DHT ACTUAL EXAM |200+
QUESTIONS | WITH
COMPLETE ANSWERS!!
1. Describe the purpose of a fire-rated door assembly and when it’s
required in a building.
Answer:
A fire-rated door assembly is designed to contain and prevent the spread of fire and smoke
within a building. It includes a door, frame, and hardware that can resist fire for a specified
period (e.g., 20, 60, or 90 minutes). Fire-rated door assemblies are required in areas such as
stairwells, corridors, and between occupancies to protect occupants by allowing safe evacuation
and to limit property damage.
2. What is the difference between a mortise lock and a cylindrical lock?
Answer:
● Mortise Lock: Installed within a rectangular pocket cut into the door edge and typically
offers higher security and durability. It is commonly used in commercial settings.
● Cylindrical Lock: Fits into a hole drilled through the door face and is easier to install.
This lock type is widely used in residential and light commercial applications.
3. When installing panic hardware, what are the essential considerations
according to code requirements?
Answer:
When installing panic hardware, essential considerations include:
● Compliance with code requirements such as the International Building Code (IBC) or
NFPA 101, which specify panic hardware in certain occupancy types.
● Proper mounting height (usually between 34 and 48 inches above the floor).
, ● The ability to unlatch with a single motion, ensuring quick egress without keys, tools,
or special knowledge.
● Fire rating compatibility if used on fire-rated doors.
4. Explain the purpose of door closers and list the main factors to consider
when selecting one.
Answer:
Door closers automatically close doors after they are opened, enhancing security, privacy, and
fire containment. When selecting a door closer, consider:
● Door weight and size: Ensuring the closer is rated to handle the door's specifications.
● Location: Outdoor closers need weather-resistant features.
● Traffic frequency: High-traffic doors may require heavy-duty closers.
● Fire rating requirements: Closers on fire-rated doors must meet specific standards for
controlled closing and holding.
5. What is an ANSI grade rating, and why is it important in door hardware
selection?
Answer:
The ANSI (American National Standards Institute) grade rating categorizes hardware quality
and durability. There are three grades:
● Grade 1: Heavy-duty, for high-traffic and commercial applications.
● Grade 2: Medium-duty, suitable for light commercial or heavy residential use.
● Grade 3: Light-duty, generally used in residential settings. The rating helps ensure the
selected hardware will withstand the expected usage levels and meet durability
requirements.
6. How is door swing direction determined, and why is it critical for
hardware installation?
Answer:
Door swing direction is determined by standing on the side where the door opens away from
you. If the hinges are on the right, it’s a right-hand door; if on the left, it’s a left-hand door.
Knowing the swing direction is critical for ordering compatible hardware like locks, hinges, and
panic devices, as incorrect orientation can lead to improper installation or functionality issues.
7. What are the differences between hollow metal, wood, and aluminum
frames, and where is each commonly used?
,Answer:
● Hollow Metal Frames: Durable, fire-resistant, and used in high-security or high-traffic
areas like commercial buildings.
● Wood Frames: Offer aesthetic appeal and are commonly used in residential and office
interiors.
● Aluminum Frames: Lightweight and corrosion-resistant, suitable for storefronts, exterior
entrances, and applications requiring a sleek look.
8. Describe the process of “backset” in lock installation and why it matters.
Answer:
The backset is the distance from the door edge to the center of the lock bore hole. Common
backsets are 2-3/8 inches and 2-3/4 inches. Accurate measurement is essential for aligning the
latch with the strike plate and ensuring smooth door operation. Incorrect backset can lead to
improper latch alignment and functionality issues.
9. What considerations should be made when selecting hinges for an
exterior door?
Answer:
When selecting hinges for an exterior door, consider:
● Weather resistance: Hinges should be corrosion-resistant if exposed to the elements.
● Load capacity: Heavy-duty hinges may be required for larger or heavier doors.
● Security features: Non-removable pins (NRP) or concealed fasteners prevent
tampering.
● Fire rating compliance if the door is fire-rated.
10. In what situations would electric strikes be used, and what factors
influence their selection?
Answer:
Electric strikes are used in access control systems to allow remote unlocking of doors, often in
commercial buildings, institutions, and restricted areas. Factors in selecting electric strikes
include:
● Voltage requirements (e.g., 12V or 24V).
● Fail-safe vs. fail-secure: Fail-safe unlocks during power failure; fail-secure remains
locked.
● Door frame material compatibility: Ensure the strike is suitable for metal, wood, or
aluminum frames.
● Fire rating if installed on fire-rated doors.
, 11. What is the purpose of a continuous hinge, and where is it commonly
used?
Answer:
A continuous hinge, also known as a piano hinge, extends the full length of the door, providing
even weight distribution along the frame and reducing stress on the hinge and door frame. It is
commonly used in high-traffic, heavy-duty doors or doors prone to sagging, such as on exterior
or oversized doors, as well as on doors requiring additional security and durability.
12. Explain the difference between a single-point lock and a multi-point
lock.
Answer:
● Single-Point Lock: Provides one locking point, typically a latch or deadbolt at the
handle level, used in standard door applications.
● Multi-Point Lock: Has multiple locking points, usually along the edge of the door (e.g.,
top, middle, and bottom), providing increased security and resistance to forced entry.
Multi-point locks are often used on exterior doors, particularly in residential and
commercial settings requiring enhanced security.
13. How should a technician determine the appropriate door undercut?
Answer:
The appropriate door undercut is determined by the type of flooring, carpet thickness, and any
clearance requirements for airflow or ADA compliance. Standard undercuts range from 1/8 to
1/2 inch but may vary based on local building codes, door size, or room pressure requirements.
Ensuring the correct undercut is essential for proper door function, sealing, and code
compliance.
14. What are the primary types of automatic door operators, and how do
they differ?
Answer:
The primary types of automatic door operators include:
● Low-energy operators (ADA-compliant): For doors that open slowly and gently,
suitable for disabled access.
● High-energy operators: Typically used in high-traffic areas, open doors quickly and
close automatically after a set time, often seen in commercial entrances.
QUESTIONS | WITH
COMPLETE ANSWERS!!
1. Describe the purpose of a fire-rated door assembly and when it’s
required in a building.
Answer:
A fire-rated door assembly is designed to contain and prevent the spread of fire and smoke
within a building. It includes a door, frame, and hardware that can resist fire for a specified
period (e.g., 20, 60, or 90 minutes). Fire-rated door assemblies are required in areas such as
stairwells, corridors, and between occupancies to protect occupants by allowing safe evacuation
and to limit property damage.
2. What is the difference between a mortise lock and a cylindrical lock?
Answer:
● Mortise Lock: Installed within a rectangular pocket cut into the door edge and typically
offers higher security and durability. It is commonly used in commercial settings.
● Cylindrical Lock: Fits into a hole drilled through the door face and is easier to install.
This lock type is widely used in residential and light commercial applications.
3. When installing panic hardware, what are the essential considerations
according to code requirements?
Answer:
When installing panic hardware, essential considerations include:
● Compliance with code requirements such as the International Building Code (IBC) or
NFPA 101, which specify panic hardware in certain occupancy types.
● Proper mounting height (usually between 34 and 48 inches above the floor).
, ● The ability to unlatch with a single motion, ensuring quick egress without keys, tools,
or special knowledge.
● Fire rating compatibility if used on fire-rated doors.
4. Explain the purpose of door closers and list the main factors to consider
when selecting one.
Answer:
Door closers automatically close doors after they are opened, enhancing security, privacy, and
fire containment. When selecting a door closer, consider:
● Door weight and size: Ensuring the closer is rated to handle the door's specifications.
● Location: Outdoor closers need weather-resistant features.
● Traffic frequency: High-traffic doors may require heavy-duty closers.
● Fire rating requirements: Closers on fire-rated doors must meet specific standards for
controlled closing and holding.
5. What is an ANSI grade rating, and why is it important in door hardware
selection?
Answer:
The ANSI (American National Standards Institute) grade rating categorizes hardware quality
and durability. There are three grades:
● Grade 1: Heavy-duty, for high-traffic and commercial applications.
● Grade 2: Medium-duty, suitable for light commercial or heavy residential use.
● Grade 3: Light-duty, generally used in residential settings. The rating helps ensure the
selected hardware will withstand the expected usage levels and meet durability
requirements.
6. How is door swing direction determined, and why is it critical for
hardware installation?
Answer:
Door swing direction is determined by standing on the side where the door opens away from
you. If the hinges are on the right, it’s a right-hand door; if on the left, it’s a left-hand door.
Knowing the swing direction is critical for ordering compatible hardware like locks, hinges, and
panic devices, as incorrect orientation can lead to improper installation or functionality issues.
7. What are the differences between hollow metal, wood, and aluminum
frames, and where is each commonly used?
,Answer:
● Hollow Metal Frames: Durable, fire-resistant, and used in high-security or high-traffic
areas like commercial buildings.
● Wood Frames: Offer aesthetic appeal and are commonly used in residential and office
interiors.
● Aluminum Frames: Lightweight and corrosion-resistant, suitable for storefronts, exterior
entrances, and applications requiring a sleek look.
8. Describe the process of “backset” in lock installation and why it matters.
Answer:
The backset is the distance from the door edge to the center of the lock bore hole. Common
backsets are 2-3/8 inches and 2-3/4 inches. Accurate measurement is essential for aligning the
latch with the strike plate and ensuring smooth door operation. Incorrect backset can lead to
improper latch alignment and functionality issues.
9. What considerations should be made when selecting hinges for an
exterior door?
Answer:
When selecting hinges for an exterior door, consider:
● Weather resistance: Hinges should be corrosion-resistant if exposed to the elements.
● Load capacity: Heavy-duty hinges may be required for larger or heavier doors.
● Security features: Non-removable pins (NRP) or concealed fasteners prevent
tampering.
● Fire rating compliance if the door is fire-rated.
10. In what situations would electric strikes be used, and what factors
influence their selection?
Answer:
Electric strikes are used in access control systems to allow remote unlocking of doors, often in
commercial buildings, institutions, and restricted areas. Factors in selecting electric strikes
include:
● Voltage requirements (e.g., 12V or 24V).
● Fail-safe vs. fail-secure: Fail-safe unlocks during power failure; fail-secure remains
locked.
● Door frame material compatibility: Ensure the strike is suitable for metal, wood, or
aluminum frames.
● Fire rating if installed on fire-rated doors.
, 11. What is the purpose of a continuous hinge, and where is it commonly
used?
Answer:
A continuous hinge, also known as a piano hinge, extends the full length of the door, providing
even weight distribution along the frame and reducing stress on the hinge and door frame. It is
commonly used in high-traffic, heavy-duty doors or doors prone to sagging, such as on exterior
or oversized doors, as well as on doors requiring additional security and durability.
12. Explain the difference between a single-point lock and a multi-point
lock.
Answer:
● Single-Point Lock: Provides one locking point, typically a latch or deadbolt at the
handle level, used in standard door applications.
● Multi-Point Lock: Has multiple locking points, usually along the edge of the door (e.g.,
top, middle, and bottom), providing increased security and resistance to forced entry.
Multi-point locks are often used on exterior doors, particularly in residential and
commercial settings requiring enhanced security.
13. How should a technician determine the appropriate door undercut?
Answer:
The appropriate door undercut is determined by the type of flooring, carpet thickness, and any
clearance requirements for airflow or ADA compliance. Standard undercuts range from 1/8 to
1/2 inch but may vary based on local building codes, door size, or room pressure requirements.
Ensuring the correct undercut is essential for proper door function, sealing, and code
compliance.
14. What are the primary types of automatic door operators, and how do
they differ?
Answer:
The primary types of automatic door operators include:
● Low-energy operators (ADA-compliant): For doors that open slowly and gently,
suitable for disabled access.
● High-energy operators: Typically used in high-traffic areas, open doors quickly and
close automatically after a set time, often seen in commercial entrances.
