ISO 354:2003

Overview

ISO 354:2003 - "Acoustics - Measurement of sound absorption in a reverberation room" defines a standardized laboratory method for measuring the sound absorption properties of materials, objects and space absorbers using a reverberation room. The standard requires measurement of reverberation time with and without the test specimen and calculation of the equivalent sound absorption area and sound absorption coefficient (αs), typically using Sabine’s equation. ISO 354:2003 is not intended for weakly damped resonators.

Key Topics and Requirements

• Measurement principle: Determine average reverberation time (T) before and after installing the specimen; compute equivalent absorption area A_T and αs = A_T / S.
• Reverberation time (T): Defined as time for a 60 dB decay of sound pressure level; can be extrapolated from shorter decay ranges.
• Measurement methods:
  • Interrupted noise method (direct decay recording)
  • Integrated impulse response method (reverse-time integration of squared impulse responses) The 2003 revision introduced the integrated impulse response method and requires a minimum number of decay measurements (see standard).
• Frequency range: Measurements in one‑third‑octave bands, nominally 100 Hz to 5 000 Hz (ISO 266 band centres).
• Reverberation room:
  • Minimum volume ≥ 150 m3 (≥ 200 m3 recommended for new construction).
  • Room shape and diffusion requirements (use of diffusers, rotating vanes) to approximate a diffuse sound field.
  • Limits on equivalent absorption area of the empty room (frequency-dependent; scaled with room volume).
• Test specimens & mounting: Plane absorbers typically 10–12 m2 (adjusted for room volume), rectangular shape, mounted per Annex B (mounting Types including A, B, J referenced). Discrete objects (furniture, persons) are positioned as in practical use.
• Reporting & precision: The standard specifies calculation methods, presentation of results and required measurement details for reproducibility.

Applications and Who Uses It

• Acoustic test laboratories and certification bodies for product performance data.
• Manufacturers of acoustic materials (panels, insulation, ceiling tiles) to quantify αs for data sheets.
• Acoustic consultants, architects and building engineers for room acoustics design, reverberation control and noise mitigation calculations.
• Designers of furniture, screens and space absorbers to evaluate real‑world absorption performance.

Related Standards

• ISO 266 (preferred frequencies / octave band centres)
• ISO 9613-1 (outdoor sound propagation - atmospheric absorption)
• IEC 61260 (octave-band and fractional-octave-band filters)

Keywords: ISO 354:2003, acoustics, sound absorption, reverberation room, reverberation time, sound absorption coefficient, one‑third‑octave bands, Sabine, diffuse sound field, integrated impulse response, interrupted noise method.