APermanent Total Enclosure (PTE) can be defined as "a permanently installed enclosure that completely surrounds a source of emissions such that all VOC emissions are captured and contained for discharge to a control device". By definition, a permanent total enclosure constructed to the Agency's specifications is presumed to preclude any fugitive emissions escaping to atmosphere.

Capture systems and PTEs may take many forms, but in essence, every capture system and PTE design must address common challenges such as regulatory requirements, safety and health considerations and operational issues. Each of these focus areas must be viewed separately as well as in conjunction with each other, since each presents a combination of interrelated and unique design challenges. The capture systems or PTE, in conjunction with high efficiency emission control devices, allow companies to successfully comply with EPA regulations*. In many applications the addition of well-designed permanent total enclosures has resulted in better process control, improved quality and reduced waste.