Carbon black

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:

November to December 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

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

Qualifier:

according to guideline

Guideline:

other: prEN 15188 “Determination of the spontaneous ignition behaviour of dust accumulations” and accroding to the method described by Beever (Beever, P. F., Spontaneous Combustion - Isothermal Test Methods, Building Research Establishment Information Paper IP23

Principles of method if other than guideline:

The material under test is placed in cubical wire mesh baskets of different sizes (side 50mm, 75 mm and 125mm). The baskets are filled with the sample and levelled with a straight edge. The material is not compacted into the cube. The filled cube is then suspended in an oven pre-heated and thereafter maintained at a known temperature to within ± 2°C. The centre and surface temperatures of the sample are monitored using 0.5 mm, stainless steel sheathed, chromel/alumel thermocouples. These are connected to a datalogger so that the self-heating process can be observed and recorded.

GLP compliance:

not specified

Key result

Relative self-ignition temperature:

183 °C

Remarks on result:

other: critical ignition temperature for a 27 m3 transport cube

Conclusions:

Thermal carbon black, stored in the volumes and at the temperatures described in the report, poses a low risk of self-heating to customers using the material. However, if the manufacture of thermal carbon black involves high temperature it is recommended that a review is made of the storage and handling in light of the results found in this report. The critical ignition temperature was determined as 183 °C for a 27 m3 transport cube.

Executive summary:

Data from the isothermal basket tests show the material to be mildly susceptible to self-ignition. Taking the largest stockpile identified of 117m3, a dc value of 2.44 is determined equating to a critical temperature in that geometry of 166°C with a calculated time to ignition of 578 days. That is to say, the material in the centre of the pile would need to be at the critical temperature stated for exothermic reactions to runaway, eventually leading to spontaneous combustion in approximately 1½ years. Since this temperature is far in excess of any storage temperatures likely to be experienced in practice, thermal carbon black, stored in the volumes and at the temperatures described in the report, poses a low risk of self-heating to customers using the material. However, if the manufacture of thermal carbon black involves high temperature it is recommended that a review is made of the storage and handling in light of the results found in this report. The critical ignition temperature was determined as 183 °C for a 27 m3 transport cube.

Reference 2

Endpoint:

relative self-ignition temperature (solids)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

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

Qualifier:

according to guideline

Guideline:

other: ASTM E 1491 (Standard Method for Minimum Autoignition Temperature of Dust Clouds)

GLP compliance:

not specified

Key result

Relative self-ignition temperature:

> 800 °C

Remarks on result:

no self ignition observed under the test conditions

Remarks:

The dust was not ignitable up to 800 deg C (highest tested temperature) over a concentration range of 200 to 1000 g / m3

Conclusions:

The dust was not ignitable up to 800 deg C (highest tested temperature) over a concentration range of 200 to 1000 g / m3

Executive summary:

Dust Cloud, Minimum Auto Ignition Temperature (MAIT), Godberg Greenwald Furnace ASTM (E1491) 800°C

Description of key information

Carbon black (solid: particulate/powder) - non nano does not readily self-heat and is not designated a dangerous substance for self-heating under the UN Recommendations on the Transport of Dangerous Goods. The auto-ignition temperature is > 140 °C (1 litre sample, 100 mm sample cube). The auto-ignition temperature is a volume-dependent parameter.

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