Ventilation Techniques (ch.1) Flashcards
Ventilation is the ______
Systematic removal of heat, smoke, and fire gases from a structure, replacing it with cooler clean fresh air.
Effective ventilation will accomplish four main objectives
- save lives
- Assist with firefighter access
- control the horizontal spread of fire
- reduce the possibility of flashover and backdraft
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
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 ____ deaths to firefighters in fire service. _____ of those deaths are due to flashover
100 deaths in fire service
85 deaths to flashover
With horizontal ventilation there are two methods usually performed
Natural and positive pressure ventilation
The key to safe and effective roof ventilation is the knowledge of ____ and ___
Rafter type and direction
There are basically only two types of ventilation holes:
- Heat Hole (Offensive)
2 Strip. Ventilation (defensive)
Strip ventilation must be done in conjunction with a ____
Heat hole
Center rafter cut is a technique when cutting ___ sheathing (4cuts)
Plywood
Decking is the material used to comprise the ____ and exterior covering.
Base
Diaphragm nailing; plywood sheathing is installed so that ____ ‘ dimension crosses the rafters and the ____ ‘ dimension
8’ crosses
4’ parallel
For diaphragm nailing
Dicing is a technique used to cut _____” or ____in solid, spaced or diagonally sheathed roofs.
1x4 or 1x6 sheathing
Metal clips used to hold the butted ends of plywood together
H clips
A head cut is a cut made through the roof decking that is made perpendicular to rafters. A head cut is used to _____
Locate rafters
The removal of sheathing is enhanced by a _____ motion
J hook
Ground ladders should be thrown to _____ of the structure
Uninvolved corners
The roof ventilation, a minimum of ______ ladders should be thrown to the involved structure
2
Nailing blocks are usually made from ____ “, laid flat between rafters. A nailing block will usually be found every ___ ft
2x4” block
Every 4ft.
a small triangular piece of roof covering (composition), which is removed from the roof to expose the roof sheathing.
Plug cut
A plug cut is used to determine ______ and ______
Sheathing type and roof comp thickness
*can identify rafter direction due to nailing pattern/direction of sheathing
A light cut of the roof covering, usually composition only
Score cut
The ___ is used on a panelized roof when you are performing the cutting technique known as louver off a purlin
Skim cut
Skylights are usually constructed from ___ or ___
Glass or plastic
On apt buildings skylights will be placed over ____ and ____. On commercial buildings, they will be placed over _____
Hallways, stairwells
Manufacturing areas
Smoke indicator holes should be placed along the path of access or eagerness every____
Every few yards
Strip ventilation is a long, narrow section of roofing material that has been removed well ahead of fire. The strip acts as a ______
Fire break
If ventilators are working correctly, leave them alone. A turbine-style ventilator is about ____% more effective when the turbine is spinning
30%
Vent pipes are plumbing pipes that extend from inside the structure through the roofline. Vent pipes can be constructed from ____
ABS plastic, cast iron, or steel pipe.
A 45 degree cut is a series of ___ cuts.
Used to identify _____ only
2 cuts
Rafter direction
A 45 degree inspection cut will tell you x5
- Rafter type
- Rafter direction
- Sheathing type
- thickness of comp
- Smoke indicator
45 degree inspection cut; when the saw makes contact with rafter, roll over the rafter and continue the cut approximately ____ to ___ in
6 to 10in
The length of the dice cut is determined by____
The reach of tool being used to pull sheathing
The chain saw operator should cut a minimum of ___ dices before puller begins removing sheathing
3
Always have a minimum of _____ unpulled section between cutter and the puller
One
Center rafter louver. When over ventilation are, make head cut to locate a minimum of ____ rafters
3
Center rafter louver; after head cut , cut a parallel cut approximately ___ to ___ in inside rafter. Make parallel cut approximately ___ ft long
2 to 3 in
3 1/2 ft long
Panelized roof dimensions;
Plywood
Beams
Purlin
Joists
Plywood = 4x8 1/2” Beams = 6x36 / 12 to 40ft spacing Purlin = 4x12/ 8ft spacing Joists = 2x4 / 24in spacing
Cut ___ to ___ inches inside of purlins to avoid hitting metal hangers
4 to 6in
While standing on purlin, start “skim cut”. Reach out as far as you comfortably can, approximately ____ ft
3 1/2 ft
