Collapse of BB CH10 Medium

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What tools does the older firefighter carry while scaling the ladder?

Gasoline-powered circular saw and an axe

Gasoline-powered circular saw and a canvas sling (correct)

Axe and a 6-foot pike pole

Canvas sling and a 6-foot pike pole

What is the size of the noncombustible construction garage involved in the fire?

250x250 foot

100x100 foot

200x200 foot (correct)

150x150 foot

What action does the battalion chief order the ladder company to take?

Vent the roof (correct)

Stretch a hoseline to the fire

Assist the first engine company

Force the front doors

What does the firefighter do with the gasoline-powered circular saw upon reaching the roof?

Lays the saw on the roof deck and vigorously shakes it Signup and view all the answers

What type of roof did the firefighter encounter during the fire?

Lightweight steel open-web bar joist roof Signup and view all the answers

What caused the roof to collapse during the fire?

Flames erupting from the vent hole Signup and view all the answers

What happens to heated steel during a fire?

It can expand, bend, twist, and sag Signup and view all the answers

What is a potential consequence of the trend towards lightweight steel buildings?

Rapid collapse during fires Signup and view all the answers

What tool did the firefighter use to cut through the steel roof deck?

High-speed carbide blade Signup and view all the answers

What did the firefighter use to lift the cut portion of the roof?

Pike pole Signup and view all the answers

What does the text highlight as a potential danger during a fire involving steel buildings?

Steel distortion and movement Signup and view all the answers

What is the main reason for the increased use of steel in buildings since World War II?

Replacing wood and masonry in structural systems Signup and view all the answers

What is the firefighter's main concern during the final cut?

The roof section sagging and nearly falling into the fire Signup and view all the answers

What is the firefighter's eventual fate after the roof collapse?

Rescued by a fellow firefighter using a portable ladder Signup and view all the answers

What is the primary reason for steel buildings being quick to construct?

Inexpensive and quick construction Signup and view all the answers

What can the use of steel in buildings lead to during a fire?

Potential for rapid collapse Signup and view all the answers

What is the failure temperature range of steel?

1,000 to 1,100 degrees Fahrenheit Signup and view all the answers

Which material has greater tensile and compressive strength than steel?

Aluminum Signup and view all the answers

What is considered the best method to protect steel from fire?

Encasement with concrete Signup and view all the answers

What is the purpose of bar joist trusses and C-beams in building construction?

To increase loadbearing capacity Signup and view all the answers

What is the failure temperature of steel according to the National Fire Protection Association?

1,000 to 1,100 degrees Fahrenheit Signup and view all the answers

What is a drawback of concrete encasement as a method to protect steel from fire?

Chunks of concrete potentially collapsing during a fire Signup and view all the answers

What is the range of failure temperature for steel in the text?

1,000 to 1,100 degrees Fahrenheit Signup and view all the answers

What are the three common methods to protect steel from fire mentioned in the text?

Encasement with concrete, installation of a fire-retarding ceiling, applying a spray-on fire retarding material Signup and view all the answers

What is the purpose of shaped steel in building construction?

To increase loadbearing capacity Signup and view all the answers

What material was the World Trade Center mostly constructed of?

Steel Signup and view all the answers

What is the range of the failure temperature of steel according to the National Fire Protection Association?

1,000 to 1,100 degrees Fahrenheit Signup and view all the answers

What is a drawback of concrete encasement as a method to protect steel from fire?

Chunks of concrete potentially collapsing during a fire Signup and view all the answers

What hazard does spalling pose to firefighters during a fire?

Falling concrete chunks Signup and view all the answers

What method uses a suspended ceiling system with one-hour fire-retarding panels to separate steel supports from a fire?

Membrane ceiling Signup and view all the answers

What danger exists with a membrane ceiling if the suspension system is not properly constructed?

Collapse danger Signup and view all the answers

Which method of protecting steel from fire heat is described as the least effective?

Spray-on fire-retarding material (SFRM) Signup and view all the answers

What have post-fire investigations shown about the effectiveness of SFRM in protecting steel during a serious fire?

Ineffective Signup and view all the answers

What is the material sprayed on steel today for fire protection?

A slurry of vermiculite, volcanic rock, or mineral fiber mixed Signup and view all the answers

When was the spray-on fire protection method known to be ineffective since its introduction?

1970s Signup and view all the answers

What factor makes the spray-on fire protection method the preferred choice for new buildings despite its ineffectiveness?

Cost and speed of application Signup and view all the answers

What effect do applications of primer paint on steel have on the adhesion of spray-on fire retarding effectiveness?

Reduce adhesion by one third to one half Signup and view all the answers

What issue arises when the spray-on slurry is not mixed properly and may not be applied evenly?

Ineffective fire protection Signup and view all the answers

What can cause the fire-retarding spray-on to blow off and leave the steel unprotected even if applied properly?

Vibrations and HVAC air movement Signup and view all the answers

What aspect of the spray-on insulation for steel structures, such as the World Trade Center, has been questioned?

The thickness Signup and view all the answers

What was a problem revealed after the collapse of the World Trade Center towers regarding the spray-on fire retarding material?

Difficulty adhering to the steel round bar of the truss Signup and view all the answers

What is the primary reason the New York City fire department prohibited the use of open web-steel joists in nonresidential high-rise buildings?

Lack of appropriate fireproofing standards Signup and view all the answers

What criteria does the construction industry now determine are necessary for the effectiveness of spray-on fire retarding material on steel during a fire?

Adhesion, consistency, and thickness Signup and view all the answers

What type of construction is well suited for large-area, commercial buildings with low hazard content?

Noncombustible construction Signup and view all the answers

What is a hazard of lightweight steel bar joists mentioned in the text?

Early collapse after fire exposure Signup and view all the answers

What should fireground commanders consider in an unprotected Type Il steel building?

A strategy of horizontal ventilation and defensive exterior attack Signup and view all the answers

What is a drawback of concrete encasement as a method to protect steel from fire?

Increased risk of structural collapse Signup and view all the answers

What is the primary reason for steel buildings being quick to construct?

Ease of fabrication and assembly Signup and view all the answers

What is the main reason for the increased use of steel in buildings since World War II?

Advancements in steel manufacturing Signup and view all the answers

What is the purpose of bar joist trusses and C-beams in building construction?

Roof and floor supports Signup and view all the answers

What is the hazard posed to firefighters during a fire involving steel buildings?

Early collapse of steel bar joists Signup and view all the answers

What is the potential danger with a membrane ceiling if the suspension system is not properly constructed?

Risk of ceiling collapse Signup and view all the answers

What is the primary concern regarding roof ventilation in 21st-century lightweight steel buildings?

Roof ventilation is less effective due to the quick collapse of lightweight steel roofs Signup and view all the answers

What is the comparison between ventilating large rectangular windows and making a 4x4-foot roof cut in one-story, noncombustible buildings with lightweight steel joists?

Ventilating windows is faster and safer than making a 4x4-foot roof cut Signup and view all the answers

What is the impact of introducing lightweight steel bar joists or C-beam roof construction in a community accustomed to standard wood construction?

It presents a new safety hazard to firefighters due to quicker collapse Signup and view all the answers

What challenge do firefighters face when transferring their experience from buildings with solid wood joists to those with lightweight steel roofs?

They cannot transfer their sense of safe operating time to a building with a lightweight steel roof Signup and view all the answers

What factor influences the failure of unprotected steel in a fire?

Fire temperature Signup and view all the answers

What is the considered failure temperature of steel in a fire?

1,100 degrees F Signup and view all the answers

What poses a significant danger to firefighters in noncombustible construction?

Lightweight steel bar joists Signup and view all the answers

What is the consequence of wide spacing of steel bar joists in noncombustible construction?

Increases risk of firefighters falling through roof openings Signup and view all the answers

What is the purpose of fire protection systems in noncombustible buildings?

Essential in buildings with high fuel load ratings Signup and view all the answers

What provides insight into the rapid rise in temperature during a fire?

The time-temperature test fire Signup and view all the answers

What is the effect of steel's ability to conduct heat and expand during a fire?

Can lead to structural collapse Signup and view all the answers

What is the main concern for firefighters in Type II noncombustible construction with steel trusses?

Compromised ability to gauge the safety of a burning building Signup and view all the answers

What is a potential consequence of the failure of noncombustible steel buildings in a fire?

Quick destruction due to lack of fire resistance Signup and view all the answers

What is the primary purpose of traditional assumptions about roof construction in the context of firefighting?

No longer hold true, and firefighters must be aware of collapse potential Signup and view all the answers

What is the potential danger of the lack of fire resistance in noncombustible steel buildings?

Structural collapse Signup and view all the answers

What is the main reason for the compromised ability of firefighters to size-up fires in Type II noncombustible construction?

Changes in noncombustible Type II construction Signup and view all the answers

What determines steel failure during a fire?

Thickness and mass of steel elements Signup and view all the answers

What are roof support systems in noncombustible buildings designed to support?

Only rain or snow accumulation Signup and view all the answers

What property does large-size steel have that aids in fire resistance?

Heatsink property Signup and view all the answers

What type of steel buildings are not suitable for high hazard occupancies?

Type II noncombustible unprotected steel buildings Signup and view all the answers

What is the nature of steel in terms of fire resistance?

Noncombustible but not fire-resistive Signup and view all the answers

What can influence the collapse of steel joists in a fire?

Roof decks such as lightweight insulation or precast concrete planks Signup and view all the answers

What is the purpose of increasing the mass of a steel element?

To increase its fire resistance to a limited degree Signup and view all the answers

What does the text highlight about the temperature rise in a fire?

Temperature reaches over half the total rise in just 10 minutes of fire Signup and view all the answers

What is the main concern when designing roof support systems?

Not considering the weight of firefighters and their equipment Signup and view all the answers

What is the drawback of lightweight steel bar joists mentioned in the text?

They can influence the collapse of steel joists Signup and view all the answers

What is the impact of fire size on steel failure?

A large-area fire will heat steel to its critical temperature more quickly Signup and view all the answers

What is the material that roof support systems in noncombustible buildings are designed to support?

Only rain or snow accumulation Signup and view all the answers

Study Notes

Fire Protection Methods for Steel Structures

Spalling, caused by the expansion of moisture in concrete into steam during a fire, poses a hazard to firefighters by causing concrete chunks to fall.
The "membrane ceiling" method uses a suspended ceiling system with one-hour fire-retarding panels to separate steel supports from a fire, but it may be ineffective due to missing or improperly placed panels and penetrations.
A collapse danger exists with a membrane ceiling if the suspension system is not properly constructed, posing a serious hazard to firefighters.
Spray-on fire-retarding material (SFRM) is the least effective method of protecting steel from fire heat and is often dissipated by the fire, distorting the steel.
Post-fire investigations have shown that SFRM is ineffective in protecting steel for the designated time during a serious fire.
The material sprayed on steel today for fire protection is a slurry of vermiculite, volcanic rock, or mineral fiber mixed and is less effective in protecting steel from fire.
The spray-on fire protection method has been known to be ineffective since its introduction in the 1970s and has been shown to be inadequate in post-fire investigations.
The method of fire protection for steel using spray-on material is less expensive and faster compared to other methods, making it the preferred method for new buildings despite its ineffectiveness.
Tests have shown that applications of primer paint on steel reduce adhesion of spray-on fire retarding effectiveness by one third to one half.
The spray-on slurry is often not mixed properly and may not be applied evenly, leading to ineffective fire protection.
Even if applied properly, vibrations and HVAC air movement can cause the fire-retarding spray-on to blow off and leave the steel unprotected.
The thickness of the spray-on insulation for steel structures, such as the World Trade Center, has been questioned, with varying thicknesses used over time.

Factors Affecting Steel Failure in Fires

Temperature reaches over half the total rise in just 10 minutes of fire (1,300°F in 8 hours).
Load stress determines steel failure during fire; roofs in modern noncombustible buildings are not designed to support the same load as floors.
Roof joists in older buildings could support the same load as floors, but modern design considers weight limitations.
Roof support systems in noncombustible buildings are designed to support only rain or snow accumulation.
The weight of firefighters and their equipment is not considered when designing roof support systems.
Roof decks, such as lightweight insulation or precast concrete planks, can influence the collapse of steel joists.
The thickness and mass of steel elements impact fire resistance; heavy, thick sections have greater resistance.
Increasing the mass of a steel element can increase its fire resistance to a limited degree.
Large-size steel has a heatsink property, absorbing and transferring heat away from flame contact.
Fire size affects steel failure; a large-area fire will heat steel to its critical temperature more quickly.
Type II noncombustible unprotected steel buildings are not suitable for high hazard occupancies.
Steel is noncombustible but not fire-resistive; it will collapse from the effects of fire without protection.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge of fire protection methods for steel structures with this informative quiz. Learn about the effectiveness and challenges of different techniques, such as membrane ceilings, spray-on fire-retarding material, and more.