ISO 20361:2019

Overview - ISO 20361:2019 (Liquid pumps - Noise test code, Grades 2 & 3)

ISO 20361:2019 defines a standardized noise test code for liquid pumps and pump units, focusing on airborne noise emission measurement at two levels of accuracy: engineering methods (Grade 2) and survey methods (Grade 3). The standard specifies the methods, operating and mounting conditions, and reporting requirements needed to determine, declare, and verify sound power levels and emission sound pressure levels of pumps under reproducible conditions. It applies to testing pumps either as the pump alone or as a pump unit (including driver and transmission elements) and explicitly excludes structure‑borne or liquid‑borne noise characterization.

Key technical topics and requirements

• Measurement scope: Airborne noise emissions expressed as sound power level and emission sound pressure level at specified positions (relevant work stations).
• Grades of accuracy: Use of Grade 2 (engineering) and Grade 3 (survey) methods to ensure reproducibility within defined limits.
• Accepted measurement methods: References and integration with established acoustics standards (e.g., ISO 3743‑1/2, ISO 3744, ISO 3746, ISO 9614‑1/2, ISO 11203).
• Test configurations: Procedures for testing a pump alone or a complete pump unit; permitted test locations include on‑site, shop test stands, or dedicated acoustic facilities.
• Measurement setup details: Requirements for reference boxes, measurement surfaces, microphone and intensity probe positions, and enclosure or guard installation.
• Operating conditions: Specification of pumped liquid, NPSHA considerations and other operating parameters to be recorded during tests.
• Uncertainty and reporting: Clause on measurement uncertainty and detailed test report content to support declaration and verification of noise emission values.
• Exclusions: Does not address structure‑borne or liquid‑borne noise from pumps.

Practical applications and who uses ISO 20361

• Manufacturers use it to declare noise emission values, validate design changes, and demonstrate noise‑control measures at the design stage.
• Acoustic test laboratories and QA teams apply the standard for reproducible noise testing and certification.
• Regulators and procurement specialists rely on standardized noise data when comparing pump performance and specifying limits.
• Consultants and integrators use emission sound pressure data for workplace noise assessments and acoustic mitigation design.

Related standards (referenced)

• ISO 3743‑1 / ISO 3743‑2, ISO 3744, ISO 3746 (sound power determination)
• ISO 9614‑1 / ISO 9614‑2 (sound intensity methods)
• ISO 11203 (emission sound pressure at work stations)
• ISO 4871 (declaration and verification of noise)
• ISO 17769‑1/2 (terms and definitions for liquid pumps)

Keywords: ISO 20361, liquid pumps, noise test code, sound power level, emission sound pressure level, Grade 2, Grade 3, pump units, noise measurement, noise declaration.