End-of-Service Life Indicator (ESLI)

描述（由申请人提供）：工业工人必须能够在存在化学危害的环境中工作。因此，他们需要得到保护，免受工作场所使用的危险化学品的危害。特别相关的是在工人暴露于化学蒸汽/气体的环境中使用呼吸防护。在大多数情况下，呼吸防护包括呼吸器面罩，该面罩配备有称为滤芯的可更换滤床。对于这些类型的呼吸器面罩，一旦吸附盒的化学品吸附能力用完，过期的吸附盒可以简单地扔掉，并用新的未使用的吸附盒替换。不幸的是，没有可靠的方法来确定滤芯何时过期，因此佩戴者经常在滤芯饱和之后但在更换滤芯之前暴露于蒸汽。OSHA呼吸器标准 滤筒的使用要求雇主提供严格的更换时间表或使用国家职业安全与健康研究所（NIOSH）认证的使用寿命终止指示器（ESLI）来确定何时需要更换呼吸器滤筒。由于没有可靠的、经过认证的商用ESLI，雇主依赖于呼吸器更换时间表。然而，这些时间表通常是不准确和不可靠的，因为用于计算盒的寿命的输入参数很少被准确地知道。因此，面罩的佩戴者通常不遵循更换时间表，并且在更换呼吸器滤筒之前经常暴露于化学蒸气。此外，劳工统计局和NIOSH调查显示，大约20 - 30%的工人决定自己的呼吸器更换时间表，这违反了OSHA法规。NIOSH批准的有效ESLI技术可以警告使用者即将发生的污染物泄漏，这将提供一种明确的方法来安全地确定何时应该更换呼吸器滤筒。然而，迄今为止，还没有用于呼吸器滤筒的商业ESLI技术，其响应于常见工业环境中普遍存在的污染物类型。如果这种技术在呼吸器滤筒中可用，ESLI不仅可以防止因偶然过度暴露于蒸汽而对工人造成的伤害，而且对雇主具有吸引力，因为它可以消除因保守的更换计划而导致的不必要的更换部分使用的滤筒而产生的额外费用。总之，有效的ESLI技术将提高美国每年超过1200万呼吸器滤筒使用者的安全性，它会被采用，因为它节省了资金（一个有效但昂贵的系统对提高安全性几乎没有帮助，因为很少有公司会使用它）。在第一阶段项目中，TDA开发并展示了一种比色ESLI，它会根据有机蒸汽、酸性气体和碱性气体的变化而改变颜色。在第二阶段的建议中，TDA建议进一步开发使用寿命终止指示器（ESLI），并在我们合作者的帮助下将其纳入呼吸器滤芯原型中。

DESCRIPTION (provided by applicant): Industrial workers must be able to function in environments where chemical hazards are present. Thus, they need protection against hazardous chemicals used in the workplace. Particularly relevant is the use of respiratory protection for environments where workers are exposed to chemical vapors/gases. In most cases, respiratory protection consists of a respirator face mask that is equipped with replaceable filter beds known as cartridges. For these types of respirator masks, once a cartridge's capacity for adsorbing chemicals is used up, the expired cartridge can simply be thrown away and replaced with a fresh, unused cartridge. Unfortunately, there is no reliable way to determine when the filter cartridge has expired, thus the wearer is often exposed to the vapors after the cartridge is saturated, but before it is replaced. An OSHA standard for respirator cartridge use requires that employers provide either a rigorous change-out schedule or use a National Institute of Occupational Safety and Health (NIOSH)-certified end-of-service-life indicator (ESLI) to determine when a respirator cartridge needs to be replaced. Because no reliable, certified commercially available ESLI has been developed, employers rely on respirator change-out schedules. These schedules, however, are often inaccurate and unreliable because the input parameters used to calculate the lifetime of the cartridges are rarely accurately known. As a result, wearers of the mask often do not follow the change-out schedules and are frequently exposed to chemical vapors prior to changing respirator cartridges. Further, the Bureau of Labor Statistics and NIOSH surveys show that some 20- 30% of all the workers determine their own respirator change-out schedules, which is against OSHA regulations. An effective, NIOSH-approved ESLI technology that warns the user of impending contaminant breakthrough would provide an unambiguous means of safely determining when a respirator cartridge should be replaced. To date, however, there is no commercial ESLI technology for respirator cartridges that responds to the types of contaminants that are prevalent in common industrial environments. Should this technology be available in respirator cartridges, not only would an ESLI prevent the harm to workers that is caused by incidental overexposure to vapors, but it would be attractive to employers because it would eliminate the added expenses incurred from unnecessary replacement of partially used cartridges resulting from conservative change-out schedules. In summary, an effective ESLI technology would improve the safety of the more than 12 million annual respirator cartridge users in the U.S., and it would be adopted because it saved money (an effective but expensive system would do little to improve safety because few companies would use it). In the Phase I project, TDA has developed and demonstrated a colorimetric ESLI that changes color in response to organic vapors, acid gases and basic gases. In the Phase II proposal, TDA proposes to further develop the end of service life indicator (ESLI) and incorporate it into prototype respirator cartridges with the help of our collaborators.