8  Ordinary Construction
Objectives  (1 of 2) <ul><li>Understand the details of ordinary construction </li></ul><ul><li>Understand how the structur...
Objectives  (2 of 2) <ul><li>Identify the problems associated with interior structural elements </li></ul><ul><li>Explain ...
Introduction <ul><li>Many of the book’s examples were taken west of the continental divide—not just from “back East” </li>...
Classifying Ordinary Construction <ul><li>Common characteristic of ordinary construction is exterior walls made of masonry...
Know the Pronunciation <ul><li>Masonry (not masonARY) </li></ul><ul><li>Lintel (not LENtil) </li></ul><ul><li>Spalling (no...
Classification <ul><li>Type III construction  </li></ul><ul><ul><li>Can be described as “Main Street, USA”  </li></ul></ul...
Masonry Walls <ul><li>May consist of brick, stone, concrete block, terra cotta tile, adobe, precast, or cast-in-place conc...
New Load-Bearing Walls <ul><li>Utilize open cell polystyrene panels </li></ul><ul><li>Rebar and concrete are inserted into...
Fire Limits <ul><li>Older code provision that would not allow a structure to be built without the use of exterior masonry ...
Exclusive Classes <ul><li>Codes and standards divide buildings into various classes </li></ul><ul><li>Sometimes, what was ...
Characteristics of Ordinary Construction <ul><li>Masonry bearing walls </li></ul><ul><li>Wood joists </li></ul><ul><li>Roo...
Bearing and Nonbearing Walls <ul><li>Use similar construction materials  </li></ul><ul><li>Often identical in appearance  ...
Wood Beam Floor <ul><li>Wider buildings need a column, girder, and beam system </li></ul><ul><li>Connection systems come i...
Void Spaces <ul><li>Inherent part of ordinary construction </li></ul><ul><li>Fire protection included embossed metal or ti...
Effective Fire Separation <ul><li>Not within an ordinary construction building </li></ul><ul><li>Often are imperfect or no...
Height of Masonry Buildings <ul><li>Inherent limits  </li></ul><ul><li>Need to increase the thickness of the wall as the h...
Monadnock Building in Chicago <ul><li>Tallest old-style masonry-bearing wall building in the United States  </li></ul><ul>...
Newer Buildings <ul><li>High-rise buildings with no wall thicker than 12 inches </li></ul><ul><li>Medium-rise brick buildi...
Masonry Construction Terms  (1 of 4) <ul><li>Adobe </li></ul><ul><li>Ashlar masonry </li></ul><ul><li>Cantilever wall </li...
Masonry Construction Terms  (2 of 4) <ul><li>Concrete masonry unit (CMU) </li></ul><ul><li>Course </li></ul><ul><li>Cross ...
Masonry Construction Terms   (3 of 4) <ul><li>Hollow masonry walls </li></ul><ul><li>Masonry columns </li></ul><ul><li>Par...
Masonry Construction Terms  (4 of 4) <ul><li>Solid masonry walls </li></ul><ul><li>Stretcher course </li></ul><ul><li>Terr...
Renovation and Restoration of Ordinary Construction <ul><li>Modifications </li></ul><ul><ul><li>Most old buildings have un...
Historical Case Example:  Brown Merrill Building <ul><li>1890 fire </li></ul><ul><li>Some interior walls on the first floo...
Renovations in  Existing Buildings <ul><li>Result of alterations  </li></ul><ul><li>One part of a building can be differen...
Preservation <ul><li>Undeniable historic value </li></ul><ul><li>Architectural heritage </li></ul><ul><li>Fire safety seem...
The Owner’s Rights <ul><li>Fundamental right anchored in our legal system </li></ul><ul><li>Only clear public danger will ...
Fire Resistance <ul><li>Building development is evolutionary </li></ul><ul><li>Piecemeal provisions of fire-resistive feat...
Recent Construction  <ul><li>Departs from ordinary construction </li></ul><ul><li>Not necessarily an improvement </li></ul...
Wood Flourishes <ul><li>Use of flourishes over masonry has left few truly noncombustible buildings </li></ul>8
Desire for Wider Spans <ul><li>Widespread use of unprotected steel for roof framing </li></ul>8
General Problems of  Ordinary Construction <ul><li>Structural stability of the masonry wall </li></ul><ul><li>Stability of...
Discovery of Hazard  (1 of 2) <ul><li>Indications of building failure </li></ul><ul><ul><li>Smoke or water flowing through...
Discovery of Hazard  (2 of 2) <ul><li>Key texts </li></ul><ul><ul><li>Construction Failures  </li></ul></ul><ul><ul><li>Bu...
Ordinary Constructed Buildings <ul><li>In most cities, have been around a long time </li></ul><ul><li>Ample opportunity to...
Clues to Disaster <ul><li>Some are evident from the street </li></ul><ul><li>Others require detailed examination </li></ul>8
Problems with Specific Types of Walls and Wall Components Hollow or Cavity Walls <ul><li>Hollow or cavity walls, including...
Hollow or Cavity Walls <ul><li>Limited penetration by rain  </li></ul><ul><li>Carbon monoxide can accumulate in the hollow...
Sheet or Foamed-In-Place Plastic Insulation <ul><li>Often placed in hollow walls </li></ul><ul><li>Has various ignition ch...
Hollow Walls of Hollow  Terra Cotta Tile <ul><li>Present a special hazard </li></ul><ul><li>Exterior and interior wythes c...
Masonry Walls <ul><li>Used to be built only of bricks </li></ul><ul><li>Now made using concrete block </li></ul><ul><li>Un...
Cast Iron <ul><li>Cast-iron columns and wrought- or cast-iron arches or lintels </li></ul><ul><li>Allowed walls to be made...
Lintels <ul><li>Beams carry the wall above an opening </li></ul><ul><li>The steel “L” lintel is common today </li></ul><ul...
Imitation Brick <ul><li>Made by spreading a coat of gray concrete on lath </li></ul><ul><li>Coat of red concrete is then a...
Structural Stability of  Exterior Masonry Walls <ul><li>Little in traditional firefighting training on this subject </li><...
General Collapse Indicators  (1 of 2) <ul><li>Inherent structural instability </li></ul><ul><li>Failure of a nonmasonry su...
General Collapse Indicators (2 of 2) <ul><li>Impact load of an explosion </li></ul><ul><li>Collapse of a masonry unit </li...
Bricks and Mortar  <ul><li>Poorly made bricks deteriorate readily </li></ul><ul><li>Mortar can force masonry out of alignm...
Wood Beams <ul><li>Can carry an amazing load </li></ul><ul><li>Construction not apparent  from the exterior </li></ul><ul>...
Cracks <ul><li>Indicate weakness in a wall  </li></ul><ul><li>Horizontal cracks </li></ul>8
Arches <ul><li>A brick or stone may fall out of an arch </li></ul><ul><li>If any arch unit is out, there is no arch </li><...
Wall Weaknesses  (1 of 2) <ul><li>All walls are inherently unstable </li></ul><ul><li>Often, front and side walls are desi...
Wall Weaknesses  (2 of 2) <ul><li>Stabilization of walls </li></ul><ul><li>Holes cut through walls create a serious weakne...
Steel Lintels <ul><li>Used without any protection for the steel </li></ul><ul><li>Steel lintels can deform and throw brick...
Bracing <ul><li>Can be a sign that a wall is in distress  </li></ul><ul><li>Braces are not always an indication of instabi...
Eccentric Loads <ul><li>Must be counterbalanced </li></ul><ul><li>Know what is at the other end of a cantilevered beam </l...
Unvented Voids <ul><li>Carbon monoxide gas in unvented voids can detonate violently </li></ul><ul><li>Masonry walls are no...
Planes of Weakness <ul><li>Floor beams are difficult to level </li></ul><ul><li>Leveling with a wood beam creates a plane ...
Effects of Interior Structural Elements and Building Contents on an Exterior Wall  (1 of 2) <ul><li>Pushing down a wall </...
Effects of Interior Structural Elements and Building Contents on an Exterior Wall  (2 of 2) <ul><ul><li>Beams can be corbe...
Effect of Fire Streams  on Brick Walls  <ul><li>Cold water hitting a hot wall has little effect </li></ul><ul><li>Wooden c...
Interior Structural Stability <ul><li>Interior collapse of an overloaded floor can cause the walls to collapse  </li></ul>...
Planning for Collapses <ul><li>Design connections to permit easy collapse of girders </li></ul><ul><li>Design easy collaps...
Fire-Resistive  Combustible Assemblies <ul><li>Combustible floor and wall assemblies have achieved fire-resistance ratings...
<ul><li>Inherent Defects </li></ul><ul><ul><li>Balloon-frame wall-carrying interior loads </li></ul></ul><ul><ul><li>Stone...
Interior Structural Support Systems of Columns, Beams, and Girders  (2 of 2) <ul><ul><li>Adjustable steel jack posts </li>...
Deficiencies of Material  (1 of 2) <ul><li>Addition of unprotected steel </li></ul><ul><ul><li>Sometimes apparent, but is ...
Deficiencies of Material  (2 of 2) <ul><li>Wood beams </li></ul><ul><ul><li>May be trussed initially or at a later date  <...
Connections in  Ordinary Construction <ul><li>Beam-to-girder </li></ul><ul><li>Beam-to-beam </li></ul><ul><li>Beam-to-colu...
Beam-to-Girder Connections <ul><li>Set the beams atop the girder </li></ul><ul><li>Add height to the walls </li></ul><ul><...
Beam-to-Beam Connections <ul><li>Made when an opening is made in wooden floor </li></ul><ul><li>Mortise and tenon joints <...
Beam-to-Column Connections <ul><li>Self-releasing floors </li></ul><ul><li>Girders </li></ul><ul><li>Dog iron </li></ul><u...
Cast-Iron Columns <ul><li>Pintles transfer loads of columns on upper floors </li></ul><ul><li>Use of pintles and cast-iron...
Interior Suspended Loads <ul><li>Balconies and mezzanines are hazardous  </li></ul><ul><li>Interior designers like to hang...
Floors <ul><li>When a stairway is relocated, old opening is usually covered over </li></ul><ul><li>Closure is lighter than...
Light Well  <ul><li>Vertical shaft with windows that provides light and ventilation to enclosed rooms </li></ul><ul><li>Of...
Flooring Construction <ul><li>Used to consist of subflooring and a finished floor </li></ul><ul><li>Now often a single thi...
Floor Collapse <ul><li>Can occur early in the fire </li></ul>8
Roofs  <ul><li>Equipment failure can cost lives, but roof also can fail </li></ul><ul><li>A roof is not designed or constr...
Fire Characteristics of Conventional Wood Roofs (1 of 2) <ul><li>Roofs supported on solid sawn rafters and beams </li></ul...
Fire Characteristics of Conventional Wood Roofs  (2 of 2) <ul><ul><li>Beam gradually weakens in a fire, and the roof becom...
Roof Hazards <ul><li>Best roof is one in which the roof beams rest on girders </li></ul><ul><li>Hangars or other metal con...
Roofs Supported on  Heavy Wood Beams <ul><li>Can be much less reliable than they appear </li></ul><ul><li>Apparent long be...
Energy Conservation and  Rapid Completion <ul><li>Important considerations in today’s buildings </li></ul><ul><li>Foamed p...
Making Use of Natural Light <ul><li>Corrugated glass-fiber-reinforced plastic panels are made to the same dimensions as co...
Ventilation Tactics <ul><li>Can accelerate collapse  </li></ul><ul><li>No such thing as zero impact </li></ul>8
Excess Live Loads <ul><li>Can accelerate collapse  </li></ul><ul><li>Water trapped on a flat roof can cause a collapse </l...
Equipment <ul><li>Often mounted on roofs </li></ul><ul><li>Grillage is affected by the fire </li></ul><ul><li>Supporting b...
Modern Roofs <ul><li>Have little or no inherent fire resistance to early failure </li></ul><ul><li>Typical non-fire-resist...
Lightweight Wood Truss Roofs  (1 of 2) <ul><li>Case Study: Fire in the gable end of a truss roof restaurant. Heavy equipme...
Lightweight Wood Truss Roofs  (2 of 2) <ul><li>Case Study: Collapse of a lightweight wood truss church roof in Lake Worth,...
Bowstring Truss Roofs <ul><li>Name comes from the curved shape of the top chord </li></ul><ul><li>Tied arches </li></ul><u...
Treated Plywood Roofs <ul><li>Builders object to the cost and leakage problems </li></ul><ul><li>Many accepted the use of ...
Void Spaces <ul><li>Voids or concealed spaces inherent part of buildings of ordinary construction </li></ul><ul><li>Requir...
Interior Sheathing <ul><li>A protective interior sheathing or finish for a structure contributes to a building’s fire safe...
Light Smoke Showing <ul><li>A misleading expression  </li></ul><ul><li>Light smoke often signals a disaster </li></ul><ul>...
Ceiling Spaces  <ul><li>Older buildings have higher ceilings than those built today </li></ul><ul><li>False ceilings conse...
Joist Spaces <ul><li>Protected from hose streams by their construction and the ceiling below </li></ul><ul><li>Wood truss ...
Combustible Gases  in Void Spaces <ul><li>Can provide the fuel for a devastating explosion </li></ul><ul><li>Generation of...
Large Voids <ul><li>Public buildings often include vast void spaces </li></ul><ul><li>Access for heavy-caliber streams is ...
Fire Extension <ul><li>Rarely is provision made to prevent the extension of fire through the stairways and halls </li></ul...
Interior Walls <ul><li>Balloon-frame construction in older buildings </li></ul><ul><li>Masonry walls do load-carrying </li...
Voids in Mixed Construction <ul><li>Some buildings are composites of older sections and newer sections  </li></ul><ul><li>...
Cornices and Canopies <ul><li>Cornice is a structure that tops the wall and projects from it </li></ul><ul><li>Collapse of...
Fire Barriers  <ul><li>Masonry bearing walls as fire barriers </li></ul><ul><ul><li>Conditions make a bearing wall less th...
Fire Doors <ul><li>Additional openings often made without proper protection  </li></ul><ul><li>Fire fighters need to be tr...
Protection from Exposure  (1 of 4) <ul><li>Adjacent buildings </li></ul><ul><ul><li>Fire coming through the lower roof may...
Protection from Exposure  (2 of 4) <ul><li>Windows </li></ul><ul><ul><li>Side windows may provide fire path to adjacent bu...
Protection from Exposure  (3 of 4) <ul><li>Narrow alleys </li></ul><ul><ul><li>Present difficult defense problems against ...
Protection from Exposure  (4 of 4) <ul><li>Outside sprinklers or spray systems </li></ul><ul><ul><li>Installed to protect ...
Party Walls <ul><li>Structural walls that are common to two buildings  </li></ul><ul><li>Established by mutual contract be...
Fire-Ground Safety <ul><li>Fire fighter safety is critical </li></ul><ul><ul><li>Set up a Board of Building Review </li></...
Summary  (1 of 2) <ul><li>Ordinary construction describes an almost infinite variety of buildings </li></ul><ul><li>Exteri...
Summary  (2 of 2) <ul><li>Many fire texts cite indications of building failure that may be observed on the fire ground </l...
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Ch 8 Ordinary Construction

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  • Ch 8 Ordinary Construction

    1. 1. 8 Ordinary Construction
    2. 2. Objectives (1 of 2) <ul><li>Understand the details of ordinary construction </li></ul><ul><li>Understand how the structural stability of a masonry wall is compromised </li></ul><ul><li>Identify specific wall and wall component problems </li></ul><ul><li>Recognize collapse indicators </li></ul>8
    3. 3. Objectives (2 of 2) <ul><li>Identify the problems associated with interior structural elements </li></ul><ul><li>Explain how masonry walls act as fire barriers </li></ul><ul><li>Understand fire spread through void spaces of ordinary construction </li></ul>8
    4. 4. Introduction <ul><li>Many of the book’s examples were taken west of the continental divide—not just from “back East” </li></ul><ul><li>Learn from the bad experiences of others </li></ul><ul><li>Prepare for your next job </li></ul>8
    5. 5. Classifying Ordinary Construction <ul><li>Common characteristic of ordinary construction is exterior walls made of masonry </li></ul><ul><li>Exterior walls are noncombustible or limited combustible, but the interior floors and walls are made of combustible materials </li></ul><ul><li>Today, the term has multiple meanings </li></ul>8
    6. 6. Know the Pronunciation <ul><li>Masonry (not masonARY) </li></ul><ul><li>Lintel (not LENtil) </li></ul><ul><li>Spalling (not spalDING) </li></ul>8
    7. 7. Classification <ul><li>Type III construction </li></ul><ul><ul><li>Can be described as “Main Street, USA” </li></ul></ul><ul><ul><li>Strip mall with lightweight wood roof trusses and concrete block walls </li></ul></ul>8
    8. 8. Masonry Walls <ul><li>May consist of brick, stone, concrete block, terra cotta tile, adobe, precast, or cast-in-place concrete </li></ul><ul><li>Cast-in-place concrete includes different types of concrete </li></ul><ul><li>May or may not be of one material </li></ul>8
    9. 9. New Load-Bearing Walls <ul><li>Utilize open cell polystyrene panels </li></ul><ul><li>Rebar and concrete are inserted into cells for strength </li></ul><ul><li>Wood joists are hung from these panels </li></ul><ul><li>Add fire safety problems for fire fighters </li></ul>8
    10. 10. Fire Limits <ul><li>Older code provision that would not allow a structure to be built without the use of exterior masonry walls </li></ul><ul><li>Wood frame buildings were banned inside the fire limits </li></ul>8
    11. 11. Exclusive Classes <ul><li>Codes and standards divide buildings into various classes </li></ul><ul><li>Sometimes, what was used was what was available </li></ul><ul><li>Often, little or no thought was given to types of construction </li></ul>8
    12. 12. Characteristics of Ordinary Construction <ul><li>Masonry bearing walls </li></ul><ul><li>Wood joists </li></ul><ul><li>Roof often similar to the floor in construction </li></ul><ul><li>Cockloft </li></ul>8
    13. 13. Bearing and Nonbearing Walls <ul><li>Use similar construction materials </li></ul><ul><li>Often identical in appearance </li></ul>8
    14. 14. Wood Beam Floor <ul><li>Wider buildings need a column, girder, and beam system </li></ul><ul><li>Connection systems come in many forms. </li></ul><ul><li>Connection weakness creates collapse potential </li></ul>8
    15. 15. Void Spaces <ul><li>Inherent part of ordinary construction </li></ul><ul><li>Fire protection included embossed metal or tin ceilings </li></ul><ul><li>Ceilings can be fire fighter barriers once fire penetrates the void space </li></ul>8
    16. 16. Effective Fire Separation <ul><li>Not within an ordinary construction building </li></ul><ul><li>Often are imperfect or nonexistent in attic spaces </li></ul>8
    17. 17. Height of Masonry Buildings <ul><li>Inherent limits </li></ul><ul><li>Need to increase the thickness of the wall as the height increases </li></ul>8
    18. 18. Monadnock Building in Chicago <ul><li>Tallest old-style masonry-bearing wall building in the United States </li></ul><ul><li>15 stories high </li></ul><ul><li>Masonry walls at base are several feet thick </li></ul>8
    19. 19. Newer Buildings <ul><li>High-rise buildings with no wall thicker than 12 inches </li></ul><ul><li>Medium-rise brick buildings with no wall thicker than 8 inches </li></ul>8
    20. 20. Masonry Construction Terms (1 of 4) <ul><li>Adobe </li></ul><ul><li>Ashlar masonry </li></ul><ul><li>Cantilever wall </li></ul><ul><li>Cavity walls </li></ul><ul><li>Composite wall </li></ul>8
    21. 21. Masonry Construction Terms (2 of 4) <ul><li>Concrete masonry unit (CMU) </li></ul><ul><li>Course </li></ul><ul><li>Cross wall </li></ul><ul><li>Flying buttress </li></ul><ul><li>Header or bond course </li></ul>8
    22. 22. Masonry Construction Terms (3 of 4) <ul><li>Hollow masonry walls </li></ul><ul><li>Masonry columns </li></ul><ul><li>Parging (or pargetting) </li></ul><ul><li>Rubble masonry </li></ul><ul><li>Rubble masonry wall </li></ul>8
    23. 23. Masonry Construction Terms (4 of 4) <ul><li>Solid masonry walls </li></ul><ul><li>Stretcher course </li></ul><ul><li>Terra cotta tiles </li></ul><ul><li>Unreinforced masonry </li></ul><ul><li>Veneer wall </li></ul><ul><li>Wythe </li></ul>8
    24. 24. Renovation and Restoration of Ordinary Construction <ul><li>Modifications </li></ul><ul><ul><li>Most old buildings have undergone extensive modifications </li></ul></ul><ul><ul><li>Modifications usually have a detrimental effect on the fire suppression </li></ul></ul>8
    25. 25. Historical Case Example: Brown Merrill Building <ul><li>1890 fire </li></ul><ul><li>Some interior walls on the first floor had been removed </li></ul><ul><li>Iron poles supported the upper floors </li></ul><ul><li>An arch in the basement had been removed </li></ul>8
    26. 26. Renovations in Existing Buildings <ul><li>Result of alterations </li></ul><ul><li>One part of a building can be different from another </li></ul><ul><li>Interior alterations and finish can make determining the true nature of the building difficult </li></ul>8
    27. 27. Preservation <ul><li>Undeniable historic value </li></ul><ul><li>Architectural heritage </li></ul><ul><li>Fire safety seems a low priority </li></ul>8
    28. 28. The Owner’s Rights <ul><li>Fundamental right anchored in our legal system </li></ul><ul><li>Only clear public danger will force repair or demolition </li></ul>8
    29. 29. Fire Resistance <ul><li>Building development is evolutionary </li></ul><ul><li>Piecemeal provisions of fire-resistive features are less than ideal </li></ul><ul><li>Concrete topping creates dead weight </li></ul>8
    30. 30. Recent Construction <ul><li>Departs from ordinary construction </li></ul><ul><li>Not necessarily an improvement </li></ul><ul><li>Noncombustible voids </li></ul><ul><li>Lightweight wood trusses and wooden I-beams can contribute to the accumulations of explosive carbon monoxide </li></ul>8
    31. 31. Wood Flourishes <ul><li>Use of flourishes over masonry has left few truly noncombustible buildings </li></ul>8
    32. 32. Desire for Wider Spans <ul><li>Widespread use of unprotected steel for roof framing </li></ul>8
    33. 33. General Problems of Ordinary Construction <ul><li>Structural stability of the masonry wall </li></ul><ul><li>Stability of the interior column, girder, and beam system </li></ul><ul><li>Void spaces </li></ul><ul><li>Masonry wall as a barrier to fire extension </li></ul>8
    34. 34. Discovery of Hazard (1 of 2) <ul><li>Indications of building failure </li></ul><ul><ul><li>Smoke or water flowing through walls </li></ul></ul><ul><ul><li>Soft floors </li></ul></ul><ul><ul><li>A small partial collapse </li></ul></ul><ul><ul><li>Walls out of plumb </li></ul></ul>8
    35. 35. Discovery of Hazard (2 of 2) <ul><li>Key texts </li></ul><ul><ul><li>Construction Failures </li></ul></ul><ul><ul><li>Building Failures </li></ul></ul>8
    36. 36. Ordinary Constructed Buildings <ul><li>In most cities, have been around a long time </li></ul><ul><li>Ample opportunity to study buildings and establish preplanned tactics </li></ul>8
    37. 37. Clues to Disaster <ul><li>Some are evident from the street </li></ul><ul><li>Others require detailed examination </li></ul>8
    38. 38. Problems with Specific Types of Walls and Wall Components Hollow or Cavity Walls <ul><li>Hollow or cavity walls, including hollow terra cotta walls </li></ul><ul><li>Sheet or foamed-in-place plastic insulation </li></ul><ul><li>Masonry walls </li></ul><ul><li>Cast iron </li></ul><ul><li>Lintels </li></ul><ul><li>Imitation Brick </li></ul>8
    39. 39. Hollow or Cavity Walls <ul><li>Limited penetration by rain </li></ul><ul><li>Carbon monoxide can accumulate in the hollow space or cavity and explode disastrously </li></ul>8
    40. 40. Sheet or Foamed-In-Place Plastic Insulation <ul><li>Often placed in hollow walls </li></ul><ul><li>Has various ignition characteristics </li></ul><ul><li>Produces large quantities of smoke </li></ul>8
    41. 41. Hollow Walls of Hollow Terra Cotta Tile <ul><li>Present a special hazard </li></ul><ul><li>Exterior and interior wythes connected with steel ties </li></ul><ul><li>If wythes move, clay tile has no tensile strength </li></ul>8
    42. 42. Masonry Walls <ul><li>Used to be built only of bricks </li></ul><ul><li>Now made using concrete block </li></ul><ul><li>Uneven settlement </li></ul><ul><li>Masonry wire trusses </li></ul>8
    43. 43. Cast Iron <ul><li>Cast-iron columns and wrought- or cast-iron arches or lintels </li></ul><ul><li>Allowed walls to be made of prefabricated cast-iron sections </li></ul><ul><li>Front may separate from side walls </li></ul><ul><li>Columns may transmit fire vertically </li></ul>8
    44. 44. Lintels <ul><li>Beams carry the wall above an opening </li></ul><ul><li>The steel “L” lintel is common today </li></ul><ul><li>Steel lintels are tied into the masonry wall </li></ul><ul><li>When heated, they elongate and the masonry can fail </li></ul>8
    45. 45. Imitation Brick <ul><li>Made by spreading a coat of gray concrete on lath </li></ul><ul><li>Coat of red concrete is then applied </li></ul><ul><li>Another method is to cement thin slices of brick onto panels of gypsum board </li></ul>8
    46. 46. Structural Stability of Exterior Masonry Walls <ul><li>Little in traditional firefighting training on this subject </li></ul><ul><li>Flying bricks hazardous </li></ul>8
    47. 47. General Collapse Indicators (1 of 2) <ul><li>Inherent structural instability </li></ul><ul><li>Failure of a nonmasonry supporting element </li></ul><ul><li>Increase in the live load </li></ul><ul><li>Collapse of a floor or roof </li></ul>8
    48. 48. General Collapse Indicators (2 of 2) <ul><li>Impact load of an explosion </li></ul><ul><li>Collapse of a masonry unit </li></ul><ul><li>Collapse of another building onto the building in question </li></ul>8
    49. 49. Bricks and Mortar <ul><li>Poorly made bricks deteriorate readily </li></ul><ul><li>Mortar can force masonry out of alignment </li></ul><ul><li>Sand-lime mortar is water-soluble </li></ul><ul><li>Restored buildings are still suspect </li></ul>8
    50. 50. Wood Beams <ul><li>Can carry an amazing load </li></ul><ul><li>Construction not apparent from the exterior </li></ul><ul><li>Heavy masonry walls are carried over openings on wooden beams </li></ul><ul><li>Check basement and attic for clues </li></ul>8
    51. 51. Cracks <ul><li>Indicate weakness in a wall </li></ul><ul><li>Horizontal cracks </li></ul>8
    52. 52. Arches <ul><li>A brick or stone may fall out of an arch </li></ul><ul><li>If any arch unit is out, there is no arch </li></ul>8
    53. 53. Wall Weaknesses (1 of 2) <ul><li>All walls are inherently unstable </li></ul><ul><li>Often, front and side walls are designed to brace one another </li></ul><ul><li>Different materials expand and contract at different rates </li></ul>8
    54. 54. Wall Weaknesses (2 of 2) <ul><li>Stabilization of walls </li></ul><ul><li>Holes cut through walls create a serious weakness </li></ul><ul><li>Construction of additional openings should be supervised by a structural engineer </li></ul>8
    55. 55. Steel Lintels <ul><li>Used without any protection for the steel </li></ul><ul><li>Steel lintels can deform and throw bricks </li></ul><ul><li>Reinforced-concrete lintels are commonly used in masonry walls </li></ul><ul><li>Bottom concrete may spall off exposing the reinforcing rods </li></ul>8
    56. 56. Bracing <ul><li>Can be a sign that a wall is in distress </li></ul><ul><li>Braces are not always an indication of instability, especially if used with spreaders in a regular pattern </li></ul><ul><li>Bracing upgrades the earthquake resistance of unreinforced masonry walls </li></ul>8
    57. 57. Eccentric Loads <ul><li>Must be counterbalanced </li></ul><ul><li>Know what is at the other end of a cantilevered beam </li></ul>8
    58. 58. Unvented Voids <ul><li>Carbon monoxide gas in unvented voids can detonate violently </li></ul><ul><li>Masonry walls are not designed to resist lateral impact loads </li></ul>8
    59. 59. Planes of Weakness <ul><li>Floor beams are difficult to level </li></ul><ul><li>Leveling with a wood beam creates a plane of weakness </li></ul><ul><li>Horizontal planes of weakness </li></ul><ul><li>Vertical planes of weakness </li></ul>8
    60. 60. Effects of Interior Structural Elements and Building Contents on an Exterior Wall (1 of 2) <ul><li>Pushing down a wall </li></ul><ul><ul><li>Tightly fitted wooden floor beams may act as a series of levers </li></ul></ul><ul><ul><li>Floor beams placed with an upward camber or rise </li></ul></ul>8
    61. 61. Effects of Interior Structural Elements and Building Contents on an Exterior Wall (2 of 2) <ul><ul><li>Beams can be corbelled out from the wall </li></ul></ul><ul><ul><li>Be wary of curtain walls </li></ul></ul>8
    62. 62. Effect of Fire Streams on Brick Walls <ul><li>Cold water hitting a hot wall has little effect </li></ul><ul><li>Wooden components more significant in the collapse </li></ul><ul><li>A heavy stream can penetrate brick veneer </li></ul><ul><li>Heavy streams can rip loosened bricks </li></ul><ul><li>Very heavy streams can smash brick walls </li></ul>8
    63. 63. Interior Structural Stability <ul><li>Interior collapse of an overloaded floor can cause the walls to collapse </li></ul><ul><li>Collapse of an exterior wall may cause an interior collapse </li></ul>8
    64. 64. Planning for Collapses <ul><li>Design connections to permit easy collapse of girders </li></ul><ul><li>Design easy collapse of floors to prevent collapse of walls with fire-cut joists </li></ul><ul><li>There is opposition to these points of view </li></ul>8
    65. 65. Fire-Resistive Combustible Assemblies <ul><li>Combustible floor and wall assemblies have achieved fire-resistance ratings </li></ul><ul><li>Used to produce code-classified protected combustible structures </li></ul>8
    66. 66. <ul><li>Inherent Defects </li></ul><ul><ul><li>Balloon-frame wall-carrying interior loads </li></ul></ul><ul><ul><li>Stone walls and interior walls </li></ul></ul>Interior Structural Support Systems of Columns, Beams, and Girders (1 of 2) 8
    67. 67. Interior Structural Support Systems of Columns, Beams, and Girders (2 of 2) <ul><ul><li>Adjustable steel jack posts </li></ul></ul><ul><ul><li>Water pipe used incorrectly </li></ul></ul><ul><ul><li>Openings in interior masonry bearing walls </li></ul></ul>8
    68. 68. Deficiencies of Material (1 of 2) <ul><li>Addition of unprotected steel </li></ul><ul><ul><li>Sometimes apparent, but is often fully concealed </li></ul></ul><ul><ul><li>Steel bar joists can be installed between each pair of wood joists to strengthen a building </li></ul></ul>8
    69. 69. Deficiencies of Material (2 of 2) <ul><li>Wood beams </li></ul><ul><ul><li>May be trussed initially or at a later date </li></ul></ul>8
    70. 70. Connections in Ordinary Construction <ul><li>Beam-to-girder </li></ul><ul><li>Beam-to-beam </li></ul><ul><li>Beam-to-column </li></ul><ul><li>Cast-iron columns </li></ul><ul><li>Interior suspended loads </li></ul>8
    71. 71. Beam-to-Girder Connections <ul><li>Set the beams atop the girder </li></ul><ul><li>Add height to the walls </li></ul><ul><li>Connection methods reduce the size of the wood </li></ul><ul><li>Effective strength is determined by the size of the thinnest portion </li></ul>8
    72. 72. Beam-to-Beam Connections <ul><li>Made when an opening is made in wooden floor </li></ul><ul><li>Mortise and tenon joints </li></ul><ul><li>Metal joist hangers </li></ul><ul><li>Lightweight hangers </li></ul>8
    73. 73. Beam-to-Column Connections <ul><li>Self-releasing floors </li></ul><ul><li>Girders </li></ul><ul><li>Dog iron </li></ul><ul><li>Transfer beams </li></ul>8
    74. 74. Cast-Iron Columns <ul><li>Pintles transfer loads of columns on upper floors </li></ul><ul><li>Use of pintles and cast-iron columns can cause a collapse due to unsafe connections </li></ul>8
    75. 75. Interior Suspended Loads <ul><li>Balconies and mezzanines are hazardous </li></ul><ul><li>Interior designers like to hang heavy loads from the overhead </li></ul>8
    76. 76. Floors <ul><li>When a stairway is relocated, old opening is usually covered over </li></ul><ul><li>Closure is lighter than the floor </li></ul><ul><li>Opening can cause collapse </li></ul><ul><li>Sheet of metal over the opening can also collapse </li></ul>8
    77. 77. Light Well <ul><li>Vertical shaft with windows that provides light and ventilation to enclosed rooms </li></ul><ul><li>Often floored over </li></ul>8
    78. 78. Flooring Construction <ul><li>Used to consist of subflooring and a finished floor </li></ul><ul><li>Now often a single thickness of plywood and carpeting </li></ul>8
    79. 79. Floor Collapse <ul><li>Can occur early in the fire </li></ul>8
    80. 80. Roofs <ul><li>Equipment failure can cost lives, but roof also can fail </li></ul><ul><li>A roof is not designed or constructed as a fire department working platform </li></ul>8
    81. 81. Fire Characteristics of Conventional Wood Roofs (1 of 2) <ul><li>Roofs supported on solid sawn rafters and beams </li></ul><ul><ul><li>Structural characteristics must be known, not just “type” </li></ul></ul><ul><ul><li>Solid-sawn wood contains “fat” wood </li></ul></ul>8
    82. 82. Fire Characteristics of Conventional Wood Roofs (2 of 2) <ul><ul><li>Beam gradually weakens in a fire, and the roof becomes spongy </li></ul></ul><ul><ul><li>NFPA 251 standard fire exposure tests </li></ul></ul>8
    83. 83. Roof Hazards <ul><li>Best roof is one in which the roof beams rest on girders </li></ul><ul><li>Hangars or other metal connections make the roof more vulnerable to failure </li></ul>8
    84. 84. Roofs Supported on Heavy Wood Beams <ul><li>Can be much less reliable than they appear </li></ul><ul><li>Apparent long beams are often several beams spliced together </li></ul>8
    85. 85. Energy Conservation and Rapid Completion <ul><li>Important considerations in today’s buildings </li></ul><ul><li>Foamed plastic is sandwiched between sheets of plywood </li></ul><ul><li>Plastic may melt away in a fire, allowing the roof panel to fall </li></ul>8
    86. 86. Making Use of Natural Light <ul><li>Corrugated glass-fiber-reinforced plastic panels are made to the same dimensions as corrugated steel </li></ul><ul><li>Fire fighter could easily step through the plastic </li></ul>8
    87. 87. Ventilation Tactics <ul><li>Can accelerate collapse </li></ul><ul><li>No such thing as zero impact </li></ul>8
    88. 88. Excess Live Loads <ul><li>Can accelerate collapse </li></ul><ul><li>Water trapped on a flat roof can cause a collapse </li></ul>8
    89. 89. Equipment <ul><li>Often mounted on roofs </li></ul><ul><li>Grillage is affected by the fire </li></ul><ul><li>Supporting beams should be watched for overheating </li></ul>8
    90. 90. Modern Roofs <ul><li>Have little or no inherent fire resistance to early failure </li></ul><ul><li>Typical non-fire-resistive roof has elements that are susceptible to failure </li></ul><ul><li>Additional roofs built over an original roof, causing additional failure risks </li></ul>8
    91. 91. Lightweight Wood Truss Roofs (1 of 2) <ul><li>Case Study: Fire in the gable end of a truss roof restaurant. Heavy equipment had been on the roof; the construction made the fire impervious to an interior attack. </li></ul>8
    92. 92. Lightweight Wood Truss Roofs (2 of 2) <ul><li>Case Study: Collapse of a lightweight wood truss church roof in Lake Worth, Texas. Heavy fire involvement of the trussloft led to extremely rapid failure of the trusses. </li></ul>8
    93. 93. Bowstring Truss Roofs <ul><li>Name comes from the curved shape of the top chord </li></ul><ul><li>Tied arches </li></ul><ul><li>Popular during the mid-20 th century </li></ul>8
    94. 94. Treated Plywood Roofs <ul><li>Builders object to the cost and leakage problems </li></ul><ul><li>Many accepted the use of fireresistant treated plywood (FRTP) roofing extending to the underside of the roof </li></ul><ul><li>Some chemicals used in FRTP react and deteriorate in ordinary temperatures </li></ul>8
    95. 95. Void Spaces <ul><li>Voids or concealed spaces inherent part of buildings of ordinary construction </li></ul><ul><li>Requirements for firestopping may not have existed or may have been ignored </li></ul><ul><li>Major firefighting problem </li></ul>8
    96. 96. Interior Sheathing <ul><li>A protective interior sheathing or finish for a structure contributes to a building’s fire safety </li></ul><ul><li>True as long as the sheathing keeps fire out of the structure </li></ul>8
    97. 97. Light Smoke Showing <ul><li>A misleading expression </li></ul><ul><li>Light smoke often signals a disaster </li></ul><ul><li>Tremendous fire threat can be concealed in voids </li></ul>8
    98. 98. Ceiling Spaces <ul><li>Older buildings have higher ceilings than those built today </li></ul><ul><li>False ceilings conserve heating and cooling </li></ul><ul><li>Lowering the ceiling rarely includes firestopping </li></ul><ul><li>Usual construction methods create a huge three-dimensional void across the ceilings </li></ul>8
    99. 99. Joist Spaces <ul><li>Protected from hose streams by their construction and the ceiling below </li></ul><ul><li>Wood truss floors have immeasurably increased this problem </li></ul>8
    100. 100. Combustible Gases in Void Spaces <ul><li>Can provide the fuel for a devastating explosion </li></ul><ul><li>Generation of carbon monoxide </li></ul>8
    101. 101. Large Voids <ul><li>Public buildings often include vast void spaces </li></ul><ul><li>Access for heavy-caliber streams is limited </li></ul><ul><li>Fire-loaded upper floors become inaccessible concealed spaces </li></ul><ul><li>Require sprinkler protection if above first floor </li></ul>8
    102. 102. Fire Extension <ul><li>Rarely is provision made to prevent the extension of fire through the stairways and halls </li></ul><ul><li>Often there are many bypasses </li></ul><ul><li>Interconnected voids provide fire paths </li></ul>8
    103. 103. Interior Walls <ul><li>Balloon-frame construction in older buildings </li></ul><ul><li>Masonry walls do load-carrying </li></ul><ul><li>Walls not carried into attic, creating combustible space </li></ul>8
    104. 104. Voids in Mixed Construction <ul><li>Some buildings are composites of older sections and newer sections </li></ul><ul><li>Any new fire­resistive addition may be at the mercy of the old building </li></ul>8
    105. 105. Cornices and Canopies <ul><li>Cornice is a structure that tops the wall and projects from it </li></ul><ul><li>Collapse of cornices has caused many fire fighter fatalities and injuries </li></ul><ul><li>Coming back into style </li></ul><ul><li>Sidewalk canopy </li></ul>8
    106. 106. Fire Barriers <ul><li>Masonry bearing walls as fire barriers </li></ul><ul><ul><li>Conditions make a bearing wall less than a fire wall </li></ul></ul><ul><ul><li>If buildings have a 12- or 16-inch unpierced bearing wall, these walls form a barrier to the passage of any fire </li></ul></ul>8
    107. 107. Fire Doors <ul><li>Additional openings often made without proper protection </li></ul><ul><li>Fire fighters need to be trained to inspect a fire door for proper operation </li></ul>8
    108. 108. Protection from Exposure (1 of 4) <ul><li>Adjacent buildings </li></ul><ul><ul><li>Fire coming through the lower roof may extend to the adjacent building </li></ul></ul><ul><ul><li>Burning material may fall out of the upper windows onto the adjacent roof </li></ul></ul>8
    109. 109. Protection from Exposure (2 of 4) <ul><li>Windows </li></ul><ul><ul><li>Side windows may provide fire path to adjacent building </li></ul></ul><ul><ul><li>Hidden windows may provide a surprise path for fire to travel </li></ul></ul>8
    110. 110. Protection from Exposure (3 of 4) <ul><li>Narrow alleys </li></ul><ul><ul><li>Present difficult defense problems against exposures </li></ul></ul><ul><ul><li>Windows facing the alley are usually protected </li></ul></ul><ul><ul><li>Wired glass is of limited value against radiant heat </li></ul></ul>8
    111. 111. Protection from Exposure (4 of 4) <ul><li>Outside sprinklers or spray systems </li></ul><ul><ul><li>Installed to protect against exposure fires </li></ul></ul><ul><ul><li>Fire department should be fully familiar with their operation </li></ul></ul>8
    112. 112. Party Walls <ul><li>Structural walls that are common to two buildings </li></ul><ul><li>Established by mutual contract between the owners </li></ul><ul><li>Are thinner than two separate walls </li></ul>8
    113. 113. Fire-Ground Safety <ul><li>Fire fighter safety is critical </li></ul><ul><ul><li>Set up a Board of Building Review </li></ul></ul><ul><ul><li>Survey major buildings </li></ul></ul><ul><ul><li>Establish time limits for staying in buildings </li></ul></ul><ul><ul><li>Prefire planning helps determine the boundary between building stability and instability </li></ul></ul>8
    114. 114. Summary (1 of 2) <ul><li>Ordinary construction describes an almost infinite variety of buildings </li></ul><ul><li>Exterior walls are made of masonry with combustible frame members </li></ul><ul><li>Modifications can have a detrimental effect on the structure </li></ul>8
    115. 115. Summary (2 of 2) <ul><li>Many fire texts cite indications of building failure that may be observed on the fire ground </li></ul><ul><li>There is one working platform fire fighters use that has cost many lives — the roof </li></ul>8
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