Frequently Asked Questions

CadnaB, BASTIAN and SONArchitect may be applied to solve various tasks in the building design process. For non-experts, it is safe and simple to calculate sound insulation within a given model of the building, e.g. to change room size, type of flooring, suspended ceiling, wall lining, door, window etc.

However, it takes some acoustical experience to make an adequate room model with respect to structural couplings between building elements, taking into account the parameters that influence the power flow between the building elements and the loss factor. Input data of building elements may be adapted to the actual case, e.g. function of light-weight floors that depend on the coupling to the supporting walls. Consulting an expert to refine the calculation model gives high return-on-investment since the constructions may be optimized to meet a given requirement.

Data taken from old versions of the database are stored in each project file (*.BAP). Thus, each calculation is documented with the element data valid at this occasion. Printing the worksheet or exporting to Excel displays all data. In case you still would like to use previous versions of the database, send us a mail. We save all versions distributed from 1999 AC.

In the SOAB database, lots of traffic and outdoor noise spectra are included, some harmonized with the new Nordic Calculation Model for the Propagation of Noise (Nord2005). This helps choose the right light-weight walls, outdoor air inlets, windows and renovation glazing have been added (contin. fall 2003). Outdoor levels refer to free field + 3dB, i.e. 2m in front of the façade (unless otherwise is stated in the description). Indoor levels refer to the diffuse field.

1. If you are certain that your measured data reflect the performance of one single element only, go to the Database menu and open the most relevant category. In the table, right-click and choose NewConstruction. Paste the data and add descriptions of the construction.

2. Be aware of the limitations of field data, i.e. they comprise flanking transmission of connected structures as well as structural loss factors that deviate from laboratory conditions (assumed in BASTIAN). Read reports available under the Learning Center - Papers & Publications or contact us for assistance.

Answer 1: Yes – on the average, provided the calculation model fits he building constructions in situ. BASTIAN does NOT return "safe" values comp to field measurements, i.e. there are NO hidden margins. Users should apply their own margins, according to local legislations and client's specifications.

Answer 2: Estimates of sound insulation in buildings with concrete elements according to the EN ISO 12354 usually agree well on the average when compared to field measurements. After a new set of comparisons in May 2013, the input data of concrete walls were increased by 1 dB 2013-06-01. Such changes are rare, this was after more than 10 years of application of the database. For calculations of timber frames or solid timber, see below.

Answer 3: There are some practical aspects you should consider to avoid unnecessary deviations - in both directions.

1. Field measurements can sometimes reveal worse results than expected. This may for instance be caused by measurement errors or poor workmanship. Examples of a few well-known shortcomings: air leakage in unintended gaps and cracks reduce airborne sound insulation; flanking transmission via a continuous outer layer of a facade is easy to forget in the calculation model. Structural bridging reduce insulation of a floating floor, even one single screw in the wrong place transfer energy.

2. Field measurements can also show better results than expected. This may be because you have not customized the calculation model to the actual building. It's not enough to just enter the apartment separating and flanking structures. You should also specify the type of junction of the adjoining structures (e.g. to include structural losses at the junctions of plaster-board back-walls). Go to the Extra, Structural Rev Time and adjust the junction types of all sides of all heavy elements. Typically, this adds 1-1,5 dB.

3. Errors in input data lead to errors in the calculated sound insulation. Consult the suppliers of the products to be used, in order to provide relevant input data. In case you find flaws in the databases, contact us. An example: impact sound reduction from the laboratory can sometimes be hard to achieve in buildings, especially after some years aging of resilient materials under carpets or parquet floors. Apply some margin at high frequencies if deteriorated elasticity may be reasonable to occur.

4. Structural losses must be handled: Input data for concrete elements must be converted since the structural losses in a laboratory (for an element itself) are lower than in the current building, which usually gives an increase of 1-3 dB if all junctions are specified. On the contrary, flanking transmission of adjoining structures to the reception room reduces the insulation. Input data for a single concrete element does not tell much about the sound insulation of a building, it is when you put together all concrete elements ("communicating vessels") that you get an estimate of what the building structure performs. All these aspects are handled by EN ISO 12354.

5. The Swedish building codes BBR and the standards SS 25267/SS 25268 contain rules that say you should fulfill the sound requirement on average within a dwelling or premises, and that single measurements may not deviate by more than 1 or 2 dB. Always make sure to fulfill req's with a calculated value. Remember, it is the rejected measurements, or the risk of getting rejected, which determines the minimal construction being appropriate. As a result, the majority of measurements are likely to meet or even exceed the requirement. This may appear as an over-estimation, but is in many cases necessary.

6. Typically I find 2-3 dB higher sound insulation measured between small rooms than large rooms. Some new test reports show that consultants sometimes only measure between small rooms or only in a favorable direction. The requirement of the standard is clear, test rooms shall be selected to match the building as a whole. In safe designs, sound requirements should be exceeded by 3 dB margin, to obtain reasonable assurance (approximately 90%) to meet the requirements for its field measurement. One or two measurements may still be below the requirement.

7. If no margin is applied, many measurements will still fulfill the requirements but you will get more negative deviations. Only when a large number of measurements is analyzed, these statistical relationships become clear.

8. Large or systematic discrepancies are probably due to the quality of field measurement. Two common reasons for measurement errors are background noise and insufficient spatial averaging (microphone positions did not cover the entire space).

9. What about the EN ISO 12354:2017? Bastian is not yet updated for the new version of the standard, but may still be "tweeked" to handle wooden structures. The uncertainty of calculated sound insulations of timber frame buildings, or building with massive wood (CLT/KL) are currently not known. Timber frame floors are in a separate category. Studded walls on concrete slabs is handled, use the appropriate junction. You may use some temporary data for CLT but be cautious. They are marked with the CA country label, to separate from homogenous concrete. The approach is then to use CLT as with concrete, but with additional layers that perform differently. Use the CA country selector to filter out other data entries than for CLT. 2021-03-18: In the Sept update, there will be 34 CLT constructions added, based on extensive comparisons with lab data. Will be published at BNAM and in Bygg&Teknik in May 2021. Contact me for further details.

1. Enter your own data into the database. See the manual, page 169. Basically, go to the Database menue, choose relevant product category and then use right hand click to open a submenue. Either choose NewAsCopy, or NewConstruction. Make sure to use input data for the construction as measured in a laboratory, i.e. without flanking transmission.

2. Contact us. We frequently assess sound insulation of new products for manufacturers and we can certainly help you as well (commissioned work). You can try using Insul, copy and paste, but you should consider the limitations of Insul prior to advising clients on critical constructions using this method (ABK 09 requirement of workmanship). In case you try and use field data, make sure to remove flanking energy before inserting the insulation values, since BASTIAN adds flanking to the model. 3. See below, there are more detailed Q:s on this topic.

The pictogram may be misinterpreted such that the L-W wall seems to be continous across the junction, thus giving unacceptable flanking transmission. This is (of course) not the case. The massive partition blocks/interrupts the lining. In case the intention of the user is to apply continous lining (e.g. a suspended ceiling in offices), apply junction #15 and give Dn,f data for the flanking element. Refer to the manual (on-line Help, or PDF-file on the BASTIAN CD)

Yes. Just choose the appropriate junctions BEFORE you choose elements. However, for timber joist floors on light weight walls, BASTIAN may underestimate the impact sound caused by flanking transmission. See manual and the FAQ advanced calculation section.

1. Enter your own data into the database. See the manual, page 169. Basically, go to the Database menu (NOT within the ConstructionChooser), choose relevant product category and then use right hand click to open a submenu. Either choose NewAsCopy, or NewConstruction. Make sure to use input data for the construction as measured in a laboratory, i.e. without flanking transmission. How to edit data in SONarchitect will be informed later on.

2. To find appropriate data for an element, get in touch with the manufacturer or contact us. We have special softwares and a large experience in estimating sound insulation of building elements. In case you enter your own data, make sure to state this in the clients report, or whether you apply data from the SOAB database.

Yes. Define the image file name in the Database menu and save the file in the Bastian-folder.

For constructions in the optional SOAB database, the www addresses of the manufacturers are given. Please look for further information at their pages or contact them.

Yes. Products advertised in the CadnaB and BASTIAN-databases are also distributed to users of SON-architect software, through a cooperation with their Scandinavian distributor Norsonic AS (www.norsonic.no). In case you find differences, those are unintentional, please inform us!