TY - JOUR A1 - Binder, Christian A1 - Brock, Thomas A1 - Hesse, Olaf A1 - Lehné, Siegfried A1 - Kasch, Thomas T1 - Ignition sensitivity of nonmetallic materials in oxygen-enriched air (NITROX): a never ending story in SCUBA diving? JF - Journal of ASTM International N2 - Self-contained underwater breathing apparatus (SCUBA) divers use different mixtures of nitrogen and oxygen as breathing gas. The so-called NITROX mixture often contains more oxygen than is contained in air and may increase the fire hazard in diving equipment. The SCUBA diving community, however, still differentiates between NITROX mixtures that contain more than 40 % oxygen or less. They consider a mixture with up to 40 % oxygen often as regular air. In filling operations of SCUBA cylinders, gas flows from high pressure to low pressure. Because of compressive heating, a sudden temperature rise in the gas occurs and nonmetallic materials, e.g., seals may ignite. BAM has used the pneumatic impact test to investigate the ignition sensitivity of ethylene propylene diene monomer (EPDM), fluorelastomer (FPM), polytetrafluorethylene (PTFE), polyetheretherketone (PEEK), and nylon (PA 6.6) to gaseous impacts in synthetic air, in various NITROX mixtures, and in pure oxygen. The test results clearly show that for nonmetallic materials, the maximum pressure of nonreaction in NITROX mixtures decreases at a content of 29 % oxygen in comparison to those in air. In addition, autoignition temperatures of the nonmetallic materials were also determined. The findings of this investigation support very well the results of other publications on oxygen enrichment. As a consequence of this study, in SCUBA diving, the same safety requirements for NITROX mixtures with more than 21 % oxygen should be applied as for pure oxygen in the industry. KW - NITROX KW - SCUBA diving KW - Filling process KW - Pneumatic impact KW - Autoignition temperature KW - Flammability KW - Nonmetallic materials KW - Oxygen mixtures KW - Fire hazard KW - Oxygen enrichment PY - 2009 DO - https://doi.org/10.1520/JAI102262 SN - 1546-962X VL - 6 IS - 8 SP - 1 EP - 7 PB - American Society for Testing and Materials CY - West Conshohocken, Pa. AN - OPUS4-20741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -