Overview
ISO 6798-3:2022 specifies an in situ survey method to determine the sound power level of reciprocating internal combustion engines using measured sound pressure. Applicable to engines covered by ISO 3046-1 (and other engines where no suitable standard exists), this Part 3 method is intended for on-site surveys with accuracy grade 3 and produces A‑weighted sound power values. The standard defines the test environment, instrumentation, measurement procedures, uncertainty assessment and reporting required to characterize engine noise in real installation conditions.
Key Topics
- Scope and applicability: Reciprocating internal combustion engines used for general purposes (see ISO 3046-1).
- Test environment: Measurement surfaces that envelop the noise source and consideration of reflecting planes (ground or multiple reflecting planes).
- Instrumentation and calibration: Requirements for sound level meters, filters and calibrators (class/grade requirements and calibration procedures).
- Measurement layout: Definition of the measurement surface, measurement distance, microphone positions, and criteria for position adequacy.
- Reference sound source (RSS) methods: Use of RSS and permitted methods such as substitution, top‑up and juxtaposition for in situ verification and comparison.
- Background noise correction and criteria: Minimum differences between source and background levels (e.g., ΔL criteria) and maximum allowed corrections (K) to ensure valid results.
- Calculation and uncertainty: Procedures to compute surface time‑averaged sound pressure levels, corrections for background noise, conversion to sound power level, and stated measurement uncertainty (A‑weighted reproducibility upper bound ~4.0 dB).
- Reporting: Required test report content including test conditions, instrumentation, measurement data and uncertainty.
Applications
- Field surveys to quantify engine noise for compliance checks, contract verification, or performance validation.
- Comparative assessments of noise radiation between engine types, installations or retrofits.
- Input data for noise control engineering and prediction of sound pressure levels at specified receiver locations.
- Acceptance testing and communication of acoustic information among manufacturers, installers and end users.
Who should use this standard
- Acoustic consultants and test laboratories performing on‑site engine noise surveys.
- Engine manufacturers and OEMs documenting radiated noise for product declarations.
- Facility engineers, installers and procurement teams verifying contractual noise limits or planning mitigation measures.
- Regulators and certification bodies requiring standardized in situ sound power assessment.
Related standards
Keywords: ISO 6798-3, sound power level, reciprocating internal combustion engines, in situ survey method, sound pressure measurement, acoustic measurement, background noise correction, reference sound source.
Open preview (PDF)Reciprocating internal combustion engines — Measurement of sound power level using sound pressure — Part 3: Survey method for use in situ
