Tue, 29 Mar 2011|
Paul Dansbach takes a look at a balloon frame home that is being renovated with a platform frame addition being built onto it.
[pause] [music] [background noises]. [SOUND] Hello, my name is Paul Dansbach, and welcome to Fire Engineering's Training Minutes. In this section of training minutes, we're gonna look at a wood frame building. This building is currently under renovation. The original building is a bloom frame construction. The addition being added to the rear of the structure is platform frame. We will have the opportunity to view and understand the fire spread potential of platform frame versus balloon frame wood frame construction. Balloon frame construction is construction in which the exterior walls and interior walls run vertically from the basement. Past the first floor, to the second floor, and potentially to the attic. With on fire stop voids. A stud bay is created by the space between two wall studs, the exterior sheathing, and what would be the back of the interior finish. That space is open to the basement in balloon frame construction. Any fire in the basement will extend vertically. Through the wall, up past the leisure board, into the second floor, and potentially into the attic. We also have the opportunity for horizontal fire extension. There is no fire stopping between the stud bay and the joist bay. The joist bay is the space created between the 2 floor joists. There is an opening between the end of the joist bay. Into the vertical stud bay. We're looking at an interior partition. It's an interior baring partition. The partition is balloon frame. It's opened down to the basement therefore any fire that occurs in the basement will extend through this combustible void space, in this stud bay, the space between the studs. Vertically it will run up into the space created by the floor joist. This partition does not extend beyond the first floor. So the fire extension in this bay will be limited from the basement to the first floor. However, once the first reaches the joist bay, the space created by two floor joists, the fire's going to run horizontally. In the case of this structure, the fire will run to the B wall and the D wall. It will run to those exterior walls, turn vertical again in the balloon framing, and head towards the attic. Another fire extension potential with balloon frame construction is when the fire starts on a floor of the dwelling. As a content fire. If the fire extends beyond the interior finish. For example, in this building the original construction was wood laq with plaster as the interior finish. Another interior finish could also be drywall. Should the fire get beyond the interior finish the fire will extend into the joyce bay. Again a space created. By the wood joists. The fire will run horizontally in the joists and will have the same fire exten, potential when the fire reaches the B and D walls of this building, where it will turn vertical and run to the second floor and the attic through the exterior walls of balloon frame construction. We are in the addition to the structure. The addition is being constructed of platform frame. Platform frame construction is one in which the foundation is constructed and then the first floor is constructed on top of the foundation. The first floor extends to the exterior wall of the structure. Then one story of woodframe studs is constructed on top of the floor. That construction method uses a two by four plate on top of the floor system. That two by four plate and this method of construction builds in the fire stopping. It is referred to as inherit fire stopping. As it is built into the structure as the building is constructed. The built in fire protection, that two by four plate at the bottom prevents any vertical fire extension from the basement up into this wall. Additionally as we run vertically in the wall we get to the top of the wall before our floor joist. And we see another two by four. A double two by four top plate that also eliminates the potential. For vertical fire extension, story to story, within this building. In balloon frame construction, we pointed out the possibility of fire extension when fire starts as a room and content fire, and pierces beyond the interior finish of the building, extending into the joist bay. With platform frame construction we do not have that potential. Sure the fire start is a room in content fire, get past the dry wall on the ceiling and run horizontally to the side wall in the [INAUDIBLE] the fire will not extend vertically to the second floor, as the plywood floor decking for the floor above is installed. Directly above that plywood floor decking is a two by four plate. That construction method eliminates the fire extension possibility between the joyce bay and the exterior wall or interior wall partition to the floor above. An area of concern in both platform framing and balloon frame construction is an area in where utilities are run vertically in the walls. Any vertical utility run poses a potential for vertical fire extension. Often time contractors will cut fire stopping away, will cut the platform frame plates, two by four plates. Away to run plumbing, ductwork and other associated utility lines. In our example here, a drain waste and vent line, a plumbing line, is installed. It runs from the basement, it runs vertically through the wall space, up, passes in through the second floor. This drain waste and vent line is avenue that has to be checked for vertical fire extension. That vent line, where it pierces through the roof, can be used as an indicator to determine where the vent line runs in the structure. Firefighters must aggressively check for vertical fire extension where that drain wasted vent line runs vertically through the building. Vertical fire extension is of paramount concern to firefighters. Understanding the difference between platform frame and balloon frame construction will help us determine the potential for vertical fire extinction in a wood frame building. Thank you for watching this session of Fire Engineering's Training Minutes. [MUSIC] [BLANK_AUDIO]