Editing Earplug (section)

== Hearing protection ==
[[File:Earplug fitting.png|alt=Three photographs of an ear with earplugs inserted into them|thumb|Badly-inserted earplug, semi-inserted earplug, and properly-inserted earplug]]
There are mainly four types of earplug fittings for hearing protection:

* '''Foam''' earplugs, mainly made from either polyvinyl chloride (PVC) or polyurethane (PU) ([[memory foam]]), which are compressed (rolled) and put into the ear canal, where they expand to plug it.
* '''Wax''' earplugs, which are rolled into a ball and carefully molded to fit over the external portion of the ear canal.
* '''Flanged''' silicone earplugs, an example of Universal-fit.
* '''Custom molded''' earplugs, made from a mold of the wearer's ear and designed to precisely fit all ear canal shapes.  Custom molded is further divided into laboratory-made and "formed in place".

[[NIOSH]] Mining Safety and Health Research recommends using the roll, pull, and hold method when using memory foam earplugs.<ref name="memear2">{{cite web|url=https://www.cdc.gov/niosh/mining/content/earplug.html|title="How To Wear Soft Foam Earplugs." NIOSH Mining Safety and Health|date=2012-09-24|publisher=Cdc.gov|access-date=2013-06-22}}</ref> The process involves the user rolling the earplug into a thin rod, pulling back on the ear, and holding the earplug deep in the ear canal with the finger.<ref name="memear2" /> To get a complete seal, the user must wait about 20 to 30 seconds for the earplug to expand inside the canal.<ref>{{Cite web|url=https://www.cdc.gov/niosh/mining/content/earplug.html|title=How To Wear Soft Foam Earplugs|website=www.cdc.gov|language=en-us|access-date=2017-03-03}}</ref>

Earplugs are most effective when the wearer has been properly trained on use and insertion. Employers can provide this training before dispensing earplugs to their employees. Training for earplug use includes: insertion, a seal check, depth check, removal, cleaning, and replacement. When training on insertion, the objective is for the worker to understand the correct insertion strategy. Proper insertion training prevents inadequate insertion, that can result in discomfort or inadequate attenuation, which can result in hearing loss. When this step is achieved, then the seal and depth need to be checked. The ear plugs all have a desired depth and seal which need to be achieved to provide the designated attenuation for the wearer. The worker will also be trained on how to properly remove the earplugs and clean them. This allows for multiple uses and reduces the chance of infection. To further prevent infection, it is important the worker understands when they will need to replace their earplugs. Once the plugs have been worn down from repeated use, they will no longer seal correctly or provide the proper attenuation level, and the device will need to be replaced.<ref name=":22">{{Cite book|title=Hearing Conservation|last=Rawool|first=Vishakha|publisher=Thieme|year=2011|isbn=978-1604062564}}</ref>
[[File:Вкладыши Ultrafit с зондом для замера уровня шума за вкладышем.jpg|right|thumb|260px|Earplugs with probe for MIRE measurements of noise exposure on the worker's eardrums]]
Noise attenuation can be verified using real-ear attenuation at threshold (REAT) or microphone in the real ear (MIRE) methods.<ref name="AIHA-6-12" /> The difference in thresholds with and without the hearing protection in place determines the amount of attenuation (REAT).<ref name=":3">{{Cite book|title=Hearing conservation manual |editor=Hutchison, Thomas L. |editor2=Schulz, Theresa Y. |publisher=Council for Accreditation in Occupational Hearing Conservation |date=2014|isbn=978-0-9863038-0-7|edition=Fifth |location=Milwaukee, WI|oclc=940449158}}</ref> Two microphones measure the sound pressure (of test signals, or noise in the workplace during a shift) outside the HPD and inside, and the difference shows the noise attenuation (MIRE).

Earplugs and other hearing protection devices can be tested to ensure that they fit properly and are successfully limiting sound exposure, which is called [[Hearing protection fit-testing|fit-testing]]. There are a number of different fit-testing systems, also known as field attenuation estimation systems (FAES). These use large headphones or specialized (surrogate) earplugs to transmit the test sounds and measure the attenuation provided by the hearing protector. These systems include the NIOSH HPD Well-Fit, Honeywell Howard Leight VeriPRO, 3MEARFit and many others.<ref name="AIHA-6-12" />  {{multiple issues|section=y|
{{jargon|tables |date=September 2024}}{{mos|tables|date=September 2024}}}}

{| class="wikitable collapsible collapsed" style="text-align:center"
! rowspan="2" | Noise, dBA 
! colspan="3" | Time reaching maximum daily dose, hours : minutes
|-
! [[Occupational Safety and Health Administration|OSHA]],<ref name="OSHA-noise">{{cite web |author1=US Occupational Safety and Health Administration |title=29 CFR 1910.95 Occupational noise exposure |url=https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.95 |website=www.osha.gov |publisher=OSHA |access-date=18 July 2023 |location=Washington, DC |language=en |date=1983}}</ref>

TWA 90 dB(A), 

exchange rate 5 dB 
! [[National Institute for Occupational Safety and Health|NIOSH]],<ref name="NIOSH-1998">{{cite book |last1=Rosenstock |first1=Linda |title=Criteria for a Recommended Standard. Occupational Noise Exposure |date=June 1998 |publisher=DHHS (NIOSH) Publication No 98-126 |location=Cincinnati, Ohio |pages=19–32 |edition=2nd |url=https://www.cdc.gov/niosh/docs/98-126/ |access-date=6 January 2023 |language=en |chapter=Chapter 3 Basis for the Exposure Standard|doi=10.26616/NIOSHPUB98126 }}</ref> 

TWA 85 dB(A), 

exchange rate 3 dB 
! [[International Organization for Standardization|ISO]] 1999,<ref>{{cite book |last1=Technical Committee ISO/TC 43 Acoustics |title=ISO 1999:2013 Acoustics — Estimation of noise-induced hearing loss |date=2013 |publisher=International Organization for Standardization |location=Geneva, Switzerland |pages=23 |edition=3 |url=https://www.iso.org/standard/45103.html |access-date=14 July 2023 |language=en}}</ref> Netherlands,<ref name="ILO-4ed" /> RF<ref name="СанПиН" />

TWA 80 dB(A), 

exchange rate 3 dB 
|-
| 80 || - || - || 8 : 00
|-
| 81 || - || 20 : 9.5 || 6 : 21
|-
| 82 || - || 16 : 00 || 6 : 02
|-
| 83 || 21 : 07 || 12 : 42 || 4 : 00
|-
| 84 || 18 : 23 || 10 : 4.8 || 3 : 10
|-
| 85 || 16 : 00 || 8 : 00 || 2 : 31
|-
| 86 || 13 : 56 || 6 : 21 || 2 : 00
|-
| 87 || 12 : 08 || 5 : 2.4 || 1 : 35
|-
| 88 || 10 : 33 || 4 : 00 || 1 : 16
|-
| 89 || 9 : 11 || 3 : 10 || 1 : 00
|-
| 90 || 8 : 00 || 2 : 31 || 48 min
|-
| 91 || 6 : 58 || 2 : 00 || 38 m
|-
| 92 || 6 : 04 || 1 : 35 || 30 m
|-
| 93 || 5 : 17 || 1 : 16 || 24 m
|-
| 94 || 4 : 36 || 1 : 00 || 19 m
|-
| 95 || 4 : 00 || 0 : 48 || 15 m
|-
| 96 || 3 : 29 || 0 : 38 || 12 m
|-
| 97 || 3 : 02 || 0 : 30 || 9.4 m
|-
| 98 || 2 : 38 || 0 : 24 || 7.5 m
|-
| 99 || 2 : 18 || 0 : 19 ||  6 m
|-
| 100 || 2 : 00 || 0 : 15 || 4 m 43 sec
|-
| 101 || 1 : 44 || 0 : 12 || 3 m 45 s
|-
| 102 || 1 : 31 || 9 min 24 sec || 2 m 58 s
|-
| 103 || 1 : 19 || 7 m 30 s || 2 m 22 s
|-
| 104 || 1 : 09 || 6 m || 1 m 53 s
|-
| 105 || 1 : 00 || 4 m 42 s || 1 m 29 s 
|-
| 106 || 52 m || 3 m 48 s || 1 m 11 s 
|-
| 107 || 45 m || 3 m || 56 s 
|-
| 108 || 40 m || 2 m 24 s || 45 s 
|-
| 109 || 34 m || 1 m 54 s || 36 s 
|-
| 110 || 30 m || 1 m 30 s || 28 s
|}
{| class="wikitable collapsible collapsed" style="text-align:center"
! colspan="3" | Permissible noise levels in different countries<ref name="ILO-4ed">{{cite book |last1=Suter |first1=Alice H. |title=Encyclopaedia of Occupational Health & Safety (Part VI. General Hazards) |date=2011-05-24 |publisher=International Labour Organization |edition=4 |url=https://www.iloencyclopaedia.org/part-vi-16255/noise/item/755-standards-and-regulations |access-date=14 July 2023 |language=en |chapter=Noise. Standards and Regulations}}</ref>
|-
! Country 
! TWA, dBA 

''(for an 8-hour shift)'' 
! Level increase corresponding to doubling the dose 

''(Exchange rate)''
|-
| Argentina || 90 || 3
|-
| Australia || 85 || 3
|-
| Brazil || 85 || 5
|-
| Canada || 85 & 82<ref>{{cite web |title=Occupational Health and Safety Code |url=https://www.alberta.ca/occupational-health-and-safety-code.aspx |website=www.alberta.ca |publisher=Government of Alberta |access-date=14 July 2023 |location=Edmonton |language=en |date=2023}}</ref> || 3
|-
| Chile || 85 || 5
|-
| China || 70-90 || 3
|-
| European Union countries || 85 || 3
|-
| Finland || 85 || 3
|-
| France || 85 || 3
|-
| Germany || 85, 70, 55<ref>For mental work</ref> || 3
|-
| Hungary || 85 || 3
|-
| India || 90 || -
|-
| Israel || 85 || 5
|-
| Italy || 85 || 3
|-
| Netherlands || 80 || 3
|-
| New Zealand || 85 || 3
|-
| Norway || 85, 55, 70 || 3
|-
| RF<ref name="СанПиН">{{cite book |title=State hygienic requirements 1.2.3685-21 "Hygienic requirements for the safety of environmental factors for humans" [СанПиН 1.2.3685-21 "Гигиенические нормативы и требования к обеспечению безопасности и (или) безвредности для человека факторов среды обитания"] |date=2021 |publisher=[[Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing]] |location=Moscow |page=337 |url=http://publication.pravo.gov.ru/Document/View/0001202102030022 |access-date=14 July 2023 |language=ru |chapter=§ 34}}</ref> || 80 || 3
|-
| Spain || 85 || 3
|-
| Sweden || 85 || 3
|-
| United Kingdom || 85 || 3
|-
| USA || 90 (100)* || 5
|-
| Uruguay || 90 || 3
|-
| colspan="3" | OSHA issued a directive to the Compliance Safety and Health Officers in 1983.<ref name="Suter">{{cite journal |last1=Suter |first1=Alice |title=Engineering Controls for Occupational Noise Exposure - The Best Way to Save Hearing |journal=Sound & Vibration |date=2012 |volume=48 |issue=1 |pages=24–31 |url=http://www.sandv.com/downloads/1201sute.pdf |access-date=7 June 2023 |publisher=Tech Science Press |location=Henderson, Nevada |issn=1541-0161}}</ref> They are ordered to stop requiring employers to install engineering noise control if noise dose < 100 dBA. This decision is considered illegal,<ref>{{cite journal |author1=Occupational Safety and Health Administration |title=Interpretation of OSHA's Provisions for Feasible Administrative or Engineering Controls of Occupational Noise |journal=Federal Register |date=2010-10-19 |volume=44 |issue=201 |pages=64216–64221 |url=https://www.federalregister.gov/d/2010-26135 |access-date=29 July 2023 |series=Proposed Rule |publisher=Office of the Federal Register |location=Washington, DC |language=en |issn=0097-6326 |quote=... the majority’s adoption of a cost-benefit test amounted to an '''unauthorized amendment''' of the standard.|quote-page=64218}} [https://www.federalregister.gov/d/2010-26135/p-33 Commissioner Cleary’s view]</ref> but it is carried out in practice in most US states.<ref name="OSHA-2022-3">[https://www.osha.gov/otm/section-3-health-hazards/chapter-5#appendixh Appendix H. Economic Feasiblity Analysis of Noise Engineering Controls] {{cite web |last1=OSHA |title=OSHA Technical Manual (OTM) Section III: Chapter 5. Noise |url=https://www.osha.gov/otm/section-3-health-hazards/chapter-5 |website=www.osha.gov |publisher=US Occupational Safety and Health Administration |access-date=18 January 2023 |language=en |date=July 6, 2022 |quote=}}</ref>

These numerical values do not fully reflect the real situation. For example, the OSHA standard<ref name="OSHA-noise" /> sets the Action Level 85 dBA, and the PEL 90 dBA. But in practice, the Compliance Safety and Health Officer must record the excess of these values with a margin, in order to take into account the potential measurement error. And, in fact, instead of PEL 90 dBA, it turns out 92 dBA, and instead of AL 85 dBA - 87 dBA.<ref name="OSHA-2022-2">[https://www.osha.gov/otm/section-3-health-hazards/chapter-5#appendixb B.9 Extended Workshifts] {{cite web |last1=OSHA |title=OSHA Technical Manual (OTM) Section III: Chapter 5. Noise |url=https://www.osha.gov/otm/section-3-health-hazards/chapter-5 |website=www.osha.gov |publisher=US Occupational Safety and Health Administration |access-date=18 January 2023 |language=en |date=July 6, 2022 |quote=Instrument accuracy must be taken into account ... . Type-2 dosimeters are considered to have an error of ±2 dBA, and the Action Level must be corrected, accordingly. For example, for an 8-hour shift, the corrected Action Level would be 87 dBA ...}}</ref>
|}