Flashcards in Building construction Deck (1287)
The combustibility of the interior finishes effects the behavior of fire and what several ways:
-It can contribute to the fire extension by flame spread over the surface of walls and ceilings
- It affects the rate of growth (which can lead to flashover).
- it add to the intensity of fire because that contributes fuel
- it can produce smoke and toxic gases that contribute to the live hazard
The term interior finish is:
-Generally applied to the materials used for the exposed face of the walls and ceilings of a building
-Including but not limited to fixed or movable walls and partitions, columns, and ceilings
-Commonly refers to finish on the walls and ceilings and not for coverings
Interior finishes can include such materials as:
Plaster, gypsum wallboard, wood paneling, ceiling tiles, plastic, fiber board, and other wall coverings
Term used in the international community for interior finish?
Building codes usually exclude surface treatments such as paint and wallpaper that are no thicker than?
During a fire , thin materials tend to behave in a manner similar to
The material to which they are attached because the heat is transmitted to the material beneath the surface material
If there are multiple layers of surface material, however, such as several layers of vinyl, the surface material acts as
An insulator and will contribute to the spread of fire
At one time, floor coverings were not considered to contribute significantly to the development of fires because heat naturally rises. What increased awareness of a need to regulate floor coverings?
The introduction of various deep pile floor Carpets
What are surface burning characteristics of the material?
The degree to which fire can spread over the surface of a material
The speed of flame spread over an interior finish is influenced by what factors?
-The composition of the material
– The shape of the space in which the material is installed
– Whether the finished material is applied to the ceiling or wall
Are an inexact science and cannot precisely duplicate the wide variety of real-life situations in which interior finish materials are found
Standardized fire test methods
When air is in motion, it possesses Kinetic energy. We feel this Kinetic energy as____
M=mass of a body
When the wind encounters a fixed object, it exerts a force. Wind exerts the following basic forces on a building:
Direct pressure-the impact effect the wind has on surface. This force may be reduced by streamlining the surface encountered.
Aerodynamic drag-when wind encounters an object, it's fluid nature causes it to flow around the object. This exerts a drag effect on the object.
Negative pressure-a suction effect produced on the downwind side of the building resulting in an outward pressure.
When wind exerts force on a building there are 3 secondary effects that may be produced:
Rocking effects- a back and forth effect due to variations in the velocity of the wind.
Vibration-wind passing over a surface such as a roof may cause vibration on the surface depending on the velocity of the wind and the harmonic characteristics of the surface.
Clean off effect-the tendency of wind to dislodge objects from a building.
The energy possessed by a moving object
In designing buildings to withstand the force of wind, the primary effect considered is the:
Force due to direct pressure.
*This force increases with the velocity of the wind and can be evaluated by the basic equation:
C= .00256 a numerical constant that accounts for the Air mass and simplifying assumptions of building behavior
When speaking about the effects of wind, the actual design pressure used by engineers must be adjusted to account for:
Specific features relating to the shape of the building
*In addition, designers must consider the combined effects of wind forces and localized conditions, such as closely spaced buildings in an urban area.
The force resulting from wind is particularly dangerous when it occurs against an ______
Fire personnel should also be alert for unbraced walls at:
Demolition sites and at fire damaged buildings where interior structural supports have collapsed or been destroyed.
The vibrational motion of the surface subjects buildings to forces known as _____ that can be very destructive, as history has shown
Forces developed by earthquakes. Seismic forces are the some of the most complex forces exerted on a building.
Earthquakes can occur anywhere on earth; however, major earthquakes occur most frequently in parts of the world known as:
Fault zones or zones of high probability
*Zones of high earthquake probability include the Pacific coast of the United States and Canada, Hawaii, Central Utah, and southern Illinois.
The vibrational motion produced by earthquakes can be:
The force produced in a structural member when it is twisted
Movements of relatively large amplitude resulting from a small force applied at the natural frequency of a structure
The magnitude of the forces developed within a building during an earthquake depends on several factors, including the following:
-Magnitude of the vibratory motion
-Type of foundation
-Nature of the soil under the building
-Stiffness of the structure
-Presence of damping mechanisms within the building
Building codes may require that materials with greater surface burning rates be installed
Over a non-combustible material
Why do building codes make use of the flame spread rating of materials?
To establish some control over interior finishes
The classification of interior finishes are used to restrict the materials in vertical exits and exit corridors to those with
Low flame spreads