Tungsten

Auto flammability

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

relative self-ignition temperature (solids)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

NA to: 2007-06-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Remarks:

Well documented study conducted according to methodology specified in UN document ST/SG/AC.10/1/Rev.9, Recommendations of the Transport of Dangerous Goods, UN, New York and Geneva, 1995.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: United States 49 CFR 173.125 & UN ST/SG/AC.10/1 (test method N4)

GLP compliance:

not specified

Key result

Relative self-ignition temperature:

>= 100 °C

Test Cube Size, mm	Test Temp., ° C	Did sample Temp. Exceed Test Temp. + 60 ° C?	Time to reach 60 °C above oven temp.	Remarks
100	140	Yes	57 minutes	Material ignited
25	140	No	N/A	Material did not appear visibly changed
100	120	Yes	67 minutes	Material ignited
100	100	Yes	79 minutes	Material ignited

Sample is a self-heating substance of Division 4.2 Packaging group III

Conclusions:

The substance at the particle size tested (0.6-0.9 um), classifies as a Self-heating, Category 2 substance under CLP.

Reference 2

Endpoint:

relative self-ignition temperature (solids)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Data from peer-reviewed handbook or collection of data.

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

Data in this peer-reviewed publication were taken from many sources, including both compilations and primary literature. Where conflicts were found, the value deemed most reliable was chosen for inclusion in the handbook. Reference sources were not provided for this parameter, nor was the experimental method.

GLP compliance:

not specified

Key result

Relative self-ignition temperature:

ca. 310 °C

Conclusions:

A minimal ignition temperature of tungsten powder deposits (self-ignition temperature) is 310 °C.

Description of key information

The self-ignition temperature for tungsten metal was reported to be 310 °C (particle size not reported). Also, tungsten metal was tested for self-heating and, at the particle size tested (0.6-0.9 um), classifies as a Self-heating, Category 2 substance under CLP.

Key value for chemical safety assessment

Autoflammability / Self-ignition temperature at 101 325 Pa:

310 °C

Additional information

Results from a test conducted according to UN test method N4 resulted in ignition of the 100 mm cubes at 140, 120, and 100 °C. However no ignition was observed for the 25 mm cube at 140 °C.