Nevada Refrigeration Contractor (C-21A) Exam Book Package

Prepare for the Nevada Refrigeration Contractor (C-21A) examination with a focused exam book package covering refrigeration systems, mechanical code requirements, piping and tubing, condensers, cooling towers, controls, valves, wiring, walk-in construction, ventilation, testing, inspection, gas, and construction safety. This package combines the Uniform Mechanical Code, 2018, which is allowed into the open-book examination, with two supplemental study references designed to strengthen technical refrigeration and safety knowledge before test day.

The Nevada C-21A examination is an open-book test. The Uniform Mechanical Code, 2018 is the exam-room-approved reference included in this package. The Modern Refrigeration and Air Conditioning, 22nd edition and Code of Federal Regulations - 29 CFR Part 1926 (OSHA) are included for study and are not allowed into the examination room.

The C-21A trade examination contains 50 questions, allows 2 hours for completion, and requires 35 correct answers to pass. Refrigeration and Refrigerants is the largest examination category, followed by Piping and Tubing and Controls, Valves and Wiring. Candidates should also prepare for condensers and cooling towers, walk-in and box construction, ducts and ventilation, testing and inspection, gas, and safety.

The Nevada C-21A Refrigeration classification covers the construction, erection, and installation of equipment used to control air temperatures below 50°F in refrigerators, refrigerated rooms, and insulated spaces. The scope also includes related insulation, ducts, blowers, registers, humidity controls, thermostatic controls, certain natural gas connections, and specified electrical service associated with refrigeration equipment.

Because refrigeration work combines mechanical principles, thermodynamics, piping, controls, electrical components, ventilation, and safety, successful preparation requires more than memorizing isolated code provisions. Candidates should understand how the refrigeration cycle works, how components interact, how systems are installed and tested, and when to use the Uniform Mechanical Code during the exam.

This package gives candidates both the exam-room code reference and additional technical books for building the knowledge needed to approach the Nevada C-21A Refrigeration Contractor examination with a structured study plan.

What You Get

• Uniform Mechanical Code, 2018 — the exam-room-approved reference covering refrigeration systems, mechanical equipment, piping, ventilation, ducts, safety provisions, installation requirements, and related mechanical code topics.
• Modern Refrigeration and Air Conditioning, 22nd edition — study-only reference covering refrigeration principles, refrigerants, compressors, evaporators, condensers, controls, piping, troubleshooting, system components, and refrigeration equipment.
• Code of Federal Regulations - 29 CFR Part 1926 (OSHA) — study-only reference supporting construction safety preparation, hazard recognition, personal protective equipment, electrical safety, ladders, tools, material handling, and other jobsite topics.
• Open-Book Exam Preparation: Use the Uniform Mechanical Code throughout preparation to develop faster reference-navigation skills.
• Trade-Focused Study: Build technical knowledge with refrigeration and safety references that support the subjects covered by the C-21A examination.

Exam Details

The Nevada C-21A Refrigeration Contractor examination contains 50 questions. Candidates are allowed 2 hours to complete the examination and must answer 35 questions correctly to pass.

The examination content is divided into the following subject areas:

• Refrigeration and Refrigerants: 17 questions
• Piping and Tubing: 8 questions
• Condensers and Cooling Towers: 4 questions
• Controls, Valves and Wiring: 7 questions
• Walk-ins/Box Construction: 2 questions
• Ducts and Ventilation: 2 questions
• Test and Inspection: 3 questions
• Gas: 3 questions
• Safety: 4 questions

Refrigeration and Refrigerants is the largest category with 17 questions. Candidates should understand the refrigeration cycle, refrigerant behavior, compressors, evaporators, condensers, metering devices, system pressures, superheat, subcooling, refrigerant properties, and general refrigeration-system operation.

Piping and Tubing accounts for 8 questions. Preparation should include refrigeration piping materials, fittings, joining methods, line sizing concepts, suction and liquid lines, oil return, supports, insulation, and installation practices.

Controls, Valves and Wiring accounts for 7 questions. Candidates should understand thermostats, pressure controls, relays, contactors, solenoid valves, expansion devices, safety controls, electrical components, and the relationship between controls and refrigeration-system operation.

Condensers, cooling towers, testing, inspection, gas, safety, walk-in construction, ducts, and ventilation make up the remaining questions and should be included in a complete study plan.

Open Book Test

The Nevada C-21A Refrigeration Contractor examination is an open-book test.

The following reference included in this package is allowed into the examination:

• Uniform Mechanical Code, 2018

The following books are included for study but are not allowed into the examination room:

• Modern Refrigeration and Air Conditioning, 22nd edition
• Code of Federal Regulations - 29 CFR Part 1926 (OSHA)

Open-book testing should not be treated as an opportunity to search the UMC for every answer. With 50 questions in two hours, candidates have a little over two minutes per question on average. Efficient preparation should combine technical refrigeration knowledge with the ability to locate a specific mechanical code provision when necessary.

The Uniform Mechanical Code should be used regularly during study sessions. Candidates should become familiar with its table of contents, definitions, refrigeration provisions, equipment requirements, piping sections, ventilation topics, and other mechanical subjects related to refrigeration work.

Timed navigation drills can help candidates determine when a code lookup is worthwhile. If a question involves a specific installation requirement, clearance, piping provision, equipment rule, or mechanical-code requirement, the UMC may provide the needed answer. Questions involving refrigeration theory or safety knowledge may need to be answered from retained knowledge instead.

Licensing Steps

1. Confirm the C-21A classification. Make sure Nevada Refrigeration Contracting matches the scope of work the business intends to perform.
2. Identify the qualifying individual. The contractor application must identify the person responsible for meeting the applicable trade qualification requirements.
3. Prepare qualifying experience information. Organize the work-history documentation required for the requested refrigeration classification.
4. Submit the Nevada contractor license application. Complete the applicable application and supporting documentation.
5. Receive examination eligibility. After the application and qualification information are reviewed, the qualifying individual can proceed with the required examinations.
6. Prepare for the C-21A trade examination. Study refrigeration systems, refrigerants, piping, controls, condensers, ventilation, testing, gas, and safety.
7. Practice UMC navigation. Use the Uniform Mechanical Code during preparation so relevant provisions can be located efficiently.
8. Prepare for Nevada Business and Law. Contractor applicants must also satisfy the applicable Nevada business and law examination requirement unless an authorized waiver applies.
9. Complete the required examinations. Take the applicable trade and business examinations.
10. Complete remaining licensing requirements. Finish the additional state requirements associated with contractor license issuance.

State Requirements

Nevada recognizes C-21A Refrigeration as a subclassification under C-21 Refrigeration and Air-Conditioning.

The C-21A scope covers the construction, erection, and installation of devices, machinery, and units used to control air temperatures below 50°F in refrigerators, refrigerated rooms, and insulated spaces.

The classification also includes installation of related insulation, ducts, blowers, registers, humidity controls, and thermostatic controls. This broad scope explains why the exam includes both refrigeration-system questions and topics involving ducts, ventilation, controls, valves, and wiring.

The scope includes lines supplying natural gas from refrigeration equipment to the point of connection with an existing gas line at the meter or at a point thereafter. It also includes specified electrical service from the unit's device protecting against excessive current to the main electrical panel, while excluding other gas or electrical services outside the scope of the classification.

Refrigeration contractors may work with equipment that requires careful coordination of piping, controls, electrical components, insulation, ventilation, and mechanical-system requirements. Candidates should understand how these different parts work together within a complete refrigeration installation.

The C-21A trade examination is one part of the Nevada contractor licensing process. Applicants must also satisfy applicable application, qualification, business and law, and other state licensing requirements before a contractor license is issued.

Reference Books

• Uniform Mechanical Code, 2018
  This exam-room-approved reference supports preparation involving refrigeration systems, mechanical equipment, refrigeration piping, ventilation, ducts, equipment installation, safety requirements, and other mechanical code provisions relevant to the Nevada C-21A examination.
• Modern Refrigeration and Air Conditioning, 22nd edition
  This study-only reference supports preparation involving refrigeration theory, refrigerants, compressors, condensers, evaporators, expansion devices, piping, controls, electrical components, troubleshooting, system operation, and practical refrigeration service knowledge. This book is not allowed into the examination.
• Code of Federal Regulations - 29 CFR Part 1926 (OSHA)
  This study-only reference supports construction safety preparation involving personal protective equipment, electrical hazards, tools, ladders, material handling, fall protection, hazard recognition, and other jobsite safety topics. This book is not allowed into the examination.

Exam Room Approved Books

• Uniform Mechanical Code, 2018
  This is the exam-room-approved reference included with the Nevada C-21A Refrigeration Contractor Exam Book Package. Candidates should use it throughout preparation to become familiar with refrigeration, mechanical equipment, piping, ventilation, and applicable code requirements.

Test Information and Study Materials

A productive Nevada C-21A study plan should begin with Refrigeration and Refrigerants because this category represents 17 of the 50 examination questions.

Candidates should understand the basic refrigeration cycle, including compression, condensation, expansion, and evaporation. Study how refrigerant pressure and temperature change as the refrigerant moves through the system and how the compressor, condenser, metering device, and evaporator work together.

Refrigerants should be reviewed in relation to system operation, pressure-temperature relationships, charging concepts, recovery practices, system conditions, and safe handling. Strong refrigeration fundamentals can help candidates reason through technical questions rather than depending on memorization.

Compressors should be studied according to their purpose and operation. Candidates should understand common compressor types, how compressors affect refrigerant pressure and flow, and how operating conditions can indicate system problems.

Condensers and Cooling Towers account for 4 questions. Review heat rejection, air-cooled and water-cooled condenser operation, airflow, water flow, fan operation, maintenance, and system-performance considerations.

Piping and Tubing deserves significant preparation because it accounts for 8 questions. Study pipe and tubing materials, fittings, joining methods, supports, insulation, suction lines, liquid lines, discharge lines, oil return, and installation practices.

Candidates should understand how poor piping design or installation can affect refrigerant flow, oil return, pressure drop, system capacity, and equipment reliability.

Controls, Valves and Wiring account for 7 questions. Review thermostatic controls, pressure switches, contactors, relays, solenoid valves, expansion devices, safety controls, and basic refrigeration electrical circuits.

Modern refrigeration systems depend on controls to maintain temperature, regulate refrigerant flow, protect equipment, and respond to changes in operating conditions. Candidates should understand the purpose of each component rather than simply memorizing names.

Walk-ins and Box Construction should include insulation, panels, doors, vapor control, temperature maintenance, equipment coordination, and general refrigerated-space construction concepts.

Ducts and Ventilation should include airflow, blowers, registers, duct installation, ventilation requirements, and how air movement interacts with refrigeration equipment and conditioned spaces.

Testing and Inspection should include system checks, leak detection concepts, pressure testing, equipment inspection, commissioning, and recognition of conditions that may indicate improper installation or operation.

Gas preparation should include the gas-related work permitted within the C-21A scope and the relationship between refrigeration equipment and associated fuel connections.

Safety accounts for 4 questions, and OSHA is not allowed into the test. Candidates should therefore use the study reference to build safety knowledge before exam day. Review personal protective equipment, electrical hazards, ladders, tools, material handling, and general construction hazard recognition.

The Uniform Mechanical Code should be used differently from the study-only books because it is available during the exam. Practice finding applicable refrigeration, ventilation, equipment, and piping provisions under timed conditions.

A useful study method is to attempt a practice question from trade knowledge first. If the question involves a specific code requirement, use the UMC to confirm the answer. This helps candidates develop judgment about when a lookup is needed.

The Modern Refrigeration and Air Conditioning, 22nd edition should be used to strengthen technical understanding. After studying a section, close the book and explain the system or component from memory. Active recall helps prepare for questions where the study book will not be available.

Timed practice is important. With two hours for 50 questions, candidates should avoid spending too much time on one difficult calculation or code search. Answer familiar questions efficiently and return to more difficult items later when possible.

How 1 Exam Prep Helps You Reach Your Goal

1 Exam Prep supports Nevada C-21A Refrigeration Contractor candidates through organized study guidance, trade-focused review, practice-oriented preparation, reference navigation, and confidence-building study structure.

The C-21A examination combines refrigeration theory, piping, controls, equipment, ventilation, inspection, gas, and safety. This package supports that preparation with an exam-room mechanical code and supplemental technical references covering refrigeration and construction safety.

The Uniform Mechanical Code, 2018 can be used throughout preparation to build familiarity with the same reference available during the open-book examination. Repeated navigation practice can help candidates locate code requirements more efficiently under timed conditions.

The Modern Refrigeration and Air Conditioning, 22nd edition provides a broader technical foundation for understanding refrigeration cycles, components, refrigerants, controls, piping, troubleshooting, and system operation.

The Code of Federal Regulations - 29 CFR Part 1926 supports safety preparation for questions that must be answered without the OSHA book in the examination room.

1 Exam Prep encourages candidates to combine reference navigation with active recall, calculations, trade review, and practice questions. When a question is missed, determine whether the issue came from technical knowledge, misunderstanding of a component, difficulty locating a code section, or exam pacing.

The goal is to help candidates approach the Nevada C-21A Refrigeration Contractor examination with stronger refrigeration knowledge, faster UMC navigation, better safety preparation, and a structured study strategy without guaranteeing a passing score or licensing approval.

How many questions are on the Nevada C-21A Refrigeration exam?

The Nevada C-21A Refrigeration Contractor examination contains 50 questions.

How much time is allowed for the C-21A examination?

Candidates are allowed 2 hours to complete the examination.

How many correct answers are required to pass?

Candidates must answer 35 questions correctly to pass the C-21A trade examination.

Is the Nevada C-21A exam open book?

Yes. The Nevada C-21A Refrigeration Contractor examination is an open-book test.

Which book is allowed into the C-21A exam?

The Uniform Mechanical Code, 2018 is the exam-room-approved reference included with this package.

Is Modern Refrigeration and Air Conditioning allowed into the exam?

No. Modern Refrigeration and Air Conditioning, 22nd edition is included for technical study but is not allowed into the examination.

Is OSHA 29 CFR Part 1926 allowed into the exam?

No. Code of Federal Regulations - 29 CFR Part 1926 is included for safety preparation but is not allowed into the examination.

What is the largest C-21A exam category?

Refrigeration and Refrigerants is the largest category with 17 questions.

How many Piping and Tubing questions are on the exam?

The examination contains 8 Piping and Tubing questions.

How many Controls, Valves and Wiring questions are on the exam?

The examination contains 7 Controls, Valves and Wiring questions.

Does the exam include condensers and cooling towers?

Yes. Condensers and Cooling Towers accounts for 4 questions.

Does the C-21A exam include safety?

Yes. Safety accounts for 4 questions.

What work does the Nevada C-21A classification cover?

The classification covers installation of refrigeration equipment used to control temperatures below 50°F in refrigerators, refrigerated rooms, and insulated spaces, along with related insulation, ducts, blowers, registers, humidity controls, thermostatic controls, and specified gas and electrical connections.

How should I study with the Uniform Mechanical Code?

Practice targeted lookups using the table of contents, index, definitions, and refrigeration-related sections. Combine UMC navigation with technical study so you know both the subject and where to find applicable code requirements.

Should I try to look up every answer during the exam?

No. Build strong refrigeration knowledge first and use the Uniform Mechanical Code strategically when a specific requirement, definition, installation provision, or mechanical code rule needs to be confirmed.

Does this package guarantee that I will pass the Nevada C-21A exam?

No. This package provides exam and study references designed to support organized preparation. Examination results depend on each candidate's experience, refrigeration knowledge, study, code-navigation ability, and performance on test day.