Sound Insulation in Buildings

Jens Holger Rindel

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781351230728
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Acoustical Engineering
• Index: Technology & Engineering

The book explains sound insulation in buildings at a level suitable for both graduate students and expert consultants.

Theoretical models are set out for sound transmission in buildings, with an emphasis on thick and heavy constructions. Thus, the description is not restrained by the common assumption of bending waves which is characteristic of thin plates, only. A general description is provided, with the modal density in the structures as a key parameter. At low frequencies statistical energy analysis is replaced by modal energy analysis. Sound transmission through windows and facades is represented by a model that allows any angle on incidence, including the special case of grazing incidence. One chapter is devoted to the subjective evaluation of sound insulation, particularly noise from neighbours, and how this can be applied in a sound classification scheme for dwellings. Measurement methods in building acoustics are presented with emphasis on modern methods using MLS signals or sine sweeps. The analysis and estimation of measurement uncertainty is discussed in detail. In a final chapter examples of experimental buildings with high sound insulation are explained.

Chapter 1
Basic concepts in acoustics

This chapter summarizes the most important basic concepts used in building acoustics. The definitions and symbols are in accordance with International Organization for Standardization (ISO) technical report (TR) 25417.

1.1 INTRODUCTION

The sound insulation of walls and floors in a building is often of major concern for the people using the building. It is of special interest in residential buildings, but also in, e.g. offices, hospitals and school buildings. Sound insulation in buildings has been under research and standardization for a long time – many contributions were made in the 1950s. However, since that time, the behaviour and habits of people, as well as their expectations, have changed. Noise sources have become louder and cover a broader frequency spectrum, and it is possible that the demands of the tenants have increased. At the same time, there are a gradual development and change in building elements and methods. Thus, knowledge of physical and other aspects of sound insulation in buildings is essential for an acoustician. Moreover, basic knowledge of sound insulation is also important in other branches of acoustics, e.g. in the development of vehicles, ships and aeroplanes.

Sound insulation is divided into airborne sound insulation, where the noise source is in the air inside or outside the building, and structure-borne sound insulation, where the noise source is located at a building structure. The most important case of structure-borne sound insulation is the impact noise sound insulation, which includes noise generated by people walking. Chapter 5 gives a basic overview of the principles of sound insulation. Chapters 8 and 9 deal more thoroughly with airborne sound insulation, and Chapter 10 addresses the impact noise.

Airborne noise sources in a building are typically people talking, sound from stereo equipment, televisions and musical instruments. The development of hi-fi stereo equipment means that these sources are much louder and cover more of the low frequencies than was the case when the building regulations for sound insulations were developed. It is thus not given that a regulation originally intended to avoid noise discomfort still does so. It is therefore most often recommended to use a broader frequency spectrum (50 Hz to 5000 Hz) than is used in the original measurement description (100 Hz to 3150 Hz), and sometimes it is also important to perform a subjective evaluation of the noise situation in more experimental buildings. Examples of external airborne noise sources are traffic and industrial noise, where the windows of a building ...