Chapter 4 Flashcards
What is the most the most common building material used in North America?
wood
What 2 things affect how wood reacts to fire conditions?
size and moisture
What specific thing affects the rate at which wood burns?
moisture content
What is green wood?
wood with high moisture content
What is oriented strand board (OSB)?
a wooden structural panel formed by gluing and compressing wood strands together under pressure. This material has been replaced by plywood and planking in the majority of construction applications. Roof decks, walls, and subfloors are all commonly made of OSB.
What is masonry?
bricks, blocks, stones, and unreinforced and reinforced concrete products
What are veneer walls?
decorative covers; walls within a surface layer of attractive material laid over a base of common material
What is spalling?
expansions of excess moisture within masonry (concrete) materials due to exposure to heat of a fire, resulting in tensile forces within the material causing it to break apart.
What happens to stones and concrete when heated?
spalling
What are the two types of iron in buildings in North America?
cast iron and wrought iron
What is the primary material used for structural support in the construction of large modern buildings?
Steel
What is steel used for?
reinforce concrete floors, roofs, and walls, as well as stairs, wall studs, windows, and door frames
What happens to steel when it is heated?
it elongates
What happens when restrained steel is heated?
if retrained from movement at the ends, it buckles and fails somewhere in the middle
A 50 ft. steel beam may elongate as much as ___ inches when heated to 1000 degrees F.
4
What is the temperature that steel structures are anticipated to fail?
1000 degrees F
What will fail first? A lightweight steel truss or a large heavy I-beam?
a lightweight steel truss
What is a lightweight steel truss?
a structural support made from a long steel bar that is bent at a 90-degree angle with flat or angular pieces welded to the top and bottom
What happens to load-bearing walls when steel is heated?
elongated steel can push out load-bearing walls and cause collapse
What are decorative and functional uses of aluminum?
Roofing, flashing, gutters, downspouts, window and door frames, and exterior curtain wall panels
What are curtain wall panels?
a nonload-bearing wall, often of glass and steel, fixed to the outside of the building and serving especially as cladding
What has replaced wood in many commercial and residential buildings?
Aluminum studs
What is affected by heat more rapidly? Steel or aluminum?
Aluminum
What usually happens to metals that are exposed to excessive amounts of heat?
it fails
What is rebar?
short for reinforcing bar; a steel bar that is placed in concrete forms before the cement is poured; when the cement hardens the rebar within it adds considerable strength
What does reinforced concrete usually contain?
rebar
What two-forms of strength does reinforced concrete contain? Why?
compressive strength of the concrete and tensile strength of the steel
What is compressive strength?
the ability to withstand pressure on the surface
What is tensile strength?
the ability to withstand being pulled apart or stretched
What is gypsum also known as?
drywall or Sheetrock
What is gypsum?
an inorganic product from which plaster and wallboards are constructed
Why is gypsum unique?
it has high water content that absorbs a great deal heat as the moisture evaporates; the water content gives gypsum excellent heat-resistant and fire-retardant properties
What is lath and plaster?
a construction process rather an a single material; horizontal wood strips called lath are nailed to wall studs and covered with a mixture of plaster to form an interior wall finish
Is glass typically used for structural support?
No
What is fiberglass usually used for?
Insulation purposes
What is asbestos?
a mineral fiber that was used before 1970 for insulation and as a fire retardant; it has ben banned since 1989
What is hybrid construction?
a type of building construction that uses renewable environmental friendly or recycled materials; aka Natural of Green Construction
What are different types of insulation?
asbestos, urea formaldehyde foam insulation (UFFI), fiberglass, mineral wool, cellulose, cotton, straw, foam
What form of insulation is usually found in the exterior walls of hybrid or natural (green) construction?
straw
What are composite materials?
composite materials are manufactured by combining two or more distinctly different materials
What are types of composite materials?
finger-jointed limber, laminated timber, medium density fingerboard (MDF), particle board, synthetic wood
(pg 142)
What/who determines the type of building construction used in a structure?
the architect, structural engineer, or contractor
Who are building codes adopted by?
building codes are adopted by the AHJ and amended to meet local requirements
What are the two major building model codes in the US?
the NFPA 5000 and the International Code Council’s (ICC) International Building Code (IBC) building codes
What is NFPA 5000?
NFPA 5000 Building Construction and Safety Code
What are the 3 elements that every building is composed of?
structural frame, floor construction, roof construction
What is type 1 construction?
type 1 construction is also known as fire-resistive construction; type 1 provides the highest level of protection from fire development and spread as well as collapse
What is expected of type 1 construction?
type 1 is expected to remain structurally stable during a fire, and is considered to be the most collapse resistant
What meets the criteria for type I construction?
reinforced concrete, precast concrete, and protected steel frame construction
What is protected steel?
steel structural members that are covered with either a fire resistant stray-on fire proofing or fully encased in an approved system
What are type 1 structures usually incorrectly referred to as? Why?
the structure won’t burn, but the structure may degrade from the effects of fire as well as the addition of combustible materials within the structure
What is type II construction?
type II construction is also known as noncombustible of limited combustible construction; type II construction is composed of materials that will not contribute to fire development or spread;
What is true about steel components used in type II buildings?
steel components used in type II do not need to be protected for the same lengths of time of have the same fire-resistance rating as type I
What is the fire-resistance rating?
the fire resistance rating is the rating assigned to a material or assembly after standardized testing by an independent testing organization; identifies the amount of time a material or assembly will resist a typical fire, as measured on a standard time-temperature curve
What is the fire-resistance rating of type II compared to type I?
type II is generally half of type I, I-2 hours, depending on the component
What is the fire-resistance rating of type I structure?
3-4 hour burn
What is type III construction?
type III construction is also known as ordinary construction; commonly found in older schools and mercantile, business, and residential structures; requires that exterior walls and structural members be constructed of noncombustible material; interior walls, columns, beams, floors, and roofs are completely or partially constructed of wood
Which type of fire kills the most FF and why?
type III bc the fire travels through the walls and is concealed to FF; roofs in this structure also collapse faster
What is the condition that affects type III fire behavior the most in type III?
voids exist inside the wooden channels created by roof and truss systems and between wall studs that will allow for the spread of a fire unless fire stops are installed in the void
What are fire stops?
solid materials such as wood blocks used to prevent or limit the vertical and horizontal spread of fire and the products of combustion in hollow walls or floors, above false ceilings, in penetrations for plumbing or electrical installations, in penetrations of a fire-rated assembly, or in cocklofts and crawl spaces
What is a hazard that comes about due to renovations?
renovations to structures can change the interior arrangement, exit paths and structural integrity of a structure
What is type IV construction?
type IV constructions is also known as heavy timber/mill construction; it is characterized by the use of large-dimensioned lumber; these structural members will be greater than 8 in; fire rating of 2 hours; dimensions of all structural elements must adhere to minimum dimension sizing
What is the stability level of type IV construction?
type IV construction is very stable and resistant to collapse due to the sheer mass of their structural members; the lack of voids of concealed spaces help to prevent fire travel
What is the weakest part of type IV structure?
bolts and fasteners
What are two things that can cause a type IV structure to fail?
- failure of bolts/fasteners
- failure of Glulam beams
Glulam beams: small-dimensioned lumber that is glued together to form a laminated structure element; element is strong; commonly found in churches, barns, etc; fails bc glue holding elements together is affected by the heat
What are load-bearing walls?
walls of a building that by design carry at least some part of the structural load of the building in the direction of the ground or base
What is type V construction?
type V construction is commonly known as wood frame or stick frame; the exterior load bearing walls are composed entirely of wood
What is a veneer wall?
a veneer offers the appearance of type III construction while providing little additional fire protection or structural support to the structure
What does type V construction consist of?
framing materials that include wood 2x4” or 2x6” studs
What is an upright post in the framework of a wall for supporting sheets of lath and plaster, wallboard, or similar material?
stud
Does type V construction include the use of prefabricated wood truss systems or solid floor joists?
prefabricated wood truss system; system creates a large open void area between the floors of the structure, rather than the closed channel system found with solid wood floor joists
What is a manufactured home/structure?
a manufactured home is a structure that is built in a factory and shipped to the location where it is installed
Are manufactured homes required to conform to the model building codes?
no; they are required to conform to a US Dept. of Housing and Urban Development (HUD) standard that is similar to type V construction
What does the National Building Code of Canada (NBCC) define as the three types of building construction?
combustible construction, noncombustible construction, and heavy timber construction
In Canada, what are the residential dwellings built under the novoclimat standard?
a standard intended to make new homes more energy efficient and better insulated; airtight structure; more likely to fail rapidly under fire conditions bc heat is trapped within the structure; design makes vertical ventilation more difficult
What are occupancy classifications defined by?
the building code and life safety code adopted by the AHJ
What are the 3 primary model building codes in use in North America?
NFPA 5000, IBC, and the National Building Code of Canada (NBCC)
What 2 type of occupancies may structures be divided into?
single use or separated use