Overview
ISO/TS 19425:2024 is a Technical Specification that defines a standardized measurement method for combustion air inlet noise from air cleaners fitted to reciprocating internal combustion engines. Published in 2024 (second edition), it specifies laboratory (engineering and survey methods) and site (survey method) procedures to determine sound power level of combustion air inlet noise and insertion loss using sound pressure. The scope covers air cleaners for engines within the field of ISO 3046‑1 and related air induction installations.
Key SEO terms: ISO/TS 19425:2024, air cleaners, reciprocating internal combustion engines, combustion air inlet noise, sound power level, insertion loss, sound pressure, acoustic testing.
Key Topics
- Measurement environment and acoustic qualification: criteria for background noise and acoustic adequacy of lab or field test environments (Clause 4; Annex A provides qualification procedures).
- Instrumentation and calibration: requirements for sound level meters, calibrators and reference sources; calibration and application guidance (Clause 5).
- Installation and operation conditions: defined installation set‑ups and engine operating points for repeatable measurements (Clause 6).
- Measurement procedures: microphone positioning, measurement radius, measurement surface concepts and microphone arrays tailored to combustion air inlet sources (Clause 7).
- Frequency range and banding: octave-band coverage from 63 Hz to 8 000 Hz (and one‑third octave 50 Hz to 10 000 Hz) for sound power calculations (Clause 3 and Annex B).
- Corrections and calculations: background noise correction, environmental correction for reflections, calculation of surface time‑averaged sound pressure and conversion to sound power levels, and computation of insertion loss (Clause 8, Annex B, Annex C).
- Measurement uncertainty and reporting: guidance on uncertainty assessment, required recorded information and standard test report content (Clauses 7, 9, 10).
Applications
ISO/TS 19425:2024 is intended to ensure consistent, comparable acoustic data for:
- Air cleaner manufacturers evaluating inlet noise and insertion loss performance.
- Engine OEMs and integrators assessing intake system acoustic behavior during design and certification.
- Acoustical laboratories and test houses conducting laboratory and field noise tests.
- Regulatory and procurement bodies needing repeatable noise metrics for specifications and compliance.
- Acoustic consultants performing noise source characterization and mitigation studies.
Using the standard helps optimize intake designs, verify noise-reduction measures, and provide validated noise data for environmental and contractual requirements.
Related standards
Adopting ISO/TS 19425:2024 improves comparability of combustion air inlet noise data and supports robust acoustic design and verification for engine air induction systems.
Open preview (PDF)Reciprocating internal combustion engines — Measurement method for air cleaners — Sound power level of combustion air inlet noise and insertion loss using sound pressure
