Why do we ventilate buildings during a fire?
• Smoke/Heat Relief
• Prevent Horizontal Fire Spread
• Reduce Backdraft Conditions
What does a 45° inspection cut tell us?
• Roof Comp Layers
• Sheathing Type
• Rafter Type/Direction
• Smoke Indicator
How do we complete a 45° inspection cut?
• 45° cut away from bearing wall
• Roll rafter & continue 6”-10” past
• Cross 1st cut back towards bearing wall
• Complete triangle
What is a score cut?
A light cut out of the roof comp only
What is a skim cut?
A light cut made through the roof comp and sheathing. Right over the top of the rafters.
When do we use the skim cut?
As the top cut on all panelized operations
What is a kerf cut?
A single cut made through the roof decking the same width as the chainsaw blade.
What is a smoke indicator hole?
A small triangle hole through the roof comp and sheathing. Placed along the path of egress every few yards.
What is a plug cut?
Cut a small triangular piece of roof comp only, to expose the roof sheathing.
What are the offensive ventilation cuts?
• Pullback
• Offensive Louver
What are the defensive ventilation cuts?
• Louver off a purlin
• Louver off a main
What mph of natural vertical air currents can be created in stair shafts simply by opening a door at the bottom and the roof level?
3 to 6 MPH
