*Bk 29- Ventilation Flashcards
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
________ is a condition where all of the contents of a room are heated to their ignition temperature. Once their ignition temperature is reached, the entire room will quickly be involved in flames.
Flashover
In a confined area, if the structure’s contents reach their ignition temperature and there is not sufficient oxygen to support combustion. Once oxygen is introduced, _________ can occur.
Backdraft
The best way to prevent backdraft is to perform ____________
Vertical ventilation
What are the two types of horizontal ventilation that can be performed?
Natural and positive pressure
With conventional construction, if time and safety permits, the roof team “WILL” cut the heat hole where?
Directly over the fire
When operating on a lightweight truss roof (or suspected
lightweight truss), the ventilation team _______________ conduct ventilation operations directly over the fire
Shall not
The two types of ventilation holes are:
- Heat hole (offensive)
1. Strip ventilation (defensive)
What type of hole is placed directly over the fire or as close to the fire as safety will allow?
Heat hole
What type of hole should be placed well ahead of the fire, and should extend the entire width of the building, creating a firebreak?
Strip ventilation hole
Before cutting a strip hole, what must be accomplished first?
Heat hole
What type of cut is a technique used when cutting plywood sheathing (4 cuts)?
Center rafter cut
_________ is the material used to comprise the base and exterior covering for a roof.
The base is the material attached to the roof rafters
Decking
When sheets of plywood are then staggered much like a brick or block wall, this is known as?
Diaphragm nailing
Plywood sheathing is installed so that the ________ ft dimension of the plywood crosses the rafters or joists and the _______ ft dimension parallels the rafters or joists
- 8
2. 4
What technique is used to cut 1” x 4” or 1” x 6” solid, spaced, or diagonally sheathed roofs?
The cuts are made _______ to rafters with no concern to locating rafters.
- Dice cut
2. Parallel
What type of metal clips are used to hold the butted ends of plywood together?
They are common on ______ roofs.
- H clips
2. Pitched
What type of cut is made through the roof decking that is perpendicular to rafters and used to locate rafters?
Head cut
A head cut must be done on roofs covered with _______ and _______ sheathing
- Plywood
2. Diagonal
The removal of sheathing is enhanced by a _______ motion with an appropriate tool.
It is more effective when used near the rafters.
J hook
_______ is a single cut made through the roof decking, the same width as the chain saw blade.
It can be used as an alternative to using the smoke indicator hole
Kerf cut
For roof ventilation, what is the “MINIMUM” amount of ladders that should be thrown to the involved structure?
2
When louvering plywood, push down on the _______ side (the side ______ to your ladder) and pull on the far side.
- Near
2. Closest
A nailing block will usually be found every _____ feet.
4
A 2” x 4” laid flat between rafters to provide a nailing surface for the edge of the plywood sheathing is known as?
Nailing block
A ______ cut is a small triangular piece of roof covering (composition), which is removed from the roof to determine what?
- Plug cut
2. Sheathing type and composition thickness
The normal and most common size for plywood is?
4’ x 8’
A _______ cut is a light cut of the roof covering, usually composition only.
It is used to facilitate the removal of multiple layers of ________ on the roof.
- Score cut
2. Roofing material (Composition)
A _______ cut is a light cut made with the chain saw, cutting through the roof covering and plywood sheathing only.
It is used on a panelized roof when you are performing the cutting technique known as ___________?
- Skim cut
2. Louver off a purlin
A ________ is a small triangular hole cut through the roof decking(sheathing and roofing material) that is used to indicate smoke and fire conditions directly below.
Smoke indicator hole
How far apart should smoke indicator holes be placed along the path of access or egress?
Every few yards
A turbine-style ventilator is about ______% more effective when the turbine is spinning
30%
Ventilators can be placed on roofs to ventilate what two things?
Attic and building interior
- If vent pipes appear to be growing out of the roof, this should be an indication that the roof has what?
- This condition is known as _____________.
- Sagged or dropped
2. Growing vent pipes
A ________ cut is a series of two cuts used to identify rafter direction “ONLY.”
45-degree cut
A __________ cut will tell you rafter type and rafter direction, the sheathing type, the thickness of roof composition and when complete, it can act as a smoke indicator hole
45-degree inspection cut
What 5 things will a 45-degree inspection cut will tell you when complete?
- Rafter type
- Rafter direction
- Sheathing type
- Thickness of roofing material (composition)
- Smoke indicator hole
When rolling a rafter during the 45-degree inspection cut, you should continue the cut approximately ___ to ___ inches past the rafter.
6 to 10 inches
When dicing, the puller can start pulling boards after a minimum of how many cuts (dices)?
3
What determines the length of a dice cut?
The tool being used to pull the sheathing
When dicing, how many un-pulled sections should be kept between the chain saw operator and the puller?
1
During a center rafter louver, the head cut is started by first cutting: (a) towards (b) away from - your ladder to locate your first“outside” rafter.
Away from
During a center rafter louver, the parallel cut should be approximately how many inches inside the rafter?
2-3 inches
During a center rafter louver, how long should the parallel cut be?
Approximately 3-1/2 feet
What are the 5 cutting techniques to ventilate a penalized roof?
- DROP METHOD (OFFENSIVE)
- PULL BACK METHOD (OFFENSIVE)
- OFFENSIVE LOUVER (OFFENSIVE)
- LOUVER OFF A LAM BEAM / MAIN BEAM (DEFENSIVE)LOUVER 5. OFF A PURLIN (DEFENSIVE)
During penalized roof ops, how far away from the purlins should you cut to avoid hitting metal hangers?
4-6 inches
Because of work area limitations while louvering off a lam-beam, the cutter and puller should __________ before louvering the section.
Exchange tools
You are performing louver off a lam-beam. Before louvering a complete section, what should be accomplished?
Start an outside cut (top cut) on the next section
You are performing a louver off a purlin. Your top cut should be a ______ cut.
How far should you reach out to perform this cut?
- Skim cut
2. 3-1/2 feet
Ventilation:
The key to safe and effective roof ventilation is the knowledge of what two things?
rafter type and rafter direction
Which panelized roof ventilation operations are considered offensive?
Which are considered defensive?
Offensive: Pullback, Drop, Offensive louver
Defensive: louver off main beam, louver off purlin
Effective ventilation will accomplish four main objectives, what are they?
- Save lives.
- Assist in firefighter access.
- Control the horizontal spread of fire.
- Reduce the possibility of flashover and backdraft
