Report of tests carried out on Viton O-ring seals to assess suitability for operation over the temperature range {minus}40 C to +220 C when used in Package Design 2863B

To satisfy the requirements of US Regulatory bodies the O-ring seals in the containment vessels of Package Design 2863B have to be shown to operate satisfactorily (i.e. remain leaktight) at the extremes of temperature that they are expected to experience during both normal and hypothetical accident conditions of transport. For Package Design 2863B this effectively means that the seals must remain leaktight over the temperature range {minus}40 C to + 220 C, but to ensure that an adequate safety margin exists the seals should preferably remain leaktight over the range {minus}50 C to +250 C. This test report describes the procedures and results of tests carried out on Viton seals over the temperature range {minus}50 C to +250 C. The variability of the results at low temperature, by both pressure drop and helium leakage testing, would indicate that the particular formulation of Viton tested cannot be used to provide a reliable leaktight seal at {minus}40 C. Although the results of the pressure drop tests at high temperature were satisfactory, insufficient testing has been carried out using helium leakage testing to draw a firm conclusion about the high temperature performance of the material tested