building acoustics
Klas Hagberg
Acouwood partnership with Kuster and Partner
Acouwood partnership with Kuster and Partner

Acouwood partnership with Kuster and Partner

Acouwood AB and Kuster + Partner AG (www.kusterpartner.ch) have been cooperating closely for some time. It is about the exchange of knowledge such as methods, research & development of essential knowledge and tools, as well as the refinement of skills. Kuster&Partner is a leading consulting company in Switzerland in the areas of building physics, including acoustics. Together we can now offer customers and architects' offices the bundled expertise from more than 30 years of timber construction from one single source, from the design to quality assurance during construction, in order to optimize the acoustic quality and energy performance. High sustainability goals and demands on a comfortable room climate combined with excellent acoustics are at the forefront of our advice. It means that we (Acouwood) broaden our source of knowledge regarding indoor climate (energy and humidity, for example) but also increase our presence in the center of Europe.

The cooperation enables us to accompany national and international projects in several languages and carry out energy and acoustic calculations and measurements at the highest level to help design optimal future buildings in terms of sustainability.

Combined services in the field of timber construction

In the association, we have a whole range of options and tools at our disposal for advising on optimal and sustainable buildings:

  • Building simulations for rooms or entire buildings to simulate various parameters such as temperature, humidity, or light

  • Simulations for the noise protection of roads, railways, airports, or industrial plants

  • Specialized tools and measurement methods for forecasting building acoustics down to 20 Hz

  • Experienced practitioners for the development and assessment of details in massive wood and lightweight construction

  • Extensive measuring equipment park to carry out the latest measurements available on the market. Especially in the field of building acoustics, we are not only able to carry out normal measurements according to the standard but also to check flanking sound (intensity and Kij measurements)

  • With Kuster&Partner test laboratories, we can develop lightweight components and building products such as windows/doors and measure them on a project basis.

We can offer our services in the following languages: German, English, Swedish, French.

 

If you have any questions regarding timber structures, please contact Klas Hagberg (Swedish, English, klas.hagberg@acouwood.com), Mr Thomas Kuster (German, English, thomas.kuster@kusterpartner.ch), Marco Kuster (German, English, marco.kuster@kusterpartner.ch) or Dr. Delphine Bard (French,English, delphine.bard @kusterpartner.ch).

*Cinema picture was kindly shared with us by Schwab Systems SA

Sound insulation in 3D

Sound insulation in 3D

One of the most challenging aspects of building acoustics is that sound insulation and sound transmission paths are present in all three dimensions, when flanking transmission is included. If you have two rooms next to each other that requires a certain sound reduction index R´w in dB between them, the first thing that comes to mind is the directly separating construction, i.e. the wall between them or the floor structure. Most of the time, you will be correct, as this is often the most important transmission path. Hence, it is easy to miss that sound transmission occurs in many other places in a real building, which are not obvious at all when looking at a 2D drawing.

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Flanking transmission in CLT dwellings – How to design a proper ceiling

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Flanking transmission in CLT dwellings – How to design a proper ceiling

A common way to construct Cross Laminated Timber (CLT) dwellings is to mount the floor slabs continuous over several apartments, thereby reducing the number of CLT elements and work time with the crane on site. There are some crucial acoustic factors to consider if you are thinking about this route. CLT is sensitive to flanking transmission in the middle frequency range from about 125-160 Hz and upwards. If CLT elements are mounted between apartments and are exposed within the dwelling, the resulting sound insulation will not fulfill Swedish requirements. The resulting sound insulation R´w will likely be in the 40-50 dB range and not 52 dB as it should be. A common way to solve this issue is to install a resilient ceiling, and the solution can be optimized in different ways depending on the rest of the structure.

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Vertical flanking sound transmission in CLT dwellings

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Vertical flanking sound transmission in CLT dwellings

Dwellings with Cross Laminated Timber (CLT) have become very popular lately. When designing a multi-family dwelling in CLT there are some critical factors to consider with regards to acoustics and sound insulation. A characteristic property of CLT is that it is very sensitive to flanking transmission i.e. sound transmission between two rooms another path than through the directly separating partition. What this means in practice, is that whatever you do, do NOT mount CLT elements that are continuous between two dwellings. That is a recipe for disaster. It might work in premises or between rooms with lower requirements, but in dwellings it is a big NO-NO. So, what solutions are there?

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Why is impact sound insulation in wooden dwellings challenging?

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Why is impact sound insulation in wooden dwellings challenging?

In Sweden, the minimum impact sound insulation requirements in dwellings is LnT,w + CI,50-2500 = 56 dB. Something worth noting about the spectrum adaptation term is that it is just a logarithmic addition of the 1/3 octave bands 50-2500 Hz. This is somewhat misleading because the way it is written it looks as if one should first calculate LnT,w, then the spectrum adaptation term and finally add them. It might have been more pedagogic to call it LnT,w,50 or something similar, which they are called now in the Swedish standard, by the way.

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Why an acoustician should use VR

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Why an acoustician should use VR

If you are an acoustician, you might recognize the following scenario. You have been involved with the design of a building, perhaps for years, and think you have a pretty solid understanding of the building. Yet, the first time you do a site visit you will probably think ”Aha, so THIS is what it looks like in real life!” Personally, I know I have had that feeling every single time. With acoustics, this can be a proper challenge. We obviously need a tool that can help us bring out that crucial ”gut feeling” in the design phase. If we have to wait for the site visit to the finished building until we can consult our gut, it is often too late because the critical decisions have already been made. So how can we solve this?

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How to use the impact ball to evalute impact sound insulation in timber buildings

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How to use the impact ball to evalute impact sound insulation in timber buildings

The most common method to evaluate impact sound insulation in buildings, is the tapping machine. One of the issues with the tapping machine however, is that it does not resemble actual walking sound at all. If you have ever visited a field measurement of impact sound insulation, you will probably recognize the hammering noise that the acoustician creates. Another method that is less common, is the so called impact ball. The impact ball might very well be the most expensive ball in the world, with its four-digit price tag (five if you’re swedish)!

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Ställ rätt krav för träbyggnader

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Ställ rätt krav för träbyggnader

“Vi är inne i en expansiv fas för det moderna bostadsbyggandet. Inte bara att det byggs mer i trä utan att det sker så oerhört mycket kreativt nytänkande i branschen. Vidare ställs det höga krav på miljö och certifiering av olika slag, vilket gör att träbyggandet har fått en välförtjänt skjuts. Det är något jag inte upplevt maken till under mina drygt 30 år i branschen. Det är glädjande och bidrar samtidigt till en spännande utveckling av branschen. Tyvärr sitter vi fast i gamla strukturer vad gäller kravställning som inte går hand i hand med den utveckling vi ser och Boverkets nya förslag till föreskrifter om ljud ser ut att cementera kraven för en lång tid framöver, eller till och med förvärra situationen. Kraven som de ser ut i förslaget kan skapa lösningar som inte är balanserade mot störningsgraden i moderna boendeformer. Kraven formuleras vidare på ett sätt som gör att tekniska lösningar inte alltid hänger ihop med andra önskemål beställaren har.”

New standard for mobile rooms is ready for final vote in ISO

Introduction

The market for mobile quiet rooms has increased significantly in recent years. It is an interesting product range that allows flexibility and plays an important role in modern offices for short small meetings and separate telephone calls. But is there anyone who can say how quiet they are? And how quiet do they need to be to be considered a quiet room? Within ISO / TC 43 / WG35 (ISO = International Organization of Standardization; TC = Technical Committee; WG = Working Group), there is now a fully developed standard that will facilitate the development of answers to these questions. The standard is complete so that it only has to pass the last step (Formal Vote) before it can be "clubbed" formally. The voting in ISO will end on June 8, 2020.

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- Klas Hagberg

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