Book 29 Flashcards
1
Q
Book 29
Ventilation
What are the four main objectives of ventilation?
A
Save lives
Assist inn firefighter access
Control the horizontal spread of fire
Reduce the possibility of flashover and backdraft
2
Q
Book 29
Four main objectives broken down.
A
- Saves live
Simplifies and expedites rescue operations
Replaces heated smoke with cooler, fresh air - Firefighter access
- Heat is reduces
- Reduces the chances of steam burns
- Rapid extinguishment reduceswater, heat, and smoke damage
- Assist with rescue, salvage, and overhaul operations
- Control the horizontal spread
- Fire, heat, smoke and fire gases travel upward to the highest point of the building, usually the roof or ceiling.
- If not released will bank down and spread laterally. This process is generally known as mushrooming.
- Strip ventilation in conjunction with and offensive ventilation heat hole can help stop the horizontal spread of fire.
- prevents flashover and backdraft.
3
Q
Book 29
What are the two types of ventilation?
A
- Horizontal
Removal of heat, smoke, and fire through wall openings such as doors and windows. - vertical
Opening roof or existing openings (skylights, hactch covers, etc.)
4
Q
Book 29
What are the two types of ventilations holes?
A
Heat hole (offensive) Strip ventilation (defensive)
5
Q
Book 29
Ventilation terminology.
A
- Center rafter cut.
Technique used when cutting plywood sheathing (4 cuts) - Decking
Material used for base and exterior covering for the roof.
Base material can consist of solid wood sheathing, plywood-type materials, corrugated metal, and other materials. - Diaphram nailing
Plywood sheathing is installed so that the 8’ dimension of the plywood crosse the rafters or joist and the 4’ dimension parallels the rafter or joist.
Sheets of plywood are staggered much like a brick or block wall. - Dicing
Techniques used to cut 1x4 or 1x6 solid, spaced, or diagonally sheathed roofs.
Made parallel to rafters with no concern to locating rafters. - “H” clips
Metal clips used to hold the butted ends of plywood together - Head cut
Made through roof decking
Made perpendicular to rafters
Used to locate rafters - “J” hook
Removal of sheathing is enhanced by a “J” hook motion - Kerf cut
A single cut made through the roof decking, the same width as the saw blade.
An alternative to smoke indicator - Nailing blocks
Usually made from 2x4 pieces of wood laid flat between rafters to provide a nailing surface for the edge of the plywood sheathing.
Plywood normally used is 4x8 in size, a nailing block will usually be found every 4 feet. - plug cut
Small triangular piece of roof covering (composition), which removed from the roof to expose the roof sheathing
Used to determine sheathing type and roof composition thickness. - Score cut
Light cut of the roof covering, usually composition only.
A score cut is used to facilitate the removal of multiple layers of roofing material (composition) - Skim cut
Light cut made with the chain saw, cutting through the roof covering and plywood sheathing
The saw is not inserted deep enough to cut through the rafters
You skim ober the top of the rafters - Ventilators
If working correctly , leave them alone
A turbine style is about 30% more effective when spinning
6
Q
Book 29
Building contstruction
Convention construction
A
Size=strength
Structural members may be 8x8 9nches for strength
7
Q
Book 29
Building contstruction
Lightweight constrcution
A
- Individual member dependant on total sum of the other members
- Compression/tenssion= strength
- Lightweight truss span up to 70 feet in length and may be comprised of 2x4’s in compression and tension
- lightweight construction is vastly different due to truss construction that depends on the sum total of members for strength
8
Q
Book 29
Roof styles
Gable roof characteristics
A
- Ridge board and rafters that cross the outside walls
- Additional support is provided by collar beams and ceiling joist
- Spaced up to 36 inches “on center” for steep pitched roofs
- 2x6 rafters or larger
- Spacing 16”-24” on center
9
Q
Book 29
Bowstring arch
A
- Used in the 1930’s, 40’s, and 50’s
- 2” x 12” or 14”
- 2x6” rafters
- Straight Sheathing: used prior to 1933
- Diagola Sheathing: used after 1933
- Fails in sections
- Earthquaking: Plywood over decking, metl straps and supports
10
Q
Book 29
Lamella arch
A
- Egg crate gemetric deisgn
- Solidly built- 2x12” framing
- 1x6” decking
- Will use internal tie rods
- 20% of the roof removed by fire, you can expect total collapse in the domino effect
11
Q
Book 29
Tied truss arch
A
- Uses metal tie rods usually 5/8”, with turnbuckle below each arched member. Prevents pushing on exterior walls
- Identification: Rods passing through wall plates
- 2x12” top cord with 2x10” rafter
- Hazards: failure of metal tie rods
- Tension: Tie rods are in tension
- Failure: will fail in section or total collapse
12
Q
Book 29
Saw tooth
A
- Commercial buildings with windows to yield lighting
- 2x8” rafters
- 1x6” decking or 1/2” plywood on newer buildings
- Ventilation: hinged panes of glass
13
Q
Book 29
Wooden I beams
A
- Stem is 3/8” plywood with 2x3” or 2x4” top/bottom cords
- spacing: spacing is 24” with nailing blocks spaced 4 feet apart
- Strengths: consider the perimeter of the building where the roof ties into the exterior walls a strong area
14
Q
Book 29
Open web
A
- 1-2 inch cold rolled steel
- Spans up to 70’ are possibl using a single 2x4” or two 2x3’s as top and bottom cord
- Single 2x4 up to 70 feet with finger jpints
- Spacing: 24” on center
- Strengths: Consider the permimeter of the building where the roof ties into the exterior walls as a strong area.
15
Q
Book 29
Metal gusset plate
A
- 2x4” trusses held together with metal gussest plate connectors
- up to 80 feet
- 3/8” or 1/2” plywood
- Strengths: Strong area to be where the trusses cross (canteliver applications) or terminate on the outside bearing walls
16
Q
Book 29
Panelized
A
- Laminated beams 6x36”
- spans: 12-40 feet, can be bolted to excess of 100 feet
- Purlins: 4x12” spaced 8 feet apart
- Rafters: 2x4” spaced 24 inches
- stengths: beams, purlins, perimiter
17
Q
Book 29
Open web bar joist
A
- 1/8” steel with 5/8” steel bar
- Used as girders spaced up to 45 feet
- steel may lose its strength at 1000 degrees
- Some have 2x4 joist with 1/2” plywood
18
Q
Book 29
Lightweight concrete roof
A
- (Robertson decking) 4x4” or 6x6”
- Wire mesh with corrugate metal
- use rotary saw with diamond blade or carbide tip blade no masonary
- Strengths: lightweight concrete roofs offer a strong, hard surface. They are structurally sound and resistant to fire
19
Q
Book 29
Construction
A
- Corrugated
Substructure of wood or steel
Covered with steel, aluminum or fiberglass
Steel loses strength at 10,000 and aluminum or fiberglass offers little resistance to fire
Roof ventilation operations on these buildings should be considered extremely dangerous - Metal beam
Sub structure of steel beams, usually coated with a spray on fire retardant material. - Tilt up
Concrete slab tilted up in place
Light weight walls
Light weight roofs
20
Q
Book 29
Construction
Pre 33
A
- Weak due to no cement, just lime
- ro rebar is used
- walls: 13” thick with straight decking
- Kings row every 4 to 7 rows
- Parapets: 3 to 5 feet tall
- Floors: “let” into the exterior walls
- Roof and floor joist are “fire cut” (ends cut on an angle) will collapse into the exterior.
21
Q
Book 29
Construction
Post 33
A
- Revised building codes due to long beach earthquake
- joist and rafters are anchored to exterior walls with ledger board, with metal hangers
- cement and rebar was added
- diagonal roof sheathing added
Walls must be atleast 9 inches thick
22
Q
Book 29
Construction
Post 59
A
- 4 to 6 inch concrete bond beams were added
- parapet walls were limited to 16 inches tall
- exterior walls are drilled at roof with steel anchors every 4 feet attached to rafters
