Z-51
Z-51 WRITTEN TEST EXAM QUESTIONS
AND CORRECT ANSWERS S
UPDATED
(2026/2027)
Hot work authorizations are issued by
A) a Responsible Person designated by the Building Owner.
B) a Building Department inspector.
C) a FDNY inspector.
D) the Building owner's insurance company. CORRECT ANSWERS A) a
Responsible Person designated by the building owner.
Insecticidal fogging operations are hazardous because chemicals
A) are corrosive.
B) are water-reactive.
C) may be toxic.
D) are highly unstable. CORRECT ANSWERS C) may be toxic.
What is a compressor safety head?
A) Rupture disc.
B) A pressure relief valve on the low side.
1
Z-51 Written
,Z-51
C) Cylinder head with a low pressure relief on the high side.
D) A spring on the valve plate. CORRECT ANSWERS
The oil collected in an oil separator is generally
A) caused by an oil overcharge. B)
returned to the compressor.
C) filtered and returned to the compressor.
D) drained and replaced by fresh oil. CORRECT ANSWERS
Where is emergency power not required according to code?
A) Fire pumps.
B) High rise elevators.
C) Egress illumination.
D) Data centers. CORRECT ANSWERS D) Data centers.
A technician shows up to service the fire alarm panel in your building. What
COF qualifications must he/she have?
A) A Q-01/Q-99 Certificate of Qualification holder who is designated by the
building owner.
B) A certified Fire Safety Director who is designated by the building owner.
C) A S-95 Certificate of Fitness holder who is employed by a FDNY certified
company.
D) A S-97/S-98 Certificate of Fitness holder who is employed by a FDNY
certified company. CORRECT ANSWERS D) A S-97/S-98 Certificate of
Fitness holder who is employed by a FDNY certified company.
2
Z-51 Written
, Z-51
In an office building, the display of cut natural trees (Christmas trees) is
A) never allowed.
B) allowed provided they are removed once they dry out.
C) always allowed.
D) allowed during the holiday season. CORRECT ANSWERS A) never allowed.
Describe the equipment's function in the picture.
A) Control flow of refrigerant to the compressor.
B) Remove non-condensable from the condenser.
C) Relieve excess pressure from the condenser.
D) Relieve excess pressure from the evaporator. CORRECT ANSWERS B)
Remove noncondensable from the condenser.
When the expansion valve is operating properly, the end of the evaporator
will contain
A) only superheated vapor.
B) saturated liquid refrigerant
C) only vapor.
D) only liquid refrigerant. CORRECT ANSWERS A) only superheated vapor.
How much extra refrigerant con be stored in a machine room?
A) 330 lbs.
B) The amount equal to the design pressure.
C) 20% above normal charge.
3
Z-51 Written
Z-51 WRITTEN TEST EXAM QUESTIONS
AND CORRECT ANSWERS S
UPDATED
(2026/2027)
Hot work authorizations are issued by
A) a Responsible Person designated by the Building Owner.
B) a Building Department inspector.
C) a FDNY inspector.
D) the Building owner's insurance company. CORRECT ANSWERS A) a
Responsible Person designated by the building owner.
Insecticidal fogging operations are hazardous because chemicals
A) are corrosive.
B) are water-reactive.
C) may be toxic.
D) are highly unstable. CORRECT ANSWERS C) may be toxic.
What is a compressor safety head?
A) Rupture disc.
B) A pressure relief valve on the low side.
1
Z-51 Written
,Z-51
C) Cylinder head with a low pressure relief on the high side.
D) A spring on the valve plate. CORRECT ANSWERS
The oil collected in an oil separator is generally
A) caused by an oil overcharge. B)
returned to the compressor.
C) filtered and returned to the compressor.
D) drained and replaced by fresh oil. CORRECT ANSWERS
Where is emergency power not required according to code?
A) Fire pumps.
B) High rise elevators.
C) Egress illumination.
D) Data centers. CORRECT ANSWERS D) Data centers.
A technician shows up to service the fire alarm panel in your building. What
COF qualifications must he/she have?
A) A Q-01/Q-99 Certificate of Qualification holder who is designated by the
building owner.
B) A certified Fire Safety Director who is designated by the building owner.
C) A S-95 Certificate of Fitness holder who is employed by a FDNY certified
company.
D) A S-97/S-98 Certificate of Fitness holder who is employed by a FDNY
certified company. CORRECT ANSWERS D) A S-97/S-98 Certificate of
Fitness holder who is employed by a FDNY certified company.
2
Z-51 Written
, Z-51
In an office building, the display of cut natural trees (Christmas trees) is
A) never allowed.
B) allowed provided they are removed once they dry out.
C) always allowed.
D) allowed during the holiday season. CORRECT ANSWERS A) never allowed.
Describe the equipment's function in the picture.
A) Control flow of refrigerant to the compressor.
B) Remove non-condensable from the condenser.
C) Relieve excess pressure from the condenser.
D) Relieve excess pressure from the evaporator. CORRECT ANSWERS B)
Remove noncondensable from the condenser.
When the expansion valve is operating properly, the end of the evaporator
will contain
A) only superheated vapor.
B) saturated liquid refrigerant
C) only vapor.
D) only liquid refrigerant. CORRECT ANSWERS A) only superheated vapor.
How much extra refrigerant con be stored in a machine room?
A) 330 lbs.
B) The amount equal to the design pressure.
C) 20% above normal charge.
3
Z-51 Written
