Hearing Augmentation & Loops

Did you know that the Building Code of Australia states that inclusion of a hearing augmentation system is mandatory? The building code has changed recently and outlines the percentage of floor space that must be covered for any new buildings.

There are two common ways to provide hearing augmentation they are 1/ an induction loop and 2/ a wireless Infra-red or FM system

Induction Loops or Hearing Loops are the most effective and inexpensive way to provide hearing augmentation to a public space, hall or theatre. Here is some technical information outlining what an induction loop is – PDF

A wireless system is just as effective as a hearing loop, and lends itself to being retrofitted to an existing building where it might be impractical or cost prohibitive to install an induction loop. Wireless systems can be secure, and are typically made up of a central transmitter, and several receivers worn by the person needing assistance (delegate). The receivers can be in the form of headphones, or a small loop of wire called a Neckloop which goes around the neck of the delegate. The neckloop uses the delegates hearing aid in the ‘T’ (telecoil) position to provide hearing assistance. There are a number of elements to consider when deciding which way method to use – speak with one of our qualified consultants to find out more.

Hearing Augmentation – General Information

These comments are for guidance only, and should not be construed as a formal statement of the obligations defined in the various documents mentioned. It should also be noted that there is no simple answer to the question, “What hearing augmentation is required for this venue?” The Building Code of Australia is generally relevant; however certain states, local governments and even educational and other institutions have adopted higher expectations within their areas of authority. No particular piece of equipment, such as a loop amplifier, can properly be said to “meet standard”. It is only the overall system performance that is of concern. There are many factors that can prevent a loop system from meeting these performance standards. Only a carefully designed system can ensure that a system will work in a particular environment.

AS60118.4 identifies measurable criteria, and the clear implication of this is that systems must be carefully designed and installed, and subsequently tested to confirm compliance.

Building Code of Australia (BCA 2009)

The BCA is the base document recognised by Local Councils for building approvals. Section D 3.7 pertains to Hearing Augmentation, and it does call on AS1428, Designing for Access & Mobility Part 1, at present. It is normally applied in conjunction with new or renovated buildings, rather than existing buildings, and is certified by Building Surveyors and Local Councils.

Currently the BCA specifies:

Where an inbuilt amplification system (except EWIS) is installed, a hearing augmentation system complying with AS 1428.1 must be provided:

(i) In any conference room, meeting room, etc with floor area of more than 100 m2.

(ii) In any room used for judicatory purposes.

(iii) In any auditorium in a Class 9b building, equitably distributed and to not less than 15% of the floor area.

(iv) At any ticket office, tellers booth, reception area, etc where the public is screened from the service provider.

Definitions:

“Class 9b building” – an assembly building, including a trade workshop, laboratory or the like in a primary or secondary school, but excluding any other parts of the building that are of another class “Assembly building” – a building where people may assemble for:

(a) civic, theatrical, social, political or religious purposes; or

(b) educational purposes in a school, early childhood centre, preschool, etc; or

(c) entertainment, recreational or sporting purposes; or

(d) transit purposes.

AS1428.1

States that signs must indicate that there is hearing augmentation available, and where the entire space is not covered the boundaries need to be designated with signs.

AS1428.2

States that a minimum of 10% needs to be covered, and that the field strength needs to meet AS1088.4 (now superseded). Some of the statements in AS1428.2  regarding loop spill and how loops should be installed do not conform to current best practice. There is a new standard in draft called AS1428.5 which will revise ‘.1’ and ‘.2’ and is expected to be released later this year.

AS1088.4

Superseded by AS60188.4-2007. The newer standard is more rigorous, making Australia internationally compliant in regard to field strength and audio quality for the hearing impaired.

AS60118.4

Defines the performance criteria of an induction loop system. The key elements may be summarised:

• Field Strength in the specified listening area shall be -20dB re 1A/m average,

using a 1kHz sinusoidal input, with a variation of +/-3dB.

• Environmental Magnetic Background noise shall be no higher than -40dB Aweighted (measured with the loop system off).

• Frequency Response of the system shall be from 100Hz to 5000Hz. The

variation should be no more than +/-3dB from the value taken at 1kHz.

Building Code of Australia (Draft 2009)

Although not currently in force, the revised BCA is expected to add significantly to the performance requirements on Hearing Augmentation Systems.

Some of these are:

• increased coverage area to 80% for induction loops

• RF and IR systems requiring receivers to cover 95%; specified numbers of receivers must be provided (eg 20 for a 500 seat venue)

Additional factors

Although the various Standards cover many of the issues that are important in

providing a functional augmentation system to serve the hearing impaired, two other factors should be considered:

• Input audio quality – the output of a system is only as good as the input

• Monitoring and maintenance – a system must continue to perform in accordance with the standards to which it was installed.