INSUL - Sound Insulation Prediction Software
INSUL - Product Features & Download

The INSUL software is developed by Marshall Day Acoustics, Auckland  - New Zealand. Navcon is the INSUL distributor for USA, Canada and Mexico.

The INSUL software predicts the sound insulation of walls, floors, ceilings and windows.  The software was developed based on simple theoretical models that only require easily obtainable construction information. The program can make reasonable estimates of the Transmission Loss (TL) and Weighted Sound Reduction Index (STC) for use in noise transfer calculations.

INSUL Product Features:

  • Predicts the sound insulation performance of single, double and triple panel Walls, Floors, Ceilings and Windows &#149
  • Single, Double and Triple Glazing Predictions
  • Accurate estimates of Transmission Loss (TL), Weighted Sound Reduction Inces (Rw, STC, OITC), Sound Level Difference (Dnt,w) including C and Ctr corrections and Impact Sound Pressure Level (Ln,w and IIC)
  • Predicts the Impact Sound Pressure Level for concrete floors with different floor coverings INSUL can also predict lightweight and timber floors
  • Evaluation based on Impact Insulation Class or Weighted Sound Pressure Level (IIC, Ln,w) Predicts rainfall on roofs, both natural rainfall and laboratory rainfall ( ISO 140-18 )
  • Calculates indoor sound levels from outdoor noise sources (EN 12354/3)
  • INSUL predicts profiled metal sheets including complex double skin constructions
  • Database of hundreds of common builders work material and floor covering
  • Material Database Editor Flanking noise indicator New Frame Types Improved user interface
  • Prediction of Composite Wall Segments by area ratio (i.e., Wall, Door, Window, etc.)
  • Leakage Calculation Freefield Incident Calculation (Panel 1) Auralisation (Vista and Windows 7)
  • Calculation Range 50 Hz to 5 kHz

Software Download

Download INSUL v9 Software / Trial Version (Installation INSUL v9.05 - Please contact Navcon for a Trial License - forschner (at) )

Software Objective

INSUL uses robust theoretical models that are quick to calculate and only require easily obtainable construction information. The program can make good estimates of the Transmission Loss (TL). Weighted Sound Reduction Index (Rw or STC) and Impact Sound Insulation (Ln,w or IIC).

INSUL takes account of finite size effects which are especially important when predicting small samples such as windows. Like any prediction tool, INSUL is not a substitute for measurement. However, extensive comparisons with test data indicate INSUL reliably predicts Rw/STC values to within 3 dB for most constructions, and IIC/Ln,w values to within 5 dB.

Software Features in Detail

Wall & Ceiling Construction

INSUL can be used to quickly evaluate new materials and systems, or to investigate the effects of changes to existing designs. It models materials using the simple mass law and coincidence frequency approach and models more complex partitions using work by Sharp, Cremer and others. It can predict the effect of installing an acoustic blanket in the stud cavity. It has evolved over several versions into a very easy to use tool that takes advantage of the Windows™ environment, and has been refined by continued comparison with laboratory tests to provide acceptable accuracy for a wide range of constructions.  INSUL will greatly enhance the ability of acoustic consultants and product manufacturers to quickly and confidently specify constructions in order to achieve a desired airborne sound insulation Leakage Calculation Composite Transmission Loss Calculation

Leakage Calculation

INSUL includes the ability to predict the effect of leakage. This is especially useful for predicting the sound insulation of doors and windows which are notoriously difficult to seal perfectly.  INSULuses the theory published by Gomperts (The Sound Transmission of Circular and Slit Shaped Apertures in Walls (Gomperts and Kihlman 1967 Acustica Vol 18)) to firstly predict the transmission loss of thin slits and then the combined transmission loss of the slit and the partition.

Composite Transmission Loss Calculation

A composite transmission loss calculator allows to compute the total Transmission Loss for a composite Wall Assembly. This software feature can either use INSUL data or the user can enter own data. The calculation works with either 1/3 or 1/1 Octave data.

Prediction of Rain Noise

INSUL predicts rain noise according to ISO 140-18.

  • Prediction for light weight & heavy roof construction
  • ISO 140-18 simulated rain or natural rainfall
  • Predictions for corrugated and ribbed roof panels
  • Predictions for single roof panels or roof panels with a ceiling beneath
  • Predictions of sound pressure level, sound intensity level and sound power level, with results given in third octave bands, octave bands, dBA, NC & PNC

Calculation from Outdoor to Indoor Transmission

INSUL calculates the noise level inside a room due to outdoor noise. Calculations are based on EN 12354/3. The prediction accounts for the sound transmission loss (STL) of the building façade, the size of the room and its acoustical characteristics. Up to five different elements (e.g door, wall, window, roof, floor) can be included. STL data can come from INSUL or be manually entered from other data. Several standard outdoor noise spectra are available (e.g. traffic noise, aircraft noise, entertainment noise, voice). INSUL can be used to design the optimum façade element to match the design requirements.

Prediction of Impact Sound for light weight floors 

INSUL can now predict the impact sound insulation of light weight floors. Impact sound insulation predictions can now be carried out for different joist constructions including timber joists and ZGirts. The prediction routines are sensitive to the dimensions of the joists, their mass and spacing and all of these variables can be set independently in INSUL. A range of floor linings is available including plywood, particle board, orientated strand board (OSB) and thin timber floor boards. As with previous versions of INSUL, ceilings can also be included in the predictions, with a range of ceiling connections including directing fixing to the joists, rubber isolation clips and separate ceiling joists. INSUL also includes the option to add infill material in the cavity of the construction.

Sound Insulation of Sandwich Panels

INSUL can now predict the sound insulation of a variety of light weight sandwich panels. A typical example would be panels with thin steel or aluminium skins, with a polystyrene or mineral wool core. For instance panels from Kingspan or Paroc. The sound insulation both of single panels and panels used in more complex constructions can be predicted. The properites of the core can be adjusted using the in built materials properties editor. In addition sandwich panels with much stiffer cores can also be predicted, a typical example would be a panel with steel facings and a light weight aerated concrete (Speedwall)

Trapezoidal Profiled Metal Panels

INSULhas improved the prediction of profiled metal panels, typically used for commercial and industrial buildings. Previously only single panels could be predicted, and not complex constructions using corrugated or profiled panels. New routines based on the work of Lam and Windle in England allow more accurate prediction of particular profiles, and of constructions using profiled panels in conjunction with flat sheets and in cavity constructions as well. For instance the effect of a layer of plywood underneath a profiled steel skin can be predicted. Then this can be extended by adding an air gap and a second lining, with or without an acoustic blanket in the cavity.

Porous Blankets and Facings

INSUL can now predict the sound transmission loss of porous blankets either alone or as a facing for a construction. Typical constructions would include modular panels for acoustic enclosures that have a steel skin with a mineral wool infill and perforated steel internal facing.