Ch 22 pg 548-552 Structural Collapse Causes and Firefighter Risks

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Questions and Answers

What might be a consequence of renovations being done without a permit?

Higher likelihood of structural weaknesses (correct)

Increased safety inspections

Guarantee of compliance with building codes

Improved structural integrity of the building

Why is a 40 yards dumpster parked in front of a building considered a significant danger sign for firefighters?

It is a sign of prior fire damage.

It indicates no one is actively using the building.

It may hide structural issues from firefighters.

It suggests ongoing renovations that could compromise safety. (correct)

What action should firefighters take if renovations are occurring without a permit?

Ignore the renovations as they will not affect safety.

Proceed with extinguishing any fires without concern.

Contact the code enforcement authorities. (correct)

Evacuate the building immediately.

What is a potential loss when a dumpster is removed from a site after renovations?

The chance for early warning signs to be identified. Signup and view all the answers

What is the primary problem associated with the failure to understand structural weaknesses during a fire incident?

It increases the likelihood of a sudden collapse. Signup and view all the answers

Which of the following is NOT a common cause of structural collapse on the fireground?

Legal renovations by certified engineers. Signup and view all the answers

What crucial acknowledgment must incident commanders and firefighters make regarding structural collapse?

Warnings may exist prior to a structural failure. Signup and view all the answers

Which disaster exemplifies the risks associated with removing a bearing wall and structural changes?

The Vendome Hotel disaster in Boston. Signup and view all the answers

What is the expected burn-through rate of wooden structural elements during open-burning time?

1 inch for every 45 minutes Signup and view all the answers

What is a major danger presented by unprotected steel pipe columns during a fire?

They can rupture explosively and cause structural failure. Signup and view all the answers

How long might lightweight steel-bar joists retain their strength in a fire?

5-10 minutes Signup and view all the answers

At what temperature should unprotected steel lally columns be expected to fail?

800°F Signup and view all the answers

What can provide warning to firefighters working on a steel deck before total failure?

Visible sagging of the steel Signup and view all the answers

What happens if fire attacks two sides of a standard 1 1/2-in.-wide (2x8) wooden joist?

It will burn completely through in less than 45 minutes. Signup and view all the answers

Which structural failure is directly associated with wooden bowstring trusses?

Dozens of firefighter deaths Signup and view all the answers

What happens when there is as little as 1 psi exerted laterally on a brick wall during an explosion?

The wall can topple easily. Signup and view all the answers

Which tactic is recommended when flammable gases or explosives are present?

Tactics be shifted away from offensive and Maintain a cautious, defensive approach. Signup and view all the answers

What precaution should firefighters take if a backdraft is suspected?

Vent at the top before entering below. Signup and view all the answers

What is a potential consequence of not venting a superheated atmosphere before entering?

Firefighters could be caught in a backdraft. Signup and view all the answers

Which chapter suggests taking precautions against destructive events like backdraft?

Chapter 3 Signup and view all the answers

What is a primary characteristic of cast iron that affects its suitability for certain structural applications?

Great compressive strength but low shear strength Signup and view all the answers

Which of the following factors does NOT contribute to the potential failure of highly heated cast-iron columns?

Increased compressive strength at elevated temperatures Signup and view all the answers

What consequence can occur when cast iron is subjected to sudden cooling after being highly heated?

Shattering of the material Signup and view all the answers

According to Professor Francis Brannigan, what is a significant risk factor for cast-iron columns leading to structural failure?

Flaws resulting in uneven thickness on one side Signup and view all the answers

What is the primary risk associated with bales of materials absorbing water?

The floor may collapse due to structural integrity due to weight and swelling. Signup and view all the answers

What weight is cited as a typical concern for bales of absorbent materials when dry?

Around 1,000 lb or more Signup and view all the answers

What type of materials are most likely to contribute to the risk of floor overload when absorbing water?

Heavy, absorbent materials like rags and cotton Signup and view all the answers

What is the weight added to a building by a 1,000-gpm master stream in one minute?

8,500 lb Signup and view all the answers

Which condition significantly contributes to structural overload during firefighting operations?

Runoff from hose streams Signup and view all the answers

How much weight does an accumulation of water 1 ft deep over an area of 20 ft by 20 ft add to a building?

25,000 lb Signup and view all the answers

Which of the following structures is mentioned as having a heavy load without fire present?

A plumbing supply store Signup and view all the answers

What is the cumulative weight of water accumulating from a single hose stream if it is not visibly draining from a building?

It may constitute a major unaccounted load Signup and view all the answers

What is the safest method of cutting flooring when structural weakness is suspected? And you don’t want vibrations

Utilizing a circular saw Signup and view all the answers

Which external factor can lead to structural collapse independent of building age?

Flooding due to storms Signup and view all the answers

What should be continually examined to predict potential collapses?

Structural integrity and surroundings Signup and view all the answers

What common misconception may lead to an underestimation of a building's collapse risk?

All buildings are designed to last indefinitely Signup and view all the answers

Which method should be employed to minimize vibrations when working near a potentially collapsing structure?

Shutting down all sources of vibrations Signup and view all the answers

Why should firefighters be cautious about cutting structural members during an overhaul?

Removing them can lead to partial collapse if they support weight. Signup and view all the answers

What is the effect of impact loads compared to gradual application of weight on a damaged structure?

Impact loads create a greater shock to the structure than gradual loads. Signup and view all the answers

Which behavior should firefighters actively avoid to maintain stability in damaged areas?

Jumping or causing any type of impact on the area. Signup and view all the answers

When is it acceptable to remove structural components during an overhaul?

When they are not supporting any additional weight. Signup and view all the answers

What should firefighters prioritize when operating in areas that are marginally stable?

Avoiding any actions that could induce vibrations or impacts. Signup and view all the answers

Study Notes

Common Causes of Structural Collapse

Structural weakness may arise from poor design, inadequate construction, or illegal renovations.
Major past incidents, like the Vendome Hotel disaster, highlight the risks linked to unauthorized structural changes.
Renovations should be evaluated by professionals to ensure safety and integrity.

Danger Signs for Firefighters

The presence of a dumpster indicates ongoing renovations that may compromise structural integrity.
Investigate what renovations are taking place and their potential effects during a fire.
Engage code enforcement when work lacks a permit, ensuring that designs are reviewed for weaknesses.

Fire Damage to Wooden Structures

Wooden bowstring trusses have been linked to several firefighter fatalities historically.
Wooden elements can burn through at a rate of 1 inch every 45 minutes of exposure, influencing load-bearing capacity.
If exposed on two sides, standard wooden joists can fail much earlier than expected.

Heating of Unprotected Steel

Lightweight steel joists lose structural strength in 5-10 minutes under fire conditions.
Steel begins to sag before failure, which may provide a warning to firefighters but may not be noticeable to those below.
Unprotected steel columns can rupture intensely when heated, leading to sudden and catastrophic failures in supported structures.

Cast-Iron Column and Facade Risks

Cast iron is often prone to shattering when exposed to high temperatures followed by rapid cooling.
Irregularities in casting may contribute to increased vulnerability to temperature fluctuations.
Critical structural failures can occur when cast-iron columns exceed about 800°F.

Explosions and Pressure Changes

Low-order explosions can dramatically increase internal pressure, posing collapse risks.
Firefighters should adopt defensive tactics if flammable substances are present and prepare for potential backdrafts.

Overloading Risks from Absorbent Materials

Manufacturing materials like newsprint and cotton can absorb water, significantly increasing weight and risk of collapse.
Heavy absorbent bales can swell, compromising structural integrity and supporting columns.

General Overloading of Floors and Roofs

Accumulated weight from snow, equipment, or runoff from firefighting can lead to structural failure.
A large volume of water can add considerable weight, stressing floors beyond their load capacity.

Risks from Cutting or Removing Structural Members

Firefighters must avoid haphazard removal of structural components during overhaul unless deemed non-load-bearing.
Careful assessment is critical to prevent unintended collapses.

Impact Load and Structural Stability

Firefighters should refrain from causing unnecessary vibrations or impact loads that could destabilize structures.
Gentle movements are safer than abrupt impacts in potentially compromised areas.

Collapse Indicators

Using elevating platforms too close to buildings can inadvertently cause structural damage.
Minimize vibrations and impacts during operations around suspected weak structures.

Miscellaneous Causes of Collapse

Natural elements like high winds or flooding can contribute to structural failures.
Aging buildings, typically over 100 years old, may be more susceptible to collapse due to accumulated stress.

Preventative Measures for Firefighters

Continuous assessment of building stability and fire conditions is crucial for avoiding collapse dangers.
Maintain vigilance as structural integrity can degrade rapidly under extreme conditions.

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Description

This quiz explores the common causes of structural collapse, including design flaws and unauthorized renovations. It highlights the dangers faced by firefighters, particularly in relation to wooden structures during emergencies. Understanding these risks is crucial for ensuring safety and compliance in construction and firefighting efforts.