ISO 18233:2006

Overview

ISO 18233:2006 - Acoustics: Application of new measurement methods in building and room acoustics - provides guidelines and requirements for using modern deterministic measurement methods (instead of classical stochastic or impulse techniques) to obtain impulse responses and frequency-response functions in building and room acoustic testing. The standard covers selection of the excitation signal, signal processing, environmental control, and requirements for linearity and time‑invariance of the system under test. It formalizes use of the Maximum Length Sequence (MLS) and the Swept‑Sine (SS) techniques as ISO 18233–MLS and ISO 18233–SS.

Key topics and requirements

• Scope of application: airborne sound insulation (between rooms and façades), reverberation time and other room acoustic parameters, sound absorption in reverberation rooms, vibration level differences and loss factor.
• Excitation signal selection: guidance on deterministic signals used to derive impulse responses reliably.
• Signal processing: methods for extracting impulse and frequency responses (e.g., deconvolution approaches) and for computing fractional‑octave‑band results.
• Environmental control: managing background noise and time‑variation during measurements to ensure validity.
• System assumptions: explicit requirement that the tested acoustic path behaves approximately as a linear, time‑invariant system; tests and procedures to detect violations.
• Performance metrics: use of effective signal‑to‑noise and peak‑to‑noise ratios as evaluation criteria when comparing new methods with classical approaches.
• Normative annexes: Annex A (MLS) and Annex B (Swept‑sine) provide prescriptive material for those specific methods.
• Reporting and precision: instructions on test reports and considerations of measurement precision and limitations.

Applications

• On‑site field measurement of airborne sound insulation for compliance testing and certification.
• Fast, low‑noise‑susceptible measurement of reverberation time and room acoustic parameters for acoustic commissioning and design verification.
• Laboratory measurement of sound absorption in reverberation rooms.
• Measurement of structural acoustic properties - vibration level differences and loss factor - in building elements and systems.
• R&D and product testing where extended measurement range and improved noise immunity are required.

Who should use ISO 18233:2006

• Acoustical consultants and test laboratories performing building and room acoustic measurements.
• Instrument manufacturers and software developers implementing MLS or swept‑sine measurement systems.
• Building designers, façade and partition product developers, and regulatory bodies seeking reliable procedures for alternative measurement methods.
• Researchers comparing deterministic and classical (ISO 140 / ISO 3382) methods.

Related standards

• ISO 140 series (building acoustics - airborne sound insulation)
• ISO 3382 series (reverberation time - room acoustics)
• ISO 17497-1 (acoustics measurement methods)
• IEC 61260 (fractional‑octave filters) and IEC 61672‑1 (sound level meters) - normative references

ISO 18233:2006 helps practitioners adopt modern measurement methods (MLS, swept‑sine) while ensuring consistent, reliable results for building and room acoustics.