The annulus, or annular space, is the space between a penetrant and anything that surrounds it, such as the sides of an opening or a sleeve, depending on the case. It is named after the corresponding geometric concept due to its shape.
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External links
External examples of the use of the term.
- Annulus, a term used within a firestop patent
- Annulus, as used in UL System C-AJ-1557 Firestop System, Configuration A
