https://www.stuvia.com/user/performance
FDNY Z-51 / RSOE Fundamentals Practice Questions (2026–
2027) (Original) EXAM | Latest Update | Original Questions &
Answers with Detailed Rationales | Graded A+
Exam Format: 110 multiple-choice questions | 193 minutes |
70% passing score
Content Source: FDNY Notice of Exam Q-01, NYC Fire Code,
ASHRAE Standards
Exam Overview and Requirements
The Z-51 exam is the computer-based written portion of the FDNY Q-01 Certificate of Qualification for
Refrigerating System Operating Engineer (RSOE). The exam consists of 110 multiple-choice questions,
and candidates must achieve a passing score of at least 70%.
Eligibility Requirements
To take the Z-51 exam, candidates must meet the following requirements:
1. High school diploma or GED (degrees from outside the USA must be evaluated by an
independent evaluation service accepted by NYC DCAS)
2. Completed Z-51 application form with required documents attached
3. Universal Technician Certification (UTC) — required by U.S. EPA regulations (40 CFR Part 82,
Subpart F)
4. One of the following qualifications:
o Current High Pressure Boiler Operating Engineer License issued by NYC Department of
Buildings
o Current Marine Engineer certificate issued by the United States Coast Guard
o Current Professional Engineer (PE) license
o At least 1 year of practical experience in the preceding 3 years
The Q-01 Certificate of Qualification has two parts: the Z-51 written exam and the Z-52 practical exam.
,https://www.stuvia.com/user/performance
Module 1: Refrigeration Fundamentals
1. What is the primary purpose of a Certificate of Fitness (COF)
issued by FDNY?
A) To allow anyone to perform fire safety duties
B) To prove a person has the required knowledge to safely
perform specific duties
C) To replace all building permits
D) To eliminate the need for fire inspections
Answer: B
Rationale: A COF verifies that an individual has passed the
required FDNY exam and understands safety responsibilities for
specific operations.
2. Efficiency of the refrigerant cycle is affected by the
operations of the condenser. A more efficient centrifugal
compressor operation results from:
A) Increasing the condensing pressure
B) Lowering the condensing pressure
C) Increasing the evaporator pressure
D) Decreasing the suction pressure
Answer: B
Rationale: Lowering the condensing pressure reduces the
compression ratio, making the centrifugal compressor more
efficient.
, https://www.stuvia.com/user/performance
3. The heat removed from the refrigerant in a condenser is:
A) Sensible heat only
B) Latent heat only
C) Sensible and latent heat
D) Neither sensible nor latent heat
Answer: C
Rationale: The condenser removes both sensible heat
(desuperheating) and latent heat (condensation) from the
refrigerant.
4. When an expansion valve is operating properly, the end of
the evaporator will contain:
A) Only liquid refrigerant
B) Only superheated vapor
C) A mixture of liquid and vapor
D) Subcooled liquid
Answer: B
Rationale: A properly operating expansion valve ensures that all
refrigerant is fully vaporized and slightly superheated by the
end of the evaporator, preventing liquid slugging to the
compressor.
5. Superheat is best described as:
A) Liquid below saturation temperature
B) Vapor above saturation temperature
FDNY Z-51 / RSOE Fundamentals Practice Questions (2026–
2027) (Original) EXAM | Latest Update | Original Questions &
Answers with Detailed Rationales | Graded A+
Exam Format: 110 multiple-choice questions | 193 minutes |
70% passing score
Content Source: FDNY Notice of Exam Q-01, NYC Fire Code,
ASHRAE Standards
Exam Overview and Requirements
The Z-51 exam is the computer-based written portion of the FDNY Q-01 Certificate of Qualification for
Refrigerating System Operating Engineer (RSOE). The exam consists of 110 multiple-choice questions,
and candidates must achieve a passing score of at least 70%.
Eligibility Requirements
To take the Z-51 exam, candidates must meet the following requirements:
1. High school diploma or GED (degrees from outside the USA must be evaluated by an
independent evaluation service accepted by NYC DCAS)
2. Completed Z-51 application form with required documents attached
3. Universal Technician Certification (UTC) — required by U.S. EPA regulations (40 CFR Part 82,
Subpart F)
4. One of the following qualifications:
o Current High Pressure Boiler Operating Engineer License issued by NYC Department of
Buildings
o Current Marine Engineer certificate issued by the United States Coast Guard
o Current Professional Engineer (PE) license
o At least 1 year of practical experience in the preceding 3 years
The Q-01 Certificate of Qualification has two parts: the Z-51 written exam and the Z-52 practical exam.
,https://www.stuvia.com/user/performance
Module 1: Refrigeration Fundamentals
1. What is the primary purpose of a Certificate of Fitness (COF)
issued by FDNY?
A) To allow anyone to perform fire safety duties
B) To prove a person has the required knowledge to safely
perform specific duties
C) To replace all building permits
D) To eliminate the need for fire inspections
Answer: B
Rationale: A COF verifies that an individual has passed the
required FDNY exam and understands safety responsibilities for
specific operations.
2. Efficiency of the refrigerant cycle is affected by the
operations of the condenser. A more efficient centrifugal
compressor operation results from:
A) Increasing the condensing pressure
B) Lowering the condensing pressure
C) Increasing the evaporator pressure
D) Decreasing the suction pressure
Answer: B
Rationale: Lowering the condensing pressure reduces the
compression ratio, making the centrifugal compressor more
efficient.
, https://www.stuvia.com/user/performance
3. The heat removed from the refrigerant in a condenser is:
A) Sensible heat only
B) Latent heat only
C) Sensible and latent heat
D) Neither sensible nor latent heat
Answer: C
Rationale: The condenser removes both sensible heat
(desuperheating) and latent heat (condensation) from the
refrigerant.
4. When an expansion valve is operating properly, the end of
the evaporator will contain:
A) Only liquid refrigerant
B) Only superheated vapor
C) A mixture of liquid and vapor
D) Subcooled liquid
Answer: B
Rationale: A properly operating expansion valve ensures that all
refrigerant is fully vaporized and slightly superheated by the
end of the evaporator, preventing liquid slugging to the
compressor.
5. Superheat is best described as:
A) Liquid below saturation temperature
B) Vapor above saturation temperature
