IEC 60849:1998 pdf download – Sound systems for emergency purposes

IEC 60849:1998 pdf download – Sound systems for emergency purposes.
IEC 60849 applies to sound reinforcement and distribution systems to be used to effect a rapid and orderly mobilization of occupants in an indoor or outdoor area in an emergency situation.
This standard applies to systems using tone signals and to systems with voice announcements for emergency purposes.
NOTE I — The use of the system for normal sound revnforcernent and distribution systems purposes under non- hazardous circumstances is not excluded
NOTE 2 — it is recommended that the system, when used for emergency purposes. should form part of a complete tacil,ty iequipment, operating procedures and training programmes) for the control of ernergencies
NOTE 3 Sound systems for emergency purposes may be the subject of approval by relevant authonties
1.2 Object
The purpose of this standard is to specify the performance requirements for sound systems which are primarily intended to broadcast information (or the protection of lives within one or more specified areas in an emergency.
The standard gives the characteristics and the methods of test necessary far the specification of the system.
2 Normative references
The following normative documents contain provisions which, through reference in this text. constitute provisions of this International Standard, At the time of publication, the editions indicated were valid. All normative documents are subject to revision and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of lEG and ISO maintain registers of currently valid International Standards.
lEG 60027: £ etter symbols to be used in electrical technology
IEC 60065:1985. Safety requirements for mains operated electronic and related apparatus for household and similar use
IEC 60068-1:1988, Environmental testing – Part 1,’ General and guidance fEC 60079: Electrical apparatus for explosive gas atmospheres
fEC 60268- 11:1987. Sound system equipment – Part 11.’ Application of connectors for the interconnect/on of sound system equipment
fEC 60268- 12:1987. Sound system equipment – Part 12.’ ApphOat/on of connectors for broadcast and similar use
fEC 60268-16:—, Sound system equipment — Part 16: Objective rating of speech intelligibilily by speech transmissiOn index1’
IEC 60364: Electrical installations of buildings
IEC 60417:1973, Graphical symbols for use on equipment
IEC 61938:1996. Audio. video and audiOvisual systems – InterconnectiOns and matching
values – Preferred matching values of analogue signals
3 Definitions
For the purpose of this standard. the following definitions apply.
area of coverage
the area. inside andor outside a building, where the system meets the requirements laid down in this standard
NOTE — Certain parts at an area may be excluded, see 5. 1
3.2
loudspeaker zone
any part of the area of coverage to which information can be given separately
3.3
information
any speech or intended audio signal
3.4
audibility
that property of sound which allows it to be heard among other sounds
NOTE – At present for objectvve analysis. for example when using the Sri equation (see IEC 60268- 76). the concept of audibility takes account of the relative loudness and frequency content of the Sound in corn panson with other sounds present at the same time
3.5
intelligibility
a measure of the proportion of the content of a speech message that can be correctly understood
NOTE – Satisfactory intethgibility requires adequate audEbihty and adequate clarity.
3.6
clarity
the property of a sound which allows its inform ation ‘bearing components to be distinguished by a listener. It is related to the freedom of the sound from distortion of all kinds
NOTE – There are three kinds of distortion involved in the reduction of clarity of a speech signal in an electroacous tic system
a) amplitude distortion, due to non-linearity in electronic equipment and transducers:
b) frequency distortion, due to non-uniform frequency response of transducers and selective absorption at high frequencies in acoustic transmission:
C) time domain distortion, due to reflection and reverberation in the acoustic domain.