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OBC Fire Protection practice questions

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Question 1Fire Safety Objectives and Functional Statements (OBC Part 1)

Under the Ontario Building Code, which document sets out the primary fire safety objectives that a building must satisfy?

  1. Division A, Part 1 of the Building Code Correct answer.
  2. The Supplementary Standards to the Building Code Act
  3. The Ontario Fire Code, Part 2
  4. Division B, Part 3 of the Building Code

Explanation

Division A, Part 1 states the objectives and functional statements that underlie every technical requirement in the Code. All of Division B's acceptable solutions are intended to achieve these stated objectives, so they are the starting point for any code analysis.

Question 2Fire Safety Objectives and Functional Statements (OBC Part 1)

What is the role of a functional statement in the Code's objective-based structure?

  1. It describes what a building element must do to achieve an objective Correct answer.
  2. It lists the acceptable materials permitted for an assembly
  3. It records the inspection history of a building
  4. It defines the occupancy classification of a suite

Explanation

Functional statements describe the function that a building or element must perform in order to satisfy an objective, such as limiting the probability of fire spread. They form the link between broad objectives and the specific acceptable solutions in Division B.

Question 3Fire Safety Objectives and Functional Statements (OBC Part 1)

A designer wants to use an alternative solution instead of the prescriptive requirements. Which statement best describes what the alternative solution must demonstrate?

  1. It must cost no more than the prescriptive solution would
  2. It must be approved by the local fire department before design begins
  3. It must achieve the level of performance intended by the applicable objectives Correct answer.
  4. It must be identical in construction to the prescriptive solution

Explanation

An alternative solution is acceptable where it achieves the level of performance intended by the relevant objectives and functional statements. It need not match the prescriptive solution in form, only in the performance it delivers.

Question 4Fire Safety Objectives and Functional Statements (OBC Part 1)

Which of the following is an objective of the Building Code relating to fire safety?

  1. Ensuring the building is aesthetically consistent with its neighbourhood
  2. Maximizing the rentable floor area of the building
  3. Reducing the construction schedule for the project
  4. Limiting the probability that occupants will be exposed to fire hazards Correct answer.

Explanation

The fire safety objectives address protection of occupants, including limiting the probability that occupants will be exposed to hazardous conditions such as fire, smoke or collapse. Aesthetic, scheduling and financial goals are outside the Code's objectives.

Question 5Fire Safety Objectives and Functional Statements (OBC Part 1)

The Code's objectives are expressed in terms of protecting which groups?

  1. Occupants, and in some cases the building itself and adjacent buildings Correct answer.
  2. Only firefighters responding to an incident
  3. Only the building owner and the insurer
  4. Only persons with disabilities

Explanation

The objectives are framed around protection of occupants from fire hazards, and also address protection of the building and exposure to adjacent buildings. Some objectives specifically consider persons with disabilities, but they are not the sole protected group.

Question 6Fire Safety Objectives and Functional Statements (OBC Part 1)

A designer proposes an atrium smoke control approach that differs from the prescriptive exhaust rates. To justify it, which analysis best supports the alternative solution?

  1. A statement that the contractor has installed similar systems before
  2. A schedule showing the system can be commissioned early
  3. A comparison showing the tenability conditions remain acceptable for the design fire Correct answer.
  4. A letter confirming the equipment supplier's warranty period

Explanation

An alternative solution must show that the level of performance intended by the objectives is achieved, which for smoke control means demonstrating tenable conditions for the design fire scenario. Supplier experience, warranties and schedules do not address performance.

Question 7Fire Safety Objectives and Functional Statements (OBC Part 1)

Which statement correctly distinguishes objectives from functional statements?

  1. Objectives apply only to Part 9 buildings
  2. Objectives are technical; functional statements are administrative
  3. Functional statements apply only to high buildings
  4. Objectives state the desired outcome; functional statements state what must be done to achieve it Correct answer.

Explanation

Objectives describe the broad outcomes the Code seeks, such as limiting the risk to occupants from fire. Functional statements describe the function a building or element must perform to satisfy those objectives.

Question 8Fire Safety Objectives and Functional Statements (OBC Part 1)

When a conflict appears between a Division B acceptable solution and a Division A objective, how should the Code be read?

  1. The objective is disregarded as advisory only
  2. Division A objectives and functional statements govern the intent of the requirements Correct answer.
  3. The conflict is resolved by the local municipality
  4. Division B always prevails because it is more specific

Explanation

Division A objectives and functional statements establish the intent that Division B's acceptable solutions are meant to achieve. Where wording is unclear, they guide interpretation of the technical requirements.

Question 9Fire Safety Objectives and Functional Statements (OBC Part 1)

Which of the following best describes an acceptable solution in the Code's structure?

  1. A performance criterion written by the designer
  2. A municipal by-law requirement
  3. A deemed-to-satisfy provision in Division B that is presumed to meet the objectives Correct answer.
  4. A manufacturer's installation instruction

Explanation

Acceptable solutions are the prescriptive provisions in Division B that are deemed to satisfy the applicable objectives and functional statements. Using them avoids the need to demonstrate equivalent performance.

Question 10Fire Safety Objectives and Functional Statements (OBC Part 1)

A renovation introduces a new mezzanine. Which approach correctly applies the objective-based framework?

  1. Apply Part 9 only because the building is small
  2. Ignore the objectives because the work is minor
  3. Apply the Fire Code only, since the building is existing
  4. Identify the applicable objectives and functional statements, then select acceptable or alternative solutions Correct answer.

Explanation

Every design begins by identifying which objectives and functional statements apply, then choosing either acceptable solutions or a demonstrated alternative solution. Building size or the fact that the building is existing does not remove this step.

Question 11Fire Safety Objectives and Functional Statements (OBC Part 1)

Which objective most directly relates to the requirement for exit signage and lighting?

  1. Limiting the probability of fire ignition
  2. Limiting damage to the building contents
  3. Limiting the spread of fire to adjacent properties
  4. Limiting the probability that occupants will be delayed in escaping Correct answer.

Explanation

Exit signage and emergency lighting support the objective of limiting the probability that occupants are delayed in escaping by helping them find and follow a means of egress. Ignition control and property protection are addressed by other objectives.

Question 12Fire Safety Objectives and Functional Statements (OBC Part 1)

What does it mean that the Code is objective-based?

  1. It allows any design that the designer considers safe
  2. It pairs stated objectives with deemed-to-satisfy solutions and permits demonstrated alternatives Correct answer.
  3. It requires a fire engineer on every project
  4. It lists only performance criteria with no prescriptive provisions

Explanation

An objective-based code states the goals to be achieved, provides prescriptive acceptable solutions that are presumed to meet them, and allows alternative solutions that demonstrate equivalent performance. It is not a free-form system without rules.

Question 13Fire Safety Objectives and Functional Statements (OBC Part 1)

A designer argues that because a proposed design meets the functional statement, no further analysis is needed. How should this be assessed?

  1. The argument is complete, since functional statements replace objectives
  2. The argument is valid only for Part 9 buildings
  3. The argument is incomplete, because the design must also satisfy the applicable objectives Correct answer.
  4. The argument is invalid, because functional statements are only advisory

Explanation

Functional statements describe what must be done, but they exist to serve the objectives. An alternative solution must demonstrate that the objectives themselves are achieved, not merely that a functional statement is addressed.

Question 14Fire Safety Objectives and Functional Statements (OBC Part 1)

Which of the following is a functional statement rather than an objective?

  1. Limit the probability that occupants will be exposed to fire hazards
  2. Protect occupants from injury due to fire
  3. Limit the probability that a building element will fail to perform its intended function under fire conditions Correct answer.
  4. Protect adjacent buildings from fire exposure

Explanation

Functional statements describe the required function of a building or element, such as performing its intended function under fire conditions. The other options state outcomes sought for occupants or adjacent buildings, which are objectives.

Question 15Fire Safety Objectives and Functional Statements (OBC Part 1)

During an alternative solution review, which factor is least relevant to demonstrating compliance with the objectives?

  1. The reliability of the proposed systems
  2. The colour of the finished ceiling in the corridor Correct answer.
  3. The maintenance assumptions supporting the design
  4. The documented fire scenario and resulting tenability

Explanation

Demonstrating compliance requires evidence about performance under fire conditions, including the design scenario, system reliability and assumptions on which the design depends. Finishes may be regulated, but colour is not a performance factor.

Question 16Fire Safety Objectives and Functional Statements (OBC Part 1)

Which statement best describes how the Code treats protection of adjacent buildings?

  1. It is addressed through objectives and functional statements on exposure protection Correct answer.
  2. It is handled only by municipal zoning
  3. It is outside the scope of the fire safety objectives
  4. It applies only to buildings over six storeys

Explanation

Exposure protection is part of the fire safety objectives, supported by functional statements about limiting the probability that fire will spread to adjacent buildings. Spatial separation and exterior construction requirements are the acceptable solutions that serve these objectives.

Question 17Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

Under the Ontario Building Code, into which major group are buildings classified according to their use and occupancy?

  1. Class A to Class D
  2. Type 1 to Type 5
  3. Division 1 to Division 4
  4. Group A to Group F Correct answer.

Explanation

Part 3 of the Ontario Building Code sorts every building into one of six major occupancy groups, labelled Group A through Group F, based on the purpose for which the building is used. Construction type and other features are addressed separately from this occupancy grouping.

Question 18Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building contains a theatre used for the performing arts. Which major occupancy group applies to that space?

  1. Group E
  2. Group F
  3. Group A Correct answer.
  4. Group C

Explanation

Group A covers assembly occupancies, which are places where people gather for entertainment, worship, recreation, or similar purposes. A theatre for the performing arts is a classic assembly use and falls within Group A.

Question 19Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

Which major occupancy group applies to a building used as a residential apartment house?

  1. Group A
  2. Group C Correct answer.
  3. Group D
  4. Group B

Explanation

Group C is the residential major occupancy group and includes dwellings, apartment houses, and other buildings where people sleep. Business and personal services occupancies are placed in Group D instead.

Question 20Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A retail store selling furniture to the public falls into which major occupancy group?

  1. Group E Correct answer.
  2. Group A
  3. Group D
  4. Group F

Explanation

Group E is the mercantile occupancy group, covering buildings or parts of buildings used for the display and sale of goods to the public. A furniture retail store is a straightforward mercantile use.

Question 21Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A factory where goods are manufactured falls into which major occupancy group?

  1. Group F Correct answer.
  2. Group E
  3. Group B
  4. Group D

Explanation

Group F is the industrial occupancy group and covers buildings used for manufacturing, assembling, processing, or storing goods. Manufacturing plants are therefore classified as Group F.

Question 22Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

Which major occupancy group includes a hospital where occupants receive care or treatment?

  1. Group A
  2. Group C
  3. Group D
  4. Group B Correct answer.

Explanation

Group B covers care or detention occupancies, where occupants are incapable of self-preservation because of age, physical limitation, or security measures. Hospitals and similar treatment facilities are classified in Group B.

Question 23Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building contains a warehouse used to store goods. Which major occupancy group applies to that storage area?

  1. Group D
  2. Group A
  3. Group F Correct answer.
  4. Group E

Explanation

Storage of goods is treated as an industrial occupancy and falls within Group F, Division 3, which covers low-hazard storage. Mercantile Group E applies where goods are displayed and sold rather than merely stored.

Question 24Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

Within Group A, what distinguishes Division 1 from Division 2 occupancies?

  1. Division 1 requires sprinklers and Division 2 does not
  2. Division 1 is for outdoor events only
  3. Division 1 applies to smaller floor areas only
  4. Division 1 involves stages or similar production features Correct answer.

Explanation

Group A is split into divisions based on whether the assembly area includes a stage or similar production element. Division 1 covers assembly occupancies with stages, while Division 2 covers those without such features.

Question 25Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building houses a laboratory where flammable liquids are processed. Which major occupancy group and division most appropriately describes this use?

  1. Group D, Division 2
  2. Group F, Division 2
  3. Group F, Division 1 Correct answer.
  4. Group E, Division 1

Explanation

Group F Division 1 covers industrial occupancies involving hazardous processes or storage, such as handling flammable liquids. Division 2 covers low-hazard industrial uses, so a high-hazard processing operation belongs in Division 1.

Question 26Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building contains a day nursery where children are cared for during the day. Which major occupancy group applies?

  1. Group C
  2. Group B Correct answer.
  3. Group A
  4. Group D

Explanation

Group B includes care occupancies where occupants are incapable of self-preservation, and a day nursery for young children fits that description. Group C is for residential sleeping accommodation, which is not the primary use here.

Question 27Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building is used for a dental office where patients receive treatment. Which major occupancy group is most appropriate?

  1. Group D Correct answer.
  2. Group B
  3. Group F
  4. Group E

Explanation

A dental office is a personal services occupancy and is classified in Group D, which covers business and personal services. Group B is reserved for care occupancies where occupants cannot care for themselves, such as hospitals.

Question 28Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building contains both a retail store and an office area. How does the OBC address such a mixed-use building?

  1. The whole building takes the occupancy of the largest floor area
  2. The building must be classified as Group F
  3. The building is automatically classified as Group A
  4. Each portion is classified according to its own use Correct answer.

Explanation

Where a building contains more than one major occupancy, the Code treats each portion as a separate major occupancy and applies the corresponding requirements to each part. The building as a whole must still satisfy the rules for multiple occupancies, such as separation and fire protection.

Question 29Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

What is the primary purpose of classifying buildings by major occupancy under the OBC?

  1. To establish zoning permissions
  2. To determine the property tax rate
  3. To set requirements for fire safety, egress, and construction Correct answer.
  4. To decide the number of parking spaces

Explanation

Major occupancy classification drives the fire and life safety requirements, including construction type, fire separations, egress, and fire protection systems. Different occupancies present different risks, so the Code tailors requirements to each group.

Question 30Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building used for a bowling alley where the public gathers for recreation falls into which major occupancy group?

  1. Group E
  2. Group F
  3. Group A Correct answer.
  4. Group D

Explanation

A bowling alley is a place where people gather for recreation, which makes it an assembly occupancy in Group A. It is not a mercantile or business occupancy because the primary use is recreation rather than sale of goods or services.

Question 31Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building contains a school with classrooms where students are taught. Which major occupancy group applies?

  1. Group E
  2. Group D
  3. Group A Correct answer.
  4. Group B

Explanation

Schools are places where people gather for education, which is an assembly use, so they fall within Group A. Group B would apply only if the occupants were incapable of self-preservation because of care or detention.

Question 32Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building is used as a hotel providing sleeping accommodation to guests. Which major occupancy group applies?

  1. Group B
  2. Group C Correct answer.
  3. Group A
  4. Group D

Explanation

Hotels provide sleeping accommodation and are therefore residential occupancies in Group C. The temporary nature of the stay does not change the fact that guests sleep in the building, which is the defining feature of Group C.

Question 33Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A portion of a building is used to store combustible goods in a low-hazard warehouse. Which classification best describes this portion?

  1. Group E, Division 1
  2. Group F, Division 1
  3. Group D, Division 1
  4. Group F, Division 2 Correct answer.

Explanation

Group F Division 2 covers low-hazard industrial occupancies, which include storage of goods that present a limited fire hazard. Division 1 is reserved for high-hazard processes or storage involving flammable or explosive materials.

Question 34Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building contains a portion used as a repair garage for motor vehicles. Which major occupancy group most appropriately applies to that portion?

  1. Group A
  2. Group E
  3. Group D
  4. Group F Correct answer.

Explanation

A repair garage involves servicing and repairing vehicles, which is an industrial activity and falls within Group F. The presence of fuels and mechanical work supports treating it as industrial rather than mercantile or business occupancy.

Question 35Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building contains a portion used as a restaurant where patrons dine. Which major occupancy group applies to that portion?

  1. Group D
  2. Group A Correct answer.
  3. Group E
  4. Group C

Explanation

A restaurant is a place where the public gathers to eat, which is an assembly occupancy in Group A. The service of food does not convert it into a mercantile or business occupancy because the principal use is public assembly.

Question 36Classification of Buildings and Occupancies by Fire Hazard (OBC Part 3)

A building contains a portion used as a supervised residence for persons requiring care because of age. Which major occupancy group applies?

  1. Group A
  2. Group D
  3. Group B Correct answer.
  4. Group C

Explanation

Where occupants require care and may be incapable of self-preservation, the occupancy is Group B even though the building provides sleeping accommodation. The care element takes priority over the residential character of the use.

Question 37Fire-Resistance Ratings, Fire Separations, and Closures

What does a fire-resistance rating of a building assembly primarily indicate?

  1. The length of time the assembly can contain a fire or retain its structural integrity under test conditions Correct answer.
  2. The maximum temperature the assembly's surface may reach during a fire
  3. The amount of smoke the assembly will release when exposed to flame
  4. The distance the assembly must be set back from a property line

Explanation

A fire-resistance rating expresses, in minutes or hours, how long an assembly withstands a standard fire exposure while continuing to perform its intended function, such as limiting flame passage or carrying structural load. It is determined by standardized fire tests or accepted calculation methods, not by surface temperature or smoke production.

Question 38Fire-Resistance Ratings, Fire Separations, and Closures

A wall is described as a fire separation with a 1-hour rating. What is the most accurate meaning of this description?

  1. The wall resists fire exposure for at least 60 minutes when tested as an assembly Correct answer.
  2. The wall has a flame-spread index of 60
  3. The wall must be made of masonry or concrete
  4. The wall must be 60 inches thick

Explanation

The rating applies to the complete assembly, including the materials, thickness, and any protective layers, as verified by a recognized fire test or accepted method. It states a duration of resistance, not a required material type, surface flame-spread number, or dimensional thickness.

Question 39Fire-Resistance Ratings, Fire Separations, and Closures

Which term describes an opening protective assembly installed in a rated wall to allow passage while maintaining the wall's fire resistance?

  1. Draft stop
  2. Fire door assembly Correct answer.
  3. Smoke barrier
  4. Fire damper

Explanation

A fire door assembly, including the door, frame, and hardware, is tested to a fire-protection rating and installed to preserve the integrity of a rated wall opening. Fire dampers serve ducts, smoke barriers limit smoke spread, and draft stops interrupt concealed spaces.

Question 40Fire-Resistance Ratings, Fire Separations, and Closures

What is the purpose of a fire stop at a penetration through a rated floor assembly?

  1. To bond the penetrating pipe to the floor slab
  2. To increase the load capacity of the floor
  3. To provide a path for thermal expansion of the penetrating item
  4. To restore the fire-resistance of the assembly at the point where it is penetrated Correct answer.

Explanation

Penetrations interrupt the continuity of a rated assembly, so an approved fire-stop system is installed to seal the annular space and restore the assembly's resistance to fire and hot gases. Fire stops are not structural reinforcement, expansion joints, or bonding devices.

Question 41Fire-Resistance Ratings, Fire Separations, and Closures

In a building, what is the function of a fire compartment?

  1. To serve as the primary means of egress from upper floors
  2. To limit the spread of fire and smoke to other parts of the building for a defined period Correct answer.
  3. To house only combustible materials away from occupants
  4. To provide a dedicated area for firefighting equipment storage

Explanation

Fire compartments are bounded by fire separations and closures so that a fire originating in one area is held back from adjacent areas for the rating period. This buys time for evacuation and firefighting; compartments are not storage rooms or egress routes.

Question 42Fire-Resistance Ratings, Fire Separations, and Closures

Which component is part of a listed fire door assembly?

  1. The door leaf, frame, and closing hardware tested together Correct answer.
  2. The ceiling membrane above the door
  3. The floor finish on each side of the opening
  4. The wall framing behind the door

Explanation

A fire door assembly is a tested system comprising the door leaf, frame, hinges, closer, latching, and other hardware as listed by the testing agency. Substituting untested components can invalidate the assembly's rating.

Question 43Fire-Resistance Ratings, Fire Separations, and Closures

What does an hourly fire-resistance rating of a structural column represent?

  1. The time the column can resist a standard fire exposure while supporting its design load Correct answer.
  2. The water application rate needed to cool the column
  3. The fire load permitted in the space around the column
  4. The time required to evacuate the floor the column supports

Explanation

Structural members are rated for the period during which they continue to carry their design load under a standard fire test, often achieved through encasement or spray-applied protection. Evacuation time, fuel load, and firefighting water rates are separate considerations.

Question 44Fire-Resistance Ratings, Fire Separations, and Closures

What is a closure in the context of fire separations?

  1. A device or assembly that closes an opening in a rated separation to maintain its integrity Correct answer.
  2. A type of foundation drain
  3. A method of joining two wall sections with adhesive
  4. A decorative trim applied around a doorway

Explanation

Closures include fire doors, shutters, dampers, and similar devices that protect openings in rated walls or floors so the separation remains effective. They are functional protective components, not decorative or drainage features.

Question 45Fire-Resistance Ratings, Fire Separations, and Closures

A 2-hour rated wall is required between two occupancies. Which installation detail most directly preserves that rating at a duct penetration?

  1. Painting the duct with intumescent coating on one side
  2. Leaving a small gap for air circulation
  3. Sealing the annular space with an approved fire-stop system listed for that penetration Correct answer.
  4. Wrapping the duct in ordinary insulation

Explanation

The rating is maintained only if the penetration is protected by a system tested and listed for the specific assembly, penetration type, and annular space. Ordinary insulation or coatings not evaluated for the application do not restore the assembly's resistance.

Question 46Fire-Resistance Ratings, Fire Separations, and Closures

A corridor is required to have a 1-hour fire separation, and the door in that wall is rated 20 minutes. Which statement best describes the design intent?

  1. The door must always match the wall rating exactly
  2. The wall rating must be reduced to match the door
  3. The door rating may be lower than the wall rating because opening protectives are assigned ratings appropriate to the assembly they serve Correct answer.
  4. The door rating is irrelevant if the door is self-closing

Explanation

Opening protectives are assigned fire-protection ratings by code based on the rating of the wall and the size and type of opening, so a door rating can be less than the wall's hourly rating. The wall rating is not reduced to match the door, and self-closing alone does not substitute for a required rating.

Question 47Fire-Resistance Ratings, Fire Separations, and Closures

A fire damper is installed where a duct passes through a rated wall. What is the damper's role?

  1. To regulate the supply air volume for comfort
  2. To filter smoke particles from the airstream
  3. To provide structural support to the duct
  4. To close automatically upon fire detection and prevent fire from traveling through the duct opening Correct answer.

Explanation

A fire damper is a closure within a duct that closes on fire exposure or signal to maintain the fire separation at the duct penetration. Smoke dampers address smoke leakage, volume dampers control airflow, and neither function replaces the fire damper's protective role.

Question 48Fire-Resistance Ratings, Fire Separations, and Closures

Why must a fire door be self-closing and latching in a rated separation?

  1. To satisfy accessibility requirements for door width
  2. To make the door easier to open for children
  3. To reduce the heating load on the building
  4. To ensure the opening returns to a closed, protected condition after use so the separation remains effective Correct answer.

Explanation

A rated separation depends on the opening being closed during a fire, so the door must close and latch automatically after each use. Energy performance, ease of operation, and clear width are separate design considerations.

Question 49Fire-Resistance Ratings, Fire Separations, and Closures

A concealed floor/ceiling space contains a rated floor assembly. What is the purpose of draft stopping within that space?

  1. To allow air to circulate for moisture control
  2. To provide structural bracing to the joists
  3. To subdivide large concealed areas so that fire and smoke cannot spread freely through the void Correct answer.
  4. To increase the fire-resistance rating of the floor finish

Explanation

Draft stops divide concealed spaces such as floor/ceiling plenums into smaller areas, limiting the horizontal spread of fire and smoke until the space is protected. They do not change the floor assembly's rating, brace joists, or serve ventilation.

Question 50Fire-Resistance Ratings, Fire Separations, and Closures

Which condition would most likely compromise a fire-resistance rating of a wall assembly?

  1. Applying the specified joint compound at the specified joints
  2. Substituting a thinner gypsum board than specified in the listed design Correct answer.
  3. Using a listed assembly with all specified layers and fasteners
  4. Installing the assembly exactly as described in the test report

Explanation

A fire-resistance rating applies to the assembly as tested, including material thickness, fastener type and spacing, and joint treatment. Reducing board thickness changes the thermal protection and can void the rating even if other details are correct.