Impact Isolation Class

This program calculates the Impact Isolation Class (IIC) given the input LN values in dB.


Updated 17 Apr 2015

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The main program is iic.
The program iic calculates the impact isolation class given the array of third octave band impact loss values, LN (dB) as input data. The program can also plot the iic reference contour and deficiencies.

This is an implementation of the calculation of IIC value according to
ASTM E492-09. Classification for Rating Impact Isolation.

To make it easier to input the frequency data, the reference values are used be default.
For inputting non-reference frequency data, a one-sixth octave band tolerance is applied to Fc when matching Fc to the reference third octave bands.

This chunk of code below may be easier to use than typing the third octave band frequencies.
Fc=nth_freq_band(3, 100, 3150);

If you find any bugs please post a comment or send an email to


1) ASTM E492 - 09 Standard Test Method for Laboratory Measurement of
Impact Sound Transmission Through Floor-Ceiling Assemblies Using
the Tapping Machine

Available from American National Standards Institute (ANSI),
25 W. 43rd St., 4th Floor, New York, NY 10036.

Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700,
West Conshohocken, PA 19428-2959, United States.

Cite As

Edward Zechmann (2023). Impact Isolation Class (, MATLAB Central File Exchange. Retrieved .

MATLAB Release Compatibility
Created with R2013a
Compatible with any release
Platform Compatibility
Windows macOS Linux

Inspired by: ISMEMBERF

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Version Published Release Notes

Fixed several bugs in the program which cause erroneous IIC ratings. Use of vocabulary words in the comments has also been improved.

Updated the Program to fix errors in the examples and update the comments.