insert/remove often?
—
Fitting a protector correctly and its care
Even the best protector is useless if fitted wrong; correct insertion is critical.
Foam plug: roll–pull–hold
With clean hands, compress the plug into a thin, crease-free cylinder — roll it. With the other hand, straighten the canal by pulling the pinna up and out — pull — then insert the plug and hold it with a finger for ~20–30 s until it expands — hold.
Earmuff: a complete seal
Keep obstacles like hair, glasses arms and collars away from between the cushion and the head. The cushions must fully surround the ear and sit against the head with no gaps; do not loosen the headband tension.
Fit check
CDC "count-and-listen" test: with the protector on, count aloud while cupping and uncupping your hands over your ears; if your voice sounds similar when cupped and uncupped, the fit is good. The most reliable method is a fit test (PAR) measurement.
Hygiene and replacement
Foam plugs are generally single/limited use; replace them when dirty. Renew earmuff cushions when they harden/wear. Clean custom/molded plugs per the manufacturer's instructions.
Source: CDC/NIOSH, CCOHS, 3M. For information only.
Reduce the source first, PPE last
Source: NIOSH — Hierarchy of Controls. For information only.
Occupational disease and rights
Assessment of noise-induced hearing loss as an occupational disease (SGK).
Noise-induced hearing loss may be assessed within the scope of occupational diseases in Türkiye; diagnosis, notification and compensation processes are subject to SGK legislation. The regulation requires health surveillance and hearing tests for early diagnosis (Art. 13) and a training obligation for reporting symptoms (Art. 11). For exact rights and processes, SGK legislation is authoritative.
Myths and facts
Common misconceptions and the truth according to official sources.
MythStuffing cotton in the ear protects enough.
FactCotton is not a noise protector and does not provide adequate attenuation. Protection requires NRR/SNR-rated protectors.
MythThe ear "gets used to it" over time and becomes resistant.
FactThis feeling is usually a temporary threshold shift; even if hearing recovers in 16–48 hours, damage accumulates and can become permanent.
MythNo pain means no harm.
FactNoise-induced loss is usually painless and insidious; it progresses unnoticed.
MythA one-time loud sound does no harm.
FactA single impulse sound such as an explosion or gunshot can cause sudden and permanent hearing loss.
MythHearing loss heals by itself later.
FactIn humans, inner-ear hair cells do not regenerate; the loss is permanent — but entirely preventable.
MythThe higher the NRR, the better, always.
FactOverprotection blocks warning sounds and communication; the goal is to bring exposure into the ~75–85 dBA range.
Source: NIDCD (NIH), CDC/NIOSH, CCOHS. For information only.
Frequently asked questions
80 dBA is the lower action value (information, provision of PPE), 85 dBA the upper action value (PPE use, signage), and 87 dBA is the exposure limit value, which cannot be exceeded. (Art. 5, 9, 10)
Determining and, if necessary, measuring exposure (Art. 6), reducing risk at source (Art. 8), providing PPE and enforcing its use (Art. 9), information and training (Art. 11), consulting workers (Art. 12) and health surveillance (Art. 13).
When the lower action value (80 dBA) is exceeded, PPE is made available; when the upper action value (85 dBA) is reached or exceeded, its use is ensured and enforced. (Art. 9)
Hearing loss found to result from workplace noise may be assessed within the scope of occupational disease; the process is subject to SGK legislation. The regulation requires health surveillance for early diagnosis. (Art. 13)
Mini glossary
- PPE
- Personal protective equipment — here, hearing protectors (earplug or earmuff).
- LEX,8h
- Daily noise exposure level: the time-weighted average of A-weighted exposure over an eight-hour working day. (Art. 4)
- Exchange rate
- The dB step that doubles/halves the sound dose. 3 dB in Türkiye/EU (energy-based), 5 dB in OSHA.
- Ppeak
- Peak sound pressure: the peak value of the C-frequency-weighted instantaneous noise pressure. (Art. 4)
- NRR / SNR
- The single-number expression of a hearing protector's attenuation; NRR (US), SNR (Europe). SNR is usually ~3 dB higher than NRR.
- STS
- Standard threshold shift: a worsening of ≥10 dB in the 2-3-4 kHz average relative to the baseline audiogram. (OSHA/NIOSH)
- Dose
- The ratio of measured exposure to permissible exposure (%); 100% indicates exposure equal to the criterion.
Official sources
“A worker's exposure may in no case exceed the exposure limit values.”
Occupational Noise Regulation · ARTICLE 10
- Regulation on the Protection of Workers from Risks Related to Noise (mevzuat.gov.tr)
- Official Gazette — 28 Jul 2013 (base text)
- CSGB — Guide to Combating Noise in Working Life
- EU-OSHA — Directive 2003/10/EC
- OSHA — Occupational Noise Exposure
- OSHA 1910.95 App. B — HPD attenuation adequacy (NRR derating)
- CDC/NIOSH — Provide Hearing Protection
- NIDCD (NIH) — Noise-Induced Hearing Loss