PSA B65 4251 Acoustic Absorbers Sound Insulation Specification

The standard “PSA B65 4251 Acoustic absorbers sound insulation specification” developed by the French automobile company Renault describes the technical characteristics that acoustic absorbers with or without glue for interior or exterior cabins must meet. This standard applies to planar or molded acoustic absorbers made of single materials or complexes. Materials subject to an adjustment procedure in the material data sheet must meet this current standard.

This standard does not apply to absorbers, soundproofing apron material, soundproofing Izovac material and similar materials used as soundproofing in the engine compartment under the bonnet. These form part of a specific standard for engine soundproofing complex materials and the material data sheet is related to the complex engine soundproofing.

Absorbers are products that perform the function of acoustic absorption. This expression indicates the dispersion of sound energy in a material exposed to the event. The absorbency of sound energy of a material is expressed by the absorption coefficient, which can be given as follows:

• Tube with impedance that gives an absorption coefficient in plane waves that varies with frequency and is expressed as a percentage: α plot. These measurements are taken on several planar samples taken on a piece. The measurement results are presented in the form of an average curve (α plot with respect to frequency).
• Alpha chamber, which gives an absorption coefficient in diffuse fields that varies with frequency and is expressed as a percentage: α diffusion. These measurements are taken on a 1,2 m2 planar sample or on a piece. The measurement results are presented in the form of a curve:
  • Diffusion α versus frequency for an example
  • Frequency-corrected equivalent absorption surface for a feathery or planar part

The corrected equivalent absorption surface corresponds to the total absorbent surface (absorption coefficient α = 100 percent) that has the same absorbent capacity as the part in question.

Absorbents are usually made of a porous material (fibrous or cellular). They may be coated with a view material, possibly with a material intended for:

• The appearance material may consist of textile (non-woven, woven or knitted)
• The right material usually consists of non-woven fabric

If the absorber contains glass fiber, the glass fiber ratio in the air of the work stations (preparation, assembly) must not exceed W0,1 fiber/cm3.

Requirements are transferred from system to subsystem according to the overall performances provided by the material in terms of:

• Regulation and consumption
• Appearance when new
• Appearance after wear and tear
• Appearance after wear and tear
• Compliance with the straight edge core competencies standard
• Technical specifications (mechanical, thermal, etc.)

In addition, the essential requirements are intended for a classification that allows their traceability to the automotive system engineering system. For example, for resistance to microorganisms (mold): MAT_VEH_TMA_301.

The encoding is in the format MAT_XXX_YYY_ZZZ:

• MAT stands for material
• XXX identifies the application:
  • VEH for the entire vehicle system
  • INT for indoor applications
  • EXT for external applications
  • SCM for under-hood applications
• YYY indicates localization
  • TMA for all applications in the environment
  • VIS for visible applications of the environment
  • NVI for invisible applications of the environment
• ZZZ indicates serial number

In general, these requirements comply with the standard “B65 0110 Trimming materials general specifications”.

During trimming, the supplier must specify the category and detailed percentage of the various subcomponents of the product. In addition, these requirements must be supported by standards. No unspecified engineering changes can be made to any of these materials without the agreement of the relevant engineering departments of the PSA Group. Any changes to the materials necessarily require a new approval.

Materials must be traced from raw material packages to finished products. Each material must be characterized by commercial assembly reference parts and a set of packages.

Materials must comply with the PSA B20 0250 standard, which specifies the relevant requirements.

Among the numerous tests, measurements, analyses and evaluation studies carried out for businesses in various sectors, our organization also provides testing services defined in the “PSA B65 4251 Acoustic absorbers sound insulation specification” standard with its trained and expert staff and advanced technological equipment.