other conduits. Firestops are also used to fill joint gaps that occur between walls, between a ceiling and the head-of-wall joints.
So-called head-of-wall joints pose a number of challenges for the fireproofing industry. Walls are increasingly being made of gypsum wallboard affixed to a framework of metal studs capped by a horizontally extending track. Ceilings are increasingly being made by pouring concrete onto fluted steel. Although the distance between the horizontally extending track at the top of the wall is often fixed in relationship to the ceiling, the gypsum wallboards are subject to expansion and contraction due to motion of other building components, ground settling, or other causes.
In order to contain the spread of smoke and fire, a fire resistant material such as, for example, mineral wool is oftenthe header track, on the legs (hereinafter also referred to as a flange) of the header track or alternatively wraps around a corner of the header track, extending both along a portion of a web of the header track and a flange of the header track. The intumescent material advantageously is held in place between the web of the header track and the floor or ceiling above the wall. When exposed to a sufficient temperature, the intumescent material expands to fill gaps at the head-of-wall. The portion of the intumescent trapped between the header track and the floor or ceiling ensures that the intumescent stays in place as it expands and does not become dislodged as a result of the expansion.
With the use of such fire-resistant material, the