ISO 13347-1:2025

Overview

ISO 13347-1:2025 - "Fans - Determination of fan sound power levels under standardized laboratory conditions - Part 1: General overview" defines the principles for measuring and reporting the acoustic performance of fans in laboratory settings. The standard describes how to determine fan sound power levels (including fan + ancillary devices such as roof cowls, dampers, or silencers) using standardized test methods and frequency band analysis. It focuses on laboratory conditions and specifies measurement frameworks, instrumentation, uncertainty treatment and reporting conventions for ducted and non‑ducted applications including jet fans.

Key topics and technical requirements

• Scope and definitions: Terms, symbols and installation categories used for acoustic rating of fans.
• Measurement uncertainty: Guidance and normative requirements for quantifying test uncertainty.
• Instrumentation: Requirements for microphones, sound level meters, frequency analysers, turbulence screens, windshields and reference sound sources (RSS).
• Test methods: General and special test procedures covering reverberant room, enveloping surface, sound intensity and in‑duct methods; limitations and considerations for small fans and installation category E.
• Operating & installation conditions: Specified fan mounting, rotational speed control, ambient condition measurement and determination of the aerodynamic operating point.
• Data handling & calculations: One‑third‑octave and octave band level calculations, A‑weighted and overall sound power computations, and evaluation practices.
• Test reporting: Required information about the fan, test site, instrumentation, measured values and subjective noise character assessments.
• Normative/Informative annexes: Topics such as rotational speed effects, gas/air condition corrections, end‑reflection corrections, uncertainty analysis, and RSS calibration.

Practical applications

ISO 13347-1:2025 is used to:

• Compare fan noise across models, sizes and speeds using standardized sound power metrics.
• Support product selection and verify compliance with acoustic performance limits.
• Scale and predict noise when changing fan size or rotational speed.
• Engineer quieter equipment by providing consistent test data for R&D and acoustic design.
• Provide auditable test reports for procurement, certification and regulatory purposes.

Who should use this standard

• Acoustic and mechanical engineers, fan manufacturers, test laboratories, HVAC designers, product certification bodies, and procurement/specification teams requiring consistent, reproducible fan noise measurements.

Related standards

• ISO 5801 (airflow/rating references), ISO 3740 series, ISO 9614‑1/2 (sound intensity), and ISO 13350 (jet fan testing). These references are cited for harmonized symbols, methods and uncertainty treatment.

Keywords: ISO 13347-1:2025, fan sound power levels, acoustic performance of fans, laboratory conditions, sound intensity, reverberant room, one‑third octave, measurement uncertainty.