Ch 9 pg 247-253 inverted and flat roofs

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Questions and Answers

What structural element sets the inverted roof apart from the standard flat roof?

The use of metal deck instead of traditional wooden boards.

The roof boards are nailed to a framework raised above the main roof joists. (correct)

The roof boards are attached directly to the main roof joists.

The 2x4s framework is positioned at the same level as the roof boards.

Which aspect of the metal deck roof is notable compared to other roof types?

It has been popular for only the last decade.

It is primarily used in residential buildings.

It dominates the flat-roof industry in the east and midwest. (correct)

It utilizes traditional wood-related materials for its structure.

What is the primary construction method used in a standard flat roof?

A metal framework supports the roof structure.

Roof boards are nailed directly to the main roof joists. (correct)

Roof boards are layered over insulation panels.

The boards are temporarily secured with adhesives.

Which of the following correctly describes the main difference between the structural support in standard flat roofs and inverted roofs?

Inverted roofs support a framework raised above the joists, while flat roofs do not. Signup and view all the answers

What feature of the inverted roof contributes to its distinct design compared to standard flat roofs?

A higher elevation of roof boards relative to the joists. Signup and view all the answers

Which method should not be used to access the roof?

Through interior stairs Signup and view all the answers

What should members vent upon reaching the roof?

Vertical shafts Signup and view all the answers

Which tool is suggested for venting the top-floor windows?

A Halligan tool Signup and view all the answers

What is the recommended starting action upon reaching the roof?

Ventilation of vertical shafts Signup and view all the answers

Which of the following is NOT specified for venting the top-floor windows?

A ladder Signup and view all the answers

What is the maximum span between supports for older flat roof beams?

20 ft Signup and view all the answers

What material is primarily used for roof decking in old-style roofs?

1x6 tongue-and-groove planking Signup and view all the answers

Which layer is typically added on top of the tar paper to retard flames?

Gravel Signup and view all the answers

What is a significant risk to firefighters on older flat roofs?

Falling through weak deck boards Signup and view all the answers

What type of buildings typically use old-style construction with exposed joists?

Garages and warehouses Signup and view all the answers

What feature is created by adding a suspended ceiling below the roof in certain buildings?

A cockloft Signup and view all the answers

How many firefighters are required for handling a working fire on a top floor of a large-area flat-roof building?

Four firefighters Signup and view all the answers

What tools should firefighters ideally bring for a working fire on the top floor?

Power saws and hooks Signup and view all the answers

What is the primary method used to determine the seat of a fire?

Observing the fire's condition Signup and view all the answers

Which of the following is NOT mentioned as a means to locate the proper site for ventilation?

Examining air pressure differences Signup and view all the answers

What defines the term 'directly over the fire' in the context of ventilation opening?

As close to the fire as is safely possible Signup and view all the answers

What is the purpose of examination holes in the roof?

To look for fire Signup and view all the answers

Which type of opening is commonly made with a power saw for fire ventilation?

Triangular opening Signup and view all the answers

What is the primary disadvantage of a kerf cut in examining a roof for fire?

It provides limited visibility of fire on either side due to its narrow width. Signup and view all the answers

How is a triangular-shaped opening created for fire examination?

By plunging the saw into the roof three times to create overlapping edges. Signup and view all the answers

What is the width of the opening created by a kerf cut?

1/4 inch Signup and view all the answers

What advantage does a triangular-shaped cut have compared to a kerf cut?

It allows for the insertion of a nozzle or pipe for extinguishing fire. Signup and view all the answers

What must be true for a triangular cut to retain its shape without falling into the structure?

It must be directly over a joist. Signup and view all the answers

What is the primary concern when positioning the cut in relation to wind?

The direction of the wind Signup and view all the answers

What should be ensured when making the initial cut?

It does not hinder further cutting efforts Signup and view all the answers

What could be a potential risk of not considering wind direction when making cuts?

Retreat paths may become cut off Signup and view all the answers

What size opening is intended to be created through the sequence of cuts?

8x8 ft Signup and view all the answers

In the event of fire venting, what should be avoided with the cut location?

Endangering nearby exposures Signup and view all the answers

What is the primary consideration before making a cut on a roof?

The means of escape from the roof Signup and view all the answers

Why is it important to have at least two means of escape from a roof?

In case one route is blocked by fire Signup and view all the answers

What should be done to ensure safety while making cuts on smaller roofs?

Avoid making cuts that block the escape routes Signup and view all the answers

What can happen if fire vents out of a hole made in a roof?

It can seal off escape paths Signup and view all the answers

What should be arranged if there is only one escape route available?

Another ladder for access Signup and view all the answers

What is the main advantage of extending an existing cut instead of starting a new one?

It ensures you are correctly positioned in the right location. Signup and view all the answers

Why is it recommended to cut as many additional bays between the joists as possible?

To utilize existing joists as draft curtains for efficient airflow. Signup and view all the answers

What role do joists play when cutting additional bays between them?

They function as draft curtains to enhance airflow. Signup and view all the answers

What should be taken into account regarding wind direction during the cutting process?

It is advisable to have the wind at your back. Signup and view all the answers

What might be an additional factor, aside from smoke, that influences a decision to retreat while cutting?

Intense heat coming from the fire. Signup and view all the answers

What is the primary concern when making cuts in a building structure?

Preventing the interior forces from being driven out Signup and view all the answers

Which of the following statements about the cutting process is correct?

Making the first seven cuts can provide relief to the attack team. Signup and view all the answers

What is the recommended action if the process of cutting takes too long?

Pull the first quarter after the initial cuts are made. Signup and view all the answers

What may happen if the cutting process takes an excessive amount of time?

The interior forces are driven out of the building. Signup and view all the answers

How many linear feet of cutting are required to make an 8x8 hole?

55 linear feet Signup and view all the answers

What is a significant risk when using a hoseline on a roof with an active fire?

It can drive smoke back toward personnel below. Signup and view all the answers

Why is it crucial to continually evaluate the stability of the roof during firefighting operations?

Existing heat levels can cause the roof to collapse unexpectedly. Signup and view all the answers

Which statement best describes the behavior of newer roofing materials when heated?

They turn into an ignitable liquid pool. Signup and view all the answers

What is the consequence of pulling the roof opening during a fire?

It can lead to a flammable liquid pooling at the opening. Signup and view all the answers

What is a notable distinction of roofs previously affected by fire or rot?

They are likely to have weakened supports. Signup and view all the answers

Study Notes

Roof Types

Standard Flat Roof: Main roof joists positioned directly at roof level with roof boards nailed to joists.
Inverted Roof: Roof boards attached to a framework of raised 2x4s, several feet above main joists.
Metal Deck Roof: Predominantly used in flat-roof construction in the eastern and midwestern U.S. for the past three decades.

Old-Style Roof Construction

Older flat roofs built with wooden beams, typically 2x10s or 3x12s, spaced 16 inches apart and capable of supporting similar loads as floor joists.
Roof decking usually consists of 1x6 tongue-and-groove planking, layered with tarpaper for moisture protection.
Roofs mopped with hot tar, sometimes topped with gravel for fire retardation.
Lifespan ranges from 20-30 years, leading to multiple layers in older structures.
Roof boards offer early warning to firefighters as they tend to burn through before supporting joists.
Exposed joists found in older garages and warehouses; suspended ceilings are used in occupied buildings for aesthetics and insulation.

Roof Safety

Firefighters must vent vertical shafts like bulkhead doors and skylights upon reaching the roof.
Top-floor windows can be vented using hooks or Halligan tools from the roof edge.

Locating the Proper Site

Ventilation openings should be made as close to the fire’s location as safely possible, taking roof conditions and collapse risks into account.
Observable indicators of fire include venting smoke and flames from windows, with examination holes providing insight into conditions beneath the roof.

Kerf Cut

A kerf cut is a narrow, quick-to-make opening (1/4 inch wide, 10 inches long) for roof examination; not ideal for fire visibility.

Triangular-Shaped Opening

Triangular cuts provide better visibility (8 to 10 inches wide) and allow for nozzle insertion if necessary.
Care must be taken to ensure cuts are made away from potential escape routes.

Second Concern

Wind direction influences cut placement, as it can affect flame propagation and firefighter safety.
Ensure multiple escape routes from the roof are available before beginning ventilation.

Other Concerns

Extending existing cuts for ventilation is often more efficient than creating new openings.
Open more bays between joists to enhance airflow and smoke removal.

The Inverted Roof

Combustible waterproofing materials like older tar paper can create significant fire hazards due to large smoke volumes and potential liquid pooling when heated.
Use of hoselines on roofs is crucial to control spreading fires, but must not be operated through ventilation openings, as this may push smoke and flames back toward firefighters.
Evaluate roof stability regularly to prevent surprises from fire or deterioration impacting structural integrity.

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Description

This quiz covers the essential safety protocols for firefighters when accessing the roof of a building. It focuses on the appropriate methods for venting vertical shafts and engaging with top-floor windows to ensure effective fire response. Test your knowledge on these critical safety measures.