Division 7 INFORMATION ON THE PHYSICOCHEMICAL PROPERTIES OF THE SUBSTANCEX1

State of the substance at 20 °C and 101,3 kPa

Melting/freezing point

The study does not need to be conducted below a lower limit of - 20 °C.

Boiling point

• for gases, or

• for solids which either melt above 300 °C or decompose before boiling. In such cases the boiling point under reduced pressure may be estimated or measured, or

• for substances which decompose before boiling (e.g. auto-oxidation, rearrangement, degradation, decomposition, etc.).

Relative density

• the substance is only stable in solution in a particular solvent and the solution density is similar to that of the solvent. In such cases, an indication of whether the solution density is higher or lower than the solvent density is sufficient, or

• the substance is a gas. In this case, an estimation based on calculation shall be made from its molecular weight and the Ideal Gas Laws.

Vapour pressure

If the melting point is between 200 °C and 300 °C, a limit value based on measurement or a recognised calculation method is sufficient.

Surface tension

• based on structure, surface activity is expected or can be predicted, or

• surface activity is a desired property of the material.

If the water solubility is below 1 mg/l at 20 °C the test does not need to be conducted.

For nanoforms, in addition the testing of dissolution rate in water as well as in relevant biological and environmental media shall be considered.

• the substance is hydrolytically unstable at pH 4, 7 and 9 (half-life less than 12 hours), or

• the substance is readily oxidisable in water.

If the substance appears ‘ insoluble ’ in water, a limit test up to the detection limit of the analytical method shall be performed.

For nanoforms the potential confounding effect of dispersion shall be assessed when conducting the study.

Partition coefficient n-octanol/water

For nanoforms the potential confounding effect of dispersion in octanol and water shall be assessed when conducting the study.

For nanoforms, whether of inorganic or organic substances, for which the partition coefficient n-octanol/water is not applicable the study of dispersion stability shall be considered instead.

Flash-point

• the substance is inorganic, or

• the substance only contains volatile organic components with flash-points above 100 °C for aqueous solutions, or

• the estimated flash-point is above 200 °C, or

• the flash-point can be accurately predicted by interpolation from existing characterised materials.

Flammability

• if the substance is a solid which possesses explosive or pyrophoric properties. These properties should always be considered before considering flammability, or

• for gases, if the concentration of the flammable gas in a mixture with inert gases is so low that, when mixed with air, the concentration is all time below the lower limit, or

• for substances which spontaneously ignite when in contact with air.

Explosive properties

• there are no chemical groups associated with explosive properties present in the molecule, or

• the substance contains chemical groups associated with explosive properties which include oxygen and the calculated oxygen balance is less than -200, or

• the organic substance or a homogenous mixture of organic substances contains chemical groups associated with explosive properties, but the exothermic decomposition energy is less than 500 J/g and the onset of exothermic decomposition is below 500 °C, or

• for mixtures of inorganic oxidising substances (UN Division 5.1) with organic materials, the concentration of the inorganic oxidising substance is:

  • less than 15 %, by mass, if assigned to UN Packaging Group I (high hazard) or II (medium hazard),

  • less than 30 %, by mass, if assigned to UN Packaging Group III (low hazard).

Self-ignition temperature

• if the substance is explosive or ignites spontaneously with air at room temperature, or

• for liquids non flammable in air, e.g. no flash point up to 200 °C, or

• for gases having no flammable range, or

• for solids, if the substance has a melting point ≤ 160 °C, or if preliminary results exclude self-heating of the substance up to 400 °C.

Oxidising properties

• the substance is explosive, or

• the substance is highly flammable, or

• the substance is an organic peroxide, or

• the substance is incapable of reacting exothermically with combustible materials, for example on the basis of the chemical structure (e.g. organic substances not containing oxygen or halogen atoms and these elements are not chemically bonded to nitrogen or oxygen, or inorganic substances not containing oxygen or halogen atoms).

The full test does not need to be conducted for solids if the preliminary test clearly indicates that the test substance has oxidising properties.

Note that as there is no test method to determine the oxidising properties of gaseous mixtures, the evaluation of these properties must be realised by an estimation method based on the comparison of the oxidising potential of gases in a mixture with that of the oxidising potential of oxygen in air.

Granulometry

The study does not need to be conducted if the substance is marketed or used in a non solid or granular form.

For nanoforms

The study does not need to be conducted if exposure to granular form of the substance during its life-cycle can be excluded.