Ch 19 485-485 concrete floors, wire cables

Questions and Answers

What is typically the last item completed in a construction project concerning fire protection systems?

Emergency exit signs

Fire alarms

Sprinkler systems (correct)

Fire doors

Which construction element should progress to within two floors of the highest level under construction?

Standpipe riser and outlets (correct)

Electrical conduits

Smoke detectors

Structural steel framing

What happens to water when hoses connected to the Fire Department Connection (FDC) are charged, if not properly shut off?

It circulates back to the water source.

It spills into the construction site.

It is diverted to fire hydrants.

It drains via cellar outlets. (correct)

What aspect of construction is often overlooked despite being required by many construction codes?

Fire doors and partitions Signup and view all the answers

What is the primary reason a building under construction is more prone to structural failure?

The absence of essential structural components like floors and roofs. Signup and view all the answers

How does a bearing wall contribute to the stability of a structure?

It carries the load which enhances overall structure stability. Signup and view all the answers

At what temperature does steel typically begin to lose strength without proper fireproofing?

1,500°F Signup and view all the answers

What role do hung ceilings play in noncombustible buildings during construction?

They serve as a fire-resistant membrane protecting exposed steel. Signup and view all the answers

Why might the fireproof coating on steel beams be compromised during construction?

The coating is often damaged or removed during alterations. Signup and view all the answers

What is a primary function of steel bracing cables in buildings under construction?

To provide temporary support until additional bracing or framing is in place Signup and view all the answers

What risk is associated with exposure of steel bracing cables to fire?

The cables fail readily, leading to potential collapse of the structure Signup and view all the answers

What action is recommended during a heavy fire affecting steel bracing cables?

Immediately evacuate the building and surrounding area or cool the cables Signup and view all the answers

In the context of building construction, what is an implication of using steel bracing cables?

Their failure could compromise the entire structural integrity Signup and view all the answers

What is the primary function of the tensioning cables in post-tensioned concrete?

To provide tensile strength to compress concrete Signup and view all the answers

What risk arises if a fire occurs while the tensioning cables are still exposed?

The cables will fail, leading to potential collapse Signup and view all the answers

How are the tensioning cables protected once the concrete has sufficiently hardened?

By packing with additional concrete and securing with clamps Signup and view all the answers

What role does the plastic coating on the tensioning cables play during construction?

To prevent concrete from adhering to the cables Signup and view all the answers

What is the main reason for utilizing the fire department connection (FDC) in standpipe systems during construction?

It is the only source for putting water into the system until the building is nearly complete. Signup and view all the answers

Why is it critical to check each floor outlet while ascending towards the fire at a construction site?

To determine if the riser is dry or if numerous valves are opened. Signup and view all the answers

What could render a standpipe system useless during firefighting operations?

Leaving the top of the riser open without a shutoff valve. Signup and view all the answers

Where are valves typically located in relation to building height?

Every 150 feet of building height or every 15 floors in residential buildings. Signup and view all the answers

What is the consequence of leaving valves closed in a standpipe system?

The entire system becomes out of use for firefighting efforts. Signup and view all the answers

What is the primary reason that poured-in-place reinforced concrete structures are most vulnerable to collapse during the first 48 hours?

The concrete has not yet reached its full strength. Signup and view all the answers

Which material is primarily responsible for giving the poured concrete its structural support once hardened?

Reinforcing steel Signup and view all the answers

What is a significant hazard present at construction sites of poured-in-place reinforced concrete buildings?

Accumulation of construction debris and flammable materials. Signup and view all the answers

What is the average weight of unhardened concrete per cubic foot?

150 lb Signup and view all the answers

How long does it generally take for concrete to harden enough to support its own weight?

48 hours Signup and view all the answers

What is a likely consequence of the failure of the 4x4 support posts during a fire?

Collapse of the entire mass of concrete above. Signup and view all the answers

Which factor could potentially dislodge the 4x4 support posts during a fire situation?

Firefighters operating hose streams. Signup and view all the answers

What secondary hazard could arise if the mass of concrete collapses onto the floor below?

It could overload the floor below, causing it to collapse. Signup and view all the answers

In the event of a fire, what is a potential risk if the 4x4 posts do not fail?

The posts may still be dislodged during firefighting operations. Signup and view all the answers

What characteristic of a fire in the specified area contributes to its rapid spread?

Proximity to flammable materials and lack of barriers. Signup and view all the answers

What is the primary purpose of the combustible coating on the ceiling material?

To prevent the ceiling from sticking to cured concrete. Signup and view all the answers

During which period is it critical for firefighters to be especially cautious due to the risk of collapse?

While the floors are braced with wooden posts after construction. Signup and view all the answers

What has been introduced in newer construction methods to improve safety compared to traditional wooden posts?

Adjustable aluminum posts and fiberglass forms Signup and view all the answers

Study Notes

Fire Protection Systems in Construction

Sprinkler systems are often the last to be installed; heads are placed only after ceilings are completed.
Standpipe riser and outlets must advance to within two floors of the highest construction level, crucial for fire codes.
Standpipes in cellars are used as drains and require manual shutoff during emergencies.

Standpipe Systems During Construction

Standpipes are generally non-automatic dry systems in buildings under construction.
Fire Department Connections (FDC) are essential water sources and should be clearly marked and accessible.
Floor outlet valves are frequently left open during construction, which may lead to operational issues.

Water Testing Procedures

First-arriving fire units should test the first-floor outlet; no water indicates potential issues in the system.
Ascend through the building checking each outlet; an open riser top renders the system ineffective.
Riser sectional valves can create zones for testing; closed valves render the system non-functional.

Structural Vulnerabilities

Buildings under construction have a higher likelihood of collapse due to incomplete structures and absent flooring or roofing.
Load-bearing walls are more stable than free-standing walls due to support from floors and ceilings.
Missing fireproof coatings on steel components can lead to rapid thermal exposure and structural failure.

Steel Bracing Cables

Temporary steel bracing cables provide essential support but are susceptible to fire exposure.
Heavy fires threaten these cables, which can lead to extensive structural collapse if not cooled or evacuated promptly.

Post-Tensioned Concrete Concerns

Tensioning cables in post-tensioned concrete are crucial for structural integrity but are vulnerable during construction phases.
Fire during the tensioning period can lead to catastrophic collapse if steel is unprotected.

Collapse Risks in Construction

Poured reinforced concrete structures are highly vulnerable to collapse when fresh concrete is curing, particularly in the first 48 hours.
The weight of unhardened concrete is significant, increasing the risk of failure during this period.

Construction Safety Awareness

Support structures like 4x4 wooden posts are essential while concrete cures; they prevent collapse during the critical period.
After 48 hours, plywood formwork is stripped, but floors must remain braced for 16-20 days after pouring.
Any fire in or above braced areas poses a high risk of structural collapse.

Evolving Construction Methods

New construction techniques increasingly use aluminum posts and fiberglass forms; however, safety principles of required support during curing remain consistent.
Disruption to supports can lead to catastrophic structural failures, especially during firefighting operations.

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Description

Test your knowledge on the principles outlined in the Fire Officer's Handbook of Tactics. This quiz covers essential aspects of fire protection systems, including their implementation in construction projects. Understand the critical timeline for various fire safety measures and improve your tactical proficiency in fire protection.