Nevada Refrigeration and Air Conditioning Contractor (C-21) Exam Book Package

Prepare for the Nevada Refrigeration and Air Conditioning Contractor (C-21) examination with a comprehensive exam book package covering refrigeration, air conditioning, fuel systems, ductwork, load calculations, hydronics, chilled water, ventilation, controls, solar systems, evaporative cooling, piping, safety, and mechanical code requirements. This package combines the references allowed into the open-book examination with supplemental study books used to build technical knowledge before test day.

The Nevada C-21 examination is an open-book test. The Uniform Mechanical Code, 2018 and NFPA 54 - Standard for National Fuel Gas Code, 2012 are the exam-room-approved references included with this package.

The package also includes Code of Federal Regulations - 29 CFR Part 1926 (OSHA), Modern Refrigeration and Air Conditioning, 22nd edition, HVAC Duct Construction Standards, Metal and Flexible, 2005, 3rd Edition, Manual N - Commercial Load Calculation for Small Commercial Buildings, 5th Edition, Solar Water and Pool Heating Design and Installation Manual, and Evaporative Air Conditioning Handbook, 3rd Edition, 1997 (USED). These supplemental books are study references and are not allowed into the examination room.

The Nevada C-21 trade examination contains 85 questions, allows 3 hours for completion, and requires 60 correct answers to pass. The exam covers more than twenty technical areas, including fuel systems, refrigerants, refrigeration, load calculations, ducts, piping, controls, furnaces, heaters, chimneys, flues, vents, solar, chillers, ventilation, safety, and mechanical-system fundamentals.

The C-21 Refrigeration and Air Conditioning classification is broad. It includes refrigeration, air-conditioning equipment and ductwork, sheet metal associated with HVAC systems, repair and replacement of refrigeration and air-conditioning components, solar air-conditioning equipment, chilled-water systems, and hot-water piping used for temperature control.

Because the examination covers such a wide range of systems, candidates should prepare by combining technical study with practical code navigation. The goal is to know the trade well enough to recognize the correct solution while using the approved UMC and NFPA 54 references strategically when a specific code requirement must be located.

What You Get

• Uniform Mechanical Code, 2018 — exam-room-approved reference for mechanical systems, refrigeration, heating, ventilation, equipment, piping, ducts, combustion air, and related requirements.
• NFPA 54 - Standard for National Fuel Gas Code, 2012 — exam-room-approved reference supporting fuel-gas piping, appliances, venting, combustion air, testing, and related gas-system requirements.
• Code of Federal Regulations - 29 CFR Part 1926 (OSHA) — study-only construction safety reference.
• Modern Refrigeration and Air Conditioning, 22nd edition — study-only reference for refrigeration, air conditioning, system components, troubleshooting, refrigerants, controls, and equipment.
• HVAC Duct Construction Standards, Metal and Flexible, 2005, 3rd Edition — study-only reference for duct construction, reinforcement, fabrication, installation, and related HVAC ductwork.
• Manual N - Commercial Load Calculation for Small Commercial Buildings, 5th Edition — study-only reference supporting heating and cooling load calculation preparation.
• Solar Water and Pool Heating Design and Installation Manual — study-only reference supporting solar-system concepts and installation preparation.
• Evaporative Air Conditioning Handbook, 3rd Edition, 1997 (USED) — study-only reference supporting evaporative cooling system design, components, operation, and application.

Exam Details

The Nevada C-21 Refrigeration and Air Conditioning Contractor examination contains 85 questions. Candidates are allowed 3 hours to complete the examination and must answer 60 questions correctly to pass.

The exam content is divided into the following subject areas:

• Piping: 6 questions
• Insulation: 1 question
• Hangers and Supports: 3 questions
• Sound, Vibration and Seismic Control: 1 question
• Heating and Cooling Principles: 3 questions
• Refrigerants and Refrigeration: 7 questions
• Load Calculations: 6 questions
• Testing, Adjusting and Balancing: 3 questions
• Controls: 5 questions
• Machine Room: 1 question
• A/C and Heat Pump Equipment: 4 questions
• Furnaces and Heaters: 4 questions
• Hydronics: 2 questions
• Chimneys, Flues and Vents: 5 questions
• Combustion Air: 2 questions
• Fuel Systems: 10 questions
• Ducts: 6 questions
• Evaporative Cooling: 2 questions
• Chillers: 3 questions
• Solar: 4 questions
• Ventilation and Exhausts: 3 questions
• Safety: 4 questions

Fuel Systems is the largest single category with 10 questions. Refrigerants and Refrigeration accounts for 7 questions, while Piping, Load Calculations, and Ducts each account for 6 questions. These areas should receive significant attention during preparation.

Open Book Test

The Nevada C-21 Refrigeration and Air Conditioning Contractor examination is an open-book test.

The following references included in this package are allowed into the examination:

• Uniform Mechanical Code, 2018
• NFPA 54 - Standard for National Fuel Gas Code, 2012

The remaining references in this package are study materials and are not allowed into the examination room.

The UMC should be used regularly when preparing for refrigeration, air conditioning, mechanical equipment, ventilation, ducts, furnaces, combustion air, piping, hydronics, and related mechanical-code questions. NFPA 54 should be used when studying fuel-gas piping, appliances, venting, combustion air, testing, and other natural gas requirements.

With 85 questions in three hours, candidates have slightly more than two minutes per question on average. Effective open-book preparation means identifying the subject quickly, choosing the correct reference, locating the applicable section or table, and returning to the question without losing unnecessary time.

Trade knowledge remains essential. Candidates should not expect to search the approved books for every answer. Questions involving refrigeration principles, load calculations, duct construction, evaporative cooling, safety, and other technical concepts often require preparation beyond code navigation.

Licensing Steps

1. Confirm the C-21 classification. Make sure Refrigeration and Air Conditioning Contracting matches the work the business intends to perform.
2. Identify the qualifying individual. The contractor application must identify the person responsible for satisfying the applicable trade qualification requirements.
3. Document qualifying experience. Prepare the required experience information supporting refrigeration and air-conditioning work.
4. Submit the Nevada contractor license application. Complete the applicable application and supporting documentation.
5. Receive examination eligibility. After the application is filed and experience is reviewed, the qualifying individual can proceed with the required examinations.
6. Prepare for the C-21 trade examination. Study refrigeration, air conditioning, fuel systems, ductwork, load calculations, piping, controls, hydronics, ventilation, chilled water, solar, evaporative cooling, and safety.
7. Practice code navigation. Use the Uniform Mechanical Code and NFPA 54 throughout preparation.
8. Prepare for Nevada Business and Law. The qualifying individual must satisfy the applicable business and law examination requirement unless a waiver applies.
9. Complete the required examinations. Take the authorized trade and business examinations.
10. Complete remaining licensing requirements. Finish the additional Nevada contractor licensing requirements applicable to license issuance.

State Requirements

Nevada's C-21 Refrigeration and Air Conditioning classification allows a license holder to perform work authorized under the C-21 subclassifications.

The scope includes refrigeration systems used to control temperatures below 50°F in refrigerated rooms and insulated spaces, together with related insulation, ducts, blowers, registers, humidity controls, thermostatic controls, and specified gas and electrical connections.

The C-21 scope also includes installation, repair, service, and maintenance of air-conditioning equipment, machinery, units, and related ductwork using evaporation, refrigeration, boilers, or combustion to control temperatures in occupied structures.

Additional work within the classification includes applicable sheet metal fabrication and installation, repair and replacement of existing refrigeration and air-conditioning system components, solar equipment used for air-temperature control, chilled-water systems, and piping used to transfer hot water for temperature control.

The broad scope explains why the C-21 examination covers refrigeration, air conditioning, sheet metal and ducts, hydronics, fuel systems, solar, chilled water, controls, load calculations, ventilation, and safety.

Reference Books

• Uniform Mechanical Code, 2018
  This exam-room-approved reference supports preparation involving refrigeration, mechanical equipment, air conditioning, heating, ventilation, ducts, combustion air, piping, hydronics, furnaces, chillers, and related mechanical requirements.
• NFPA 54 - Standard for National Fuel Gas Code, 2012
  This exam-room-approved reference supports fuel-gas piping, appliances, sizing, testing, combustion air, venting, regulators, connections, and related natural gas requirements.
• Code of Federal Regulations - 29 CFR Part 1926 (OSHA)
  This study-only reference supports construction safety preparation involving personal protective equipment, ladders, electrical hazards, tools, material handling, fall protection, and general jobsite safety.
• Modern Refrigeration and Air Conditioning, 22nd edition
  This study-only reference supports refrigeration cycles, refrigerants, compressors, condensers, evaporators, metering devices, controls, heat pumps, air conditioning, troubleshooting, and system operation.
• HVAC Duct Construction Standards, Metal and Flexible, 2005, 3rd Edition
  This study-only reference supports duct fabrication, reinforcement, joints, supports, flexible ducts, construction methods, and installation practices.
• Manual N - Commercial Load Calculation for Small Commercial Buildings, 5th Edition
  This study-only reference supports heating and cooling load calculations for small commercial applications and helps candidates practice the load-calculation portion of the C-21 exam.
• Solar Water and Pool Heating Design and Installation Manual
  This study-only reference supports solar energy, collectors, piping, storage, circulation, design concepts, and installation preparation.
• Evaporative Air Conditioning Handbook, 3rd Edition, 1997 (USED)
  This study-only reference supports evaporative cooling principles, equipment, water distribution, airflow, system design, operation, and practical applications.

Exam Room Approved Books

• Uniform Mechanical Code, 2018
  Approved for use during the Nevada C-21 Refrigeration and Air Conditioning Contractor examination for applicable mechanical, refrigeration, heating, cooling, ventilation, piping, and equipment requirements.
• NFPA 54 - Standard for National Fuel Gas Code, 2012
  Approved for use during the examination for applicable fuel-gas piping, appliance, venting, testing, combustion-air, and related gas-system requirements.

Test Information and Study Materials

A productive C-21 study plan should begin with the highest-weight examination categories and then expand to the supporting subjects.

Fuel Systems should receive significant attention because it accounts for 10 questions. Review natural gas piping, sizing, pressure, regulators, appliance connections, shutoffs, testing, combustion air, venting, and related requirements using NFPA 54.

Refrigerants and Refrigeration should include the refrigeration cycle, pressure-temperature relationships, compressors, condensers, evaporators, metering devices, refrigerants, superheat, subcooling, system operation, and troubleshooting fundamentals.

Piping preparation should include materials, fittings, routing, joining methods, insulation, supports, pressure drop, refrigerant lines, hydronic piping, and proper installation practices.

Load Calculations should be practiced rather than simply read. Candidates should become comfortable identifying design conditions, evaluating building loads, and working through the calculation process used for small commercial HVAC systems.

Ducts should include sheet-metal and flexible duct construction, joints, reinforcement, supports, airflow, leakage considerations, installation, and coordination with HVAC equipment.

Controls should include thermostats, relays, contactors, pressure controls, safety devices, dampers, valves, and the basic relationship between electrical controls and mechanical-system operation.

Chimneys, Flues and Vents should be studied alongside fuel systems. Candidates should understand venting principles, connectors, clearances, terminations, appliance venting, and combustion-product removal.

A/C and Heat Pump Equipment and Furnaces and Heaters should include system components, operation, installation, airflow, fuel considerations, electrical controls, and troubleshooting concepts.

Chillers and Hydronics should include pumps, valves, coils, piping, cooling towers, chilled-water circulation, hot-water systems, and the relationship between water flow and temperature control.

Evaporative Cooling should include airflow, pads or media, pumps, water distribution, temperature reduction, and system applications. The Evaporative Air Conditioning Handbook can support this preparation.

Solar should include collectors, piping, storage, circulation, energy transfer, and equipment used in solar-assisted temperature-control systems.

Testing, Adjusting and Balancing should include airflow, system performance, measurement, commissioning concepts, and recognizing conditions that prevent proper equipment operation.

Ventilation and Exhausts should include airflow, exhaust systems, mechanical ventilation, ductwork, equipment, and code-based requirements.

Safety should be learned before test day because OSHA is not allowed into the examination. Candidates should review electrical hazards, ladders, personal protective equipment, tools, material handling, fall protection, and other construction safety subjects.

The study-only references should gradually transition from reading material to active recall. After reviewing a topic, close the book and explain the system, calculation, or procedure without looking at the page. Then use practice questions to test retention.

The Uniform Mechanical Code and NFPA 54 should be handled differently because they are available during the examination. Practice targeted lookups using the table of contents, index, definitions, chapters, and tables until the books are familiar.

Timed practice is especially important. With 85 questions in three hours, candidates should know when a lookup is worthwhile and when it is better to answer from technical knowledge and continue.

How 1 Exam Prep Helps You Reach Your Goal

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

The C-21 examination covers a broad range of HVAC and refrigeration subjects. Organizing the material by systems helps candidates focus separately on refrigeration, fuel gas, ductwork, load calculations, heating, controls, hydronics, chillers, solar, evaporative cooling, ventilation, and safety.

The Uniform Mechanical Code, 2018 and NFPA 54, 2012 can be used throughout preparation to build faster navigation with the same code references available during the open-book examination.

The supplemental books add technical depth in refrigeration, duct construction, load calculations, construction safety, solar systems, and evaporative cooling. Because these books are not available in the exam room, active recall and practice questions can help reinforce the material before test day.

1 Exam Prep encourages candidates to identify why they miss questions. A missed problem may come from a technical knowledge gap, a calculation error, choosing the wrong code reference, or spending too much time searching. Addressing the specific weakness can make study sessions more productive.

The goal is to help candidates approach the Nevada C-21 Refrigeration and Air Conditioning Contractor examination with stronger HVAC knowledge, better code-navigation skills, improved calculations, and a structured study strategy without guaranteeing a passing score or licensing approval.

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

The Nevada C-21 Refrigeration and Air Conditioning Contractor examination contains 85 questions.

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

Candidates are allowed 3 hours to complete the examination.

How many correct answers are required to pass?

Candidates must answer 60 questions correctly to pass the C-21 trade examination.

Is the Nevada C-21 exam open book?

Yes. The Nevada C-21 Refrigeration and Air Conditioning Contractor examination is an open-book test.

Which books are allowed into the C-21 exam?

The Uniform Mechanical Code, 2018 and NFPA 54 - Standard for National Fuel Gas Code, 2012 are the exam-room-approved references 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 study but is not allowed into the examination.

Is OSHA 29 CFR Part 1926 allowed into the exam?

No. OSHA 29 CFR Part 1926 is a study-only reference for the C-21 examination.

Is HVAC Duct Construction Standards allowed into the exam?

No. HVAC Duct Construction Standards is included for ductwork preparation but is not allowed into the examination.

Is Manual N allowed into the C-21 exam?

No. Manual N is included for load-calculation study and is not allowed into the examination.

What is the largest C-21 exam category?

Fuel Systems is the largest individual category with 10 questions.

How many Refrigerants and Refrigeration questions are on the exam?

The examination contains 7 Refrigerants and Refrigeration questions.

Does the exam include load calculations?

Yes. Load Calculations accounts for 6 questions.

Does the C-21 examination include ductwork?

Yes. Ducts accounts for 6 questions.

Does the exam include solar and evaporative cooling?

Yes. Solar accounts for 4 questions, and Evaporative Cooling accounts for 2 questions.

How should I prepare for the open-book portion of the exam?

Practice targeted navigation with the Uniform Mechanical Code and NFPA 54. Learn which reference applies to each subject, then use timed practice questions to improve lookup speed.

Should I look up every answer during the exam?

No. Build strong refrigeration and air-conditioning knowledge first and use the approved references strategically when a specific code rule, table, definition, or requirement needs to be confirmed.

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

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