DEFINITIONS
Annular space: The opening
around the penetrating item.
This is essentially the gap be-
tween the penetrating item and
the surrounding base construc-
tion material of the fire-resis-
tance-rated and/or smoke-resis-
tant assembly the penetration
is breaching. This breach or
annular space affords a path for
flames, smoke or hot gasses to
spread into or through the rated
assembly. The annular space
is typically either filled with a
firestopping material or covered
by a device to protect the open-
ing. Figure 2.3 illustrates the an-
nular space.
PIPE
PENETRATION
When protecting penetrations, it
is important to understand an-
nular space limitations specified
in the tested and listed systems
published by third-party listing
organizations. Each system will
specify the required annular
space, and how the penetrant
is allowed to be installed within
the opening. Many systems will
include minimum and maximum
dimensions for annular space.
Figures 2.4 and 2.5 show exam-
ples of how annular space may
vary depending on the place-
ment of the penetration within
the opening.
FLOOR OR WALL
ANNULAR SPACE
PLAN VIEW
ANNULAR SPACE
IS THE GAP BETWEEN
THE PENETRATION
AND SURROUNDING
CONSTRUCTION
SECTION
(Fig 2.2 Annular Space)
PIPE
PENETRATION
CONCRETE
FLOOR OR WALL