What is ISO 11925-3?

22 July 2019 Kingspan Insulation UK
ISO 11925 3  Full width-1


BS EN ISO 11925-3: 2010, also known as the multi-source test, provides a test method to determine the ignitability of a product when subjected to direct impingement of a flame source to either the face or edge of a specimen.  

In principle, specimens are exposed to specified flames of different sizes and intensities and their ignition behaviour is observed.

How does the single-flame source test work?


The test should be performed in a room equipped with an extractor fan or other means of ventilation.
One of eight possible ignition sources are selected, each defined by their:
  • intensity;
  • area of impingement;
  • duration of exposure;
  • presentation and whether or not it impinges;
  • orientation in relation to the specimen; and
  • the ventilation in the vicinity of the ignition source.
The test specimen should be no more than 50 mm thick. The length and width of the specimen are dependent on the type of ignition source chosen for the test. The table below from BS EN ISO 11925-3:2010 outlines the appropriate size for each ignition source.
ISO 11925 3
It is recommended that a minimum of six specimens are tested against each ignition source and for each ignition time: three for surface ignition; and three for bottom ignition.

Test Process

Once the test specimen is appropriately positioned in the test holder, the chosen ignition source is positioned and applied to either the face or bottom edge of the specimen, with the timer simultaneously started.

The distance between the ignition source and the specimen is dependent on the chosen ignition source.

Test Observations

For each specimen the following observations outlined in clause 17 of the test standard are recorded:
  • flame source used;
  • flame application time;
  • face or edge exposure;
  • whether a sustained ignition or transient ignition occurred;
  • whether debris separated and whether it flamed / glowed (the possibility of the material causing secondary ignition of other materials is considered by the observation of burning droplets or debris which may be formed); and
  • whether flaming reached any edge during application of the ignition source / within 4 s of the end of the flame application time. 
After the specified application time, the ignition source is withdrawn from the test specimen and the test is concluded.

Test Report

The final test report will include:
  • reference to this part of ISO 11925;
  • identification and description of the product tested including its colour, thickness and density;
  • full description of the test procedure, reference to a published method of test or reference to the test method detailed in this part of ISO 11925;
  • for each specimen, the information recorded in accordance with clause 17; and
  • the statement: “The test results relate only to the behaviour of the test specimens of the product under the particular conditions of test; they are not intended to be the sole criterion for assessing the potential fire hazard of the product in use”.
You can download the full testing standard from the International Organization for Standardization: https://www.iso.org/standard/45782.html

ISO 11925-3 – Determining the ignitability of building products

In this video we learn how the ignitability of a building product material can be determined when subjected to direct impingement of a flame source by using ISO 11925-3 test method.

#TheFactsMatter: Related Articles

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