ISO 12999-1:2020

Overview

ISO 12999-1:2020 - Acoustics: Determination and application of measurement uncertainties in building acoustics - Part 1: Sound insulation - specifies standardized procedures to assess and apply measurement uncertainty for sound insulation in buildings. The standard covers three complementary approaches: a detailed uncertainty budget, uncertainty estimation by inter‑laboratory tests, and practical application of uncertainties to measurement results. It also provides typical uncertainty values for quantities measured according to ISO 10140, ISO 16283 and ISO 717.

Key topics and requirements

• Scope and measurands: Defines measurand and measurement result concepts specific to building acoustics (frequency‑band levels and single‑number ratings).
• Uncertainty definitions: Clarifies standard uncertainty (u), combined standard uncertainty (uc), expanded uncertainty (U) and coverage factor (k) in the context of sound insulation.
• Uncertainty budget (Clause 4 / Annex C): Recommends deriving a detailed uncertainty budget to identify dominant contributions and reduce overall uncertainty. Useful for individual measurement results rather than broad families of tests.
• Inter‑laboratory determination (Clause 5): Describes procedures to estimate uncertainties via inter‑laboratory tests using repeatability and reproducibility concepts. Participating laboratories should use their normal procedures, report details in advance, and typically at least eight labs are required for reliable statistics.
• Measurement situations: Distinguishes three cases - laboratory characterization (Situation A), multiple teams at one location (in‑situ, Situation B), and repeat measurements by the same operator/equipment (repeatability, Situation C).
• Practical measurement conditions: Specifies that specimens should not be remounted between repeats, microphone/source position sets should be selected anew to reflect procedure variability, and calibration/rounding rules must be defined for inter‑laboratory exercises.
• Single‑number uncertainties (Clause 6–7): Addresses uncertainties for single‑number ratings (ISO 717) and typical measurands referenced to ISO 10140/16283.

Applications

• Demonstrating compliance with acoustic performance requirements and tolerance for building components (walls, floors, facades).
• Verifying laboratory performance and inter‑laboratory comparability for test facilities and third‑party laboratories.
• Supporting product comparison, procurement specifications, and certification by quantifying uncertainty in sound insulation metrics.
• Informing acoustic design decisions and risk assessment where measurement variability may affect conformity.

Who should use this standard

• Acoustic testing laboratories and facility operators
• Building acoustics consultants and designers
• Manufacturers of building elements (partitions, glazing, floor systems)
• Certification bodies, regulators and procurement specialists
• Researchers conducting inter‑laboratory studies or uncertainty analyses

Related standards

• ISO 10140 (laboratory measurement procedures for airborne and impact sound insulation)
• ISO 16283 (in‑situ measurement procedures)
• ISO 717 (single‑number rating methods)
• ISO/IEC Guide 98‑3 (GUM) and ISO 5725 series (repeatability/reproducibility methods)