Building Construction

Question 1

What are the two main model building codes in the US?

Answer 1

The NFPA 5000, Building Construction and Safety Code, and the International Code Council’s (ICC) International Building Code (IBC). While minor differences exist between the two, they both classify building construction into 5 types:

• Type I - Fire Resistive
• Type II - Noncombustible
• Type III - Ordinary Constuction
• Type IV - Heavy Timber
• Type V - Wood Frame

Note, these are important to assess since it determines how quickly fire will spread and the building will collapse!

Question 2

What is Type I construction?

Answer 2

Fire resistive construction provides the highest level of protection from fire spread as well as structural collapse. (However it is not fireproof!)

All structural members are composed of noncombustible or limited combustible materials with a high fire rating so that they don’t add to the fuel load. As a result, Type I buildings will remain structurally stable longer than other construction types during a fire and are the most collapse resistant. Concrete, precast concrete, and protected steel frame construction meet this criteria.

Note that while the structure may not burn from fire, it will still degrade. During a fire, be aware of the following conditions:

• Compartments can retain heat which contributes to potential for rapid fire development
• Roofs may be extremely difficult to penetrate
• Windows may not open or be breakable causing challenges for ventilation

Question 3

What is Type II construction?

Answer 3

Noncombustible construction has structural members that will not contribute to the fuel load / fire development, but they don’t meet the stricter requirements of Type I construction because they’re constructed of lighter-weight materials with lower fire-resistance ratings.

Most common types of these materials include metal framing members, metal cladding, or concrete block wall and unprotected open web joists supporting metal roof decks.

Most modern commercial buildings are Type II.

Question 4

What differentiates Type II construction from Type I construction?

Answer 4

Type II construction is also made of noncombustable materials, but given that they are lighter-weight and have lower fire ratings, it does not have as much collapse resistance as Type I.

Question 5

What is Type III construction?

Answer 5

Ordinary construction has exterior walls and structural members constructed of noncombustible or limited combustible materials like brick and interior walls, columns, beams, floors, and roofs are completely or partially constructed of wood. This is commonly found in mercantile structures, businesses, residential structures, and older schools.

Note that the following conditions can influence fire behavior:

• Fire will spread through void spaces, such as inside the wooden channels that roof and truss systems create between wall studs, unless fire stops are installed
• Prefabricated wood truss systems similar to those used in Type V construction may also be found in Type III construction and they fail quickly when exposed to fire.

Question 6

What is Type IV construction?

Answer 6

Heavy timber construction is characterized by the use of large dimensioned lumber or laminated wood. It’s extremely stable and resistant to collapse due to the sheer mass of the large structural members. It will take a while for them to catch on fire, but once they start burning, they go fast. They also burn very hot! Therefore anything surrounding these structures when they’re on fire is an exposure risk.

In Type IV construction, exterior walls are constructed of noncombustible materials while interior elements such as floors, walls, and roofs are solid or lamenated wood with no concealed spaces. This lack of voids helps prevent unforeseen fire travel.

Note that the metal joists / screws holding these beams together will fail first. Also, glue-laminated beams may fail when exposed to fire as the heat will melt the glue.

Question 7

Is Type IV construction resistant to fire?

Answer 7

No. They are resistant to collapse, due to their sheer mass, but wood is a non fire resistant material.

Question 8

What is the difference between Type III and Type V construction?

Answer 8

Type III has a noncombustable base and walls with a wooden ceiling whereas Type V has all-wooden framing and ceiling with only a protective outer layer of brick or siding.

Question 9

What is Type V construction?

Answer 9

In wood frame construction the exterior load-bearing walls are composed entirely of wood. Don’t be fooled by a veneer of stucco, brick, or stone. It may look like Type III construction but it’s not. (This could become a danger in a fire as it can come loose and fall on you.) An example of Type V construction is single family homes.

Conditions to be aware of during a fire include:

• The roof and floor are made of trusses and I-beams that burn more quickly than solid lumber
• Vinyl siding will melt and is combustible. It can contribute to fire development and spread.

Question 10

What’s the difference between a “balloon” and a “platform” frame for Type V construction?

Answer 10

The studs in a balloon frame extend from the foundation to the rafters without fire stops, whereas in a platform frame, the studs are independent on each story and have fire stops built in. This increases the risk of vertical fire spread from story to story in balloon frame construction versus platform.

Question 11

Which is a bigger indicator of structural collapse: the type of building construction or size-up, duration of fire, and fireground actions?

Answer 11

Size-up, duration of fire, and fireground actions!

Question 12

What are factory-built homes?

Answer 12

Factory-built homes (also known as menufactured, prefabricated, modular, and industrialized) are structures that are partially or completely built in a factory and shipped to a location where they’re installed. They take many forms, including mobile homes.

Question 13

What is a manufactured home?

Answer 13

A mobile home. These are the most common type of factory-built housing. They’re almost completely prefabricated prior to delivery and are the least expensive. Note that they do not conform to the model building codes and are governed by a HUD standard instead.

While the use of lightweight building materials makes forcible entry easy, they are susceptible to early failure in a fire. Fire may also spread more quickly in mobile homes because there are fewer interior walls.

Question 14

What has contributed to the decreased the number of manufactured house / mobile home fires?

Answer 14

• Factory installed smoke and carbon monoxide alarms
• Use of flame retardant materials in interior finishes
• Safer heating and cooking appliances
• Installation of Gypsum boards rather than wood paneling finishes
• Factory installed sprinkler systems

Question 15

What is a modular home?

Answer 15

A modular home is a type of factory-built construction in which sections are transported to the construction site and attached to a permanent foundation, which may include a full basement. They must comply with the same local building codes as site-built homes.

Question 16

What is a panelized home?

Answer 16

A type of factory-built construction in which preconstructed panels made of foam are sandwiched between two sheets of plywood are assembled on-site. No framing is required.

Question 17

What is a pre-cut home?

Answer 17

A type of factory-built construction in which individual parts are custom cut and then assembled on-site. Pre-cut home come in the following styles:

• Pole houses
• Post-and-beam construction
• Log homes
• A-frames
• Geodesic domes

Question 18

What is a hybrid modular structure?

Answer 18

Sections of the home are built off site and delivered to the site and placed onto a permanent foundation, then panels are added.

Question 19

What may be between the floor/ceiling or ceiling/roof?

Answer 19

• Duct work
• Wiring
• Water or natural gas pipes
• Recessed lighting
• Audio speakers
• Insulation

Question 20

What is a fire wall?

Answer 20

A fire wall is a fire-rated wall designed to limit the spread of a fire within a structure or between adjacent structures. It is built with fire-resistive materials and has a specified degree of fire resistance (measured in hours). It usually extends from the foundation through the ceiling of the building.

Question 21

What contruction implementations can reduce the effectiveness of a fire wall?

Answer 21

Pipes, wires and ducts that transverse the fire wall can make it void.

Question 22

Why is a fire in the basement one of the most dangerous fires to fight?

Answer 22

• Lack of egress
• Little or no ventilation
• Limited light
• Smoke blows up in your face, limiting visibility
• Many people have combustible materials in their basements
• Many basements are unfinished, so the structural elements are exposed (as opposed to protected by dryfall) so they become part of the fuel load. If these members fail, then the floor above will collapse into the basement.

Question 23

What is the difference between stairs that are a means of egress and access or convenience stairs?

Answer 23

Stairs in commercial and multifamily buildings that are part of the required means of egress (i.e. an unobstructed way to exit the building) must provide protection for the occupants as they travel to safety. Stairs meeting these requirements are protected or enclosed because they are built to resist the spread of fire and smoke.

• Protected stairs are enclosed with fire-rated construction, usually with a 1 - 2 hour rating, depending on building height. Note that they are a critical component of the life safety system in a building but can adversely affect occupants if they don’t maintain a breathable atmosphere.

In contrast, stairs that aren’t part of a means of egress, which typically only connect two floors, do not provide such protection. As a result, they may serve as a flow path for fire and smoke.

Question 24

How long should enclosed, protected stairs be able to resist the spread of fire?

Answer 24

1-2 hours

Question 25

Should firefighters keep the doors open in pressurized stairwells?

Answer 25

No because it may negate the intention of the pressurization.

Question 26

What are some disadvantages of an exterior stair case?

Answer 26

The weather and sunlight can deteriorate the building materials over time.

Question 27

Should firefighters use fire escapes?

Answer 27

No, first we use the interior stairs and then we use ladders. The weight barring capabilities of the fire escape is simply unknown and cannot be risked.

Question 28

What are the 3 prevalent types of roofs?

Answer 28

• Flat
• Pitched
• Arched

Note that these types can be used in combination as well.

Question 29

What are the 10 most common roof styles?

Answer 29

Question 30

What are the four kinds of arched roofs?

Answer 30

• Ribbed
• Pleated
• Lamella (diagonal grid)
• Bowstring

Question 31

What are the two kinds of roof supports?

Answer 31

Beams and truss assemblies

Question 32

What is a Gusset Plate?

Answer 32

A sheet of metal with spikes on it, used for connecting trusses.

Question 33

What are the 4 types of trusses?

Answer 33

Question 34

Are lightweight steel and wooden trusses expected to last for a long time during a fire?

Answer 34

No, due to their slight build, they are quickly affected by fire and usually result in collapse.

Question 35

What are purlins?

Answer 35

They are roof deck components that support the roof covering.

Question 36

What are the two types of concrete roofs?

Answer 36

Cast-in-place and precast. Both are extremely difficult to penetrate.

Question 37

What are green roofs?

Answer 37

Roofs that are modified to accommodate a garden. Some dangers are that the roof will need to be built stonger or be modified to support the dead load of the garden. During a fire, the roof under the garden can collapse first.

Question 38

What are cold roofs?

Answer 38

Roofs designed for cold climates. The purpose is to insulate the home from the cold and to insulate the snow on the roof from the heat of the house, so that ice does not form. There are several layers of insulation between the trusses and the shingles. This presents difficulty to firefighters during vertical ventilation operations.

Question 39

What is a photovoltaic roof?

Answer 39

A roof with solar panels. They present a shock danger to firefighters even when power to the building is shut off. They also pose a triping and slipping hazard so contact should be avoided.

Question 40

What is a rain or snow roof?

Answer 40

A pitched roof built over top of a flat roof which acts as protection against rain and snow. These pose several challenges / risks:

• The void that the rain roof creates can conceal a fire and allow it to burn undetected
• HVAC units may be hidden by the rain roof, increasing collapse potential

Ventilating a rain roof will not remove smoke from within the structure until the original roof is penetrated. However, firefighters should never enter the void space to penetrate the original roof because they can:

• Become trapped
• Be overcome by heat and smoke trapped in the void
• Fall through the original, weakened roof
• Be caught in extreme fire condition as the heated gases mix with fresh air

Question 41

What danger do roof-mounted objects like HVAC and telecommunications equipment pose to firefighters?

Answer 41

Collapse

Question 42

What are the 5 main types of doors?

Answer 42

• Swinging
• Sliding
• Folding
• Vertical
• Revolving

Doors are an important tool for fire and flow path control.

Question 43

Is door design more important than door material?

Answer 43

No. The construction material determines its effectiveness as a fire barrier and the degree to which it can be forced open during an emergency.

Question 44

What is a fire door?

Answer 44

A specifically constructed, tested, and approved fire-rated door assembly that’s designed and installed to prevent fire spread by automatically closing and covering a doorway in a fire wall to block the spread of fire through the door opening.

Note that some fire doors automatically close when fusible links activate during a fire and can be hard or impossible to manually open. Firefighters may therefore become trapped and hoses can become caught.

Question 45

Why do some buildings have fewer operational windows than in years prior?

Answer 45

The elimination of windows that can be opened enhances the energy efficiency of buildings, but this limits building access for firefighters and makes it difficult for them to perform ventilation and rescue.

Question 46

What are the 8 types of movable windows?

Answer 46