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Figure 2.1 from Development of local exhaust ventilation (LEV) system performance test method and guideline for sustainable maintenance | Semantic Scholar
![ANSI/ASSP Z9.2-2018: Fundamentals Governing the Design and Operation of Local Exhaust Ventilation (LEV) Systems - ANSI Blog ANSI/ASSP Z9.2-2018: Fundamentals Governing the Design and Operation of Local Exhaust Ventilation (LEV) Systems - ANSI Blog](https://blog.ansi.org/wp-content/uploads/2018/08/Large-Ducting-Pipes-in-Factory.jpg)
ANSI/ASSP Z9.2-2018: Fundamentals Governing the Design and Operation of Local Exhaust Ventilation (LEV) Systems - ANSI Blog
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