Building construction
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Transcript of Building construction
Washington Twp. Fire & Rescue
Provides information on NFPA 1001, Standards for Fire Fighter Professional Qualifications
Objectives
Describe the effects of fire and suppression activities on the common building materials.
Describe items to be observed during size-up of a building.
Describe dangerous building conditions created by a fire or by actions taken while trying to extinguish a fire.
Objectives Continued
Identify indicators of building collapse.
Describe actions to take when imminent building collapse is suspected.
Describe building conditions that create additional risk in construction, renovation, and demolition.
IC's, fire officers, and firefighters must be able to identify the buildings in which they fight
fires. Fire behavior, fire travel, and the potential for structural failure are critical pieces
of information that can be gained simply by reading a building and understanding
construction characteristics for each classification or type of building.
The stability of a structure is dependent on the structural elements designed, engineered, and installed to support the total weight of the structure and its contents.
Every ounce of the structure's weight and the weight of its contents is applying pressure, and gravity is constantly trying to pull it to the ground.
Review
Type I
Know as fire-resistive construction, it maintains its structural integrity during a fire. Intended to allow occupants time to exit a building. This construction consists mainly of reinforced concrete with structural members that retard the spread of fire through the building. The primary fire hazard in this construction is the interior finishes.
Strengths
Resists direct flame impingement Confines fire well Little collapse potential from the
effects of fire alone Impervious to water damage.
Weaknesses
Difficult to breach for escape/access Difficult to ventilate Massive debris following collapse Floors, ceilings, and walls retain
heat
Type II
Known as noncombustible construction, it is made up of the same materials as fire-resistive construction except that the components lack the insulation or other protection of a type I. It has a rating on all parts of the structure. Materials like wood can only be used in limited quantities. Heat build up can cause members to fail. Fire extension to the roof can lead to eventual roof involve and fail.
Strengths
Almost as resistive to fire as Type I Confines fire well Almost as structurally stable as
Type I Easier to vertically vent than Type I
Weaknesses
Difficult to breach for access/escape Unprotected steel can fail due to
heat Roof less stable than Type I Steel components subject to
weakening by rust and corrosion Massive debris following collapse
Type III
Know as ordinary construction, it requires that the exterior walls and structural members be made of noncombustible or limited combustible materials such as concrete, clay, and brick. The primary fire concern specific to this construction is the problem with fire and smoke spreading through concealed spaces. Fire stops can help reduce with this spread.
Strengths
Resists fire spread from outside
Relatively easy to vertically ventilate
Weaknesses
Interior structural members vulnerable to fire involvement
Fire spread potential through concealed spaces
Susceptible to water damage
Type IV
Known as heavy-timber construction, it requires that exterior and interior walls and associated members be made of noncombustible or limited combustible materials. Type IV was used extensively in old factories, mills, churches; but is rarely used today. Primary fire hazard is the massive amount of combustible contents from the members as well as content. Although Type IV remains stable for long periods of time under a fire condition, they give off tremendous amounts of heat.
Strengths
Resists collapse due to flame impingement
Stable Relatively easy to ventilate Relatively easy to breach for
access/escape Manageable debris following collapse
Weaknesses
Susceptible to fire spread from the outside
Potential for fire spread to other structures
Susceptible to rapid interior flame spread Susceptible to water damage
Type V
Know as wood-frame construction, its walls, floors, roofs, and other supports are made completely or partially of wood or materials of smaller dimension than Type IV. Most common type of construction. Used to construct most single-family residence. It has the highest potential for fire extension.
Strengths
Easy to breach Resistant to collapse from
earthquakes due to its light weight and flexibility
Collapse debris is relatively easy to manage
Weaknesses
Susceptible to fire spread from the outside
Susceptible to rapid flame spread inside
Susceptible to total collapse due to fire of explosion
Susceptible to water damage
Size Up
The size up of a structure is one of the first tasks to be completed by the first-in company. It allows all incoming units to have an idea of what they are about to arrive to. It also has a large roll in giving a firefighter a “situational awareness” plan. The incoming companies will arrive and be able to start their assigned tasks quicker knowing what they dealing with, and not have to take the extra time looking at and assessing the situation.
Size Up, continued
Things the firefighters need to take into account in the size up, and may add to the broadcast are:
Age of the building (are there signs of weathering or deterioration?) Construction materials (is it all metal, concrete, brick with cable tattle-
tails?) Roof type (is it arched or lightweight?) Renovations or modifications (have rooms or sections been added,
facades or false ceilings?) Dead loads (are there large HVAC units, water tanks, or heavy objects on
the roof?) Exposures Occupancy type Other visible hazards
Building construction information is a key part of size-up.
Proper identification of the building and its occupancy will provide valuable information.
Utilities and building services: Plumbing
Electrical
Heating
Air conditioning
Ventilation for restrooms
Stair systems
Elevators
Fire protection systems
These items should be recorded on a Pre-Fire Plan.
Dangerous Building Conditions
There are two primary types of dangerous building conditions that may be posed by a building
Conditions that contribute to the spread and/or add to the intensity of the fire
Conditions that make the building susceptible to collapse
Other dangerous building conditions
Fire loading
Combustible furnishings and finishes
Roof coverings
Wooden floors and ceilings
Large, open spaces
Water weight
Give examples to each above
Collapse
All firefighter should have knowledge of the indicators of building collapse. We all know that collapse is possible whenever there is heavy fire involvement, high heat, and excessive water usage. Some other indicators are:
Cracks or separations in walls, floors, ceilings, and roof structures Evidence of existing structural instability such as the presence or
tie rods or star that hold walls together Loose bricks, blocks, or stones or the debris around the structure Deteriorated mortar between masonry Walls that appear to be leaning Structural members that appear distorted
Collapse, continued
Material that can support/add to collapse:
Gusset plates/gang nails
Steel or wooden trusses
Bowstring construction
Wooden I-beams
Glues
*Note*
As units arrive, it is the OIC, truck officer’s and engineer’s responsibility to insure the placement of the apparatus is out of the collapse zone and that the equipment and personnel are in a safe area.
Construction, Renovation, and Abandoned Hazards
Buildings under construction, renovation or abandoned are extremely vulnerable to fire due to the building materials are open and exposed. Dry wall and other coverings are not yet installed or are just missing. There are a lack of doors and other barriers that would normally slow fire spread. Other contributing factors are the additional fire loads and ignition sources brought by contractors and their associated equipment. Voids and concealed spaces are created such as rain roofs (second roof installed over an old roof) installed in roofs that are beyond repair, mansard fascias, and secondary floors.
Summary
Failure to recognize the potential dangers of a type of construction and effects that fire, heat, and water play may have on it, can be catastrophic to firefighters. For everyone's safety we all must have the basic knowledge of building construction. Knowledge of methods, materials, and designs and how anything we do any effect the building (ventilation, water suppression, breaching, ect). This information will help promote a safer and more effective fire attack.