EN 13819-2-2020 pdf download.Hearing protectors – Testing – Part 2 : Acoustic test methods.
4.1 Insertion loss (earmuffs only)
4.1.1 Principle
The insertion loss of each cup of the earmuffs is measured at specified one-third-octave band centre frequencies.
4.1.2 Apparatus
The required equipment, including a suitable acoustic test fixture and test site, is described in EN ISO 4869-3. For mounted earmuffs, a supporting pad. an example of which is shown in Figure 1. shall be fitted to the acoustic test fixture in order adequately to support the complete mounted earmuff in position.
4.1.3 Procedure
Follow the procedure given in EN ISO 4869-3, subject to the following modifications:
a) either the random incidence sound field or the plane progressive wave sound field shall be used. When using the plane progressive wave sound field, If the requirement for insertion loss is not satisfied, the test shall be repeated using the random incidence sound field. If the requirement for insertion loss is then satisfied, this shall be deemed to be the definitive result;
b) the insertion loss shall be measured at all one-third-octave bands from 250 [Iz to 8 000 Hz;
c) in the case of universal earmuffs the insertion loss shall be measured in only one mode of wearing, preferably over-the-head;
d) if means to adjust the headband force is incorporated, the force shall be adjusted to its maximum setting;
e) in the case of mounted earmuffs, for a given model of earmuffs fitted to more than one size of the same model of carrier, insertion loss shall be tested using only one size of carrier;
fl in the case of headband or mounted earmuffs with electronic supplementary functions that show – as purposely intended by the manufacturer — different sound attenuation on left and right cups, mean and standard deviation shall be reported separately for left and right cups.
4.1.4 Report
For each centre frequency and for each cup, individual values of insertion loss shall be reported in accordance with 4.1.3 b). For all cups. the mean value and standard deviation at each frequency shall also be reported in accordance with 4.1.3 b).
4.2 Sound attenuation
4.2.1 Principle
The attenuation of the hearing protector is measured at specified one-third-octave band centre frequencies.
4.2.2 Apparatus
The required apparatus, including test sites and sound field, is specified in EN ISO 4869-1. 4.2.3 Procedure
4.2.3.1 Measure the sound attenuation of defined specimens in accordance with EN ISO 4869-1:2018, Clause 4.
4.2.3.2 If means to adjust the headband force is incorporated, adjust the force to its minimum setting.
4.2.3.3 In the case of earplugs. supply each subject with a separate pair of earplugs of appropriate size. If different sizes are available, choose the size that gives the best fit.
4.2.3.4 In case earplugs are provided in different versions that are considered to be equal with respect to attenuation, one measurement should be performed and the samples used for that measurement should include all of the versions.
NOTE Examples of different versions could be earplugs offered in different colours, with different handgrips or with and without a connecting cord.
4.2.3.5 In the case of custom moulded earplugs, impression taking shall be carried out by a trained specialist. A trained specialist should have the appropriate qualification and knowledge of taking ear impressions safely and accurately.
4.2.3.6 In the case of custom moulded earplugs that are provided by the manufacturer to be used with a special cream that eases insertion and improves the fitting the sound attenuation shall be measured without this cream.
4.2.3.7 In the case of mounted earmuffs which do not fit all size ranges according to EN 13819-1:2020, 4.2, ask each test subject if the specimen fits. If it does fit, perform the test. If it does not fit, reject the subject from the panel and provide a replacement for him/her.
4.2.3.8 In the case of universal earmuffs and headband earplugs with different modes of wearing, provide sound attenuation values for each intended mode of wearing.EN 13819-2-2020 pdf download.