ISO 11546-1:1995

Overview

ISO 11546-1:1995 - "Acoustics - Determination of sound insulation performances of enclosures - Part 1: Measurements under laboratory conditions (for declaration purposes)" specifies laboratory methods for determining the sound-insulation performance (insertion loss) of small machine enclosures. The standard applies to a total enclosure only (not individual panels) and is specifically geared to freestanding enclosures with internal volumes less than 2 m3 (with conditional provisions for larger volumes when using the actual sound source). Results are expressed as reductions in sound power level or sound pressure level, including A-weighted and single-number ratings.

Key Topics

• Scope and applicability
  • Laboratory methods for small machine enclosures (total enclosure only).
  • Not intended for individual panels, close-fitting covers or cabins.
  • Preferred for freestanding enclosures; special notes for enclosures fixed to machines.
• Measurement methods
  • Actual sound source method - uses the machine/noise source for which the enclosure is designed (preferred when practicable).
  • Reciprocity method - uses an external diffuse sound field to infer insulation (applicable for volumes < 2 m3).
  • Artificial sound source method - alternative when the actual source cannot be used; described in Annex A.
• Quantities and indices
  • Sound power insulation (Dw), A-weighted (DwA), sound pressure insulation (Dp), and A-weighted equivalents.
  • Weighted single-number values (e.g., DprW, Dww) determined per ISO 717-1 principles adapted for enclosure testing.
  • Estimated noise insulation for specific source spectra (method in Annex C).
• Instrumentation, uncertainty and reporting
  • References and alignment with ISO series for sound power and pressure measurements (ISO 3740 series, ISO 11200, ISO 9614).
  • Requirements for instrumentation, test conditions, recorded data and uncertainty evaluation.
  • Information to be recorded/reported: test object, test conditions, instrumentation, acoustical data and further information.

Applications

• Useful for acoustic engineers, laboratory test houses, machine/enclosure manufacturers, and product compliance teams who need declared laboratory-rated insertion loss for small enclosures.
• Helps in product specification, comparative selection of enclosures, supplier declarations, and pre‑production acoustic verification.
• Applicable when estimating how an enclosure will reduce A‑weighted noise at a workplace when the source spectrum is known or assumed.

Related Standards

• ISO 11546-2 (Measurements in situ - for acceptance and verification)
• ISO 3740 / ISO 3741 / ISO 3743 series (sound power determination methods)
• ISO 11200 (sound pressure at workstations)
• ISO 9614 (sound intensity)
• ISO 717-1 (single-number rating method adapted for enclosure data)

Keywords: ISO 11546-1:1995, acoustics, sound insulation, enclosure testing, laboratory measurements, insertion loss, reciprocity method, artificial sound source, sound power, sound pressure, noise control.