BK29 Flashcards
How many chapters in book 29?
9
The original distribution of book 29 will include the binder index tabs, and how many chapters?
4
Ventilation is the “_________” removal of heat, smoke, and fire gases from a structure, and replacing it with cooler, clean, fresh air.
systematic
What four objectives will effective ventilation accomplish?
- Save lives
- Assist in firefighter access
- Control horizontal spread of fire
- Reduce possibility of flashover and backdraft
Ventilation will also reduce the chance of ___ burns to firefighters from their hose stream
steam
If the heat, smoke, and fire gases are not released, they will accumulate at the highest point of the structure and begin to bank down and spread laterally. This process is generally known as?
Mushrooming
What is a condition where all of the contents of a room are heated to their ignition temperature?
Flashover
Each year in the United States, there is an average of 100 deaths to firefighters in the fire service. On an average, ___ of those deaths are due to flashover, and the number is slowly rising each year.
85
With horizontal ventilation, there are two methods usually performed, which are what?
natural and positive pressure ventilation.
The key to safe and effective roof ventilation is the knowledge of what?
rafter type and rafter direction
There are basically only TWO types of ventilation holes. What are they?
Heat hole (Offensive) and Strip Ventilation (Defensive)
Center rafter cut is a technique used when cutting what?
plywood sheathing (4 cuts)
Which cut provides the largest hole possible with the minimum amount of cuts?
Center Rafter Cut
Plywood sheathing is installed so that the __’ dimension of the plywood crosses the rafters or joists and the __’ dimension parallels the rafters or joists.
8’, 4’
“H” clips are metal clips used to hold the butted ends of plywood together. “H” clips are common on what types of roofs?
pitched roofs
A head cut is used for what?
locate rafters
A head cut must be done on roofs covered with plywood and _________ sheathing.
diagonal
What motion brings the pulling tool under and up to the decking in a smooth, forceful motion that will separate the decking material from the rafters?
“J” hook
What is a single cut made through the roof decking, the same width as the chain saw blade?
Kerf Cut
For roof ventilation a minimum of how many ladders should be thrown to the involved structure?
two
When louvering, once all 4 cuts are complete, use a rubbish hook and push down on the ____ side (the side closest to your ladder)
near
Nailing blocks will usually be found every how many feet?
4
What is a cut through the roof decking made parallel to the roof rafters?
Parallel Cut
What is a small triangular piece of roof covering, which is removed from the roof to expose the roof sheathing?
Plug Cut
What is a plug cut used for?
Determine sheathing type and roof composition thickness
What does OSB stand for?
oriented strand board
What is a light cut of the roof covering, usually composition only?
Score Cut
What is a light cut made with chain saw, cutting through the roof covering and plywood sheathing?
Skim Cut
Skylights are usually constructed from what?
glass or plastic
What is a small triangular hole cut through the roof decking (sheathing and roof material) made with the chain saw or an axe?
smoke indicator hole
Smoke indicator holes should be placed along the path of access or egress how far apart?
every few yards
Why is a rubbish hook recommended and superior to pick-head axe as a sounding tool?
because of its weight and reach
A turbine-style ventilator is how much more effective when the turbine is spinning?
about 30%
What cut is a series of two cuts used to identify rafter direction “ONLY”
45-degree cut
45-degree cut. when you hit a rafter, “STOP”. Make a second cut __________________ to the exterior wall
parallel or perpendicular
What will a 45-degree inspection cut tell you?
- rafter type
- rafter direction
- sheathing type
- composition thickness
- smoke indicator hole (when complete)
When doing a 45-degree inspection cut, when the saw makes contact with a rafter, roll over the rafter and continue cut for approximately how far?
6 to 10 inches
What are the three cutting techniques?
Dicing, center rafter louver, and panelized
When dicing, after the chain saw operator makes the ____ cut, the puller can start pulling boards.
third
What is all that needs to be known for dicing?
rafter type and direction
How long are dices?
determined by reach tool
Always leave a minimum of how many un-pulled section(s) between the cutter and the puller?
one
When making a center rafter louver you must determine the location of how many rafters?
3
Rafter type and direction is determined by the use of what diagnostic tools?
plug cut, 45 degree inspection cut, sounding, etc.
Center rafter louver, after cutting head cut, move back to the first “outside” rafter and cut a parallel cut approximately how far inside the rafter?
2 to 3 inches
Center rafter louver, make parallel cuts approximately how long?
3-1/2 feet
Drop method. Cut how far inside the purlins to avoid hitting metal hangers?
4 to 6 inches
What are different types of panelized cuts?
- Drop (offensive)
- Pullback (offensive)
- Offensive louver (offensive)
- Louver off a main (Defensive)
- Louver off a purlin (Defensive)
When louvering off a main beam, reach out approximately how far?
3-1/2 feet
When louvering off a purlin, start a “skim cut”, reaching out as far as you comfortably can, approximately how far?
3-1/2 feet
Heavy timbers have been replaced by smaller dimension lumber, and ____________ based compounds have replaced conventional building materials, regardless of building size.
petrochemical
What is one of the most valuable factors we are losing as chemical composition of building materials change?
time
A working knowledge of building construction provides foundation for effective, timely, and safe operation in what areas?
- ladder placement
- forcible entry/search and rescue
- ventilation feasibility
What is a mental evaluation that assists in determining a course of action and the methods necessary to accomplish a desired goal?
Size-up
What do conventional structural members depend on for their strength?
size
What do lightweight truss construction rely on for strength?
multiple members in tension and compression
A single lightweight truss structural member can span ___ feet and may be comprised of 2x4’s in compression and tension to form an integral unit.
70
Roof styles can be divided into what categories?
- Gable
- Hip
- Flat
- Bridge truss
- Arch
- Sawtooth
Conventional construction, gable rafters are usually how big?
2x6 inches or larger. 16 to 24 inches on center
Conventional gable ridge boards were comprised of what?
1x6” or no ridge board and 2x6” rafters butted together
Rafter spacing can be up to how far on-center for steep pitched roofs?
36 inches
What is most common size of metal gusset plate connectors?
18 gauge steel plate with prongs that produce 3/8” penetration
Eighteen-gauge “roof truss clips” may be found nailed to the bottom chord of every how many trusses and top plate of interior walls?
every 3 to 5 trusses
What is common “on-center” spacing for truss rafters?
24 inches
Newer gable roofs will use what size plywood as decking instead of 1x4” or 1x6”
3/8” or 1/2”
Bridge truss roofs are found primarily constructed what years?
1930s and 1940s
Bridge trussWood truss members are build from what size lumber?
2x12”
Rafter size on bridge truss roof are usually what size?
2x6” or larger
What years were bowstring arch roofs constructed?
1930s, 1940s and 1950s
Arch trusses are usually constructed using what size lumber?
2x12” or 2x14”
What are rafter size on bowstring arch roof?
2x6” or larger
Lamella arch roof is constructed from what size lumber?
2x12”
With Lamella arch roofs, total roof collapse may occur if fire removes how much roof structure?
more than 20% (“the domino effect”)
What size are tie rods in tied truss arch roofs?
5/8th inch diameter with turnbuckles
What are rafter size on tied truss arch roof?
2x10” or larger
What size is top cord usually on tied truss arch roof?
2x12 or larger
Sawtooth roofs usually constructed with what size rafters?
2x8” or larger
Sheathing on sawtooth roof is usually 1x6 sheathing or ___ plywood in newer roofs
1/2”
Plywood sheathing on flat roofs may be what size?
3/8” to 5/8”
The stem on a wooden I Beam may be what size?
3/8” plywood or chip-board
Nailing blocks are placed perpendicular to the top chords and are spaced how far apart?
4’
The ability to accurately estimate the amount of time that a structure can be considered structurally strong is dependent of what factors?
- Type of construction
- How long fire has been burning
- Fire intensity
The integrity of what must be evaluated for safe operations?
working surface (roof and floor decking)
Open web steel tube members are prefabricated from what size cold rolled steel tubing with ends pressed flat into semicircle with a hole punched through end?
one to two inch
Open web steel pins up to what size are driven through the chord members flattened ends?
up to one inch
Open web spans up to how long are possible using 2x4 or two 2x3’s as top and bottom chords.
70’
A single 2 x 4 up to 70 feet is made possible by joining different lengths in glued, mitered “__________.”
finger joints
Utilization of 2x4’s in metal gusset plate roofs can span up to how long?
80’
what size is decking usually on metal gusset plate roofs?
1/2
metal gusset plate dwellings will use what size plywood?
3/8 or 1/2 inch
what size are laminated beams in a panelized roof?
6x36”
Panelized beams are spaced how far apart?
12 and 40 feet
Panelized beams may be bolted together to provide lengths well in excess of what?
100’
Purlins are installed with metal hangers how far apart?
8’
Common size for purlin is what?
4x12”
what size are panelized rafters?
2x4, 24” OC
what size are panelized sheets of plywood?
1/2” 4’x8’
Strengths of a Panelized roof?
- Beams
- Purlins
- Building Perimeter
Panelized beam span supports of ___ inch steel pipe may be found
4”
Open web bar joist, top and bottom chords are usually made from what size steel?
1/8”
Open web bar joist web supports are what size?
solid 5/8” steel bar
open web bar joist, large buildings may have bar-joists used as girders spaced up to how far?
45 feet
Open web bar Joists are spaced ____ feet apart to accept corrugated metal decking covered by alternating layers of tar and tar paper.
8’
Open web bar joist may also be found with what size plywood as decking?
1/2”
metal exposed to fire or sufficient heat, steel begins to lose its strength at what temperature?
1000F
A steel or wood sub-structure covered by corrugated metal is also known as what?
Robertson Decking
An air-entrained mixture of sand, cement and, occasionally, pea gravel is pumped on top of the corrugated metal decking and 4 x 4 inch or 6 x 6 inch wire mesh to a thickness of what?
three to four inches
What should you use to ventilate lightweight concrete roof?
rotary saw with a diamond blade or carbide tipped wood blade
What are types of metal construction methods?
corrugated and metal beam
When exposed to sufficient heat, metal beams can expand how far which can push out walls?
9” per 100’
Concrete tilt ups can be up to how high?
5 stories
Brick buildings constructed up until the 1930’s are commonly classified as?
unreinforced masonry buildings.
URM exterior walls are about how thick?
13”
Pre-33 URM, parapet walls can be ___ feet about the roof line, and ___ feet or more if used as a facade on the front of building
3, 5
How are pre-33 floor and roof rafters inserted into the inside of the exterior walls?
“let” (penetrated or resting in a cavity)
Pre-33 how are roof and floor joist cut so they would pull loose from the exterior walls?
“fire cut”
What earthquake occurred in 1933?
Long Beach
Post 33 walls are required to be how thick?
9”
Post 33 walls were reinforced with what?
rebar
Post 33 added what to mortar for strength?
cement
Post 33 how were all joists and rafters anchored to exterior walls?
Ledger board to masonry wall and attach with metal hangers
When was the Tehachapi earthquake?
1959
Post 1959, what size bond beam cap was laid on top of lowered parapet walls along public ways and exits?
4 to 6 inch
Post 1959, including bond beam cap, parapet walls should not be higher than what?
16 inches
Post 1959, Exterior walls drilled at the roof rafter level and a steel anchor bar/rod installed every _____ feet and attached to the existing roof rafter. This modification rendered the fire cut of the roof rafter ineffective. The steel anchor bar/rods are secured to the exterior of the building by a plate/nut combination that is known as “rafter tie plates.”
4
what earthquake happened in 1971?
Sylmar earthquake
What earthquake caused a committee to form to evaluate URM buildings, which was instrumental in retroactive corrections (earthquake ordinance)
1971 Sylmar Earthquake
Post 1971, earthquake ordinance designed to prevent exterior walls from collapsing outward by stabilizing the building by?
- Anchoring walls to floor and roof systems: add steel bracing from parapet walls to roof structural members.
- Strengthening roof construction: Metal straps across the width of the roof and attached to opposing walls. The straps are usually 1/3 of the length of the building back from the front and rear walls. Remove the layers of composition and cover the sheathing with ½ inch plywood. This decking is then recovered with composition.
Brick identification, window frames are “set” to the inside of the wall, thereby exposing about ____ inches of brick return on the exterior of a building.
8
“king row” is row of bricks, one row will have been laid “on-end” how often?
In every four to seventh row
Earthquake Ordinance. Metal straps across the width of the roof and attached to opposing walls. The straps are usually ____ of the length of the building back from the front and rear walls.
1/3
Earthquake ordinance. Remove the layers of composition and cover the sheathing with ___ inch plywood.
1/2
When arch roofs (particularly the bowstring and tied truss) are modified as per the Earthquake Ordinance, the additional roof stability provided by plywood and metal straps can increase the potential for collapse of what?
front/rear walls
exterior walls may suddenly collapse (during fire conditions) outward a distance of what?
that is equal to at least the height of the wall.
Metal straps across the width of the building _______ feet from walls are hard on power saws.
three to four
A facade can be defined as an “identifiable style of construction on the exterior of a building that will conceal and spread the travel (extension) of fire.” To summarize, facades are external _______.
attics
Facades are used for what?
conceal equipment and machinery on flat roofs
With facades, the extension of fire will be affected by the presence or lack of what?
“fire stops”
Facades are usually _____ to the attic of a building.
open or common
If a facade is exposed to fire, expect the facade to collapse outward how far?
at least the distance of the overhang of the facade.
The structural stability of a facade will be enhanced if supported by what?
pillars, posts or other means that are often used for style of decoration.
Bungalow and balloon construction were constructed during when?
1920s, 1930s, 1940s
Bungalow and balloon construction primarily utilized in SFD and multi-story habitational occupancies up to how many stories?
4
Bungalow and balloon construction can be classified as what?
“old type” of lightweight construction
Bungalow and balloon construction utilized 2x3 or 2x4 inch rafters for room structural members and ridge that is comprised of what?
1x6
Knob and tube insulators were made of what?
ceramic
Depending on the particular method that is employed, “curtain” construction can be about ___% faster than conventional construction.
60
Curtain construction can be identified by pre fire planning or recognizing what look?
“cube” or “smooth”
What are three general time periods that can be used to classify buildings?
- Pre-1933
-1933 to Late 1950’s
-1950’s to present
To ensure effective and safe fireground operations when it comes to lightweight construction, personnel must address what four areas?
-Identification
-Communication
-Time
-Operations
Smoke removal. The primary goal of effective ventilation operations is the reduction or removal of smoke, heat, and fire gases (contaminants) from a structure or enclosed area in a _________.
timely manner
Smoke removal. Plans for ventilation operations should begin by identifying what?
the direction (horizontal or vertical) contaminants must travel to exit the contaminated area
What are two basic methods utilized to pressurize a contaminated area to enhance or direct travel of contaminants to the exterior?
Natural and Mechanical positive pressure ventilation
Natural Ventilation is dependent on what factors?
- Proximity of the ventilation opening to the contaminants to be removed.
- Ability of the contaminants to travel unobstructed to a ventilation opening.
- Number and size of ventilation openings.
- Direction of wind.
- Humidity.
- Temperature differential between the interior and exterior of a building.
Effective ventilation DRAMATICALLY assists in what?
attack, control and extinguishment of a structure fire
Utilizing portable blowers, the natural ventilation process can be dramatically assisted or replaced by _________ the movement of contaminants to Exits through pre-selected and/or controlled openings.
Forcing
What are the current methods that are utilized to provide pressurized ventilation with portable blowers?
negative and positive pressure ventilation
Exterior blowers are efficient in removing contaminants where?
top, bottom and corners of a room or building
Compared to negative pressure ventilation, positive pressure ventilation is approximately _____ as effective at removing contaminants from a building.
twice
The effective implementation of positive pressure is dependent on the entrance opening, airflow between openings, exhaust opening, weather, training and ____________.
communication
The location of the exhaust opening is dependent on what?
the location of heat and smoke, and the prioritization of suppression operations.
Positive pressure is most efficient when the exhaust opening is what size?
between 3/4 to 1-3/4 the size of the entrance opening
If a gasoline powered blower is being utilized and an exhaust odor is noticeable inside the building or area to be ventilated, this is an indicator of what?
exhaust opening is not large enough
Temperature, humidity, and rain do or do not have any appreciable effect on positive pressure ventilation?
do not
As in any ventilation operation, maximum efficiency can be obtained by utilizing the prevailing wind direction to an advantage, which is what way?
windward to leeward
Positive pressure has proven effective against winds leeward to windward up to how many mph?
25
