所有的工业工厂。具有需要工业通风和排气系统的工艺，以提供安全的工作环境，避免工业污染物，包括雾、灰尘、烟雾和气体。将防止对大多数工人产生不利影响（职业病、残疾或死亡）的安全污染水平定义为阈值限值（TLV）。TLV可以基于8小时加权平均值、最大上限值或短期偏移率。工业通风或排气系统的目的是提供始终低于TLV水平的环境（空气质量）。随着1970年《职业安全与健康法》（OSHA）的通过，工业通风系统的可靠性对工业厂房来说变得更加重要。目前需要高效设计的局部排气系统，该系统在满足安全环境水平方面具有高度的可靠性。 然而，需要一个基于准确气流理论的设计程序，并为设计工程师提供一个系统，该系统将运行并提供所需的空气质量，而不会过度过度设计排气系统。这种过度设计不仅会妨碍系统正常工作，而且额外能源的成本也是浪费。许多工业工厂的一个共同要求是焊接作业的排气通风。本文对焊接烟尘和气体的排放进行了讨论和分析。目的是分析焊接排气系统失效的方法。故障意味着焊工暴露在TLV以上的空气污染水平下。作为焊接排气系统故障分析的示例，选择了威斯康星州一家工厂的独特设计，并选择故障树图（FTD）作为焊接排气系统故障分析。 引文:德克萨斯州达拉斯阿什雷交易录第82卷第一部分

All industrial plants. have processes which require industrial ventilation and exhaust systems to provide a safe working environment from industrial contaminates, which include mists, dusts, fumes, and gases. The safe contamination level which will prevent adverse effects (occupational illness, disability or death) to most workers is defined as the threshold limit value (TLV). The TLV can be based on either 8-hr weighted average, maximum ceiling value, or a short excursion rate. The purpose of the industrial ventilation or exhaust system is to provide an environment (air quality) that is always below the TLV level.With the passage of the Occupational Safety and Health Act (OSHA) in 1970, the reliability of industrial ventilation systems has become more important to the industrial plant. The present need is for efficiently designed local exhaust systems, which will have a high degree of reliability in meeting the safe environmental levels. However, the need is for a design procedure that is based on accurate airflow theory, and will provide the design engineer with a system which will operate and provide the air quality that is required, without excessive over design of exhaust systems. This over design not only prevents the system from working properly, but the cost in extra energy is wasteful.One requirement common to many industrial plants is exhaust ventilation for welding operations. This paper is a discussion and analysis of the exhausting of welding fumes and gases. The objective is to analyze the method by which a welding exhaust system fails. Failure means that the welder is exposed to air contamination levels above the TLVs. As an example to be used for the failure analysis of the welding exhaust system, a unique design in a Wisconsin plant was chosen, and the fault tree diagram (FTD) was chosen as a analysis of the welding exhaust system failure.