Audio-frequency Induction Loops (AFILS) work by transmitting amplified sound to NHS hearing aids allowing them to participate more fully in general conversation, ordering goods or services etc. Induction loop systems are governed by BS7594 (The Code of Practice for Audio-Frequency Induction Loop Systems) and EN60118-4 (Magnetic field strength in audio frequency induction loop systems for hearing aid purposes).

According to the Royal National Institute for the Deaf (RNID):-
• Over 9 million people are deaf or hard of hearing (one in seven of the UK population)
• 2 million of these people have hearing aids
• 1.4 million people use hearing aids regularly
• 3 million people experience significant hearing difficulties

Audio-frequency induction loop systems allow hearing impaired people to hear more clearly.
Most hearing aids have a ‘T’ or ‘MT’ switch which allows them to pick up the electromagnetic field generated by an induction loop system. The hearing aid converts this signal into a sound suited to its user’s specific hearing requirements. Any person with a hearing aid positioned within or near the loop can hear the loop signal by switching their hearing aid to the correct position, allowing them to participate more effectively in general conversation, ordering goods or services, listening to public performances, etc.

An induction loop system therefore comprises the following main elements:-
4 The audio source - typically a microphone, television or radio (or a combination of these).
4 The induction loop amplifier
4 The loop - typically a single turn of wire usually run around the perimeter of the room or
a special counter loop fixed to the underside of a table.
4 The receiver(s) - any hearing aid with a ‘T’ or ‘MT’ switch or a specially designed loop
listening device.

In addition to the many routine benefits for hearing aid users, induction loop systems can also be used for other limited area broadcasting applications such as museum ‘walk through’ guided tours and surveillance talkback systems.

Legislation