一時的放出(fugitive emissions)を防止する

Fugitive emissions in the United States have been estimated to account for upwards of 300,000 metric tonnes of industrial waste per year, making them responsible for one-third of the total organic compounds released by chemical and petrochemical plants.What's more, valves alone account for 50% of the loss in pipes and fittings. This situation is mirrored in Europe, and is likely much worse in other parts of the world where environmental standards and levels of policing are less stringent. Environmental devastation aside, petrochemical resources are becoming ever more valuable, and plants can no longer afford to operate wastefully. In addition to the visible cost of emissions, invisible costs include labor and material needed to repair leaks, wasted energy, low plant efficiency, environmental clean up and potential fines, loss of market share due to poor public perception, and, increasingly, claims due to personal injury. Industries worldwide are facing enormous pressure to establish programs that will help minimize potential harm to the environment. On the vanguard of industry regulations are two major standards, ISO15848-1 and API622, which were released in 2005 and 2006 respectively.The ISO15848-1 standard classifies valves into three tightness classes (A, B, C), with class A valves having the lowest leak rate.The API622 standard, on the other hand, classifies the packing arrangements used in the valve.