STAIRS
RANDOM THOUGHTS
One of the most used, abused, and overlooked operations in our job concerns our use of stairs at fire buildings, both inside the structure (interior stairs) and outside the structure (fire escapes and “smoke-proof” towers. Each installation presents its own set of problems. Each staircase may have different exit points on the floors it serves. Some stairs may withstand intense heat, and others may serve as a flimsy “fuse” for fire and its toxic byproducts to extend from floor to floor. Some may withstand a great deal of punishment, while others may fail after moments of fire exposure. Some are wide, while others are too narrow. Some may have enough room to stretch more than one handline, while others guarantee that after the second line is stretched one of the lines will get in trouble. Some require only 10 feet of hose per story, while others require one length or more per story.
Commonalities. All stairs sharesome common characteristics. All legal stairs have a maximum height that a single, vertical step riser can be bcforc it must support a horizontal step tread that has a minimum depth. Depending on the occupancy (use group), stairs must support a minimum load in pounds per square foot; factories at 90 pounds and multipledwellings at 80 pounds arc just two examples of how some building codes can assist with this problem. Regardless of the* type* of stairs, firefighters should adopt some universal habits and techniques while using stairs.
Always ensure that your weight is placed over the riser and not on the tread. Treads fail more easily than risers do (look at your abandoned buildings).
When climbing stairs, always use theside affixed to the wall or the side of the fire escape closest to the building. In the case of interior stairs, it is the strongest part of the stair assembly. If you remember Physics 101, you will recall that stress-weight is multiplied as it is applied farther away from the support point. Just look at multiple floor buildings under demolition. Once the inside bearing wall is exposed, the stair pattern and the step support members are still in place.
If the firefighters are at the banister side of the stair, the stair is forced to support a tremendous additional weight. If the stair assembly is weakened (use any part of your experienced imagination here), you most assuredly will assist in the collapse of the assembly by unnecessarily increasing the physical load it must bear.
Second, the banister and its support assemblies on the open side of the stair are decorative and the weakest part of the assembly. Sudden movement of the stair (pending collapse) or of the firefighter (trips or falls) can cause this support to fail with the resultant two-or-more-story fall of the firefighter(s).
Private dwellings. Oneor twofamily buildings (or those converted to multiple dwellings) have the weakest stair assemblies of all. The open interior stair probably is the greatest threat to the life safety of occupants of these buildings during fire. They are the “hottest” and weakest to use for access to the floor above the fire. They also are the narrowest. Even if you can get to the floor above the fire by using them, you will be unable to gain an area of refuge should the fire overwhelm the control forces belowyou.
W hat makes them so weak and such a threat to safety? First, they usually are made of the cheapest wood possible. Today’s trend of wall-to-wall carpet covers stair assemblies made of one-inch fir or other “scrap.” Most that serve the second floor are over the cellar stairs and therefore open and unprotected from direct fire attack below. Your barrier from fire below is less than one inch of weak wood!
However, don’t let stair fire or a fire-weakened staircase stop you. Even though a stair fire is awesome in appearance, it easily is controlled with a quick dash of an aggressive handline. Then be prepared to throw the proper size portable ladder on top of the strongest parts—the risers, from the base to the top of the staircase. Many of today’s private dwellings have converted attic spaces; in that case, you’ll be using narrow, steep, substandard assemblies.
Older dwellings—of balloon construction and called “Victorians” and “Queen Annes” —are common in the Northeast and older sections of the West (San Francisco, for instance). These “rich family” homes had servant quarters usually on the uppermost floors. “Servant stairs” are located in the rear and usually connect only the kitchen area with the third floor. These stairs provide no access to the family areas of the second floor. It is important to know of their presence, location, and description if you are fighting fire in these surprise tinderboxes. Good for additional line placement for fire on upper floors; bad for spread and access problems for fires on lower floors.
Out of space again — and so much to talk about. We’ll continue next time. In the meantime, let me know what you think about these “thoughts” and the column in general. I w ould love to hear from you!«