Overview
EN ISO 5114-1:2024 - Acoustics - Determination of uncertainties associated with sound emission measures - Part 1: Sound power levels determined from sound pressure measurements (ISO 5114-1:2024) provides guidance for estimating measurement uncertainty when deriving sound power levels from sound pressure measurements. It applies to measurements carried out according to ISO standards such as ISO 3741, ISO 3743‑1/2, ISO 3744, ISO 3745, ISO 3746 and ISO 3747, or noise test codes based on them. The standard aligns uncertainty evaluation with the principles of ISO/IEC Guide 98‑3 and gives practical models for reporting credible uncertainty values for sound power levels in octave or one‑third‑octave bands and A‑weighted values.
Key topics and requirements
- Uncertainty framework: Sound power uncertainty uL (in dB) is expressed by the total standard deviation σ_tot. The standard defines the relationship between σ_tot, the method reproducibility σ_R0, and the standard deviation due to operating and mounting conditions σ_omc: σ_tot² = σ_R0² + σ_omc².
- Expanded uncertainty: The expanded measurement uncertainty UL is calculated as UL = k · σ_tot, where the coverage factor k is chosen according to the desired confidence level; guidance is provided on appropriate k values.
- Determination methods:
- Round‑robin tests to derive σ_R0 (reproducibility of the method).
- Mathematical modelling and detailed uncertainty budgets to estimate components of uncertainty.
- Detailed budgets: Informative annexes provide example uncertainty budgets for typical measurement environments and methods:
- Annex A - (approximated) free‑field direct enveloping method
- Annex B - (approximated) diffuse‑field direct method
- Annex C - use of a reference sound source
- Terminology and concepts: Defines measurement result, measurement uncertainty, repeatability, reproducibility, and operating/mounting condition variability.
Practical applications and users
- Who uses it:
- Acoustic test laboratories and certified measurement bodies
- Manufacturers performing noise declarations and conformity testing
- Design and R&D engineers assessing product noise performance
- Certification and regulatory bodies evaluating compliance with noise limits
- Practical value:
- Produces defensible, traceable uncertainty statements for sound power results
- Supports comparison with regulatory or contractual noise limits
- Helps select appropriate measurement methods and define test protocols for different machine families
- Informs noise test codes and machine‑specific uncertainty tables
Related standards
Keywords: EN ISO 5114-1:2024, acoustics, sound power levels, sound pressure measurements, measurement uncertainty, ISO 3744, uncertainty budget, round‑robin, acoustic testing.
