ISO 9053-1:2018

Overview

ISO 9053-1:2018 - "Acoustics - Determination of airflow resistance - Part 1: Static airflow method" specifies a laboratory method to measure the static airflow resistance of porous materials used in acoustical applications. The method measures the pressure drop across a material under controlled, unidirectional (laminar) airflow to derive quantities such as airflow resistance, specific airflow resistance, airflow resistivity and permeability. This standard is used to characterize sound-absorbing foams, fibrous media, textiles and other porous acoustic materials.

Key topics and technical requirements

• Principle: Measure differential pressure across a specimen while imposing a controlled volumetric airflow; calculate resistance as Δp / qv.
• Required equipment:
  • Measurement cell (cylindrical or rectangular) sized to the specimen.
  • Stable airflow source with fine flow control.
  • Volumetric flow meter and differential pressure instrument.
  • Thickness gauge for specimen in-situ.
• Performance & calibration:
  • Measurement instruments should be calibrated (conventional methods) at least every 2 years.
  • Volumetric flow and differential pressure measurements require approximately ±5% accuracy.
  • Differential pressure instrumentation must measure down to low pressures (standard specifies capability for very small pressure differences).
  • A calibration test specimen shall be measured daily and after significant environmental or hardware changes; measured calibration values must agree with theoretical values within ±10%.
• Measurement cell & specimen geometry:
  • Minimum measurement cell diameter specified; lateral specimen dimensions must include a sufficient number of pores/fibres/grains (or a minimum diameter/edge when microstructure is unknown).
  • Test support must have minimum open area (≥50%) and hole sizes (≥3 mm); support airflow resistance should be negligible (<1% of specimen).
• Specimen handling:
  • Thickness measured in position and must not be altered by mounting.
  • Superimposing thin specimens is permitted only if it does not alter microstructure (e.g., aligned fibre orientation, matching perforations).
• Test procedure: sealing edges, positioning specimen, measuring thickness, controlling flow and recording Δp and qv to compute resistivity.

Applications

• Product characterization for absorptive materials in building acoustics, automotive interiors, HVAC silencers, loudspeaker linings and noise control systems.
• Quality control testing in manufacturing of foams, non-wovens, felts and porous panels.
• Research and development for acoustic material design and modelling (linking resistivity to sound absorption performance).

Who should use this standard

• Acoustic test laboratories and certification bodies
• Manufacturers of porous acoustic materials and components
• R&D engineers and acoustical consultants working on sound absorption and noise control
• Product standards developers that reference material airflow resistivity requirements

Related standards

• ISO 9053 series (other parts cover alternate methods and guidance). Consult your national standards body or ISO catalogue for adjacent parts and product-specific test standards.