AS 1428.5:2021 pdf free download – Design for access and mobility Part 5: Communication for people who are deaf or hearing impaired

AS 1428.5:2021 pdf free download – Design for access and mobility Part 5: Communication for people who are deaf or hearing impaired.
AS 1428.5 sets out requirements for the design, application of arid measurements to be performed on hearing augmentation systems to enable access to auditory communication for people who have a hearing impairment or who are deal.
This Standard sets out definition of and requirements for:
(a) Hearing augmentation systems, which include —
(I) audio frequency Induction loop systems (AFILS), commonly called hearing loop systems;
(II) systems requiring the use of receivers; and
(Hi) systems for use at counters.
(b) Sound field amplification systems.
(c) Inbuilt amplification.
(d) Screens and barriers at counters.
(e) Warning and alerting systems.
NOTE 1 For information on comparison of hearing augmentation systems. see Appendix L,
NOTE 2 For information on hearing loss, see AppendixB.
NOTE 3 The locations where hearing augmentation systems are required is specified in the NCC,
1.1.2 Application
This document is intended for use by planners, designers, regulators, builders, facility managers and operators of buildings and terminals to choose appropriate design solutions and equipment [or the design, installation, operation and maintenance of hearing augmentation, communication and warning systems.
1.2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this docume’nt:
NOTE I Documents referenced for inlormative purposes are listed in the Bibliography.
AS/NZS 1428.1, Desiijn for access and mobility, Part 1: General requl rements for access
AS 1603.17:2020, Automatic fire detection and alarm systems, Port 17 Warnin.g equipment for people with hearft Impairment
NOTE 2 The personal hearingdevice is designed to do all the necessary frequency correction loran Individual’s hearing loss.
3.2.7 MagnetIc Geld strength
The magnetic field strength shall be tested at the weakest point inside the loop-cabled area, with the
input signal level set above the knee ol the automatic audio level control using —
(a) simulated speech: and
(b) peak hold capability.
NOTE 1 Tplcally In a perimeter loop the weakest point Is In the centre of the loop cabled area.
NOTE 2 For a single loop less than 4 m wide, the centre may be the strongest, hence the weakest point is typically closer to the loop cable.
NOTE 3 In the event that the hearing loop system amplifier Is not capable of maintaining output for the time taken to determine the weakest point inside the looped cable area, the amplifier output level may be adjusted down by approximately 6 dB from maximum while identilying the measurement reference point. Once this point has been identified, increase the output to the required level to satisfy requirements and measure at the reference point.
The magnetic field strength level shall not —
(I) be less than —3dB re 400 mA/rn for speech peaks in accordance with Table 3.2.11 and
(ii) be greater than .3 dB re 400 mA/rn for speech peaks.
The clipping indicator on the hearing loop amplifier shall not Illuminate.
3.2.8 Distortion
Total harmonic distortion of the hearing loop system shall not exceed 4%. when the hearing loop system. has been set to meet the frequency response and field strength requirements of Clauses 12.6 and 12.2.
Total harmonic distortion shall be measured with a distortion meter and may be measured with a 1 kHz sine wave, or with pink noise.
The clipping Indicator shall not be lit when performing this test.
3.2.9 Automatic level control
To compensate for fluctuating signal Input levels, a system that maintains the audio signal to the user at a constant level shall be employed.
The maximum variation of the output signal shall be 3 dB for a 30 dB variation of the input signal. This shall be tested with a 1 kHz tone, measuring the field strength. Then the input signal level shall be increased by 30 dB and the magnetic field strength recorded. Any change more than 3 dB shall be deemed non-conforming.
NOTE The automatic level control is required as hearing loss affects a user’s ability to cope with variations in volume level.