New York City Civil Service Custodian Engineer Exam
Practice Test | Complete 200-Question Study Guide
with 100% Correct Verified Answers | Already Graded
A+ | 2026 Edition
New York City Department of Citywide Administrative Services (DCAS) Custodian Engineer
Examination | Comprehensive 200-Question Practice Resource: Explicitly built to align with
the NYC DCAS test blueprint for NYC Department of Education (DOE) and public facilities.
Covers New York City Department of Buildings (DOB) Boiler Regulations, New York City
Fire Code (FDNY Certificate of Fitness targets), High/Low-Pressure Steam Boiler
Calculations, HVAC/R System Maintenance, Electrical Safety, Civil Service Rules,
Personnel Supervision, and Collective Bargaining Agreements (Local 891/Local 32BJ
frameworks) | 100% Correct Verified Solutions | Graded A+ for Immediate Exam Success
Introduction
This fully updated 2026 New York City Custodian Engineer examination study guide
delivers the highly concentrated technical and administrative curriculum required to pass the
civil service exam on your first attempt. It bridges NYC statutory codes, emergency
response procedures, mechanical formulas, and labor management rules. Every question
integrates the verified multiple-choice solution with an authoritative explanation to maximize
your study efficiency and ensure you master the material.
Section A: NYC DOB Rules, Boiler Operations, & Steam Calculations
Q1. According to the New York City Department of Buildings (DOB) regulations, a
high-pressure steam boiler is explicitly defined as a boiler that operates at a pressure
exceeding how many pounds per square inch (psi)?
,A) 5 psi
B) 15 psi
C) 50 psi
D) 100 psi
Answer: B
Explanation: Under the NYC Construction Code and DOB rules, a low-pressure boiler
operates at a steam pressure of 15 psi or less. Any boiler operating at a steam pressure
greater than 15 psi is classified as a high-pressure boiler and requires a licensed High-
Pressure Boiler Operating Engineer to supervise.
Q2. When converting boiler capacity to Boiler Horsepower (BHP), one BHP is
mathematically defined as the evaporation of how many pounds of water per hour
from and at a temperature of 212°F?
A) 14.7 lbs
B) 34.5 lbs
C) 970.3 lbs
D) 1,200 lbs
Answer: B
Explanation: One Boiler Horsepower (BHP) is standardly defined as the thermal capacity to
evaporate exactly 34.5 pounds of water per hour from and at 212°F, which is equivalent to
33,475 BTU per hour.
,Q3. To check for latent internal structural leaks in a newly repaired low-pressure
steam boiler, a Custodian Engineer performs a hydrostatic test. What is the standard
NYC DOB rule for the test pressure applied?
A) 1.5 times the maximum allowable working pressure (MAWP)
B) 2.0 times the maximum allowable working pressure (MAWP)
C) Exactly 100 psi regardless of design
D) 50% of the normal operating limit
Answer: A
Explanation: Hydrostatic testing protocols under DOB and ASME codes dictate that a boiler
must be filled completely with water and pressurized to 1.5 times its maximum allowable
working pressure (MAWP) to verify structural integrity.
Q4. What is the absolute most critical safety device installed on a steam boiler,
designed to open automatically to prevent an explosive over-pressurization
catastrophe if all automated electrical cutoffs fail?
A) Low-Water Fuel Cutoff (LWCO)
B) Main Steam Stop Valve
C) Safety Valve
D) Feedwater Regulator
Answer: C
Explanation: The safety valve is a purely mechanical device designed to pop open at a
, predetermined pressure setting, venting excess steam directly to the atmosphere to prevent
a catastrophic structural explosion.
Q5. If the water level inside a low-pressure steam boiler drops out of sight below the
bottom of the gauge glass while the burner is actively firing, what immediate
emergency action must the Custodian Engineer execute?
A) Immediately open the city water supply bypass to flood the boiler with cold water.
B) Shut off the fuel supply to the burner immediately, allow the boiler to cool down naturally,
and inspect for thermal structural damage.
C) Turn down the thermostat but leave the burner running.
D) Blow down the water column to see if the level returns.
Answer: B
Explanation: Adding cold water to a hot, dry boiler causes instantaneous thermal shock and
metal contraction, which can trigger a catastrophic boiler explosion. The fuel must be killed
immediately, and the unit must cool before any water is introduced.
Q6. What mechanical system or chemical process is utilized to remove scale-forming
minerals (such as calcium and magnesium) from raw city makeup water before it
enters the boiler feed system?
A) Deaeration tank venting
B) Water Softener (utilizing ion-exchange resin)
C) Continuous surface blowdown
Practice Test | Complete 200-Question Study Guide
with 100% Correct Verified Answers | Already Graded
A+ | 2026 Edition
New York City Department of Citywide Administrative Services (DCAS) Custodian Engineer
Examination | Comprehensive 200-Question Practice Resource: Explicitly built to align with
the NYC DCAS test blueprint for NYC Department of Education (DOE) and public facilities.
Covers New York City Department of Buildings (DOB) Boiler Regulations, New York City
Fire Code (FDNY Certificate of Fitness targets), High/Low-Pressure Steam Boiler
Calculations, HVAC/R System Maintenance, Electrical Safety, Civil Service Rules,
Personnel Supervision, and Collective Bargaining Agreements (Local 891/Local 32BJ
frameworks) | 100% Correct Verified Solutions | Graded A+ for Immediate Exam Success
Introduction
This fully updated 2026 New York City Custodian Engineer examination study guide
delivers the highly concentrated technical and administrative curriculum required to pass the
civil service exam on your first attempt. It bridges NYC statutory codes, emergency
response procedures, mechanical formulas, and labor management rules. Every question
integrates the verified multiple-choice solution with an authoritative explanation to maximize
your study efficiency and ensure you master the material.
Section A: NYC DOB Rules, Boiler Operations, & Steam Calculations
Q1. According to the New York City Department of Buildings (DOB) regulations, a
high-pressure steam boiler is explicitly defined as a boiler that operates at a pressure
exceeding how many pounds per square inch (psi)?
,A) 5 psi
B) 15 psi
C) 50 psi
D) 100 psi
Answer: B
Explanation: Under the NYC Construction Code and DOB rules, a low-pressure boiler
operates at a steam pressure of 15 psi or less. Any boiler operating at a steam pressure
greater than 15 psi is classified as a high-pressure boiler and requires a licensed High-
Pressure Boiler Operating Engineer to supervise.
Q2. When converting boiler capacity to Boiler Horsepower (BHP), one BHP is
mathematically defined as the evaporation of how many pounds of water per hour
from and at a temperature of 212°F?
A) 14.7 lbs
B) 34.5 lbs
C) 970.3 lbs
D) 1,200 lbs
Answer: B
Explanation: One Boiler Horsepower (BHP) is standardly defined as the thermal capacity to
evaporate exactly 34.5 pounds of water per hour from and at 212°F, which is equivalent to
33,475 BTU per hour.
,Q3. To check for latent internal structural leaks in a newly repaired low-pressure
steam boiler, a Custodian Engineer performs a hydrostatic test. What is the standard
NYC DOB rule for the test pressure applied?
A) 1.5 times the maximum allowable working pressure (MAWP)
B) 2.0 times the maximum allowable working pressure (MAWP)
C) Exactly 100 psi regardless of design
D) 50% of the normal operating limit
Answer: A
Explanation: Hydrostatic testing protocols under DOB and ASME codes dictate that a boiler
must be filled completely with water and pressurized to 1.5 times its maximum allowable
working pressure (MAWP) to verify structural integrity.
Q4. What is the absolute most critical safety device installed on a steam boiler,
designed to open automatically to prevent an explosive over-pressurization
catastrophe if all automated electrical cutoffs fail?
A) Low-Water Fuel Cutoff (LWCO)
B) Main Steam Stop Valve
C) Safety Valve
D) Feedwater Regulator
Answer: C
Explanation: The safety valve is a purely mechanical device designed to pop open at a
, predetermined pressure setting, venting excess steam directly to the atmosphere to prevent
a catastrophic structural explosion.
Q5. If the water level inside a low-pressure steam boiler drops out of sight below the
bottom of the gauge glass while the burner is actively firing, what immediate
emergency action must the Custodian Engineer execute?
A) Immediately open the city water supply bypass to flood the boiler with cold water.
B) Shut off the fuel supply to the burner immediately, allow the boiler to cool down naturally,
and inspect for thermal structural damage.
C) Turn down the thermostat but leave the burner running.
D) Blow down the water column to see if the level returns.
Answer: B
Explanation: Adding cold water to a hot, dry boiler causes instantaneous thermal shock and
metal contraction, which can trigger a catastrophic boiler explosion. The fuel must be killed
immediately, and the unit must cool before any water is introduced.
Q6. What mechanical system or chemical process is utilized to remove scale-forming
minerals (such as calcium and magnesium) from raw city makeup water before it
enters the boiler feed system?
A) Deaeration tank venting
B) Water Softener (utilizing ion-exchange resin)
C) Continuous surface blowdown
