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, as the case may be.[1] It is named after the corresponding geometric concept due to its shape.

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

References

edit
  1. ^ "Fire Stop Technologies". firestopstl.com. Retrieved 2024-01-15.
edit

External examples of the use of the term.