ISO 27327-2:2014

Overview

ISO 27327-2:2014, "Fans - Air curtain units - Part 2: Laboratory methods of testing for sound power," specifies laboratory procedures to determine the acoustic performance (sound power) of air curtain units. The standard addresses measurement methods for air curtain units alone or combined with ancillary devices, focusing on controlled laboratory environments rather than in‑situ or site measurements. Results are reported in one‑third‑octave and one‑octave bands and can be used for A‑weighted and overall sound power evaluations.

Key topics and technical requirements

• Scope and purpose: Defines how to measure sound power levels of air curtain units for comparison, specification limits, and noise prediction.
• Methods of test: Includes both the comparison method and the direct method for determining sound power (laboratory procedures).
• Acoustic environment: Requirements for test rooms (reverberant rooms, room qualification for broadband and tonal sources) and environmental control.
• Instrumentation and calibration: Specification of measurement equipment such as microphones, frequency analysers, turbulence screens/windshields, and reference sound sources (RSS); includes calibration and uncertainty considerations.
• Measurement uncertainty: Guidance and normative annex for uncertainty analysis to ensure result traceability and repeatability.
• Test setup and operating conditions: Detailed information on air curtain installation, mounting methods, microphone positions/travel, rotational speed control, aerodynamic operating point and ambient condition measurement.
• Data processing and reporting: Calculation of one‑third‑octave and overall sound power, background corrections, A‑weighted results, and the required content of the test report (instrumentation, site description, subjective noise character assessment).
• Normative and informative annexes: Includes uncertainty analysis, RSS calibration, filter‑weighted measurements, and room qualification procedures.

Practical applications and who uses it

ISO 27327-2 is used by:

• Acoustic test laboratories conducting certified sound power testing of air curtain units.
• Manufacturers who need standardized noise data for product development, quality control, and technical datasheets.
• Acoustic engineers and specifiers evaluating or comparing air curtain units for noise limits and room noise predictions.
• Regulatory bodies and purchasers requiring reproducible laboratory sound power ratings for procurement and compliance.

Typical uses:

• Comparing noise emissions between models or sizes.
• Assessing suitability against specified upper sound emission limits.
• Scaling noise from one size/speed to another of the same unit type.
• Supporting acoustic design and product improvements.

Related standards

• ISO 27327-1 (aerodynamic performance rating)
• ISO 5801, ISO 13347 series (fan testing references)
• ISO 3740, ISO 3741, ISO 3743 (sound power determination and reverberant room methods)

Keywords: ISO 27327-2:2014, air curtain units, sound power, laboratory methods, acoustic performance, fan noise testing.