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Physical & Chemical properties

Flammability

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Description of key information

There is one study available on flammability which was conducted according the commission regulation (EC) No. 440/2008 method EU A.10. In this study thiourea is considered to be not highly flammable.

Key value for chemical safety assessment

Additional information

There is one standard guideline study available on flammability. The study was conducted according the commission regulation (EC) No. 440/2008 method EU A.10. The test item was formed into an unbroken strip or powder train 250 mm in length on a non-combustible and non-porous plate. This preliminary test was performed to determine if after ignition by a gas flame propagation by burning with flame or smouldering occurs and propagates over a length of 200 mm. When in this preliminary test the test item cannot be ignited or the propagation time for the 200 mm is longer than 4 minutes the performance of the main test is not required. In such cases the substance is assessed to be not highly flammable. The drying loss of the substance was determined to be 0.11 % using the drying balance. After application of the flame at one end of the pile a transparent molten mass was visible but no ignition of the substance could be ascertained. According to the guideline the execution of the main test was not necessary. The substance does not have to be considered as "highly flammable" according to the definitions in the commission regulation (EC) No. 440/2008, method A.10.

In addition to the standard test results above test were conducted to determine the "BWZ" of thiourea. Thiourea was dried before testing. The dried test substance could be ignited by the 1000 °C hot platinum wire, which was dipped for 5 seconds into the substance. The substance ignites but the flame does not continue to burn when the hot platin wire is removed.

In a second test approx. 200 mg of thiourea were put into a flat iron bowl and heated with an open gas flame burner for 10-15 seconds. The substance could be ignited and was melting. The ignition process was terminated when the flame was removed.

In a third test approx. 150 mg test substance and a 1:1 mixture of the test substance with potassium nitrate was put into a red heated iron bowl for 60 seconds. Both, the substance and the 1:1 mixture with potassium nitrate did melt and burned rapidly.

Therefore it is concluded that the test substance is not highly flammable.

Justification for classification or non-classification