1. Building Construction

2. Most fires start in the contents of a building. For example, a smoldering cigarette starts a fire in a stuffed chair or mattress. But if the flames are not quickly extinguished while in the content phase; they will extend to, and throughout the structure. It spreads throughout concealed spaces, poke through walls, common roof or attic spaces. Sometimes even along the outside of the building. Structural Fire Spread

3. Extinguishing a structure fire, is much more complex than quenching a content fire. The concealed flames must be located and cut off, in addition to extinguishing the original content fire. To do this effectively fire officers must know the various ways fire can spread throughout a structure. We study our local building codes and construction techniques. But at the scene of a fire we cannot expect to know every construction detail of a building.

4. However, we should know the basic construction types in our community, and we should be able to associate the burning building with one of the basic construction types. If we can do this, we can determine approximately how a fire may spread.

5. Five types of construction and Fire Spread There are five basic groups of building construction used throughout the United States. We should know them. Each one has a fire- resistive weakness, which results in a reoccurring fire spread throughout its structure. By knowing how a fire can spread, it helps us extinguish the fire quickly and most important protects firefighters from becoming trapped by fire, killed or injured. There are five basic groups of building construction used throughout the United States. We should know them. Each one has a fire- resistive weakness, which results in a reoccurring fire spread throughout its structure. By knowing how a fire can spread, it helps us extinguish the fire quickly and most important protects firefighters from becoming trapped by fire, killed or injured.

6. Construction Types All buildings in America can be associated with one of five basic types of construction, identified by Roman numerals in building codes and by engineering schools throughout the nation: All buildings in America can be associated with one of five basic types of construction, identified by Roman numerals in building codes and by engineering schools throughout the nation: Type I - Fire-resistive Type I - Fire-resistive Type II - Non-combustible Type II - Non-combustible Type III - Ordinary Type III - Ordinary Type IV - Heavy-timber Type IV - Heavy-timber Type V - Wood-frame Type V - Wood-frame

7. Type I Fire-resistive construction (type I) was originally designed to contain fire inside the building to one floor. This concrete and steel structure, called fire resistive when first built at the turn of the century, was supposed to confine a fire by its construction. Today, that is no longer true. Fire-resistive construction (type I) was originally designed to contain fire inside the building to one floor. This concrete and steel structure, called fire resistive when first built at the turn of the century, was supposed to confine a fire by its construction. Today, that is no longer true.

8. Type I

10. Fire does spread several floors in a modern fire-resistive building, despite its steel and concrete structure. Two avenues by which fire and smoke can spread throughout a fire-resistive building are by central air conditioning ducts and by auto- exposure, a term used by the fire service to describe flames extending vertically from window to window. Fire does spread several floors in a modern fire-resistive building, despite its steel and concrete structure. Two avenues by which fire and smoke can spread throughout a fire-resistive building are by central air conditioning ducts and by auto- exposure, a term used by the fire service to describe flames extending vertically from window to window.

11. Type II Non-combustible (type II) constructed building has a different recurring fire spread problem: fire spreads on the roof deck. A type II building has steel or concrete walls, floors and structural framework; however, the roof covering is combustible, it burns and spreads fire. Non-combustible (type II) constructed building has a different recurring fire spread problem: fire spreads on the roof deck. A type II building has steel or concrete walls, floors and structural framework; however, the roof covering is combustible, it burns and spreads fire.

12. Type II

14. When a fire occurs inside a type II building, flames rising to the underside of the steel roof deck may conduct heat through the metal and ignite the combustible roof covering above. The asphalt, felt paper and foam insulation may bum and spread fire along the roof covering. When a fire occurs inside a type II building, flames rising to the underside of the steel roof deck may conduct heat through the metal and ignite the combustible roof covering above. The asphalt, felt paper and foam insulation may bum and spread fire along the roof covering.

15. Type III Ordinary constructed (type III) building is also called a brick-and joist structure. It has masonry-bearing walls but the floors, structural framework and roof are made of wood or other combustible material. Ordinary construction has been described by some firefighters as a "lumberyard enclosed by four brick walls." Ordinary constructed (type III) building is also called a brick-and joist structure. It has masonry-bearing walls but the floors, structural framework and roof are made of wood or other combustible material. Ordinary construction has been described by some firefighters as a "lumberyard enclosed by four brick walls."

16. Type III

18. The major recurring fire spread problem of type III construction is concealed spaces and poke-through holes. These small voids, crevices and openings through which smoke and fire can spread are found behind the partition walls, floors and ceilings. The major recurring fire spread problem of type III construction is concealed spaces and poke-through holes. These small voids, crevices and openings through which smoke and fire can spread are found behind the partition walls, floors and ceilings.

19. Type IV Heavy-timber (type IV) construction is sometimes called "mill construction" because it was the type of structure used at the turn of the century to house textile mills. These buildings have masonry walls like type III buildings but the interior wood consists of large timbers. The floor and roof are plank board. In a heavy- timber building a wood column cannot be less than eight inches thick in any dimension and a wood girder cannot be less than six inches thick. Heavy-timber (type IV) construction is sometimes called "mill construction" because it was the type of structure used at the turn of the century to house textile mills. These buildings have masonry walls like type III buildings but the interior wood consists of large timbers. The floor and roof are plank board. In a heavy- timber building a wood column cannot be less than eight inches thick in any dimension and a wood girder cannot be less than six inches thick.

20. Type IV

22. One difference between a heavy timber building and ordinary construction is that a heavy-timber building does not have plaster walls and ceilings covering the interior wood framework. The exposed wood timber girders, columns, floor beams and decks, if ignited in a fire, create large radiated heat waves after the windows break during a blaze. One difference between a heavy timber building and ordinary construction is that a heavy-timber building does not have plaster walls and ceilings covering the interior wood framework. The exposed wood timber girders, columns, floor beams and decks, if ignited in a fire, create large radiated heat waves after the windows break during a blaze.

23. Type V Wood-frame (type V) construction is the most combustible of the five building types. The interior framing and exterior walls may be wood. A wood-frame building is the only one of the five types of construction that has combustible exterior walls. Wood-frame (type V) construction is the most combustible of the five building types. The interior framing and exterior walls may be wood. A wood-frame building is the only one of the five types of construction that has combustible exterior walls.

24. Type V

26. When sizing up a fire in a wood building, the outside walls must be considered for the fire spread. Flames can spread out a window and then along the outside wood walls (in addition to the interior fire spread). To combat fire in a wood-frame building, a FF must position a hoseline or master stream outside the structure in addition to the attack line inside the structure. When sizing up a fire in a wood building, the outside walls must be considered for the fire spread. Flames can spread out a window and then along the outside wood walls (in addition to the interior fire spread). To combat fire in a wood-frame building, a FF must position a hoseline or master stream outside the structure in addition to the attack line inside the structure.

27. Construction Wall Types Load bearing - Support structural weight. Most exterior walls are load bearing. Load bearing - Support structural weight. Most exterior walls are load bearing. Non-load bearing - does not support structural weight. Non-load bearing - does not support structural weight. Party – Supports two adjacent structures and is load bearing. Party – Supports two adjacent structures and is load bearing. Partition – Divides two areas in a structure and is non-load bearing. Partition – Divides two areas in a structure and is non-load bearing.

28. Construction Wall Types

30. Effects of fire on Common Building Materials Wood – The reaction of wood to fire conditions depends mainly on two factors: Wood – The reaction of wood to fire conditions depends mainly on two factors: The size of the wood The size of the wood The smaller the wood is, the more likely it is to lose structural integrity. The smaller the wood is, the more likely it is to lose structural integrity. The moisture content of the wood The moisture content of the wood Wood with a high moisture content (green) does not burn as fast as dried or cured wood. Wood with a high moisture content (green) does not burn as fast as dried or cured wood.

31. Effects of fire on Common Building Materials Masonry – Includes bricks, stones & concrete masonry products. Masonry – Includes bricks, stones & concrete masonry products. Masonry is minimally affected by fire & exposure to high temps. Masonry is minimally affected by fire & exposure to high temps. Bricks rarely show signs of loss of integrity. Bricks rarely show signs of loss of integrity. Stones may spall or lose portions of their surface. Stones may spall or lose portions of their surface. Block may crack, but usually retain most of their strength & structural stability. Block may crack, but usually retain most of their strength & structural stability.

33. Effects of fire on Common Building Materials Cast Iron – Rarely used in modern construction, but typically found in older buildings. Cast Iron – Rarely used in modern construction, but typically found in older buildings. Cast iron stands up well to fire & intense heat, but may crack or shatter when rapidly cooled with water. Cast iron stands up well to fire & intense heat, but may crack or shatter when rapidly cooled with water.

35. Effects of fire on Common Building Materials Steel – Primary material used for structural support in modern construction. Steel – Primary material used for structural support in modern construction. Steel members elongate when heated. Steel members elongate when heated. If steel is restrained from movement at the ends, it buckles & fails somewhere in the middle. If steel is restrained from movement at the ends, it buckles & fails somewhere in the middle. The temp at which steel fails depends on many variables: size, load, composition and geometry of the member. The temp at which steel fails depends on many variables: size, load, composition and geometry of the member.

36. Effects of fire on Common Building Materials Steel Steel From a firefighting perspective, FF’s must be aware of the type of steel used in a structure. FF’s also need to determine the length of exposure to the steel members to have an indication when steel members might fail. From a firefighting perspective, FF’s must be aware of the type of steel used in a structure. FF’s also need to determine the length of exposure to the steel members to have an indication when steel members might fail. Consider that expanding steel members may expand and push out load bearing walls, causing collapse. Consider that expanding steel members may expand and push out load bearing walls, causing collapse.

38. Effects of fire on Common Building Materials Reinforced Concrete – Concrete that is internally fortified with steel reinforcement bars or steel mesh. Reinforced Concrete – Concrete that is internally fortified with steel reinforcement bars or steel mesh. This gives the material the compression strength of concrete and the tensile strength of steel. This gives the material the compression strength of concrete and the tensile strength of steel. Does not perform well under fire conditions, it loses strength & spalls. Does not perform well under fire conditions, it loses strength & spalls. Heating may cause a failure of the bond between the concrete & the steel. Heating may cause a failure of the bond between the concrete & the steel.

40. Effects of fire on Common Building Materials Gypsum – An inorganic product from which plaster & plasterboards are constructed. Gypsum – An inorganic product from which plaster & plasterboards are constructed. The high water content gives it excellent heat-resistant & fire retardant properties. The high water content gives it excellent heat-resistant & fire retardant properties. Commonly used to provide insulation to steel and wood structural members. Commonly used to provide insulation to steel and wood structural members. Breaks down gradually under fire conditions. Breaks down gradually under fire conditions.

42. Effects of fire on Common Building Materials Glass/Fiberglass Glass/Fiberglass Glass is not typically used for structural support & is not an effective barrier to fire extension. Glass is not typically used for structural support & is not an effective barrier to fire extension. Fiberglass is typically used for insulation purposes. The glass component is not a significant fuel, but the materials used to bind fiberglass may be combustible & difficult to extinguish. Fiberglass is typically used for insulation purposes. The glass component is not a significant fuel, but the materials used to bind fiberglass may be combustible & difficult to extinguish.

44. Common Terminology Fire Load – The maximum heat that can be produced if all the combustible materials in a given area burn. Fire Load – The maximum heat that can be produced if all the combustible materials in a given area burn.

45. Fire Loads

49. Common Terminology Lightweight Steel Truss – Made from a long steel bar that is bent at a 90 degree angle with angular pieces welded to the top & bottom. Lightweight Steel Truss – Made from a long steel bar that is bent at a 90 degree angle with angular pieces welded to the top & bottom.

50. Lightweight Steel Truss

51. Common Terminology Lightweight wood trusses – Constructed of 2x3” or 2x4” wood boards that are connected by gusset plates or joints. Lightweight wood trusses – Constructed of 2x3” or 2x4” wood boards that are connected by gusset plates or joints.

52. Common Terminology Gusset plates – Are small metal plates with prongs that penetrate about ¾” into the wood. Gusset plates – Are small metal plates with prongs that penetrate about ¾” into the wood. Experience has shown that lightweight metal & wood trusses will fail after 5-10 minutes of exposure to fire. Experience has shown that lightweight metal & wood trusses will fail after 5-10 minutes of exposure to fire.

54. Common Terminology Wooden I-Beams / Engineered Joists – Are structural components manufactured from wood, laminates & adhesives. Wooden I-Beams / Engineered Joists – Are structural components manufactured from wood, laminates & adhesives.

55. Common Terminology Bowstring Truss – Used in buildings with large open spaces. Bowstring Truss – Used in buildings with large open spaces. Easily denoted by their rounded appearance.

56. Common Terminology Tension Loading – Vertical & horizontal stresses that tend to pull things apart. Tension Loading – Vertical & horizontal stresses that tend to pull things apart. Compression Loading – Vertical & horizontal stresses that tend to press things together. Compression Loading – Vertical & horizontal stresses that tend to press things together.

57. Compression & Tension Loads Compression Load Tension Load

58. Building Collapse A collapse zone should be 1 ½ times the height of the building. A collapse zone should be 1 ½ times the height of the building. Apparatus should only be placed at the corners of the building. Apparatus should only be placed at the corners of the building.

59. Building Collapse

61. Knowledge of building construction can assist a firefighter in his/her size-up and make the firefighting actions of locating, confining and extinguishing a structure fire more effective.

62. Questions ?