Summary
The international performance standard for hearing loops: the magnetic field strength, frequency response and measurement methods a loop system must meet for telecoil users.
Key findings
- Applies to audio-frequency induction-loop systems whose alternating magnetic field provides the input for hearing aids with a telecoil, and assumes those hearing aids meet the other parts of IEC 60118.
- Sets requirements for field strength meant to give an adequate signal-to-noise ratio without overloading the hearing aid, and a minimum frequency response for acceptable intelligibility.
- Specifies how to measure the magnetic field strength, with annexes on measuring equipment and on the information to be given to the system's operator and users.
- Does not cover loop driver amplifiers, microphones or other signal sources (left to IEC 62489-1), or the field produced by telephone handsets (covered by ITU-T P.370).
- This third edition replaced the 2006 edition and added annexes G, H and I on practical considerations and measurement methods. A consolidated version with Amendment 1 was published on 9 November 2017, and the IEC lists 2029 as the date to which the content stays unchanged.
- Its introduction says a loop's performance is determined by the building it is installed in, particularly by large amounts of iron, steel or aluminium in the structure, and that the layout of electrical cables and equipment may create background magnetic fields that interfere with reception.
- It also covers small loops for communicating with a hearing aid user close by, naming neck loops, ticket-counter systems, portable systems and chairs with built-in loops as examples.
- Its contents include a clause on measuring the site's magnetic background noise, with recommended maximum noise levels (clause 7), a section on care of the system (E.5), and informative annexes on the effects of metal in the building structure (with a 10 m by 14 m loop showing the effect of iron in the floor), calibration of field-strength meters, the effect of a loop's aspect ratio on the field, and overspill of the field into other areas, with examples and ways to address it.
- The catalogue lifecycle metadata dates both Amendment 1 (IEC 60118-4:2014/AMD1:2017) and consolidated edition 3.1 to 9 November 2017; the amendment date is separately listed, not inferred from the consolidated cover.
- Its introduction explains that loops help telecoil users listen through protective windows or amid background noise and can improve the signal-to-noise ratio where acoustic transmission is degraded; it names ticket offices and bank counters among uses (consolidated preview, Introduction, page 8).
- The public consolidated preview contents identify Annex G as informative and title it Calibration of field-strength meters; the figure list names Figure G.1 as a triple Helmholtz coil for calibration of meters. The preview does not include the annex procedure itself.
Limits
Read from the IEC webstore abstract and from the public preview of the consolidated edition 3.1 (2017) published by the German standards publisher VDE Verlag (https://www.vde-verlag.de/iec-normen/preview-pdf/info_iec60118-4%7Bed3.1%7Db.pdf), which shows the cover, the contents, the introduction and the scope; the rest of the 109-page text is paywalled. Neither states the numeric targets (reference field strength, tolerances, frequency limits, maximum background noise), so any figure quoted for them comes from secondary summaries, such as manufacturers' commissioning guides, and has not been checked here against the standard.
Read the original
webstore.iec.ch/en/publication/798
Cited in
- Which systems satisfy the ADA and building codes, and does a listener's own phone count?Disputed
- Auracast, hearing loop, infrared, RF or Wi-Fi: which suits which room?Disputed
- Can Auracast serve ticket windows, service counters and reception desks?Open
- How is an installed hearing loop checked against IEC 60118-4, and how often does it pass?Partly answered
- Where do hearing loops fall short: metal, spill, noise and upkeep?Partly answered
- Are telecoils switched on and set up well enough for loops to work?Not reliable yet
- Should a venue keep its hearing loop when it adds Auracast, and can one system serve both?Partly answered
- How do listeners learn that a venue has assistive listening, and which signs and symbols do the rules ask for?Partly answered
- What works in places of worship, and what do the rules ask of them?Partly answered
- Do neckloops give telecoil users good sound from FM, infrared, Wi-Fi and Auracast receivers?Not reliable yet
- What works in hospitals, clinics and pharmacies, where a misheard word can matter most?Partly answered
- Do portable and counter loops work, and how should they be set up and used?Partly answered
- Which meters and apps measure loops and Auracast, and how accurate are they?Partly answered
- What should a venue specify and ask for when it buys an assistive listening system?Partly answered
Cite this source
IEC TC 29 (Electroacoustics). IEC 60118-4:2014 Electroacoustics - Hearing aids - Part 4: Induction-loop systems for hearing aid purposes - System performance requirements. International Electrotechnical Commission. 11 December 2014. https://webstore.iec.ch/en/publication/798 (accessed 13 October 2026).
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