ISO 10848-4:2017

Overview

ISO 10848-4:2017 - part of the ISO 10848 series on building acoustics - specifies laboratory and field measurement methods for characterizing flanking transmission of airborne, impact and building-service-equipment sound across junctions where at least one element is a Type A element (see ISO 10848-1). The standard defines how to measure the vibration reduction index (Kij) for junctions, how to report results, and how to interpret laboratory (suppressed flanking) versus field (in‑situ) measurements. Measured data are suitable for product comparison, specification limits, or as input to prediction methods such as ISO 12354-1 and ISO 12354-2.

Key topics and requirements

• Measured quantity: Vibration reduction index, Kij, reported by frequency (one‑third octave bands) and as single‑number ratings per ISO 10848-1.
• Scope: Applies when at least one junction element is a Type A element (influenced by boundary conditions and modal behavior).
• Laboratory vs field:
  • Laboratory tests aim to suppress unwanted flanking paths to quantify the junction itself.
  • Field tests characterize in‑situ performance; unwanted flanking is often unavoidable and results are representative of that specific building installation.
• Instrumentation & test arrangement: Equipment and general facility requirements follow ISO 10848‑1. Installation details differ for Type A and Type B elements.
• Modal considerations: For Type A elements the mode count and modal overlap factor (M) are critical for measurement accuracy. M should be ≥ 1 at 250 Hz and above where possible; results where M < 0.25 must be flagged and treated with caution. Achieving 5+ modes per one‑third octave band is often recommended.
• Results and reporting: Kij values to one decimal place, plotted vs frequency on a logarithmic scale. Guidance is given for converting one‑third octave results to octave bands and for reporting structural reverberation times and test conditions.