Flashcards in taxpayer sec 1-5 Deck (32):
Define: Axial load
a force perpendicular to the supporting member. An axial load is straight and true and is evenly applied to the bearing structure.
define: Eccentric load
a force whose resultant is perpendicular to the supporting member but does not pass through the center of mass. The load is not evenly applied to the supporting or bearing member.
define: impact load
are loads delivered, in a short time, on structural members and produce stresses on structural members that may not have been provided for in design and may cause collapse.
define: lateral load
are loads that are exerted outwardly on a horizontal plane. these forces may take place during a collapse or an explosion. walls are not usually designed to withstand severe lateral loads
What are the rules for sprinklers in taxpayers?
A. 1938 code
B. 1968 code
C. 2008 code
A. Area exceeding 10,000 square feet
B. Area exceeding 7500 square feet
C. Full building - area exceeding 12,000 square feet or the combined area on all floors including mezzanine exceeds 24,000 square feet.
Occupancy within building- area exceeding 7500 square feet OR area of any size is located 3 stories above grade OR area of any size is located in a high rise building OR area of any size contains an unenclosed stair or escalator connecting two or more floors.(2.5.1)
T or F: Cocklofts in taxpayers can vary in height ranging from 4 inches to more than six feet.
What is the most common roof found on taxpayers?
Wood joists covered with either tongue and groove boards or plywood. The roof is then covered with combustible waterproofing material commonly called tarpaper or built up roofing which may be several layers thick.(3.3.1)
what is sometimes constructed over an existing roof and forms an additional cockloft?
Inverted, raised or reversed roof construction is used to create a pitch to provide drainage.(3.3.2)
The truss is composed of two major members. The top one is called ___1___ and the lower one is called ____2____. Shorter members, called ___3___, connect the top and bottom chords.
1. top chord
2. bottom chord
You arrive at a building that has a hump-like roof profile. What does this tell you?
Wooden bowstring truss(3.3.3)
Updated calculations have revealed that bowstring truss roofs may only support ____ of the load they were originally designed to hold.
T or False: Failure of one truss element can cause failure of the entire truss. This in turn may pull down a number of trusses. In a domino effect which will cause the entire roof, or a large portion, to collapse.
True or False: Wood truss roofs become spongy or sag. This is a warning sign that it will fail.
Wood truss roofs appear to fail without warning. The roof does NOT sag or get spongy. Steel trusses tend to stretch when losing their strength because of elevated temperatures, but wood tends to snap. (3.3.3 j)
Unprotected open web steel joists are particularly vulnerable to elevated temperatures of a fire and may collapse after only ______.
a. 5-10 minutes
b. 10-15 minutes
c. 20 minutes
d. 15-20 minutes
A. 5-10 minutes
How is the stability of masonry walls dependent on the integrity of the roof?
The roof acts as a monolithic brace which ties the walls together. In effect the roof is holding up the walls by providing lateral support.
Marquees are hollow boxes which can fill up with run off water at a fire operation due to use of heavy streams. A 12' x 24' marquee 4 feet deep when filled can contain approximately how many tons of water?
B. 35 tons of water (3.5.1)
in effect a hanging swimming pool. In 1956 6 firefighters lost their lives in a collapse of a marquee at a furniture store.
1. An average 50 foot long steel beam, heated uniformly over its length to 970 F will extend how long?
2. At 1000 F a 100 foot steel beam will have extended how much?
1. 4 inches
2. nine and a half inches
T or F: Cooling a steel member will cause it to regain strength and load carrying ability.
True. Steel will contract to its original length as it is cooled and if the beam has sagged, this shortening may pull the end of the beams off their supports or twist the beam allowing the joists to drop.(3.6.4)
Cast iron columns are unpredictable and fail, on the average, in about _____ minutes in fire endurance test.
A heavy body of fire burning out of control for_______ minutes or more, particularly in a large open floor area is a sign for potential structural collapse.
It must be remembered that when a high heat condition, combustible gases and highly heated contents are present, a room or fire area requires only_____% of its space to contain the explosive mixture for the entire area to possibly explode
25% (4.4.1 F)
Who controls all horizontal and initial vertical ventilation?
Ladder company officer
What is the recommended size of the roof cut for a taxpayer?
eight feet by eight feet
The immediate ventilation and cutting of an effective size hole on the roof calls for____ saws and ______ members on the roof.
2 saws and 4 members (5.4.12)
When must a roof sector supervisor supervise roof operations?
when more than one power saw is working on the roof (5.4.12)
when using the fog nozzle(FT-2 tip) to relieve an area of smoke and heat how is this done?
adjust fog pattern to width of opening and stand back four to five feet. (5.4.16)
1.At cellar fires, when cutting the first floor to provide ventilation where shall this cut be made?
2.What is needed when making these cuts?
1.Cut shall be made as near to windows as possible and away from doorways and aisles.(5.5.22)
2. all such cuts should be covered by hoselines(5.5.22)
T or False: Under no circumstances shall any member operate on the roof of any building involved in a content or structural fire with a wooden, metal or combination bowstring truss design.
While cutting the roof of a taxpayer you notice a white powdery residue. what does this tell you and what should be done?
the roof is a gypsum roof deck and members should immediately notify the roof sector supervisor and IC and evacuate the roof (5.5.26 H)
How wide ishould a trench cut be?
At least three feet wide(5.6.1)
What situations warrant a second alarm?
transmit second alarm for extension to the cockloft,adjoining occupancy or for an advanced fire in the cellar.(5.7.4)