Sound insulation performance loss testing service

Sound Insulation Performance Loss Testing Service – Accredited ISO/IEC 17025 Acoustic Durability and Aging Assessment for the Croatian Market

Sound insulation performance loss is a critical parameter that quantifies the degradation of acoustic insulation properties of materials, components, and systems over time, under environmental stress, mechanical wear, aging, and contamination. This property is essential for ensuring the long‑term acoustic comfort, privacy, safety, and regulatory compliance of building partitions, automotive interiors, industrial enclosures, aircraft cabins, marine vessels, and acoustic barriers. In the Croatian market, where the Hrvatski zavod za norme (HZN), the Ministarstvo graditeljstva i prostornoga uređenja, the Državni inspektorat, the Ministarstvo gospodarstva i održivog razvoja, and the Carinska uprava enforce strict quality, durability, and building acoustics standards aligned with EU directives and HRN EN (Croatian standards based on European norms), the accurate evaluation of sound insulation performance loss is essential for product certification, building approval, supplier qualification, quality control in manufacturing, and import‑export processes. Our laboratory offers a comprehensive sound insulation performance loss testing service, applying standardized methods such as ASTM E90, ISO 10140‑1, ISO 717‑1, ASTM C423, ISO 354, ASTM E2238, and HRN EN ISO 10140‑1 to measure the change in sound transmission loss, sound absorption coefficient, and overall acoustic performance after exposure to controlled aging, weathering, thermal cycling, and mechanical stress. All tests are performed under our ISO/IEC 17025 (CNAS) accreditation, and the resulting reports are fully accepted by Croatian authorities and notified bodies, making them indispensable for regulatory compliance, product validation, and market access in Croatia and the European Union.

Acoustic Materials and Systems We Regularly Test

Our laboratory receives a wide variety of acoustic materials, components, and systems for sound insulation performance loss testing. Typical samples include:

• Building partitions and wall assemblies – gypsum boards, masonry walls, glass partitions, and modular wall systems.
• Floor and ceiling assemblies – floating floors, acoustic ceilings, and underlayment systems.
• Doors and windows – acoustic doors, glazing, and window systems with seals and gaskets.
• Automotive and transportation components – door panels, headliners, floor mats, dash insulators, and acoustic packages.
• Industrial and machinery enclosures – acoustic covers, silencers, mufflers, and soundproof cabinets.
• Acoustic insulation materials – fiberglass, mineral wool, foam panels, mass‑loaded vinyl, and composite sound barriers.
• Prototype and new acoustic designs – submitted by manufacturers for validation of long‑term acoustic durability before series production.
• Field‑retrieved components – for failure analysis and remaining acoustic life assessment.

Acoustic Performance Aging and Durability Assessment – Evaluating the Loss of Sound Insulation

Sound insulation performance loss is evaluated by measuring the acoustic performance (sound transmission loss, sound absorption coefficient, and insertion loss) before and after the exposure of the material or component to specified aging and weathering conditions. Our tests follow international standards and the requirements of the Croatian construction, automotive, and industrial sectors.

• Sound transmission loss comparison before and after aging (ASTM E90 / ISO 10140‑1 / HRN EN ISO 10140‑1 / NTC 5600 – for building partitions) – we measure the sound transmission loss (TL) of the test specimen (in 1/3‑octave bands from 50 Hz to 5000 Hz) using the standard two‑room method (source and receiving rooms). The test is performed on a fresh (un‑aged) specimen and on a specimen that has been subjected to a specified aging protocol (e.g., thermal cycling, humidity exposure, or mechanical stress). The loss in the weighted sound reduction index (Rw) and the sound transmission class (STC) are calculated. We report the TL, Rw, and STC before and after aging, and the performance loss (in dB).
• Sound absorption coefficient comparison before and after aging (ASTM C423 / ISO 354 / NTC 5601 – for acoustic materials) – we measure the sound absorption coefficient (α) of the acoustic material using the reverberation room method (or the impedance tube method). The test is performed on a fresh specimen and on an aged specimen. The reduction in the noise reduction coefficient (NRC) and the sound absorption average (SAA) are calculated. We report the α, NRC, and SAA before and after aging, and the performance loss (in %).
• Insertion loss comparison before and after aging (ISO 7235 / NTC 5602 – for silencers and mufflers) – we measure the insertion loss (IL) of the acoustic device (e.g., a silencer) in a duct system, with and without the device, before and after the aging of the device. The reduction in the IL is reported. We report the IL before and after aging, and the performance loss (in dB).
• Acoustic impedance change measurement (NTC 5603 – for the material stiffness change) – we measure the acoustic impedance (Z) of the material (or the resonant frequency) before and after aging, using an impedance tube or a two‑microphone method. The change in the impedance is correlated with the loss of the acoustic performance. We report the impedance change and the acoustic performance loss.
• Frequency‑dependent loss analysis (NTC 5604 – for the spectral performance loss) – we analyze the acoustic performance loss as a function of the frequency (in 1/3‑octave bands). The frequency range where the loss is most significant is identified. We report the performance loss vs. frequency curve.

Environmental Aging and Weathering – Simulating Real‑World Service Conditions

Acoustic insulation materials can lose their performance over time due to environmental exposure to UV radiation, humidity, temperature fluctuations, and moisture. Our environmental aging tests simulate these conditions and evaluate the long‑term stability of the acoustic properties, which is essential for the diverse Croatian climate (coastal, continental, and mountainous).

• Thermal aging and its effect on acoustic performance (ASTM D573 / ISO 188 / NTC 5610 – for the heat‑aged materials) – we age the acoustic material in an oven at a specified temperature (e.g., 70 °C, 100 °C) for a specified duration (e.g., 7, 14, or 28 days). We then re‑measure the acoustic performance (TL, α, or IL). The loss in the acoustic performance is reported. We report the acoustic performance loss after thermal aging and the retention of the acoustic properties.
• Humidity and water immersion effect (ASTM D570 / NTC 5611 – for the moisture‑exposed materials) – we expose the acoustic material to a high‑humidity environment (e.g., 40 °C, 95 % RH) or to water immersion for a specified duration (e.g., 7 days). We then re‑measure the acoustic performance. The loss in the performance is reported. We report the performance loss after humidity exposure and the moisture uptake.
• UV and weathering effect (ASTM G154 / NTC 5612 – for the outdoor‑exposed materials) – we expose the acoustic material to UV radiation (UVA‑340) and condensation cycles for a specified duration (e.g., 500 hours). We then re‑measure the acoustic performance. The loss in the performance is reported. We report the performance loss after UV exposure and the change.
• Freeze‑thaw effect (NTC 5613 – for the cold‑climate applications) – we subject the acoustic material to repeated freeze‑thaw cycles (e.g., -20 °C to +20 °C) and then re‑measure the acoustic performance. The loss in the performance is reported. We report the performance loss after the freeze‑thaw cycles and the effect.
• Chemical exposure effect (ASTM D543 / NTC 5614 – for the chemically exposed materials) – we immerse the acoustic material in various chemicals (e.g., mineral oil, cleaning agents, or solvents) for a specified duration (e.g., 7 days) and then re‑measure the acoustic performance. We report the performance loss after the chemical exposure and the compatibility.

Mechanical Wear and Fatigue – Evaluating the Performance Loss under Physical Stress

Acoustic insulation materials can lose their performance due to mechanical wear, compression, fatigue, and structural damage. Our tests simulate these conditions and evaluate the resulting acoustic performance loss, which is essential for applications subject to foot traffic, vibration, and repeated loading.

• Compression and creep effect on acoustic performance (ASTM D2990 / ISO 899-1 / NTC 5620 – for the compressed materials) – we apply a compressive load (or a constant strain) to the acoustic material for a specified duration (e.g., 24 hours, 100 hours) at a specified temperature. We then re‑measure the acoustic performance. The loss in the performance due to the compression set is reported. We report the performance loss after compression and the compression set.
• Abrasion and surface wear effect (ASTM D4060 / NTC 5621 – for the worn surfaces) – we subject the surface of the acoustic material to a specified number of abrasion cycles (e.g., using a Taber abraser) and then re‑measure the acoustic performance. The loss in the performance due to the surface wear is reported. We report the performance loss after abrasion and the wear depth.
• Fatigue and cyclic loading effect (ASTM D7791 / NTC 5622 – for the fatigue‑tested materials) – we apply a cyclic mechanical load (e.g., compression, bending, or flexing) to the acoustic material for a specified number of cycles (e.g., 10,000 cycles, 100,000 cycles) and then re‑measure the acoustic performance. The loss in the performance due to the fatigue is reported. We report the performance loss after fatigue and the fatigue life.
• Impact and shock effect (NTC 5623 – for the impact‑damaged materials) – we apply a controlled impact (e.g., a drop weight) to the acoustic material and then re‑measure the acoustic performance. The loss in the performance due to the impact damage is reported. We report the performance loss after the impact and the impact energy.
• Vibration and resonant fatigue effect (NTC 5624 – for the vibration‑exposed materials) – we subject the acoustic material to a vibration profile (sinusoidal or random) at a specified frequency and amplitude for a specified duration (e.g., 24 hours) and then re‑measure the acoustic performance. The loss in the performance due to the vibration is reported. We report the performance loss after the vibration and the vibration profile.

Microstructural and Physical Degradation Analysis – Identifying the Cause of Performance Loss

To fully understand the cause of the acoustic performance loss and to correlate it with the physical and microstructural changes of the material, we perform complementary analyses, including density measurement, thickness measurement, and microscopic examination.

• • Density and mass change measurement (NTC 5630 – for the material density change) – we measure the density (in kg/m³) and the mass (in g) of the acoustic material before and after the aging or the mechanical stress. The change in the density is correlated with the acoustic performance loss. We report the density change and the mass change.
  • Thickness and dimensional change measurement (NTC 5631 – for the material thickness change) – we measure the thickness (in mm) of the acoustic material before and after the aging or the mechanical stress. The change in the thickness is correlated with the acoustic performance loss. We report the thickness change and the dimensional change.
  • Scanning electron microscopy (SEM) – ASTM E1508 / NTC 5632 – for the microstructural analysis) – we use scanning electron microscopy (SEM) to examine the microstructure of the acoustic material (the fiber morphology, the cell structure, and the presence of defects) before and after the aging or the mechanical stress. The microstructural changes are correlated with the acoustic performance loss. We report the SEM images and the microstructural changes.
  • Porosity and pore size distribution (ASTM D4404 / NTC 5633 – for the pore structure change) – we measure the porosity (in %) and the pore size distribution of the acoustic material before and after the aging or the mechanical stress. The changes in the pore structure are correlated with the sound absorption loss. We report the porosity change and the pore size distribution change.
  • FTIR spectroscopy (ASTM E168 / NTC 5634 – for the chemical degradation) – we use FTIR spectroscopy to analyze the chemical composition of the acoustic material (e.g., the polymer degradation, the oxidation, or the loss of plasticizer) before and after the aging or the mechanical stress. The chemical changes are correlated with the acoustic performance loss. We report the FTIR spectra and the chemical changes.

Performance Loss Classification and Pass/Fail Criteria – Ensuring Regulatory Compliance

The measured acoustic performance loss is compared with the requirements of the relevant standards and the customer specifications to determine the conformity of the product. Our tests provide a clear pass/fail result and a statement of compliance with the applicable standards and the building regulations.

• Performance loss limit verification (NTC 5640 – for the compliance with the specification) – we compare the measured acoustic performance loss (e.g., the loss in Rw, STC, NRC, or IL) with the maximum allowable loss specified in the product standard or the customer's requirement. We report the measured loss, the specified limit, and the pass/fail status.
• Classification of the aging effect (NTC 5641 – for the durability rating) – we classify the aging effect on the acoustic performance based on the measured loss (e.g., Excellent for a loss of < 1 dB or < 5 %, Good for a loss of 1‑3 dB or 5‑10 %, Poor for a loss of > 3 dB or > 10 %). We report the classification and the durability rating.
• Compliance with the building regulations (NTC 5642 – for the building approval) – we compare the acoustic performance after aging with the minimum requirements of the Croatian building regulations (based on the HRN EN standards) for the specific application (e.g., the minimum Rw for a residential wall). We report the compliance and the pass/fail status.
• Guarantee verification (NTC 5643 – for the contractual purposes) – we test the acoustic material to verify that its performance loss is within the guaranteed value specified in the purchase order or the design specification. We report the measured loss and the margin relative to the guarantee.
• Extended test report for the EU compliance (NTC 5644 – for the CE marking and the declaration of conformity) – we provide a comprehensive test report that includes all the measured acoustic parameters before and after the aging, the performance loss, and the compliance statement. The report is suitable for the CE marking and the declaration of conformity, as required by the EU construction products regulation (CPR). We report the compliance and the certification status.

Complementary Tests – Hardness, Tensile, and Acoustic Impedance for Performance Correlation

To provide a comprehensive assessment of the acoustic performance loss and to correlate it with the material's physical properties, we perform complementary tests, including hardness testing, tensile testing, and acoustic impedance measurement.

• Hardness testing (ASTM D2240 / NTC 5650 – Shore A or Shore D for the acoustic materials) – we measure the Shore A or Shore D hardness of the acoustic material before and after the aging or the mechanical stress. The change in the hardness is correlated with the acoustic performance loss. We report the hardness change and the correlation.
• Tensile strength and elongation (ASTM D638 / ISO 527 / NTC 5651 – for the tensile properties) – we measure the tensile strength (in MPa) and the elongation at break (in %) of the acoustic material before and after the aging or the mechanical stress. The loss of the tensile properties is correlated with the acoustic performance loss. We report the tensile properties and the correlation.
• Dynamic mechanical analysis (DMA) – ASTM D4065 / NTC 5652 – for the modulus and the damping) – we use DMA to measure the storage modulus (E'), the loss modulus (E''), and the loss factor (tan δ) of the acoustic material as a function of the temperature and the frequency. The changes in these parameters are correlated with the acoustic performance loss. We report the DMA results and the correlation.
• Acoustic impedance and flow resistance measurement (ASTM C522 / NTC 5653 – for the porous material characterization) – we measure the acoustic impedance (Z) and the flow resistance (in Pa·s/m³) of the acoustic material before and after the aging or the mechanical stress. The changes in these parameters are correlated with the sound absorption loss. We report the impedance and the flow resistance changes.
• Micro‑hardness and indentation testing (NTC 5654 – for the local mechanical property) – we measure the micro‑hardness (using a Vickers or a Shore micro‑indenter) of the acoustic material at a microscopic scale, before and after the aging or the mechanical stress. The change in the micro‑hardness is correlated with the acoustic performance loss. We report the micro‑hardness change and the correlation.

Test Report and Recognition in the Croatian Construction, Automotive, and Industrial Sector

All procedures described are within the scope of our ISO/IEC 17025 accreditation, with equipment calibrated periodically (acoustic test chambers, impedance tubes, universal testing machines, and environmental chambers) and traceability to international standards (NIST, PTB). Our test reports are issued in English (with a Croatian summary available on request) and include:

• Full identification of the acoustic material (manufacturer, product type, density, thickness, and intended application).
• Detailed description of the test methods applied (ASTM/ISO/EN/HRN EN/NTC standards, test conditions, aging protocols, and measurement parameters).
• Numerical results: sound transmission loss (TL, dB), weighted sound reduction index (Rw), sound transmission class (STC), sound absorption coefficient (α), noise reduction coefficient (NRC), sound absorption average (SAA), insertion loss (IL, dB), and performance loss (dB or %).
• Graphical data: TL vs. frequency curves (before and after aging), α vs. frequency curves (before and after aging), and performance loss vs. aging time curves.
• Comparative tables against the values specified by the client or against the limits of the relevant standards (ASTM E90, ISO 10140‑1, ISO 717‑1, HRN EN ISO 10140‑1, and the requirements of the HZN, Ministarstvo graditeljstva, and Državni inspektorat).
• Photographs and micrographs (SEM) of the acoustic material before and after the aging or the mechanical stress, showing the physical and microstructural changes.
• Recommendations for material selection, design improvement, and quality control measures to reduce the acoustic performance loss and to enhance the long‑term durability.
• Expanded uncertainty (k=2) for all key measurements, calculated according to the ISO/IEC 98‑3 Guide.

These reports are fully accepted by the Hrvatski zavod za norme (HZN) for the verification of product conformity, by the Ministarstvo graditeljstva i prostornoga uređenja for building approval and acoustic compliance, by the Državni inspektorat for market surveillance, and by the Carinska uprava (Croatian Customs) for tariff classification and quality verification in the import of acoustic materials and components. Additionally, we offer consulting services for the selection of durable acoustic materials, the design of long‑life acoustic systems, and the implementation of acoustic performance monitoring programs, contributing to the acoustic comfort, safety, and sustainability of buildings, vehicles, and industrial facilities in the diverse and growing Croatian market, from the coastal tourist destinations to the continental manufacturing and energy sectors.