Packages for liquids - Internal Pressure Test

The basic requirements for transport of dangerous gods are that a packaging shall be able to withstand certain mechanical and chemical stresses, as stated in SRVFS 2006:7. The requirements shall guarantee a reasonable level of protection for both humans and environment and is intended to create a system taking into account different types of substances and packaging. Principles for classification, packing requirements, testing procedures shall be simple and clear and guarantee that a minimum level of safety can be achieved without advanced technical equipment and expertise. No requirements concerning test temperatures are given in the regulations but in the standard SS-EN-ISO 16104:2003 “Packaging – Transport packaging for dangerous goods – Test Methods” the internal hydraulic pressure test, for plastics drums, jerricans and composite packaging, shall be performed at a temperature of +12 °C, otherwise the internal test pressure shall be adjusted with a pressurization factor corresponding to the temperatures used in the test. At temperatures below +12 +/- 2 °C the test pressure is increased and if the temperature is higher the pressure is lowered. Correction factors exist from +2 °C to +20 °C, and for all temperatures above +20 °C the correction factor is the same as for +20 °C. Neither ADR, IMDG-code, ICAO-TI or the UN-recommendations recommend any test temperature. The aim with this project was to perform internal pressure test at different water temperatures. Three jerricans of each type were tested at the following temperatures: +3, +20, +40 and +55 °C.As can be seen in the test results the burst pressure decreases substantially with rising temperature. For jerrican A the burst pressure is reduced from 234 kPa at +3 °C to 175 kPa at +20 °C, 151 kPa at 40 °C and 114 kPa at +55 °C. At +55 °C the burst pressure is reduced to less than half what it was at +3 °C. Jerrican B is also reduced from 545 kPA at +3 °C to 226 kPa at +55 °C while jerrican C is only reduced from 185 kPa to 136 kPa in the same temperature interval. The gradient of the correction factor in table 3 in EN ISO 16104:2003 correspond very well with gradient of the tested jerricans in the temperature span between +2 °C and +20 °C.All jerricans were made of PE. The pressure/temperature curves show a linear gradient but indicates that the gradient can differ between different materials. Jerrican A and B are produced by the same manufacturer in the same material and show corresponding behaviour, also corresponding to the correction factors in the standard. Jerrican C is produced by another manufacturer and does not show such significant reduction of burst pressure at higher temperatures