EN ISO 9038 Determination of Persistent Flammability of Liquids

The standard “EN ISO 9038 Determination of persistent flammability of liquids”, which has its basis in a European standard and was later published by the International Organization for Standardization (ISO), describes a procedure used to determine whether a liquid product classified as flammable due to its flash point at temperatures up to 100 degrees will continue to burn, for example, at temperatures specified in regulations.

Many national and international regulations classify liquids as presenting a flammable hazard based on their flash points, determined by a recognized method. Some of these regulations provide exemptions if the substance cannot sustain combustion at a certain temperature.

This standard is applicable to paints (including water-based paints), varnishes, paint binders, solvents, petroleum or related products and adhesives having a flash point. It is not applicable for assessing potential fire hazards for painted surfaces. This test method is applicable for assessing the fire hazard of a product, in addition to the flash point test methods.

For the purposes of this standard, the following terms and definitions apply:

• Sustained flammability refers to the behavior of a material such that, under specified test conditions, its vapor can be ignited by an ignition source and, after ignition, sufficient flammable vapor is produced to continue burning for at least 15 seconds after the ignition source is removed.
• Flash point refers to the lowest temperature of the test section at which the application of an ignition source will cause the vapour of the test section to ignite and the flame to spread to the surface of the liquid under the specified test conditions, adjusted from 101,3 kPa to account for changes in atmospheric pressure.

When testing, a test portion of a specified volume is inserted into a test vessel held at the test temperature. After a specified time, an ignition source is applied.

In conjunction with the United Nations recommendations on the transport of hazardous substances and the globally harmonized system of classification and labeling of chemicals, as well as derived national and European Union legal regulations, temperatures of 60,5 degrees and 75,0 degrees are specified for this test.

The ability of a product to sustain combustion is assessed by whether its vapours or components ignite when exposed to an ignition source and continue to burn after the ignition source is turned off. The igniter off and test positions are shown in the figure given in the standard.

The main equipment used in these tests includes:

• Flammability tester (specifications are included in the standard annex: Annex A).
• Electric heater attached to the bottom of the test vessel to transfer heat efficiently. The heater control shall be capable of maintaining the test vessel temperature measured on the temperature measuring device and in a draft-free area to within plus/minus 100 degrees for test temperatures of at least 0,5 degrees. The flammability tester, heater and heater control unit may be comprised in an integrated device.
• Measuring device to check that the centre of the gas jet is 2,2 mm plus/minus 0,1 mm above the top of the test vessel. A calibrated metal strip is suitable.
• Temperature measuring instrument with a resolution of 0,5 degrees or better, suitable for horizontal operation, with appropriate range and dimensions. A resolution of 0,1 degrees is recommended as it simplifies verification and calibration. This instrument should have an accuracy of plus/minus 0,5 degrees. When in position, on the block, the temperature measuring instrument should be surrounded by heat transfer paste to ensure good heat transfer between the block and the measuring instrument.
• A stopwatch or other suitable timing device capable of measuring 15 seconds plus/minus 1 second, 30 seconds plus/minus 1 second, and 60 seconds plus/minus 2 seconds. The timing device may be equipped with an audible signal generator.
• Syringe or pipette capable of delivering 0,05 ml with an accuracy of plus/minus 2,00 ml.
• Ignition source and gas supply by gas jet operating on natural gas, coal gas, butane or any other gas found suitable and equipped with a suitable regulator or other means of regulating the gas flow, so that the flame width can be adjusted to 4,0 mm plus/minus 0,5 mm.
• To minimise draft, a draft shield is fitted to the back and sides of the instrument. A shield measuring 350 mm high, 480 mm wide and 240 mm deep is suitable. The shield should not be placed too close to the instrument to prevent air turbulence over the test section.
• The barometer measures absolute pressure with an accuracy of 0,5 kPa and a resolution of 0,1 kPa. Pre-corrected aneroid barometers, such as those used in weather stations and airports, are not used to give sea level readings.

Our organization has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. Among the numerous test, measurement, analysis and evaluation studies provided for businesses in various sectors, there are also testing services in accordance with the "EN ISO 9038 Determination of the persistent flammability of liquids" standard.