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Flammability

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Endpoint:
flammable solids
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2016-05-19
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
UN Manual of Tests and Criteria: Test N.1 (Test method for readily combustible solids)
Version / remarks:
2015
Deviations:
no
Qualifier:
according to
Guideline:
other: VDI 2263, sheet 1
Version / remarks:
1990
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
signed 2013-03-22
Key result
Test procedure:
burning rate test: preliminary screening test
Burning time:
0 s
Remarks on result:
other: the test item could not be ignited by a flame, and thus did not propagate combustion by burning with flame or smouldering.

Preliminary Test

The test item did not ignite at room temperature using a flame as ignition source for 5 minutes. The test item glowed and melted.  

Main Test

In the preliminary test, the test item could not be ignited by a flame, and thus did not propagate combustion by burning with flame or smouldering. Therefore, the performance of the main test was not necessary.

Final Results

The test item Strontium could not be ignited applying a flame as ignition source for 5 minutes. Therefore, the test item is classified as follows:

UN Transport Regulation:

The test item in its commercial form (i.e. rods) does not meet classification criteria of a readily combustible solid in Class 4, Division 4.1 according to the UN Transport Regulation.

GHS (CLP Regulation EC 1272/2008: Annex 1: 2.7):

The test item in its commercial form (i.e. rods) does not meet classification criteria of a flammable solid according to GHS and EC 1272/2008 (CLP Regulation) Annex 1: 2.7.

Interpretation of results:
GHS criteria not met
Conclusions:
The test item Strontium could not be ignited applying a flame as ignition source for 5 minutes.Therefore, the test item is classified as follows:UN Transport Regulation: The test item in its commercial form (i.e. rods) does not meet classification criteria of a readily combustible solid in Class 4, Division 4.1 according to the UN Transport Regulation.GHS (CLP Regulation EC 1272/2008: Annex 1: 2.7): The test item in its commercial form (i.e. rods) does not meet classification criteria of a flammable solid according to GHS and EC 1272/2008 (CLP Regulation) Annex 1: 2.7.
Endpoint:
substances / mixtures which in contact with water emit flammable gases
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2016-05-19 to 2016-05-23
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
UN Manual of Tests and Criteria: Test N.5 (Test method for substances which in contact with water emit flammable gases)
Version / remarks:
2015
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
signed 2013-03-22
Test procedure:
step 1
Identity of evolved gas:
other: hydrogen
Remarks:
assumption
Remarks on result:
other: The test item emitted gas when placed in a bowl containing distilled water, but a spontaneous ignition was not observed.
Test procedure:
step 2
Identity of evolved gas:
other: hydrogen
Remarks:
assumption
Remarks on result:
other: The test item emitted gas when placed onto a filter paper floating on the surface of a bowl containing distilled water, but a spontaneous ignition was not observed.
Test procedure:
step 3
Identity of evolved gas:
other: hydrogen
Remarks:
assumption
Remarks on result:
other: The test item emitted gas when a few drops of water were added to the test item, but a spontaneous ignition was not observed.
Key result
Test procedure:
step 4
Max. rate of gas release:
200 L/kg min
Identity of evolved gas:
other: hydrogen
Remarks:
assumption
Remarks on result:
other: form of the test item: swarf

The temperature during the tests was 21 °C

Step 1

The test item emitted gas when placed in a bowl containing distilled water, but a spontaneous ignition was not observed.

Step 2

The test item emitted gas when placed onto a filter paper floating on the surface of a bowl containing distilled water, but a spontaneous ignition was not observed.

Step 3

The test item emitted gas when a few drops of water were added to the test item, but a spontaneous ignition was not observed.

Step 4

Pieces and nuggets of the test item of different forms and sizes with a weight of approximately 10 or 5 g were used for the three tests. The following tables show the results of Step 4:

Table 1: Results of step 4 (Test 1)

Amount of test item [g] Test 1
10.00 (small pieces and swarf)
Amount of water [mL] 20
Temperature (H2O) [°C] 21.1
Time [s] Amount of emitted gas [mL] Time [s] Amount of emitted gas [mL]
40 200 134 1300
75 300 144 1400
90 400 157 1500
95 500 169 1600
100 600 186 1700
103 700 200 1800
106 800 223 1900
110 900 248 2000
115 1000 390 >2000
120 1100 930 >2000
126 1200 -- --

As Table 1 indicates, the whole test item reacted with water within 930 s. The highest gas evolution rates were observed between 103 and 106 s of about 200 L/kg/min (12,000 L/kg/h).

Table 2:   Results of step 4 (Test 2)

Amount of test item [g]

 

Test 2

5.10 (three nuggets)

Amount of water [mL]

20

Temperature (H2O) [°C]

21.1

Time [s]

Amount of emitted gas [mL]

Time [s]

Amount of emitted gas [mL]

690

200

2228

600

780

240

2430

640

830

260

2715

700

925

300

2940

740

1085

340

3300

800

1305

400

3600

840

1485

440

8100

1440

1740

500

10800

1440

1940

540

--

 --

As Table 2 indicates, the whole test item reacted with water within 8100 s. The highest gas evolution rate was observed at 780 s of about 5.2 L/kg/min (314 L/kg/h).

Table 3:   Results of step 4 (Test 3)

Amount of test item [g]

Test 3

5.59 (one nugget)

Amount of water [mL]

20

Temperature (H2O) [°C]

20.6

Time [s]

Amount of emitted gas [mL]

Time [s]

Amount of emitted gas [mL]

760

200

3580

780

1150

260

3680

800

1350

320

3933

840

1635

400

4180

880

2088

500

6110

1080

2200

520

7635

1200

2303

540

9630

1320

2500

580

15291

1420

2607

600

16320

1440

2812

640

18730

1460

3023

680

20760

1480

3121

700

22600

1480

3343

740

24420

1500

In test 3, most of the test item reacted with water within 24420 s. The residue of the test item was left in the apparatus over the weekend. After three days the total gas volume was determined to be 1540 mL. The highest gas evolution rate was observed at 1350 s of about 3.2 L/kg/min (193 L/kg/h).

Depending on the physical form of the test item, whether it exists in small pieces and sor in bigger nuggets, different results are obtained.

The following table summarizes the highest gas evolution rates.

Gas evolution rate

 

Test 1

Test 2

Test 3

Physical form

Small pieces & swarf

3 nuggets

1 nugget

Max. gas evolution rate [L/kg/h]

12,000

314

193

Max. gas evolution rate [L/kg/min]

200.0

5.2

3.2

Interpretation of results:
Category 1 (substances or mixtures which in contact with water release flammable gases which may ignite spontaneously) based on GHS criteria
Conclusions:
The test item Strontium emitted gas in contact with water in each of the 4 steps of the test procedure. Based on the chemical reaction, it is assumed that hydrogen, an extremely flammable gas (Flam. Gas 1, H220), evolves upon contact of strontium with water.According to the results of the test for substances which in contact with water emit flammable gases (max. gas evaporation rate of 200 L/kg/min, no self-ignition of the evolved gas, gas assumed to be flammable), the test item in the tested form (i.e. swarf) meets the following classification criteria:UN Transport Regulation:The test item in the tested form (i.e. swarf) meets the classification criteria of Class 4 Division 4.3 “Substances which in contact with water emit flammable gases” according to the UN Transport Regulation.Packaging group Ishould be assigned to the test item in the tested form (i.e. swarf).GHS and EC 1272/2008 (CLP-Regulation)Annex 1: 2.12:The test item in the tested form (i.e. swarf) meets the classification criteria of a “Substance or mixture which in contact with water emit flammable gases”according to GHS and EC 1272/2008 (CLP-Regulation) Annex 1: 2.12,category 1.

Description of key information

Möller (2016) Flammability (solids) A.10: No

Möller (2016) Flammability in contact with water A.12: GHS and CLP-Regulation, Category 1 (H 260).

CRC (2016, 2018) Pyrophoric properties of solids: No

Key value for chemical safety assessment

Flammability:
substances and mixtures which in contact with water emit flammable gases

Additional information

Flammability (solids) A.10:

Strontium in its commercial form (rods) could not be ignited applying a flame as ignition source for 5 minutes, and thus, does not meet classification criteria of a flammable solid according to GHS and EC 1272/2008 (CLP Regulation) Annex 1: 2.7.

Flammability in contact with water A.12:

Strontium (rods) emitted gas in contact with water in each of the 4 steps of the test procedure. According to the results of the test for substances which in contact with water emit flammable gases (max. gas evaporation rate of 200 L/kg/min, no self-ignition of the evolved gas, gas assumed to be flammable), strontium in its commercial form (rods) meets the classification criteria of a “Substance or mixture which in contact with water emit flammable gases” according to GHS and EC 1272/2008 (CLP-Regulation) Annex 1: 2.12,category 1.

Pyrophoric properties of solids A.13:

According to Regulation (EC) No 1907/2006, Annex XI, Section 1, the study does not need to be conducted since strontium metal rods did not show any phyrophoric properties in contact with air in the flammability studies according to UN Test N.1 and N.5. Thus, it may be assumed not to be pyrophoric under the conditions given in EU-Method A.13.

In the literature (Merck, 2006), the following is stated: The finely divided metal ignites spontaneously in air. However, the particle size of strontium was not stated. The smallest commercial form of strontium are rods with the size of approximately 20 mm x 15 mm. Even at smaller size of approximately 2 mm diameter, a spontaneous ignition in air was not observed in the UN Test N.5. Thus, pyrophoric properties of strontium in its smallest commercial form can be excluded.

Justification for classification or non-classification