1 .l This International Standard specifies measurements
on silencers in situ. It is applicable to measurements
on silencers in practical applications for
acoustic analysis, acceptance tests and similar
evaluations. Results obtained in accordance with this
International Standard cannot be compared to performance
data obtained from laboratory measurements
on ducted silencers in accordance with
IS0 7235, partly because of different test conditions
(such as sound field distribution, flow, temperature and
mounting conditions) and partly because of different
definitions.
Depending on the method used, the measurement is
either of
- insertion loss Dis, or
- transmission loss Dt,.
The measurement method depends upon the type of
silencer and the installation conditions (e.g. insertion
loss measurements must be carried out for blowdown
silencers).
NOTE 1 The subscripts denote the practical application of
the silencer and the particular installation and operating
conditions: s stands for ¿I situ, t for transmission, and
i for insertion.
Additional characteristic quantities, which could include
measurements taken using artificial sound
sources or measurements taken to determine the directivity
of sound propagation from the silencer, may
be agreed upon in accordance with this International
Standard.
1.2 This International Standard is applicable to
a) silencers which are installed either as a whole or
in the form of individual baffles in the propagation
path of sound (e.g. openings of ducts) originating
from a sound source (machine, building, plant
Diese ÖNORM trifft Festlegungen für Messungen an Schalldämpfern im Einsatzfall. Sie ist anwendbar für Messungen an Schalldämpfern im praktischen Anwendungsfall zum Zweck schalltechnischer Analyse, für Abnahmeprüfungen und für ähnliche Beurteilungen.