Fire Prevention & Protection, Firefighter Training, Truck Company

Reading A Building: More Building Styles

By John W. Mittendorf

Having covered the six basic types of roofs, it is time to continue with other building size-up considerations including this week’s topic: the “style” of a building. For size-up purposes, there are 12 basic styles of buildings. However, the number of building styles is not as important as what you are thinking about when confronted by a particular building style.

Modular Dwellings
These structures are commonly recognized by the following characteristics:

  • Do not fall into the category of “center hallway” or “garden apartment”.
  • Normally are two stories.
  • Can be conventional construction, but are normally lightweight construction.
  • Each “module” normally consists of two, four, and sometimes more, separate occupancies. Often, the modules are grouped into clusters in a particular development.
  • Each occupancy can be a single story, or two story.
  • There are no hallways, and each occupancy has its own entrance doorway.

The main points of consideration follow.

Common attics
Common attics are a standard in these structures unless a division wall is present. However, even if a division wall is present, consider it “violated” (cable, electrical, plumbing, etc) until proven secure.

If this type of structure has been built in the last 20 years or so, it is likely lightweight construction, even if it appears to have masonry walls.

Access is relatively easy, as first-floor occupancies are accessed by an entrance door on the first floor, and second floor occupancies are accessed by stairs to a doorway or a landing that serves two adjacent occupancies. The point is: what is your secondary means of access/egress. If you planned ahead, it has to be some type of ladder (portable or aerial device).

Walls are walls, right? Wrong! For this discussion, there are three basic types of walls as follows:

  • Division walls go from the floor, through a roof, and should extend above a roof at least 18″. These walls provide a separation between occupancies, attic spaces, etc.
  • Partition walls go from the floor to a ceiling only, resulting in common attics. These walls are common between rooms and occupancies (i.e, garden apartments, modular occupancies).
  • Offset walls are similar to partition walls as they are also used to separate rooms, occupancies, etc. However, the big difference is found in the studs in the wall. They are offset to provide enhanced insulation and sound deadening properties over partition walls. The potential problem is the offset studs will allow the extension of fire in a horizontal and vertical plane (past the upper and lower plates, as they are normally several inches apart). These walls are common in newer modular occupancies.

Center Hallway Occupancies
Center hallway occupancies can be easily found in commercial or residential configurations in virtually any municipality. The main points of consideration follow.

The age of the building is a good indicator of conventional or lightweight construction. Again, if constructed during the last 20 years, it is likely lightweight construction. If you think it is lightweight and it turns out to be conventional, that’s in your favor. However, if you think it is conventional and it turns out to be lightweight, that is not in your favor.

Common Attics
A standard unless equipped with division wall(s).

Be careful with this one. Older, more expensive, more exclusive center hallway motels and hotels are configured so the upper floors can be accessed by stairs and/or elevator(s) in the lobby area. However, the newer budget motels/hotels (i.e., Holiday Inn Express, etc) are configured so the upper floors are only accessed from the lobby area by an elevator or the stairs in the ends of the building. If suppression personnel want to access upper floors with hose lines, they must use the stairs at the ends of the building.

The hallways run down the middle of the building with occupancies or units on either side of the hallways. This configuration allows the most units compared to garden occupancies. However, during a fire, these hallways become a channel for fire, heat, and smoke.

John W. Mittendorf joined the Los Angeles City (CA) Fire Department (LAFD) in 1963, rising to the rank of captain II, task force commander. In 1981, he was promoted to battalion chief and in the year following became the commander of the In-Service Training Section. In 1993, he retired from LAFD after 30 years of service. Mittendorf has been a member of the National Fire Protection Research Foundation on Engineered Lightweight Construction Technical Advisory Committee. He has provided training programs for the National Fire Academy in Emmitsburg, Maryland; the University of California at Los Angeles; and the British Fire Academy at Morton-in-Marsh, England. He is a member of the editorial advisory board of Fire Engineering and author of the books Truck Company Operations (Fire Engineering, 1998) and Facing the Promotional Interview (Fire Engineering, 2003).