100+ Free RETA CIRO Practice Questions

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IIAR 2 classifies ammonia refrigeration machinery rooms based on what key criterion?

Room paint color

Quantity of ammonia, ventilation provisions, and ignition-source controls

Number of windows

Compressor brand

to track

2026 Statistics

Key Facts: RETA CIRO Exam

135

Total Questions

RETA CIRO handbook

125

Scored Questions

RETA CIRO handbook

3 hours

Time Limit

RETA CIRO handbook

Minimum Passing Score

RETA CIRO handbook

$785

Non-Member Exam Fee

RETA application

$490

RETA Member Exam Fee

RETA application

2 years

Experience Required

RETA CIRO eligibility

3 years

Recertification Cycle

RETA recertification

The RETA CIRO exam has 135 multiple-choice questions (125 scored + 10 pilot), a 3-hour time limit, and a 70 minimum passing score. CIRO candidates must document at least two years of industrial refrigeration plant operation or technician experience. Content covers Safety Standards and Practices (20 questions), Electricity (15), Heat Flow (15), Monitoring System Performance (20), Valves, Controls and DX Systems (20), Liquid Overfeed and Flooded Systems (20), Two-Stage and Secondary Coolant Systems (15), and Evaporator Defrost (10). The exam uses on-screen references, so CIRO candidates need strong command of IIAR 2/6/7/9, OSHA PSM (29 CFR 1910.119), EPA RMP (40 CFR Part 68), ASME B31.5 piping, pressure-enthalpy diagrams, and industrial ammonia system design fundamentals.

Sample RETA CIRO Practice Questions

Try these sample questions to test your RETA CIRO exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1IIAR 2 classifies ammonia refrigeration machinery rooms based on what key criterion?

A.Room paint color

B.Quantity of ammonia, ventilation provisions, and ignition-source controls

C.Number of windows

D.Compressor brand

Explanation: IIAR 2 and ASHRAE 15 define machinery-room construction and ventilation requirements tied to the ammonia charge and occupancy. Classification affects ventilation sizing, electrical classification, and detector placement. Supervisors must ensure their room meets the applicable edition of the standard.

2A supervisor reviewing PSM mechanical-integrity records should confirm which of the following is scheduled for pressure relief valves on ammonia vessels?

A.Annual replacement of PRV body castings

B.Periodic inspection, testing, and replacement per manufacturer and IIAR-recommended intervals (commonly every 5 years for pilot-operated/soft-seat styles)

C.Removal and permanent capping

D.Adjustment of set pressure during each operator round

Explanation: IIAR 6 and manufacturer guidance call for periodic PRV replacement on a documented schedule. Many facilities replace pressure-relief valves on a 5-year cycle and document the change. Field adjustment of set pressure by operators is prohibited; PRVs are sealed devices.

3Under 29 CFR 1910.119, which is an example of a Management of Change (MOC) trigger that a CIRO-level supervisor must ensure is routed through the MOC process?

A.Replacing a broken pressure gauge with an identical new one (replacement in kind)

B.Changing the refrigerant charge capacity by adding a new low-temperature evaporator circuit

C.Replacing a light bulb in an office

D.Painting the exterior of the machinery room

Explanation: Adding an evaporator circuit changes refrigerant inventory, relief requirements, and operating procedures. This is a change beyond replacement-in-kind and must go through MOC review including process-hazard review, drawing updates, and operator retraining before startup.

4An ammonia facility's Emergency Action Plan (EAP) must include which of the following elements per OSHA 1910.38?

A.Only phone numbers for the local LEPC

B.Procedures for emergency evacuation, accounting for personnel, reporting emergencies, and handling of employees with medical duties or firefighting roles

C.Only a list of firefighting equipment

D.Only a map of the parking lot

Explanation: OSHA 1910.38 requires a written EAP that covers reporting emergencies, evacuation procedures and routes, accountability, emergency rescue/medical duties, names/job titles of EAP contacts, and alarm systems. Supervisors must ensure the plan is current and drilled.

5When performing an ammonia system's pressure-relief calculation, IIAR 2 ties required relief capacity primarily to:

A.Vessel color

B.External wetted vessel surface area exposed to fire and vessel/piping characteristics

C.Vessel vendor warranty

D.Number of operators on shift

Explanation: IIAR 2 and ASHRAE 15 size relief valves based on the external wetted area exposed to fire (for fire-case vessels) and other scenarios. Supervisors overseeing MOC-driven design changes must verify relief sizing remains adequate after modifications.

6A safe procedure for opening a refrigerant line for service on a CIRO-supervised system includes:

A.Loosening flanges slowly under full operating pressure

B.Performing pumpdown and isolation, relieving pressure safely, following LOTO, confirming zero energy, and wearing appropriate PPE before opening

C.Cracking the line rapidly to blow out any moisture

D.Skipping LOTO if the supervisor is present

Explanation: Written operating procedures under PSM require energy isolation (LOTO), pumpdown, relieving residual pressure to a safe point, and verifying zero energy before opening lines. PPE must match the hazard (face shield, gloves, respiratory protection as needed).

7The EPA General Duty Clause under Clean Air Act Section 112(r)(1) applies to ammonia facilities:

A.Only if they exceed the 10,000-lb RMP threshold

B.Regardless of inventory, requiring facilities with extremely hazardous substances to prevent releases and minimize consequences

C.Only if they are located in California

D.Only to trucking operations

Explanation: The General Duty Clause requires facilities with extremely hazardous substances, at any quantity, to identify hazards, design safe facilities, prevent releases, and minimize consequences. Smaller ammonia sites are not exempt simply because they fall below the RMP 10,000-lb threshold.

8Which of the following is a typical element of an Incident Investigation under OSHA 1910.119(m)?

A.Wait 6 months before documenting the event

B.Initiate investigation promptly (within 48 hours), use a team including at least one person knowledgeable in the process, determine root cause, and track corrective actions to closure

C.Investigate only releases above 1,000 lb

D.Keep results internal and discard after 30 days

Explanation: OSHA 1910.119(m) requires prompt investigation (within 48 hours), a team with process knowledge, a documented report, root-cause analysis, and tracking of corrective actions through resolution. Records must be retained at least five years.

9Under IIAR 6, inspection and testing of ammonia refrigeration systems should be performed at frequencies determined by:

A.The operator's preference

B.IIAR-recommended baseline intervals adjusted for equipment condition, history, and manufacturer guidance

C.Whenever the compressor breaks down

D.Only once when the plant is commissioned

Explanation: IIAR 6 supplies baseline intervals for various components (valves, vessels, safety relief devices, detectors) that facilities customize based on the condition monitoring program, failure history, and OEM guidance. Documentation closes the PSM mechanical-integrity loop.

10IIAR Bulletin/Standard on ammonia safety information requires a facility's documentation package to include:

A.Only P&IDs

B.P&IDs, equipment data sheets, relief-valve sizing calculations, safe upper/lower operating limits, materials of construction, electrical classification, and hazard evaluations

C.Only operator phone numbers

D.Only the compressor warranty

Explanation: Process Safety Information under PSM (and mirrored in IIAR practice) requires a comprehensive technical package supporting safe operation. CIRO supervisors must ensure this package is current after any MOC-driven change.

About the RETA CIRO Exam

RETA CIRO is the advanced Certified Industrial Refrigeration Operator credential. CIRO verifies that an operator has the experience, knowledge, and judgment needed to supervise industrial ammonia refrigeration system operations, including multi-compressor plants, two-stage and secondary coolant systems, and PSM/RMP-regulated facilities.

Assessment

Single exam, 135 multiple-choice questions (125 scored + 10 pilot)

Time Limit

3 hours

Passing Score

70 (minimum passing score)

Exam Fee

$785 non-member / $490 RETA member (Refrigerating Engineers and Technicians Association (RETA))

RETA CIRO Exam Content Outline

15%

Safety Standards and Practices

IIAR 2/6/7/9, OSHA PSM (1910.119), EPA RMP (40 CFR 68), General Duty Clause, MOC, incident investigation, PHA, operating procedures, eyewash/shower requirements (ANSI Z358.1), emergency action plans, LEPC coordination, and ammonia-compatible materials.

11%

Electricity

Three-phase motors, wye-delta starting, voltage unbalance, single-phasing, ladder diagrams, oil-pressure interlocks, rotation checks, VFDs, power factor correction, overload troubleshooting, and machinery-room electrical classification.

11%

Heat Flow

Pressure-enthalpy diagrams, COP, BHP/ton, Q = UA*deltaT, enthalpy values, ammonia latent heat, heat rejection ratio, specific volume, subcooling and flash-gas formation, and isentropic efficiency.

15%

Monitoring System Performance

Pressure/temperature trend diagnostics, condenser approach, evaporator TD, kW/ton, KPI dashboards, floating head pressure, compressor sequencing, slide-valve feedback, chronic non-condensable diagnosis, and mechanical integrity documentation.

15%

Valves, Controls, and DX Systems

Solenoid and TXV pairs, back-pressure and crankcase-pressure regulators, pilot-operated valves, electronic expansion valves, solenoid failure modes, high-side floats, ammonia piping per ASME B31.5 and IIAR 2, defrost check valves, high-to-low relief regulators, and hand expansion valves.

15%

Liquid Overfeed and Flooded Systems

Overfeed ratios (3-4x), surge drums, pump NPSH, gas-pumped CPR systems, oil drain pots and rectifiers, liquid-line sizing, level instrumentation with high/low cutouts, and advantages of flooded operation.

11%

Two-Stage and Secondary Coolant Systems

Interstage pressure selection (geometric mean), open and closed intercoolers, NH3/CO2 cascade designs, glycol brine maintenance (pH, freeze point, inhibitor), and two-stage troubleshooting of high low-stage discharge temperature.

Evaporator Defrost

Hot gas defrost sequencing, pressure-relief regulators on defrost drains, soft gas and pressure equalization, time/temperature termination, trace-heated drain pans, water defrost limits, and electric defrost trade-offs.

How to Pass the RETA CIRO Exam

What You Need to Know

Passing score: 70 (minimum passing score)
Assessment: Single exam, 135 multiple-choice questions (125 scored + 10 pilot)
Time limit: 3 hours
Exam fee: $785 non-member / $490 RETA member

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

RETA CIRO Study Tips from Top Performers

1Master the pressure-enthalpy (P-h) diagram for ammonia. Be able to plot typical industrial operating points, identify subcooling, superheat, isentropic vs real compression paths, and net refrigerating effect, because CIRO scenarios frequently reference chart reading.

2Memorize IIAR 2 vs IIAR 6 vs IIAR 7 vs IIAR 9 so you can tell which standard applies to design, testing/maintenance, operating procedures, or minimum safety criteria for existing systems.

3Study OSHA 1910.119 PSM elements line-by-line: Process Safety Information, PHA, Operating Procedures, Training, Contractors, Pre-Startup Safety Review, Mechanical Integrity, Hot Work, Management of Change, Incident Investigation, Emergency Planning, Compliance Audits, and Trade Secrets.

4Understand two-stage systems deeply: why interstage pressure is chosen near the geometric mean of suction and discharge pressures, how open flash intercoolers combine desuperheating and subcooling, and how closed intercoolers use a coil in a bath of boiling intermediate ammonia.

5Practice liquid-overfeed concepts: 3-4x feed ratio, surge drum sizing and level instrumentation, NPSH for mechanical pumps, and the difference between mechanical pump and gas-pumped (CPR) systems.

6Drill electrical fundamentals that appear on CIRO: voltage unbalance calculations (max deviation from average, divided by average), wye-delta starting, single-phasing symptoms, rotation checks on screw compressors, and typical ladder-diagram interlocks.

7Review hot gas defrost sequencing end-to-end: isolate liquid feed, pump down coil, de-energize fans, admit hot gas with a pressure-relief regulator on the drain, terminate on time or temperature, equalize pressure softly before returning to refrigeration.

8Memorize key exposure limits and detector alarm setpoints: OSHA PEL 50 ppm 8-hr TWA, ACGIH TLV-TWA 25 ppm, STEL 35 ppm, NIOSH IDLH 300 ppm, odor threshold 5-50 ppm, and common machinery-room alarm staging (25 ppm, 150 ppm for emergency ventilation, higher for ESD).

Frequently Asked Questions

How many questions are on the RETA CIRO exam and how long is the exam?

CIRO consists of 135 questions with a 3-hour time limit, per the 2020 RETA CIRO certification application handbook. CIRO includes 10 pilot questions that are evaluated for future exams and do not count in the candidate's score; candidates are scored on the remaining 125 active questions. The minimum passing score is 70.

What experience is required to take the RETA CIRO exam?

RETA requires a minimum of two years of verified experience in industrial refrigeration plant operation or services as a technician, including maintenance, service, troubleshooting, system start-ups, and/or direct supervision. A supervisor, superior, or colleague must sign the CIRO Verification of Experience form as part of the application.

How much does the RETA CIRO exam cost?

Per the 2020 RETA CIRO application handbook, the exam fee is $490 for RETA members and $785 for non-members. Retesting (available within 12 months of the initial failed test and within 90 days of retest fee payment) is $330 for members and $525 for non-members. Always confirm current fees at reta.com before applying.

What content areas does the CIRO exam cover and how are questions distributed?

RETA's CIRO content outline distributes the 135 questions as Safety Standards and Practices (20), Electricity (15), Heat Flow (15), Monitoring System Performance (20), Valves/Controls/DX Systems (20), Liquid Overfeed and Flooded Systems (20), Two-Stage and Secondary Coolant Systems (15), and Evaporator Defrost (10).

Where do I take the RETA CIRO exam?

CIRO is administered through the Kryterion Testing Network at more than 450 community colleges, universities, and training centers in the U.S., plus RETA Network Test Centers. RETA also offers Online Proctored (OLP) testing on the candidate's personal computer. CIRO uses on-screen references you can consult during the exam.

How is CIRO different from CARO?

CARO is the entry-level Certified Assistant Refrigeration Operator credential with no experience prerequisite and 110 questions focused on basic operation under supervision. CIRO is the advanced Certified Industrial Refrigeration Operator credential with a 2-year experience requirement and 135 questions focused on supervision-level concepts, including two-stage systems, secondary coolants, and full PSM/RMP-scale safety programs.

What references should I study for CIRO?

RETA's CIRO exam is based on Industrial Refrigeration I, II, and IV (Plant Operation and Safety), plus Basic Electricity I and II (Ladder Diagrams). Strong candidates also study IIAR 2, IIAR 6, IIAR 7, and IIAR 9 standards, ASHRAE 15, ASME B31.5 refrigeration piping, OSHA 29 CFR 1910.119 (PSM), and the IIAR Ammonia Data Book.

How often do I need to recertify CIRO?

CIRO certification expires every three years and must be renewed through 24 Professional Development Hours (PDHs) of approved training relevant to refrigeration operation, service, repair, maintenance, or engineering, or by retaking the current CIRO examination.