Article · Wikipedia archive · Last revised Jun 12, 2026

Annulus (firestop)

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.

Last revised
Jun 12, 2026
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Sprinkler branch pipe through-penetration with plastic sleeve - missing firestop in concrete fire separation. The space between the sleeve and the pipe is the annulus or annular space source ↗

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.1 It is named after the corresponding geometric concept due to its shape.

References

References

  1. "Fire Stop Technologies". firestopstl.com. Retrieved 2024-01-15.
External links

External examples of the use of the term.