SIST EN ISO 20270:2023 PDF

Overview

EN ISO 20270:2022 (ISO 20270:2019) - Acoustics - Characterization of sources of structure‑borne sound and vibration - Indirect measurement of blocked forces - defines an indirect, in‑situ method to determine the blocked forces exerted by a vibrating component where it connects to a receiver structure. The method applies when vibration at all contact degrees of freedom (DOFs) can be measured and the assembly’s frequency response functions (FRFs) are linear and time invariant. The standard is validated for stationary signals (frequency‑domain presentation) and, with appropriate processing, can be applied to time‑varying signals (transients) while preserving FRF linearity.

Key topics and requirements

• Scope and applicability: Intended for components such as pumps in ships, servo motors in vehicles/machines, and plant in buildings - essentially any vibrating component considered as a structure‑borne sound source.
• DOF selection: Guidance on choosing contact, indicator and validation DOFs to capture all relevant contact motions.
• Test arrangement: Use of real assemblies or specially designed test receivers; design guidance to ensure representativeness and to avoid secondary noise sources.
• Measurement procedures: Requirements for operational tests, FRF measurement (direct and reciprocal), multi‑channel acquisition and appropriate vibration sensors.
• Analysis method: Indirect (inverse) calculation of blocked forces from measured responses and FRFs; includes procedures for handling stationary and non‑stationary signals.
• Uncertainty and validation: Guidelines to minimize measurement uncertainty and an on‑board validation procedure to evaluate result quality (the standard does not set pass/fail criteria).
• Reporting: Prescribed test report contents and informative annexes with case studies (e.g., electric rear axle drive example), validation tests and DOF selection criteria.

Applications and users

EN ISO 20270:2022 is used to:

• Quantify source strength for transfer path analysis (TPA) and source‑path contribution (SPC) studies.
• Support NVH (noise, vibration, harshness) design and troubleshooting in automotive, marine, industrial machinery and building services.
• Provide input data for predictive sound and vibration models and for supplier OEM specifications.

Typical users:

• Acoustics and vibration engineers
• NVH test laboratories and R&D teams
• Design engineers specifying vibration limits or mitigation
• Standards and conformity bodies consulting on measurement methods

Related standards

• ISO 9611 - Measurement of free vibration (free velocity) of machines (referenced in ISO 20270 introduction)
• Transfer path analysis methodologies (TPA/SPC) - complementary techniques for diagnosing structure‑borne sound paths

Keywords: EN ISO 20270:2022, ISO 20270, blocked forces, structure‑borne sound, indirect measurement, FRF, DOF, on‑board validation, transfer path analysis, NVH.