The “PSA D45 5430 Felts, fillings, polyurethane foams - Measurement of acoustic absorption factor with impedance tube” standard, developed by the French automotive manufacturer PSA Group (now part of Stellantis), aims to define the equipment and operating mode to be used for measuring the acoustic energy absorption factor of fibrous or cellular materials. This standard applies to felts (synthetic or natural fibers), foams, complex textiles on felt or foam, and similar materials.
During the test, a sound source for impedance is integrated into one end of the tube, and the sample to be measured is placed at the other end. The loudspeaker produces a wide band of white noise. Plane waves propagating in the tube strike the sample; some are reflected, and some are absorbed by the material. This creates a contamination condition between the random and observed waves inside the tube. By measuring the acoustic pressure in two static tests of the tube and then calculating the frequency response function between the two microphones, it is possible to accurately determine the reflection factor of the material. From the reflection factor, the absorption coefficient of the material is subtracted. The frequency ranges of the measurements are determined by the diameter of the tubes, as well as the distance between the two microphones.
Test specimens or samples must be representative of the scale being characterized. To ensure this representativeness, the baseline characteristics of the population under study must be determined. The selection criteria for test specimens or samples must be stated in the test report in accordance with standard A10 0156.
Depending on the nature of the material, the measurement distribution can vary significantly, with physical parameters directly related to the material, such as buoyancy, thickness, and weight, having an effect. Therefore, the number of samples to be measured should be adjusted according to the type of material being tested.
Samples should be placed on two A4 plates (half on one, half on the other). Additionally, a 100 mm x 100 mm sample should be taken from each A4 plate and its weight measured according to the PSA D45 1012 test method.
It is recommended that material samples be conditioned for 24 hours prior to measurement at a temperature of 23 degrees plus/minus 2 degrees and a relative humidity of 50 percent plus/minus 5 percent. The operator must ensure that the sample is not subjected to mechanical or thermal stresses that could cause deformation.
The measured samples must be of good quality, have a homogeneous thickness, and be undamaged. The operator notes the specific information about the measured samples:
The gram weight of small tube samples should be within a range of plus/minus 20 percent compared to the gram weight measured according to the PSA D45 1012 standard. The gram weight of large tube samples should be within a range of plus/minus 10 percent compared to the gram weight measured according to the PSA D45 1012 standard.
All samples must have thicknesses within a range of plus/minus 10 percent compared to the average thickness according to the PSA D45 1195 standard. Otherwise, all samples will be considered unsuitable and the tests will not be performed.
In the high-risk world of automotive manufacturing, where every component must meet stringent performance criteria, standards set by PSA and major manufacturers play a crucial role. PSA standards guarantee that materials used in vehicles (from interior to exterior) provide safety, durability, and comfort. Among these, the D45 series standards cover everything from color fastness to thermal resistance, focusing on polymeric materials, textiles, and foams.
The PSA D45 5430 standard includes a precise method for evaluating the acoustic absorption properties of materials such as felt, padding, and polyurethane foam. In today's world, where electric vehicles demand quieter cabins and noise, vibration, and harshness control are key differentiators in the competitive landscape, understanding this standard is crucial for engineers, suppliers, and manufacturers aiming to improve vehicle acoustics.
Modern cars are designed not only for speed and efficiency, but also for sensory comfort. Road noise, engine hum, wind noise, and tire vibrations can negatively impact the driving experience, leading to driver fatigue and a decrease in perceived quality. Interior materials such as dashboard padding, door panels, and carpeting serve as the first line of defense against these auditory intruders.
Traditional test methods based on ISO or ASTM standards provide broad acoustic measurements. However, original equipment manufacturers like PSA demand specific protocols tailored to their vehicle architectures. The PSA D45 5430 standard offers a test method that measures how well porous materials absorb sound waves and how effectively they prevent echo and resonance in the passenger compartment. This standard is particularly important for electric vehicles.
The main objectives of this standard are:
For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "PSA D45 5430 Felts, fillings, polyurethane foams - Measurement of acoustic absorption factor with impedance tube" standard.
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