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Administrative data

Link to relevant study record(s)

Reference
Endpoint:
flammable solids
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
2010-07-02 to 2010-08-12
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
GLP study, conducted according to Part III, sub-section 33.2.1, of the UN-MTC method. The reliability of this study for this substance tested is a K1, but in application of read-across to a different substance, ECHA's guidance specifies that the score can be a maximum of a K2.
Justification for type of information:
1. HYPOTHESIS FOR THE CATEGORY APPROACH: The hypothesis is that properties are likely to be similar or follow a similar pattern because of the presence of a common metal ion, in this case tungstate.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES):
Source: Tungsten Carbide
Target: Fused tungsten carbide
3. CATEGORY APPROACH JUSTIFICATION: See Annex 3 in CSR
4. DATA MATRIX: See Annex 3 in CSR
Reason / purpose:
read-across: supporting information
Qualifier:
according to
Guideline:
other: Part III, sub-section 33.2.1, of the UN-MTC
Qualifier:
equivalent or similar to
Guideline:
EU Method A.10 (Flammability (Solids))
GLP compliance:
yes
Key result
Test procedure:
burning time (test type not further specified)
Remarks:
or specified in description of method (migrated information)
Burning time:
> 1 200 s
Remarks on result:
substance does not ignite and propagate combustion either by burning with flame or smouldering along 200 mm of the powder train within the 2 minutes test period
Remarks:
Since the tungsten carbide powder samples did not burn or smolder during the preliminary testing period (e.g. 5 minutes ignition plus 20 additional minutes), no further testing for flammability was required.

Approximately 95 to 150 mm length of each tungsten carbide powder sample tested that was near or in direct contact with the flame turned a light yellow color. Since the tungsten carbide powder samples did not burn or smolder during the preliminary testing period (eg 5 minutes ignition plus 20 additional minutes), no further testing of flammability was required.

Interpretation of results:
GHS criteria not met
Remarks:
Migrated information
Conclusions:
None of the three test substance samples (sizes 0.53, 0.60, and 0.84 um (FSSS) burned with a flame or smoldered in the preliminary test. Therefore, no further testing was needed, and the tungsten carbide samples were not considered to be flammable.
Executive summary:

Due to the similar chemical constituency and structure between the source substance (tungsten carbide) and the target substance (fused tungsten carbide), the physico-chemical properties would be expected to be the same or sufficiently similar such that application of this read-across is appropriate for this endpoint. For more details, refer to the attached read-across approach document.

Description of key information

Fused tungsten carbide is not expected to be flammable at any particle size based on read-across to tungsten carbide. Testing was conducted on tungsten carbide down to FSSS size 0.53 µm (nominally 0.47 µm).

Key value for chemical safety assessment

Flammability:
not classified

Additional information

Due to the similar chemical constituency and structure between the source substance (tungsten carbide) and the target substance (fused tungsten carbide), the physico-chemical properties would be expected to be the same or sufficiently similar such that application of this read-across is appropriate for this endpoint. For more details, refer to the attached read-across approach document.

Justification for classification or non-classification

None of the three test substance samples of the source substance tungsten carbide (sizes 0.53, 0.60, and 0.84 µm FSSS) burned with a flame or smoldered in the preliminary test.  Therefore, no further testing was needed, and then fused tungsten carbide (target substance) is not considered to be flammable.