ISO 3405 Petroleum products - Determination of distillation characteristics at atmospheric pressure
WARNING - The use of this International Standard may involve hazardous materials, operations and equipment. This International Standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this International Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.

1 Scope
This International Standard specifies a laboratory method for the determination of the distillation characteristics of light and middle distillates derived from petroleum with initial boiling points above 0 °C and end-points below approximately 400 °C, utilizing either manual or automated equipment, with the manual procedure being the referee method in cases of dispute, unless otherwise agreed.

NOTE The method is applicable to petroleum products incorporating a minor constitution of components from non-petroleum origin, but the precision data may not apply in all cases.

The distillation (volatility) characteristics of hydrocarbons have an important effect on their safety and performance, especially in the case of fuels and solvents. The boiling range gives important information on composition and behaviour during storage and use, and the rate of evaporation is an important factor in the application of many solvents. Limiting values to specified distillation characteristics are applied to most distillate petroleum product specifications in order to control end-use performance and to regulate the formation of vapours which may form explosive mixtures with air, or otherwise escape into the atmosphere as emissions (VOC).

2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.
ISO 918:1983, Volatile organic liquids for industrial use - Determination of distillation characteristics
ISO 3170:1988, Petroleum liquids - Manual sampling
ISO 3171:1988, Petroleum liquids - Automatic pipeline sampling
ISO 4259:1992, Petroleum products - Determination and application of precision data in relation to methods of test
ISO 4788:1980, Laboratory glassware - Graduated measuring cylinders

3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1 decomposition point
thermometer reading (corrected) which coincides with the first indications of thermal decomposition of the liquid in the flask.

NOTE Characteristic indications of thermal decomposition are an evolution of fumes and erratic thermometer readings which usually show a decided decrease after any attempt has been made to adjust the heat.

3.2 dry point
thermometer reading (corrected) that is observed at the instant the last drop of liquid evaporates from the lowest point in the flask; any drops or film of liquid on the side of the flask or on the thermometer are disregarded.

NOTE The end-point (final boiling point), rather than the dry point is intended for general use. The dry point can be reported in connection with special purpose naphthas, such as those used in the paint industry. Also, it is substituted for the end-point (final boiling point) whenever the sample is of such a nature that the precision of the end-point cannot consistently meet the requirements given in clause 12.

3.3 end-point/final boiling point
maximum thermometer reading (corrected) obtained during the test.

NOTE This usually occurs after evaporation of all liquid from the bottom of the flask.

3.4 initial boiling point
thermometer reading (corrected) that is observed at the instant that the first drop of condensate falls from the lower end of the condenser tube.

3.5 percent evaporated
sum of the percent recovered and the percent loss.

3.6 percent loss
100 minus the total recovery.

NOTE Sometimes called "front-end loss"; this is the amount of uncondensed material lost in the initial stages of the distillation.

3.7 corrected loss
percent loss corrected for barometric pressure.

3.8 percent recovered
volume of condensate observed in the receiving graduated cylinder at any point in the distillation, expressed as a percentage of the charge volume, in connection with a simultaneous temperature reading.

3.9 percent recovery
maximum percent recovered, as observed in accordance with 9.10.

3.10 percent residue
volume of residue measured in accordance with 9.11, and expressed as a percentage of the charge volume.

3.11 percent total recovery
combined percent recovery and residue in the flask, as determined in accordance with 10.1.

3.12 thermometer reading
temperature recorded by the sensor of the saturated vapour measured in the neck of the flask below the vapour tube, under the specified conditions of this test.

3.13 temperature reading
thermometer or temperature-measurement device reading (3.12) which is corrected to 101.3 kPa barometric pressure.

3.14 emergent stem effect
offset in temperature reading caused by the use of a total immersion mercury-in-glass thermometer in the partial immersion mode.

NOTE The emergent part of the mercury column is at a lower temperature than the immersed portion, resulting in a lower temperature reading than that obtained when the thermometer was completely immersed for calibration.

3.15 temperature lag
offset in temperature reading between a mercury-in-glass thermometer and an electronic temperature-measurement device, caused by the different response time of the systems involved.

4 Principle
The sample is assigned into one of five groups based on its composition and expected volatility characteristics, each group defining the apparatus arrangement, condenser temperature and operational variables. A 100 ml test portion is distilled under the specified conditions appropriate to the group into which the sample falls, and systematic observations of thermometer readings and volumes of condensate recovered are made. The volume of the residue in the flask is measured, and the loss on distillation recorded. The thermometer readings are corrected for barometric pressure, and the data are then used for calculations appropriate to the nature of the sample and the specification requirements.