When these services pass from one compartment to other it leaves
an opening which creates a breach in the compartment. This is
where systems like through penetration fire stop are used to restore
the fire resistance of the opening by using tested through-penetra-
tion fire stop systems for that particular opening. Through Penetra-
tions are those which pass all the way through the barrier.
In the case of only membrane penetrations, the penetration passes
through a part of the barrier but not the complete barrier. Exam-
ples – outlet boxes, junction boxes, conduits that lead to the ceiling
above from the back-box.
(Fig 3.2)