Willow, Salix alba, ext.

Explosiveness

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

explosive properties of explosives

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019-01-28 to 2019-02-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: UN Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria, Appendix 6

Version / remarks:

rev. 6 (2015)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD 113 Screening test for thermal stability and stability in air

Version / remarks:

adopted 12 May 1981

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Key result

Test series:

other: Screening test on exothermal decomposition energy performed

Method:

other: DSC

Parameter:

other: Exothermic decomposition energy

Result:

other: >500 J/g; <800 J/g

Remarks on result:

not determinable

Remarks:

Additional tests have to be performed for a classification or an exclusion as explosive substance.

See details in ESR IUCLID section "Additional physico-chemical information".

Interpretation of results:

other: See conclusions below

Conclusions:

Results from DSC analysis of exothermic decomposition energy, with interpretation according to UN Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria, rev. 6 (2015), Appendix 6:
The heat of decomposition was above 500 J/g. Therefore additional tests have to be performed for a classification or an exclusion as explosive substance.
The heat of decomposition was below 800 J/g. Therefore, neither a Series 1 type (a) propagation of detonation test nor a Series 2 type (a) test of sensitivity to detonative shock is required.

Executive summary:

The submission substance was tested for classification requirements regarding explosiveness and self-reactiveness. According to UN Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria, rev. 6 (2015), Appendix 6 (Screening Procedures), these properties can be excluded based on analysis of the exothermic decomposition energy. To this end, the exothermic decomposition energy was determined in a reliable and valid test performed compliant with GLP using differential scanning calorimetry under nitrogen in closed crucibles. The study methodology followed the UN Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria as well as OECD test guideline 113 (Screening test for thermal stability and stability in air).

Results from DSC analysis of exothermic decomposition energy, with interpretation according to UN Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria, rev. 6 (2015), Appendix 6:

The heat of decomposition was above 500 J/g. Therefore, additional tests have to be performed for a classification or an exclusion as explosive substance.

The heat of decomposition was below 800 J/g. Therefore, neither a Series 1 type (a) propagation of detonation test nor a Series 2 type (a) test of sensitivity to detonative shock is required.

Reference 2

Endpoint:

explosive properties of explosives

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental phase: 2019-08-23 to 2019-08-23

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

In an earlier DSC screening test on thermal stability, the energy release was > 500 J/g (maximum 785 J/g starting at 140 °C; determined in study PS20180395-10 dated March 25, 2019), i.e. exceeding the screening criterion for explosive properties according to the UN Manual of Tests and Criteria (Sixth revised edition; United Nations 2015; Appendix 6 SCREENING PROCEDURES). In case of a decomposition energy above 500 J/g further tests are necessary for a classification or exclusion from the classification. Depending on the energy in the DSC-measurement the appropriate tests have to be selected (e.g. Koenen-Test and Time-Pressure-Test).
If the decomposition energy is below 800 J/g (which is the case for White Willow bark extract) only a test for heating under confinement (e.g. Koenen-Test) and ignition under confinement (e.g. Time-Pressure-Test) are necessary (Recommendations on the Transport of Dangerous Goods - Manual of Tests and Criteria, rev.6 (2015), appendix 6). In this robust study summary, the performance and outcome of the Koenen-test is described.

Qualifier:

according to guideline

Guideline:

UN Manual of Tests and Criteria: Part I: Classification procedures, test methods and criteria relating to explosives of Class 1

Version / remarks:

Rev. 6, 2015

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Key result

Test series:

UN Test series 1

Method:

UN Test 1 (b): Koenen test

Parameter:

limiting diameter (mm)

Value:

1

Result:

result is considered "-" (negative)

Remarks:

< 1 mm

Key result

Test series:

UN Test series 2

Method:

UN Test 2 (b): Koenen test

Parameter:

limiting diameter (mm)

Value:

1

Result:

result is considered "-" (negative)

Remarks:

< 1 mm

The Koenen-Test was started with a diameter of 5 mm and subsequently continued with 2 mm, 1.5 mm and 1 mm. The physical state of the test item (solid) excludes the enrichment of high-energy components caused by evaporation of volatile solvents. Therefore, an explosion with larger nozzles could be excluded. 6 tests were performed.

The results are given in the following table:

Koenen-Test: Results

Amount	Diameter of orifice	t1	t2	Reaction	Effect
g	mm	s	s
21.3	5.0	28	>300	Flame	O
21.3	2.0	30	>300	Flame	O
21.3	1.5	28	>300	Flame	O
21.3	1.0	28	>300	Flame	O
21.3	1.0	28	>300	Flame	O
21.3	1.0	29	>300	Flame	O

t₁: Time to the first reaction;   t₂: Time to the main reaction;  O: Tube unchanged

Interpretation of results:

GHS criteria not met

Conclusions:

The Koenen-test was performed within this study and showed the following results:
UN-Tests 1(b) and 2(b): „-“ (negative)
UN-Test E.1: „no“ (the limiting diameter is less than 1 mm and the effect of all tests is of type "O", i.e. tube unchanged)

Due to the results presented above from the UN-tests 1(b) (effect of heating under confinement) and 1(c) (effect of ignition under confinement - see respective IUCLID endpoint study record - time/pressure test) the test item can be excluded from classification in class 1 (explosives) according to series 1 of the UN Recommendations on Transport of Dangerous Goods - Manual of Test and Criteria, rev. 6 (2015).

Executive summary:

In an earlier DSC screening test on thermal stability with test item White Willow bark extract, the energy release was > 500 J/g (maximum 785 J/g starting at 140 °C; determined in study PS20180395-10 dated March 25, 2019), i.e. exceeding the screening criterion for explosive properties according to the UN Manual of Tests and Criteria (Sixth revised edition; United Nations 2015; Appendix 6 SCREENING PROCEDURES). In case of a decomposition energy above 500 J/g further tests are necessary for a classification or exclusion from the classification. Depending on the energy in the DSC-measurement the appropriate tests are to be selected (e.g. Koenen-Test and Time-Pressure-Test).

If the decomposition energy is below 800 J/g (which is the case for White Willow bark extract) only a test for heating under confinement (e.g. Koenen-Test) and ignition under confinement (e.g. Time/Pressure Test) are necessary (Recommendations on the Transport of Dangerous Goods - Manual of Tests and Criteria, rev.6 (2015), appendix 6).

The Koenen-Test was performed compliant with GLP according to UN tests 1(b), 2(b) and E.1 as described within the UN "Recommendations on Transport of Dangerous Goods - Manual of Test and Criteria", rev. 6 (2015).  

The method involves heating the substance or preparation in a steel tube, with various degrees of confinement being provided by nozzle-plates with different diameters of orifice, to determine whether the substance or preparation is liable to explode under conditions of thermal stress and confinement.

Results: up to the highest confinement (limiting diameter was less than 1 mm), the only reaction observed was "Flame", but the tubes remained unchanged.

Interpretation:

UN-Tests 1(b) and 2(b): „-“ (negative)

UN-Test E.1: „no“ (the limiting diameter is less than 1 mm and the effect of all tests is of type "O", i.e. tube unchanged);

Conclusion:

Together with the results from the Time/Pressure test (see respective IUCLID endpoint study record), explosive properties of the test item White Willow bark extract can be excluded according to series 1 of the UN Recommendations on Transport of Dangerous Goods - Manual of Test and Criteria, rev. 6 (2015).

There are no classification requirements regarding explosive properties.  

Reference 3

Endpoint:

explosive properties of explosives

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental phase: 2019-06-04 to 2019-06-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

In an earlier DSC screening test on thermal stability of White Willow bark extract, the energy release was > 500 J/g (maximum 785 J/g starting at 140 °C; determined in study PS20180395-10 dated March 25, 2019), i.e. exceeding the screening criterion for explosive properties according to the UN Manual of Tests and Criteria (Sixth revised edition; United Nations 2015; Appendix 6 SCREENING PROCEDURES). In case of a decomposition energy above 500 J/g further tests are necessary for a classification or exclusion from the classification. Depending on the energy in the DSC-measurement the appropriate tests have to be selected (e.g. Koenen-Test and Time-Pressure-Test).
If the decomposition energy is below 800 J/g (which is the case for White Willow bark extract) only a test for heating under confinement (e.g. Koenen-Test) and ignition under confinement (e.g. Time-Pressure-Test) are necessary (Recommendations on the Transport of Dangerous Goods - Manual of Tests and Criteria, rev.6 (2015), appendix 6). In this robust study summary, the performance and outcome of the Time/Pressure test is described.

Qualifier:

according to guideline

Guideline:

UN Manual of Tests and Criteria: Part I: Classification procedures, test methods and criteria relating to explosives of Class 1

Version / remarks:

UN Recommendations on the Transport of Dangerous Goods - Manual of Tests and Criteria, rev. 6 (2015), Time/pressure test 1(c), 2(c) and C.1

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Key result

Test series:

UN Test series 1

Method:

UN Test 1 (c) (i): Time/pressure test

Parameter:

other: Whether a gauge pressure is reached of 2070 kPa and - if so - the time taken to for the pressure to rise from 690 to 2070 kPa guage.

Result:

negative, no or slow deflagration

Remarks:

negative (Maximum pressure reached in any one test is less than 2070 kPa gauge.)

Remarks on result:

p = 2070 kPa: no

Key result

Test series:

UN Test series 2

Method:

UN Test 2 (c) (i): Time/pressure test

Parameter:

other: Whether a gauge pressure is reached of 2070 kPa and - if so - the time taken to for the pressure to rise from 690 to 2070 kPa guage.

Result:

negative, no or slow deflagration

Remarks:

negative (Maximum pressure reached in any one test is less than 2070 kPa gauge.)

Remarks on result:

neither a test for propagation of detonation nor a test for sensitivity to detonative shock is required because the exothermic decomposition energy of the organic substance is less than 800 J/g

Key result

Test series:

other: UN test series C

Method:

other: UN test C.1

Parameter:

other: Whether a gauge pressure is reached of 2070 kPa and - if so - the time taken to for the pressure to rise from 690 to 2070 kPa guage.

Result:

negative, no or slow deflagration

Remarks:

A pressure rise to 2070 Pa above atmospheric is not achieved.

Remarks on result:

p = 2070 kPa: no

Time/pressure test - results

Table 1 shows the used amounts of sample and the results from the Time/pressure test. Figure 1 (see attached illustration) shows the time/pressure profiles of the Time/pressure tests.

Table 1: Amount used for and times of the Time/pressure tests

	Test 1	Test 2	Test 3
Amount in g	5.0	5.0	5.0
Time to 690 kPag in s	-	-	-
Time to 2070 kPag in s	-	-	-
Pressure rise time in s	-	-	-

None of the three tests reached a pressure of 2070 kPa. Therefore, the result had to be evaluated as negative according to UN tests 1(c), 2(c) and C.1:

UN tests 1(c) and 2(c): “-“ (negative)

UN test C.1: “no“ (A pressure rise to 2070 Pa above atmospheric is not achieved.)

These evaluations indicate no (or slow) deflagration according to the UN tests 1(c), 2(c) and C.1.

Interpretation of results:

GHS criteria not met

Conclusions:

The Time/Pressure test was performed within this study and showed the following results:
UN tests 1(c) and 2(c): “-“ (negative)
UN test C.1: “no“ (A pressure rise to 2070 Pa above atmospheric is not achieved.)

Due to the results presented above from the UN tests 1(c) (effect of ignition under confinement) and 1(b) (effect of heating under confinement - see respective IUCLID endpoint study record - Koenen test) the test item can be excluded from classification in class 1 (explosives) according to series 1 of the UN Recommendations on Transport of Dangerous Goods - Manual of Test and Criteria, rev. 6 (2015).

Executive summary:

In an earlier DSC screening test on thermal stability with test item White Willow bark extract, the energy release was > 500 J/g (maximum 785 J/g starting at 140 °C; determined in study PS20180395-10 dated March 25, 2019), i.e. exceeding the screening criterion for explosive properties according to the UN Manual of Tests and Criteria (Sixth revised edition; United Nations 2015; Appendix 6 SCREENING PROCEDURES). In case of a decomposition energy above 500 J/g further tests are necessary for a classification or exclusion from the classification. Depending on the energy in the DSC-measurement the appropriate tests are to be selected (e.g. Koenen-Test and Time-Pressure-Test).

If the decomposition energy is below 800 J/g (which is the case for White Willow bark extract) only a test for heating under confinement (e.g. Koenen-Test) and ignition under confinement (e.g. Time/Pressure Test) are necessary (Recommendations on the Transport of Dangerous Goods - Manual of Tests and Criteria, rev.6 (2015), appendix 6).

The Time/Pressure test was performed compliant with GLP according to UN tests 1(c), 2(c) and C.1 as described within the UN "Recommendations on Transport of Dangerous Goods - Manual of Test and Criteria", rev. 6 (2015).  

This test is used to determine the effects of igniting a substance under confinement in order to determine if ignition leads to a deflagration with explosive violence at pressures which can be present with substances in normal commercial form.

5.0 g of test item were filled into the autoclave so as to be in contact with the ignition system. The filled autoclave was closed with a bursting disc and put into the support stand (bursting disc at its top). The charge was fired externally, and the time/pressure profile was recorded. In neither of three replicate experiments a pressure rise up to 2070 kPa gauge could be determined:

UN tests 1(c) and 2(c): “-“ (negative)

UN test C.1: “no“ (A pressure rise to 2070 Pa above atmospheric is not achieved.)

Conclusion:

Together with the results from the Koenen test (see respective IUCLID endpoint study record), explosive properties of the test item White Willow bark extract can be excluded according to series 1 of the UN Recommendations on Transport of Dangerous Goods - Manual of Test and Criteria, rev. 6 (2015).

There are no classification requirements regarding explosive properties.  

Description of key information

Explosiveness Screening Study (DSC; Siemens, 2019)

Results from DSC analysis of exothermic decomposition energy, with interpretation according to UN Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria, rev. 6 (2015), Appendix 6:

The heat of decomposition was above 500 J/g. Therefore additional tests have to be performed for a classification or an exclusion as explosive substance.

The heat of decomposition was below 800 J/g. Therefore, neither a Series 1 type (a) propagation of detonation test nor a Series 2 type (a) test of sensitivity to detonative shock is required.

Koenen Test (test for heating under confinement; Siemens, 2019)

The Koenen-test was negative based on the following results:

UN-Tests 1(b) and 2(b): „-“ (negative)

UN-Test E.1: „no“ (the limiting diameter is less than 1 mm and the effect of all tests is of type "O", i.e. tube unchanged)

Time/Pressure Test (ignition under confinement; Siemens, 2019)

The Time/Pressure test was negative based on the following results:

UN tests 1(c) and 2(c): “-“ (negative)

UN test C.1: “no“ (A pressure rise to 2070 Pa above atmospheric is not achieved.)

Overall result:

The test item White Willow bark extract was determined to be non-explosive (no classification requirements regarding explosive properties according to GHS criteria).

Key value for chemical safety assessment

Explosiveness:

non explosive

Additional information

The submission substance White Willow bark extract was tested for classification requirements regarding explosiveness and self-reactiveness. According to UN Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria, rev. 6 (2015), Appendix 6 (Screening Procedures), these properties can be excluded based on analysis of the exothermic decomposition energy. To this end, the exothermic decomposition energy was determined in a reliable and valid test performed compliant with GLP using differential scanning calorimetry under nitrogen in closed crucibles. The study methodology followed the UN Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria as well as OECD test guideline 113 (Screening test for thermal stability and stability in air).

Results from DSC analysis of exothermic decomposition energy, with interpretation according to UN Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria, rev. 6 (2015), Appendix 6:

The heat of decomposition was above 500 J/g. Therefore, additional tests have to be performed for a classification or an exclusion as explosive substance.

The heat of decomposition was below 800 J/g. Therefore, neither a Series 1 type (a) propagation of detonation test nor a Series 2 type (a) test of sensitivity to detonative shock is required.

Accordingly, both, the Time/Pressure test as well as the Koenen test, was performed to rule out any potential explosive properties.

The Time/Pressure test was performed compliant with GLP according to UN tests 1(c), 2(c) and C.1 as described within the UN "Recommendations on Transport of Dangerous Goods - Manual of Test and Criteria", rev. 6 (2015).  

This test is used to determine the effects of igniting a substance under confinement in order to determine if ignition leads to a deflagration with explosive violence at pressures which can be present with substances in normal commercial form.

5.0 g of test item were filled into the autoclave so as to be in contact with the ignition system. The filled autoclave was closed with a bursting disc and put into the support stand (bursting disc at its top). The charge was fired externally, and the time/pressure profile was recorded. In neither of three replicate experiments a pressure rise up to 2070 kPa gauge could be determined:

UN tests 1(c) and 2(c): “-“ (negative)

UN test C.1: “no“ (A pressure rise to 2070 Pa above atmospheric is not achieved.)

The Koenen-Test was performed compliant with GLP according to UN tests 1(b), 2(b) and E.1 as described within the UN "Recommendations on Transport of Dangerous Goods - Manual of Test and Criteria", rev. 6 (2015).  

The method involves heating the substance or preparation in a steel tube, with various degrees of confinement being provided by nozzle-plates with different diameters of orifice, to determine whether the substance or preparation is liable to explode under conditions of thermal stress and confinement.

Results: up to the highest confinement (limiting diameter was less than 1 mm), the only reaction observed was "Flame", but the tubes remained unchanged.

Interpretation:

UN-Tests 1(b) and 2(b): „-“ (negative)

UN-Test E.1: „no“ (the limiting diameter is less than 1 mm and the effect of all tests is of type "O", i.e. tube unchanged);

Justification for classification or non-classification

In combination of results from a) the DSC screening test on exothermic decomposition energy (maximum 785 J/g starting at 140 °C), b) Time/Pressure test (A pressure rise to 2070 Pa above atmospheric was not achieved), and c) Koenen test (the limiting diameter is less than 1 mm and the effect of all tests is of type "O", i.e. tube unchanged) explosive properties of the test item White Willow bark extract can be excluded according to series 1 of the UN Recommendations on Transport of Dangerous Goods - Manual of Test and Criteria, rev. 6 (2015).

There are no classification requirements regarding explosive properties.