ISO 717-2:2020

Overview

ISO 717-2:2020, "Acoustics - Rating of sound insulation in buildings and of building elements - Part 2: Impact sound insulation", defines a standardized method to convert frequency-dependent impact sound measurements into single-number ratings. The standard covers laboratory and field measurement inputs and provides rules to derive rating quantities used to express impact sound insulation of floors, floor coverings and floating floors, simplifying acoustical requirements in building codes and specifications.

Key topics and technical requirements

• Single-number quantities: Defines how to obtain a single-number rating from measured spectra by shifting a reference curve and reading its value at 500 Hz (the result is reduced by 5 dB as specified). An additional evaluation in 0.1 dB steps is available where uncertainty must be expressed.
• Measurement bands and ranges: Rules apply to measurements in one‑third‑octave bands (100 Hz–3 150 Hz) and, for field work only, octave bands (125 Hz–2 000 Hz).
• Input measurements: Uses results from standardized measurement methods (ISO 10140-3 laboratory measurements and ISO 16283-2 field measurements).
• Weighted quantities and spectrum adaptation: Defines quantities such as the weighted normalized impact sound pressure level (L’n,w / Ln,w), spectrum adaptation terms (C_I), and procedures for calculating weighted reduction in impact sound pressure level (ΔLw / ΔLt,w) for floor coverings.
• Special procedures and annexes:
  • Annex A: rating over an enlarged frequency range,
  • Annex B: method for bare heavy floors in combination with floor coverings,
  • Annex C: example calculations,
  • Annex D: rating method for heavy and soft impact sources (rubber ball) including A‑weighted maximum impact sound pressure level.

Practical applications

• Use ISO 717-2 to produce single-number ratings for:
  • Building code compliance and acoustic performance specifications
  • Product data sheets for floor systems, floor coverings and floating floors
  • Contract requirements and acceptance testing for multi‑unit residential and commercial buildings
• Helps translate detailed measurement data into actionable performance thresholds (e.g., minimum impact sound ratings for occupiable spaces).

Who uses this standard

• Acoustical consultants and testing laboratories
• Architects and building designers
• Flooring manufacturers and product developers
• Building code authorities and compliance officers
• Contractors responsible for floor installations and acoustic remediation

Related standards

• ISO 10140-3 (laboratory measurement of impact sound insulation)
• ISO 16283-2 (field measurement of impact sound insulation)
• ISO 10140-1, ISO 10140-5, ISO 12999-1 (associated measurement, equipment and uncertainty guidance)

Keywords: ISO 717-2, impact sound insulation, sound insulation rating, floor coverings, weighted reduction, one‑third‑octave bands, ISO 10140-3, ISO 16283-2.