SIST EN 352-5:2003/A1:2006

SIST EN 352-5:2003/A1:2006 is the Slovenian adoption of EN 352-5:2002/A1:2005 from SIST. It covers hearing protectors, specifically active noise reduction ear-muffs, and sets amended safety and testing requirements for manufacturers, test laboratories, and anyone checking product performance data. The amendment focuses on the linearity check and on the wearer information and test reporting that go with it.

What does SIST EN 352-5:2003/A1:2006 specify?

SIST EN 352-5:2003/A1:2006 specifies an amendment to the European standard for active noise reduction ear-muffs. In practice, it changes how linear operation is checked, what wearer information must accompany the ear-muffs, and how the Annex B test method and report are written.

The document is organized around:

• subclause 4.3.3, which covers the maximum sound pressure level for linear operation
• subclause 6.1, which covers wearer information
• Annex B, which covers test sound, test method, and reporting

What are the key requirements of SIST EN 352-5:2003/A1:2006?

• Linearity must be checked up to 110 dB. Subclause 4.3.3 requires the highest external test-noise level for which the sound pressure level at the subject’s ear remains linearly related to the external sound pressure level to be determined in accordance with 5.3. In practice, this tells the tester how far to push the product before reporting its limit of linear operation.

• The limit of linearity must be reported in wearer information. The same subclause requires the result to be reported in 6.1. For a buyer or quality manager, that means the product information must show where linear performance stops, not just that the earmuff was tested.

• Wearer information is expanded. Subclause 6.1 says the ear-muffs must be supplied with wearer information in addition to the information required by EN 352-1 or EN 352-3 as appropriate. This matters because the product instructions have to cover the active noise reduction function as well as the base ear-muff type.

• The test sound should be broad-band noise. Annex B.2 says broad band noise spectrum should be used for determining diffuse-field related sound pressure levels, with adequate electrical signal-to-noise ratio and possible minor equalisation. In practice, the laboratory needs a stable test signal that supports measurements across the test band.

• The active attenuation test uses MIRE and diffuse-field correction. Annex B.3 proposes EN ISO 11904-1 as an interim procedure and describes measurement with the microphone in the real ear technique (MIRE) in the open ear canal. The measured levels are then corrected to diffuse-field related sound pressure level, so the results are usable for comparison and reporting.

• Eight subjects are used, with both ears measured. Annex B.3 specifies eight subjects and measurements on both ears. That gives a repeatable test sample and means the result reflects person-to-person and ear-to-ear variation.

• The linearity check uses 5 dB steps up to 110 dB. Annex B.3 requires the external sound pressure level to be increased in 5 dB steps while monitoring the 125 Hz octave band at the ear, and the test stops if linearity is still maintained at 110 dB. If the limit is reached, the report must state the highest level for which linearity held.

• Oscillation or acoustic malfunction must be handled and reported. If a subject reports sustained oscillation or acoustic malfunction, the subject refits the ear-muffs and retries the ANR system; if the problem persists, the subject is withdrawn and the event is reported. This matters because active systems can fail in use, and the standard requires that behavior to be captured, not ignored.

What terms does SIST EN 352-5:2003/A1:2006 define?

• Active attenuation - the difference in diffuse-field related sound pressure level at the wearer’s ear between active mode and passive mode.
• Diffuse-field related sound pressure level - the sound pressure level corrected so it represents diffuse-field conditions at the ear.
• Maximum Sound Pressure Level for linear operation - the highest external test-noise level at which the ear’s sound pressure level still changes linearly with the external level.
• MIRE - microphone in the real ear, the measurement technique used in Annex B for the open ear canal.
• Passive attenuation - the attenuation from the ear-muff without the active noise reduction function, used as the basis for total attenuation calculations.
• Wearer information - the information supplied with the ear-muffs for the user, including the additional content required by this amendment.

Who uses SIST EN 352-5:2003/A1:2006?

Manufacturers of active noise reduction ear-muffs use this standard to design the product, set the wearer information, and prepare test evidence. Test laboratories use it to run the Annex B procedure and document active attenuation and linearity.

Certification bodies, quality managers, and buyers use it to check that product data are based on the same test method and reporting format. It is also relevant to occupational hearing protection programs that compare products for workplace use.

What changed in SIST EN 352-5:2003/A1:2006 from the previous edition?

SIST EN 352-5:2003/A1:2006 is an amendment to EN 352-5:2002. The stated changes are:

• a revised linearity requirement that checks performance up to 110 dB and requires the limit of linearity to be reported
• a revised first sentence in 6.1 on wearer information
• updated Annex B text for the test sound, test method, and reporting requirements

Which standards are used with SIST EN 352-5:2003/A1:2006?

• EN 352-1 - provides the passive attenuation data used for assumed total protection values and is one of the standards that can define the base wearer-information requirements.
• EN 352-3 - provides the corresponding passive attenuation data when the ear-muffs are of the appropriate type and is also referenced for wearer-information requirements.
• EN ISO 11904-1 - provides the microphone in the real ear technique used in Annex B as an interim test procedure.
• EN 13819-2 - describes the general test procedure that Annex B refers to for hearing-protector testing.

What does the SIST EN 352-5:2003/A1:2006 document contain?

The document contains the amended wording for subclause 4.3.3, subclause 6.1, and Annex B. Annex B gives the test sound, the measurement approach, the subject handling rules, and the reporting items for active attenuation and linear operation.

It also sets out how to calculate and report mean active attenuation, standard deviation, and assumed protection values of total (active plus passive) attenuation. For practical use, that means the document is not only about the product requirement, but also about the test setup and the exact data that must be recorded.