Sound insulation in buildings - Part 34: Data for verification of sound insulation (component catalogue) - Additional layers fixed to solid structural elements; Amendment A1
1Key Takeaways
Sound insulation in building construction – Part 34: Data for the calculation of sound insulation (component catalog) – Additional layers fixed to solid structural elements; Amendment A1 This document contains amendments to DIN 4109-34:2016-07, Sound insulation in building construction — Part 34: Data for the calculati…
2Expert Interpretation
This article provides an in-depth analysis of the revised DIN 4109-34/A1:2019 standard for sound insulation in buildings, focusing on the calculation methods for the acoustic performance of exterior wall insulation systems (WDVS). It covers key technical parameters such as single- and double-layer insulation materials, the impact of anchors, and bond area correction, providing a complete standardized calculation framework and implementation recommendations.
Technical Interpretation of the DIN 4109-34/A1 Standard Amendment
DIN 4109-34/A1:2019, a significant addition to the German building acoustics standard system, provides a standardized method for calculating the acoustic performance of exterior wall insulation systems (WDVS). This amendment comprehensively updates and improves the 2016 standard based on the latest research findings.
Background of the Standard Revision and Technological Evolution
With increasing demands for building energy efficiency, exterior wall insulation systems are increasingly used in German buildings. However, a unified assessment method for the impact of WDVS on the acoustic performance of building envelope structures has long been lacking. The 2019 amendment establishes a scientific calculation model based on multiple research findings from the IBP Institute (IBP-Bericht B-BA 6/2002, 4/2005, 1/2016, and 1/2014). The core innovation of the amendment lies in the introduction of dynamic stiffness and resonant frequency as key calculation parameters, using a mathematical model to accurately predict the improvement effect of WDVS on airborne sound insulation. This approach considers both the physical properties of the insulation material and the impact of the construction process.
WDVS acoustic performance calculation framework
| Calculation parameters | Symbol | Calculation formula | Applicable scope |
|---|---|---|---|
| Reference condition improvement | ΔRw,S | a·lg(f0) + b | All WDVS types |
| Anchor correction | KD | -0.34·ΔRw,S + 0.4 dB | Contact anchor only |
| Bond area correction | KK | 0.052·F - 2.1 dB | F is the percentage of bond area |
| Flow resistance correction (fibrous materials) | KS | -0.11·r + 3.8 dB or -0.38·r + 9.8 dB | Fiber-based insulation materials only |
| Base wall correction | KTW | (-1.4·lg(f0) + 3.6)·(Rw,o - 53 dB) | All WDVS types |
The total acoustic improvement is calculated as follows: ΔRw,WDVS = ΔRw,S + KD + KK + KS + KTW
Detailed Explanation of Key Technical Parameters
Resonance Frequency Calculation
The resonance frequency f0 is the core parameter for calculating the acoustic performance of WDVS. The calculation formula is: f0 = 160·√(s'/m'), where s' is the dynamic stiffness of the insulation material (MN/m³) and m' is the surface density of the plaster layer (kg/m²). 4, b=82.4
Special Treatment for Double-Skin Insulation Systems
For double-skin insulation WDVS systems, the standard stipulates special calculation conditions: the surface density of the interlayer adhesive must not exceed 4.0 kg/m² and must not exceed 40% of the total mass of the outer plaster layer. The comprehensive dynamic stiffness of the double-skin system is calculated using the parallel spring model: 1/s'res = 1/s'1 + 1/s'2.
Low-frequency noise performance evaluation
A new Appendix A provides a method for calculating the improvement of low-frequency noise (50-5000Hz). The calculation of Δ(Rw + Ctr,50-5000) takes into account more complex frequency characteristics and uses a different coefficient system:
| Parameter type | Standard calculation | Low frequency calculation |
|---|---|---|
| Anchor effect | Linear correction | Exponential relationship correction |
| Bond area correction | KK = 0.052F - 2.1 | KK = 0.043F - 1.7 |
| Applicable range | 100-3150 Hz | 50-5000 Hz |
Project Implementation Recommendations
Design Phase Considerations
1. Prioritize insulation materials with lower dynamic stiffness to reduce resonant frequency and maximize acoustic improvement.
2. Control the bonding area to approximately 40% to avoid over-bonding that can degrade acoustic performance.
3. Use embedded anchors whenever possible to avoid direct contact between the anchors and the render, forming an acoustic bridge.
Construction Quality Control
1. Strictly adhere to the bonding area specified in the design, with deviations within ±5%.
2. Anchors must be installed at a depth that does not contact the render.
3. For double-layer insulation systems, strictly control the amount of interlayer adhesive.
Acceptance Test Requirements
1. The calculated acoustic improvement should be within the range of 6-19 dB.
2. When precise calculation is not possible, a conservative value of ΔRw,WDVS = 6 dB may be used.
3. The low-frequency improvement Δ(Rw + Ctr,50-5000) is limited to 5-4 dB.
Application Value and Outlook of the Standard
The release of DIN 4109-34/A1:2019 fills a gap in the quantitative evaluation of WDVS acoustic performance, providing architects and engineers with a scientific design tool. This standard is not only applicable to the German market but also holds important reference value in the field of architectural acoustics worldwide.
With the increasing requirements for green buildings and energy conservation, the application of WDVS will become even more widespread. The mathematical model and calculation methods established in this standard lay the foundation for the acoustic design of more complex composite wall systems in the future, and subsequent versions are expected to further expand its scope of application and accuracy.