ISO 12354-3:2017

Overview

ISO 12354-3:2017 - Building acoustics - Part 3: Airborne sound insulation against outdoor sound - specifies a calculation model to estimate the sound insulation (or level difference) of façades and external building surfaces from the acoustic performance of their constituent elements. The model combines direct and flanking transmission and produces results that correspond approximately to field measurements (see ISO 16283‑3). Calculations can be made in one‑third‑octave or octave frequency bands or as single‑number ratings, and can be used to estimate indoor sound pressure levels from sources such as road traffic (Annex E).

Key Topics

• Calculation model and principles: framework for predicting façade performance from element data, including limitations and accuracy guidance.
• Sound reduction index (R): use of laboratory-measured element R values (ISO 10140 series) as primary input.
• Apparent and normalized quantities: R′ (apparent sound reduction), D2m,n and D2m,nT (normalized/standardized level differences) for practical building performance assessment.
• Direct vs. flanking transmission: methods for determining transmission through primary elements and through connecting paths (flanking).
• Small technical elements and joints: treatment of transfer air devices, ducts, joints and slits (normalized level difference Dn,e, joints Rs).
• Façade geometry: influence of façade shape on incident sound levels (Annex C).
• Supporting material: lists of symbols (Annex A), practical guidance (Annex F), calculation examples (Annex G), and procedures for estimating indoor levels (Annex E).
• Accuracy & limitations: guidance on expected agreement with field measurements and need for conservative margins or refined input data.

Applications

• Pre‑construction performance prediction of façades and external walls against outdoor noise (road, rail, environmental sources).
• Early design and specification for architects, façade engineers and acoustic consultants to select materials and assemblies that meet target D or R′ values.
• Regulatory compliance checks and assessment of retrofit solutions to improve indoor comfort.
• Input to acoustic simulation tools and software for building design and noise mitigation planning.

Who Should Use It

• Acoustical experts and consultants
• Façade and building envelope designers
• Architects and building services engineers
• Product manufacturers (windows, walls, ventilation components)
• Regulatory authorities and building certifiers

Related Standards

• ISO 16283‑3 (field measurement of façade/outsider sound insulation)
• ISO 717‑1 (rating of sound insulation - airborne)
• ISO 10140‑1 (laboratory measurement of sound insulation of building elements)
• ISO 12354‑1 (airborne sound insulation between rooms)

Keywords: ISO 12354-3:2017, building acoustics, façade sound insulation, airborne sound insulation, sound reduction index, flanking transmission, ISO 16283-3, D2m,n.