Water impervious intumescent firestop collapsing conduit

DETAILED DESCRIPTION The embodiments of the invention in which an exclusive property is claimed as follows: 1.
A collapsible length of firestop conduit made of fusible material, having two ends which are coupleable to other lengths of external conduit, said firestop conduit being provided between its ends around its outer surface with a layer of intumescent material to collapse the conduit when the conduit is heated to a fusible temperature, said intumescent material being totally contained by and enclosed within a substantially water and water vapour impermeable barrier that serves to limit passage of water and water vapour into or out of the intumescent material, said impermeable barrier being in the form of an entirely encircling flexible sleeve of water and water vapour barrier film.
2.
A firestop conduit as in claim 1 where the film is a metallized polymeric plastic.
3.
A firestop conduit as in claim 1 wherein the film is polypropylene.
4.
Intumescent material for application to the exterior surface of a conduit made of fusible material, the intumescent material being in the form of a wrappable strip and being contained by and entirely within a substantially water and water vapour impermeable barrier that serves to limit the passage of water and water vapour into or out of the intumescent material, said barrier being a barrier film in the form of a flexible sleeve which wrapped and sealed around the intumescent material.
5.
An intumescent material as in claim 4 wherein the barrier film is composed of metallized polymer plastic.
6.
An intumescent material as in claim 5 wherein the polymeric plastic ts polypropylene.




Description:
FIELD OF THE INVENTION This invention relates to barriers for preventing the spread of fire through openings or penetrations in the walls and floors of buildings.
Such penetrations are used to route plumbing and electrical wiring.
More particularly, this invention relates to a means for protecting intumescent material from infiltration of water vapor for fitting such penetrating passages that will seal-off the passage in the event of a fire