Z51 FDNY practice test

The Z-51 Refrigerating System Operating Engineer (RSOE) certificate from the FDNY (Fire Department of New York), Z51 RSOE is a certification for individuals who operate or maintain refrigerating systems in New York City.

The Z51 RSOE certificate is one of the best certificates issued by the FDNY. It has some difficulty, but with hard work and experience you can obtain it. It is one of the requirements for the Q01 RSOE certificate.

How can you benefit from the practice test? When you complete the test, write down the questions you got wrong with their topics and when you study, focus on them.

1 / 15

Calculate the required pump head for a cooling tower circulation pump if the system flow rate is 1000 gpm?

52.3 ft

72.3 ft

92.3 ft

112.3 ft

2 / 15

What is the minimum required rupture pressure for the rupture disk in a refrigeration system using R-22?

325 psig

350 psig

275 psig

300 psig

3 / 15

According to ASHRAE Guideline 3, what is the maximum allowable non-condensable gas concentration in a refrigeration system?

0.1% by volume

0.5% by volume

1% by volume

2% by volume

4 / 15

In a transcritical CO₂ refrigeration system, what is the typical range for the gas cooler approach temperature?

0.5-1.5°C

2-5°C

7-10°C

12-15°C

5 / 15

What is the minimum required ultimate strength of steel pipes used for Group A1 refrigerants in NYC?

30,000 psi

35,000 psi

40,000 psi

45,000 psi

6 / 15

Calculate the isentropic efficiency of a compressor if the actual work input is 85 kJ/kg and the isentropic work input is 70 kJ/kg.

82.40%

121.40%

17.60%

78.60%

7 / 15

What is the maximum allowed CO₂ equivalent for a refrigeration system using R-410A in a public assembly occupancy?

100

8 / 15

In a shell-and-tube heat exchanger with a 1-2 pass configuration, what is the correction factor (F) for a temperature effectiveness (P) of 0.7 and a ratio of fluid capacitance rates (R) of 0.8?

0.85

0.92

0.98

0.76

9 / 15

What is the minimum required ventilation rate for a machinery room containing ammonia refrigeration equipment?

5 cfm/ft²

0.5 cfm/ft²

2 cfm/ft²

1 cfm/ft²

10 / 15

According to NFPA 70, what is the maximum allowed voltage for a Class 2 remote-control circuit?

24V

30V

42.4V

50V

11 / 15

In a steam turbine-driven centrifugal chiller, what is the primary purpose of the gland seal system?

Lubricate bearings

Prevent air ingress

Control turbine speed

Regulate steam flow

12 / 15

Which type of metering device is most suitable for a system with widely varying load conditions?

Capillary tube

Thermostatic expansion valve

Electronic expansion valve

Float valve

13 / 15

Calculate the mass flow rate of refrigerant in a system with a cooling capacity of 500 kW using R-134a.

3.33 kg/s

0.30 kg/s

75.00 kg/s

33.33 kg/s

14 / 15

In a centrifugal compressor, what phenomenon occurs when the flow rate drops below a critical value?

Cavitation

Surge

Choke

Stonewall

15 / 15

What is the maximum allowable concentration of R-717 (ammonia) in an occupied space according to ASHRAE Standard 15?

25 ppm

50 ppm

100 ppm

150 ppm