Ch. 7 Sloping peak roof construction Flashcards
The roofs structural framing, Roof deck, and the slate or tile roof shingles are all examples of what type of hazards of a sloping peak roof?
They are all examples of a collapse hazard.
The 3 most common types of sloping roofs are?
GABLE- which has sides sloping up from 2 walls
HIP- which has sides sloping up from 4 walls
GAMBREL-which has sides sloping up from 2 sides, with the lower slope steeper than the upper slope.
What are the 3 less common types of sloping roofs?
Shed, saltbox and mansard
A primary structural member is a structure that supports another structural member and the collapse of a primary structural member may lead to the failure of another part of the bldg. In sloping roof construction ridge rafters, hip rafters, and bearing walls are primary structural members.
How many primary structural members in a Flat roof?
Flat roofs have 2 primary structural members, the 2 bearing walls
A primary structural member is a structure that supports another structural member and the collapse of a primary structural member may lead to the failure of another part of the bldg. In sloping roof construction ridge rafters, hip rafters, and bearing walls are primary structural members.
How many primary structural members in a Gable roof?
Gable roofs have 3 primary structural members, the 2 bearing walls and 1 ridge rafter.
A primary structural member is a structure that supports another structural member and the collapse of a primary structural member may lead to the failure of another part of the bldg. In sloping roof construction ridge rafters, hip rafters, and bearing walls are primary structural members.
How many primary structural members in a Hip Roof?
*NEW
Hip roofs have 9 primary Structural members, 4 BEARING WALLS, one ridge rafter and 4 hip rafters.
When structural supports are close together a spongy feeling of the roof deck indicates what?
Char or fire weakening
When a roof or floor has structural supports spaced several feet apart this will create what type of effect?
A SPRINGBOARD effect.
The 3 most common type of wood construction used for sloping roofs are timber truss, plank and beam, and rafter construction. Of the 3 which has the least amount of unsupported deck and is the safest to walk on?
Rafter Constructed roof-least amount safest to walk on.
Plank and beam- has unsupported deck area but not as much as truss.
Truss roof- have the most amount of unsupported deck and are the most dangerous
Slate & tile roofs are considered fire retardant roof coverings. They protect the wood from sparks or air-borne embers, their fire retarding effect slows any fire and heat in an attic from traveling upward. They can also negatively impact fire operations in what way?
They conceal a fire weakened structure. The roof rafters & roof deck below can be almost completely destroyed by fire yet the roof shingles can look stable, un-scorched and un-blistered. They have the same effect as a terrazzo floor, they can conceal fire, heat, and smoke below and then collapse in one large section.
A sloping roof is measured by its pitch. A low pitched roof (“2 in 12”) 2 units of roof rise to 12 units of rafter span, such as a ranch type house can be walked on, while a medium pitched roof “5 or 6” in 12” should have a roof ladder either secured to the ridge or butted by a base of a parapet wall to ensure footing for operating. Can a high pitched roof (15” in 12”) such as a A-frame or Tudor house be walked on with the assistance of a roof ladder?
A high pitched roof cannot be walked on safely even with the assistance of a roof ladder. A FF MUST operate from an extended aerial ladder or the bucket of a tower ladder.
FF’s should avoid walking on roof edges, where the slope of the roof changes and where a sloping roof abuts a VERTICAL plane for what reason?
Accumulations of snow or ice on sloping roofs can result in areas of rotted or decayed roof deck, which can collapse under the weight of a FF
The SOP for dealing with sloping roofs at a fire should be:
(3) answers in order of preference?
Life safety
Fire containment
Property Protection
