chap 11 Flashcards
roofs
what is waterproofing for a building
roof
fundamental ‘’’’ regarding roofs are:
nots as strong as floors, designed to hold lighter live loads
concealed spaces b’tw ceiling and roof ( had to determine extent a fire has developed)
overtime loads are added to which they where not designed for
p. 278
safety points
from a FF standpoint roofs can be classified into 3 styles which are
flat , pitched and curved
types of flats roofs can be found on:
WH
F
SM
S
warehouses, factories, shopping centers, schools
what is the easier roof to work on
flat
what roof is designed to shed water and snow
pitched
low slope roofs have a slope of up to ‘’ meaning for each 12 unit of horizontal dimensions the roof slopes upward of 3
3/12 p. 279
slopes of 4/12 to 12/12 (45 degree angel ) are ?
medium to high slopes
some slopes of 18/12 or higher can including what type of buildings
churches, mansions ( to steep to work on w/ roof ladder)
10 types of roofs:
G,H,G,M,B,M,S,S,A,F
gable, hip, gambrel, mansard, butterfly, monitor , sawtooth , shed , arched , flat
common roof style that consist of 2 inclined surfaces that meet at their high side to form a ridge
gable roof
style that slopes in 4 directions and has a degree of slope similar to the gable roof
hip roof
slopes in 2 directions, but there will be a break in the slope on each side. ( spaces under can be used as attic or living space_
gambrel roof
has a break in the slope of the roof on 4 sides .( one with a flat deck is sometimes called )
mansard roof
modern mansard or roof deck p. 280
roof style that slopes in 2 directions ( 2 shed roofs that meet ar low eaves
butterfly
style designed to provide light and ventilation. ( commonly used on factories)
monitor roof
the vertical side of this monitor section Regarding monitor roof, which are normally openable windows are know as
clerestories
style of roof also once comply used on industrial buildings for lights and vents( ideally faced north b/c of northern light and glare of sun can be avoided )
sawtooth roofs
curved roofs are most frequently supported by
ARCHES /bowstrings p. 281
forces of a dome roof are similar to arch however, the forces in a dome are excepted around a ‘’ instead of just 1 plane
complete circle
more architecturally spectacular curved roofs can be created using
lamella arches or geodesic domes
arched roof structure composed of a series of intersecting , skewed arches made up short, straight members
lamella arch
lamellas can form
domes and arches
if compression or tension rings in lamella dome are damaged to the point of failure what will happen
entire structure will fail
lamellas roofs have been used for occupancies including:
G
EH
A
gyms, exhibition halls , auditoriums
what is created using spherical triangulations.
geodesic dome
geodesic domes can be constructed of:
W
S
C
P
B
A
wood , steel , concrete, plywood, bamboo and aluminum p. 282
what is usually provided in building with pitched roofs to increase living space in attic
dormers
what roofs may be supported by open web steel joists and steel beams
flat roofs
horizontal structural member used to support a ceiling or floor.
joist p. 283
Traditional wood joist roof uses solid wood joist that tend to lose their strength gradually, this loss of strength results in the roof becoming ‘’
soft or spongy b4 failure
in modern construction box beams and i beams are made of ‘’ and wood truss joist are often used to support ‘’
plywood /flat roofs
i beams render ‘’ in a fire
fail early
open web design of truss joist permits the rapid spread of fire in direction ‘’’’’ to the truss joist instead of simply along the dimension of members.
perpendicular
unprotected lightweight open web joist of any material should be expected to ;; in fire
fail quickly
fire proofing can be omitted from roof supports when the roof is located more than ‘’ above the floor in an assembly
20 ft p. 284
deflection and vibration are an indication of
lightweight roof construction and should use caution
with what roof is the main joist located at the level of the ceiling and a framework is constructed above the main joist to support the roof deck.
inverted roof
from outside ‘’ look like any other flat roof but the design creates ‘’ that may be several ft in eight between ceiling and roof deck
inverted roof /concealed space
truss that is constructed w/ deep triangular portion projecting down instead of up
inverted truss
WHAT ‘’’’’ roofing system constructed on site, often uses dimensional lumber with nails and screws I can also use pre-engineered components..
Uses incline members to support some types of pitch roots that are built on site utilizing dimensional lumber construction of this type of roof is becoming less common as construction techniques because this type of instruction has higher requirements than prefabricated framing systems EX:
Knowledge and skill of the construction crew
Cost material
Time needed for construction
conventionally framed roof
inclined beams that support roof , runs parallel to the slope to which the roof deck is attached
rafters
highest horizontal member in a pitched rood which the upper ends of the rafters attached also know as ‘’
ridge board/ ridgepole
horizontal roof framing members in the top 3rd of the framing system braces roof framing against the uplift of wind
collar tie
horizontal roof framing member at the bottom of the framing system ; helps keep walls from spreading due ti the weight of roof
rafter tie p285
most common roof types with conventional framing include:
S
g
H
G
M
shed, gable, hip , gambrel, mansard
if architect desires to leave the underside of the roof exposed w/o joists, a structural ‘’ must be used to support rafter s
structural ridge beam
fasteners common to conventional roof framing
nails /screws at connection points
hvy bolts or brackets in heavy timber construction
architectural hardware for exposed beams
what are completely made of wood
rafters
ridge beams are often ‘’ size larger that rafter
1 p. 286
what are common roof supports systems
pre engineered roof framing ( roof trusses )
truss structure w/ the chords and diagonal members arranged in parrallel planes. also known as
commons truss /monoplane truss
Viod spaces in truss roof construction are large b/c of the unblocked distance b’tw the ‘’/’’ chord and ‘‘supports of truss systems
top bottom, internal
when fighting fire in a building w/ structural truss components, th AHJ should consider prioritizing what ?
defensive fire opts p. 287
what trusses which use a curved top chord were once commonly used for roofs and many remain in use.
bowstring
the top chord ‘’ tries to ‘’ the bottom chord ‘’ TO maintain the shape of the top chord through ‘’
bow, strengthen, string , tension
'’failure of what element of a bowstring truss will lead to catastrophic failure
any single.288
what trusses are most common types used for pitched roofs
fink and pratt
what will often behave true to their construction material in fire
arches
material used in arches:
M
LW
S
masonry , laminated wood , steel
tie rods extending through the interior of the building are usually
unprotected
roof covering made of flexible material that may be applied to the roof decks as a continuous sheet( used on shallow pitch roofs)
roll roofing
horizontal member b’tw trusses that support the roof
purlin
components of ‘’’ include:
sheathing
roof planks or slabs
purlins p. 289
roof decks
what decking is frequently used in application where it serves as both decks and the exterior roof covering
corrugated steel
materials used in ‘’’ include:
plywood
wood planks
corrugated steel
precast gypsum or concrete planks
pored gypsum
poured concrete
cement planks counting wood fiber
roof decks
wood planks will have a minimum ‘’ nominal thickness
1 inch
corrugated steel uses roof decking from ‘’ The thinnest gauge to ‘’ thickest Gauge. The overall depth varies from ‘’’
29 - 12 gauge
3/4 -2 in
gypsum has the advantage of being
nailable p. 290
practice in multistory building w/ flat roofs is to use the same structural system for the ‘’ as the ‘’ b’c its more economical
roofs and floors
some factors that affect the choice of roof covering include
maintenance requirement
durability
fire resistance
ex. of conditions ‘’’ material must resist include :
punctures from hail
corrosion from fog, salt air, smoke and other pollutants
expansion and contraction from roof top temps p. 291
roofing
what roofs drain more slowly that pitched roofs
flat roofs
what is designed to reduce the diffusion of interior moisture into the insulation layer
vapor barrier
Vapor barrier consist of a continuous sheet of material resistant to the passage of water vapor including:
P
AF
KP
ASRF
plastic
aluminim foil
kraft paper laminated w/ asphalt
asphalt saturated roofing felt
what layer reduces heat loss through the roof…. In addition to resisting the flow of heat, the insulation should have resistance to mechanical damages such as gouging, moisture decay, and fire
thermal layer
what can be poured insulation materials
portland cement or gypsum
what used under roof consists of waterproof material that keep out rain and snow from interior of building
membrane
3 general categories of ‘’’ are:
built up
single ply
fluid applied
membranes
What type of membrance uses several overlapping layers of roofing felt saturated w/ a bituminous material that may be tar or asphalt
built up membrane
single membrane laid in sheets on the roof deck. Material comes in sheets, 10 or 20 feet wide and up to feet long the membranes are typically’’’’ thick
single ply membrane p. 292
.003-.10 inch
most common ‘’’ is made OF :
synthetic rubber material
ethylene propylene diene monomer ( EPDM)
other materials
polyvinyl chloride
chlorinated polyethylene
singe ply membrane
membrane useful for curved roof surfaces are what kind of membrances ?
fluid applied membranes
materials used in ‘’ are:
neoprene
silicone
polyurethane
butyl rubber p. 293
membrane
built up roofs that use gravel as the wear course are commonly known as
tar and gravel roofs
what which consist of bundles of reeds, grasses or leaves is also a covering for pitched roofs
thatch
asphalt shingles are usually installed over ‘’ which is a layer of roofing felt or synthetic covering
underlayment
modern asphalt shingles are ‘’ based
fiberglass
most come size of asphalt shingle
12x36p. 294
what shingles are fundamnetly combustible. they tend to drip and run under fire conditions and produce heavy black smoke
asphalt
historically ‘’’ where made up of:;
rag, paper or wool fiber p. 295
asphalt shingles
different b’tw wood shingles and shakes are
method of production
wood shingles are thin slabs of ‘’ that are sawn from peices of ‘’
thin slabs of wood the are sawn from pieces of tree trucks
shakes are ‘’ split from the wood and are ‘’ than shingles
manually or machined / thicker
how much is exposed of a wood shingle when installing
1/3
’’ x3 tiles are noncombustible and produce fire - resistant roof covering that have excellent resistance to flying brands
clay, slate and cement
problems with tiles
get lose and fall
slippery
brittle and my have sharp edges p. 296
’’ is produced from hard rock that has a tendency to split along one plane, this makes it produced in a smooth sheet as thin as 1/16 or as thick as 1 1/2
slate , 1/16, 1/1/2 in
slate had a weight of
8-36 pounds per sq ft
slate has a life expectancy of
150 years
’’ tile is dense, had and nonabsorbent material and can be used for flat or curved tiles . curved tiles are known as
clay / mission used in spanish architect
tiles made from portland cement , aggregate and water
concret tiles
’’’ roof coverings may use several materials such as:
galvanized or painted sheet metal
copper
zinc
aluminum
lead
metal
practice to avoid corrosion may include
use same nail as metal or use insulating between nail and sheeting p. 297
in order to be a ‘’’ product, material are subject to 6 Separate test including:
intermittent flame exposure text
during brand test
flying brand test
rain test
weather test
spread of flame
3rd party listed
class a roof covering are effective against
severe fire exposure
class B coverings are effective against
moderate fire exposure
class c coverings are effective against
light fire exposure
standard of methods of fire test of roof coverings
NFPA 256
what test evaluates the fire hazard of specific roof covering
astm e-108
what is the building 1st line of defense against the elements
roof
reason rain roofs may be installed over existing roofs
to cover deterred roofing element
change profile of building
update architectural design p. 299
cost effective
less disruptive
rains roofs ‘’’ for FF:
when products of combustible enter a void space they can be difficult to detect , access and extinguish
The existence of two separate roofs can also impend rapid and effective ventilation
Small spaces between the two roofs can create an unwrapped hazard for firefighters
not structural strong enough to support the weight of ff ops
problems
greatest benefit of green roofs / hazard
increase energy effeciency / increased weight p. 300
’’ produces reliable clean energy.
photovoltaic system ( solar )
a single unit of solar energy collector is referred to as as
cell
a series of solar cells is called a
panel or module
a system of solar panels or shingles is called a
array
energy feed from photovoltaic cells cannot be
isolated or shut off even when power is shut off the cells are isolated from building electric system ( they continue to store power )
all wiring and conduits must be assumed to be
live p. 301
codes for ‘’ include:
clear space along edges and ridges of roofs
clear aisle space
min visibility of components
labeling
external shutoff switches
ability to rapid shut down system
solar
whats roofs take many forms such as potted plants and flower boxes ro layer of earth with growing plants covering large areas
green roof
a rooftop garden is a what load
dead p. 302
small structures on main roof , for the purpose of stairways enclosure, elevator machinery enclosure, equipment enclosure or addition living space
penthouses
purpose of ‘’ is to provide natural light to building ,
skylights
building code restricts the material used in ‘’’ to:
plastic, wired glass or tempered glass
skylight
what can be spring loaded or manually operated
skylights p. 303
Aluminum and steel sheets can have what done to increase their strength
Corrugation page 297
’’’’’ coverings may use Galvanized or painted sheet metal as materials, including:
Galvanized or painted sheet metal
Copper
Zinc
Aluminum
Lead
Page 298
Metal roof
Roofs are not usually a strongest floor because they are typically designed to support
Lighter live loads
Many types of construction have inherent concealed spaces between the ceiling and the roof deck, making it difficult to determine
The extent to which a fire has developed
Many flat roofs are provided with slight slopes, typically from’’’ , to facilitate training.. these roofs drains may have the capacity to handle a heavy rainfall, but not water from ‘’’’
Front to rear
Master sTREAM
Pitched Roof present a major hazard to FF because of ?
Steepness and lack of secure footings P. 279
Which two metrics are often used to indicate the pitch of a roof?
Rise and run
A common roof style that has two inclined surfaces that meet at their high side to form a ridge is known as what roof ?
Gable
Which type of roof has a break in the slope of the roof on all four sides?
MANSARD
Modern ventilation and lighting systems have mostly eliminated which two types of roofs? (p. 281)
Monitor
Sawtooth
’’’’’ are commonly made of wood and vary in thickness from 2x8 TO 3x16 and in length varying from 8-14ft
LAMELLA ARCH
the short LAMELLA are Bolted together in a diagonal pattern, with a special plate known as a
LAMELLA washer
The curvature of the LAMELLA arch results from
BEVELING
A horizontal structural member used to support a ceiling or floor would be known as what? Regarding flat roof
Joist
What is a rafter tie used for in conventional roof framing? (p. 285)
Anchoring the top of the rafter
A collar tie is used in which portion of the framing system? (p. 285)
Top 1/3 OF the system
’’’ framing components include
Rafterrs
Ridge boards
collar ties
Ceiling joist, and rafter ties
Conventional framing components
How does a rafter run in comparison to the slope of the roof?
Parallel
What kind of thrust is created against the walls in a raftered roof? (p. 286)
An outward thrust
How does the weight of a roof truss compare to that of the supporting walls? (p. 287)
Much lighter than supporting walls
When fighting a fire in a building with structural truss components, which type of operations should be prioritized? (p. 287)
Defensive fire suppression
Supports are often substantial with ridge beams typically ‘’’ size larger than a rafter
1x
Void spaces in trust roof construction are’’’ because of the unblocked distance between the top cord and the bottom cord and internal components of the trust
Large
What type of connectors are used for the majority of the joints in a bowstring truss? (p. 288) except the ‘’ plates located at the end of the stability
Split ring connectors
Heel plates
Where is roll roofing commonly used? (p. 289)
Shallow pitched roofs
Vapor barriers are commonly found in roofs where ‘’ fluctuation is common. (p. 292)
Where temp fluctuations are common
’’ decks serve several purposes, including separating the structure from the effect of whether and supporting the weight of the materials used to weatherproof the structure
Roof decks
’'’decking is frequently used in application where it serves as both the deck and the exterior roof covering
Corrugated steel decking
For wood plank roof decks, what minimum nominal thickness must be present?
1 inch
poured insulation materials can be 2 which are ?
Portland cement or gypsum
What is designed to reduce the diffusion of interior moisture into the insulation layer? It is used in climate where significant temperature fluctuations are common.
Vapor barriers
How many layers of roofing felt are most commonly used on built-up membrane roofs? (p. 292)
4
Roofing felt is usually supplied in rolls of what width? (p
3ft
Two broad categories of a roof coverings used on pitch roof are
Shingles and metal roof coverings
Why are cedar and redwood often used for wood shakes used on roofs in North America? (p. 296)
Resistance to decay
Where are corrugated aluminum or steel roofs primarily used? (p. 297)
Industrial/ architectural buildings
Corrugated roofing sheets are usually stiff enough that they don’t have to be installed on roofs with what feature? (p. 298)
Decking
What support the corrugated roofing sheets
Roof beams or purlins
Roofing felt ‘’’ the fire resistance of a roof because it act as an insulating layer and protects the wood decking against heat of external exposing fires
Increase
Roofs with intentionally enhanced biodiversity are known as what? (p. 300)
Brown roof
A green roof’s load can be accounted for in a similar way to what? (p. 302)
Snow load
