What Is the Arizona C-74 Contractor Classification?

Arizona's C-74 classification is called Boilers, Steamfitting and Process Piping, Including Solar.

The classification allows qualifying contractors to install, alter, and repair steam and hot water systems and boilers, including solar systems.

The scope also includes work involving:

• Chimney connections.
• Flues.
• Refractories.
• Burners.
• Piping and fittings.
• Valves.
• Thermal insulation.
• Boiler accessories.
• Fuel and water lines serving boilers.
• Process and specialty piping.
• Related process equipment.
• Pneumatic controls.
• Electrical controls.

Arizona also allows a new circuit to be added to an existing service panel or sub-panel when necessary for the permitted work. Installing a new service panel or sub-panel is excluded from this classification.

C-74 vs. CR-74: What Is the Difference?

The examination material is commonly identified by PSI as the C-74 (CR-74) Boilers, Steamfitting and Process Piping, Including Solar examination.

Review the Arizona Registrar of Contractors license classifications for the current legal scope before submitting your application.

Step 1: Understand the Required Examination Path

Arizona currently identifies C-74 and CR-74 as classifications requiring the Statutes and Rules Exam, a trade examination, and a solar examination.

You may see these abbreviated as:

• SRE: Arizona Statutes and Rules Exam.
• T: Trade examination.
• S: Solar examination.

The Arizona Registrar of Contractors maintains the SRE, while PSI administers the trade-specific examinations.

The SRE is a computer-based training course and examination covering Arizona contractor statutes and rules. Current PSI information lists the SRE cost at $61.

Exam waivers can apply in certain situations, so applicants should confirm their exact requirements with the Arizona ROC instead of assuming every applicant follows the identical path.

Step 2: Know the C-74 Trade Exam Numbers

PSI may also place a small number of experimental questions in contractor examinations. These questions are not scored, but they still consume examination time.

That makes efficient reference use important. An open-book exam is helpful, but only when you know which book to open.

Step 3: Learn the C-74 Exam Breakdown

The official C-74 trade outline divides the 50 scored questions into nine categories.

Boilers are the largest single category, but notice what happens when you combine the piping subjects. Steam and hot water piping, gas piping, and process piping account for 18 questions.

This is a boiler exam with a very strong piping personality.

Step 4: Know the Separate C-74 Solar Exam

Because the classification includes solar, candidates also need to prepare for the separate C-74 Solar examination when required.

The solar examination currently contains:

• 30 questions.
• 75-minute time limit.
• 70% passing score.

The official content breakdown is:

• Collection Loops: 5 questions.
• Components: 4 questions.
• Installation: 5 questions.
• Maintenance: 2 questions.
• Mounting: 4 questions.
• Principles: 5 questions.
• Solar Systems Piping: 5 questions.

Collection loops, installation, principles, and solar systems piping make up 20 of the 30 questions. Those four areas deserve a large part of your solar study time.

Step 5: Get the Correct C-74 Reference Books

The PSI C-74 content outline identifies three main references that are allowed in the examination center.

• Code of Federal Regulations, 29 CFR Part 1926, OSHA, with the latest available amendments, or PSI's applicable selections.
• International Mechanical Code, with the listed 2012, 2015, or 2018 editions.
• International Fuel Gas Code, with the listed 2012, 2015, or 2018 editions.

Before ordering books, check PSI's current outline again. Code editions are important because PSI states that code questions are based on the listed code editions.

Browse the Arizona contractor exam books and study resources from Contractor Exam Preps when assembling your exam materials.

Step 6: Know Which Study Books Are Not Allowed in the Exam

Several useful C-74 study references are listed by PSI but are not allowed inside the examination center.

They include:

• Low Pressure Boilers, 3rd Edition, 2009, by Frederick M. Steingress and Daryl R. Walker.
• Modern Hydronic Heating for Residential and Light Commercial Buildings, Second Edition, 2004.
• IPT's Pipe Trades Handbook, 1991, by Robert A. Lee.

These books can still be valuable during preparation. They help build the trade knowledge needed to understand boiler systems, hydronic systems, and pipe-trade concepts.

The trick is remembering the difference between study reference and exam-room reference. Those are not the same thing.

Step 7: Prepare for the Solar Exam Without Expecting a Book Rescue

PSI identifies the Solar Water and Pool Heating Design and Installation Manual as a reference for the C-74 Solar exam.

However, PSI's current C-74 outline states that this reference is not allowed in the examination center.

That means the solar portion deserves real study before test day.

Build a working understanding of:

• Solar thermal principles.
• Collector operation.
• Collection-loop arrangements.
• Pumps and controls.
• Storage.
• Heat transfer.
• Solar piping.
• Mounting.
• System installation.
• Maintenance and troubleshooting concepts.

If the book cannot come with you, the useful part has to arrive in your head.

Step 8: Prepare Your Open-Book References Correctly

PSI allows approved exam-room references to be prepared before the examination.

References may be:

• Highlighted before the test.
• Underlined before the test.
• Annotated before the test.
• Indexed before the test.
• Marked with permanent tabs.

PSI defines permanent tabs as tabs that would tear the page if removed.

Temporary tabs, Post-it notes, and other removable tabs are not permitted. Candidates also may not bring unauthorized loose or attached papers with approved references.

If you download an approved reference from the internet, PSI permits it when properly bound, such as spiral binding or hole punching the pages and placing them in a binder.

Do all highlighting, annotating, underlining, indexing, and tabbing before the examination. PSI does not allow candidates to continue marking references during the test.

Step 9: Make Boilers Your Strongest Individual Category

Boilers account for 10 questions, making them the largest single section of the trade exam.

Review boiler fundamentals such as:

• Steam boiler operation.
• Hot water boiler operation.
• Boiler fittings and accessories.
• Pressure controls.
• Temperature controls.
• Low-water protection.
• Safety and relief devices.
• Feedwater.
• Combustion.
• Operating controls.
• Inspection.
• Maintenance.

Do not study every device as an isolated object. Understand what it does in the complete system and what happens when operating conditions change.

Step 10: Put Serious Time Into Piping

Piping categories make up a huge portion of the exam.

Steam and hot water piping contributes six questions, gas piping contributes six, and process piping contributes another six.

Review:

• Steam supply and return systems.
• Condensate systems.
• Hydronic supply and return piping.
• Circulation.
• Expansion.
• Valves.
• Fittings.
• Pipe materials.
• Pipe supports.
• Joining methods.
• Gas pipe sizing.
• Gas pressure testing.
• Process piping terminology.
• Process piping installation practices.

Become comfortable with tables in the International Fuel Gas Code and the piping-related portions of the International Mechanical Code.

Step 11: Study Burners and Controls Together

Burners and controls each contribute five questions, giving you 10 questions between them.

Study burner operation, combustion, ignition, fuel supply, flame safety, operating controls, limit controls, pressure controls, temperature controls, and common system sequences.

Try to understand the order in which equipment operates instead of memorizing a pile of separate component definitions.

Ask yourself what should happen when there is a call for heat, when ignition begins, when flame is proven, when operating pressure is reached, or when a safety limit opens.

Sequence questions become much easier when the system makes sense in your head.

Step 12: Review Flues, Vents, Testing, and Inspection

Flues and vents account for four questions, while testing and inspection contribute another four.

Review areas such as:

• Vent materials.
• Vent connectors.
• Draft.
• Termination locations.
• Clearances.
• Combustion air.
• Chimney connections.
• Pressure testing.
• System inspection.
• Operational checks.
• Safety-device verification.

These subjects are good candidates for code-book lookup practice because the wording of a requirement can matter as much as your general field knowledge.

Step 13: Practice Sizing and Estimating

The C-74 exam contains four questions on sizing and estimating.

Practice solving problems instead of only reading solutions.

Depending on the question, you may need to work with dimensions, quantities, pipe sizing, capacities, or other trade-related calculations.

PSI currently allows a basic, silent, nonprinting, non-programmable, non-scientific calculator in the examination center.

Use the same type of calculator while practicing. You do not want to spend exam time staring at a calculator as if you have never met before.

Step 14: Practice Book Navigation, Not Just Reading

Reading an approved code book from page one to the end is rarely the most efficient exam strategy.

Instead, learn how the book is organized.

1. Review the table of contents.
2. Learn how to use the index.
3. Identify major chapters related to your exam categories.
4. Place permanent tabs on high-value sections.
5. Highlight definitions, tables, and important requirements.
6. Practice finding answers under a timer.

For every practice question, identify which reference should contain the answer before opening a book.

That habit can save valuable minutes on test day.

Step 15: Use a Four-Week C-74 Study Schedule

Adjust the schedule to match your experience. If process piping is already your daily work but solar thermal systems are new to you, your study calendar should reflect that.

You can also review Arizona contractor exam preparation materials while building your study plan.

Step 16: Practice With the Real Time Limits

Use the actual exam limits during some of your practice sessions.

For the C-74 trade exam, practice answering 50 questions in 120 minutes.

For solar, practice answering 30 questions in 75 minutes.

Do not spend eight minutes searching for one answer while several easier questions wait for you.

Make a first pass through questions you can answer confidently. Mark difficult questions and return to them with your remaining time.

PSI's computer examination system allows candidates to return to questions and change responses as long as examination time remains.

Step 17: Know the Current PSI Retake Rules

If you do not pass an examination, the current PSI bulletin requires a 30-day wait before retesting.

Candidates are allowed three attempts to pass each examination. After three failed attempts, a 90-day waiting period applies before another attempt at the examination that was not passed.

PSI provides diagnostic information after an unsuccessful attempt showing areas of strength and weakness.

Use it to change your study plan. Scheduling the same exam with the same weak areas and hoping the computer feels generous this time is not ideal preparation.

Step 18: Complete the Arizona Licensing Requirements

Passing C-74 and the solar exam is only part of becoming licensed.

Arizona currently identifies C-74 and CR-74 as four-year experience classifications. The required experience must satisfy the ROC's qualifying standards.

The licensing process can also involve:

• Selecting C-74 or CR-74.
• Designating the qualifying party.
• Documenting qualifying experience.
• Completing the SRE when required.
• Passing the trade examination.
• Passing the solar examination.
• Completing required background checks.
• Obtaining the required contractor license bond.
• Providing business and identification documents.
• Submitting the contractor license application.
• Paying applicable ROC fees.

PSI currently instructs candidates to complete the licensing requirements and submit the application and original score report to the Arizona ROC within two years of passing the necessary examination.

A Simple C-74 and CR-74 Exam Roadmap

1. Confirm whether you need C-74 or dual CR-74.
2. Verify your current Arizona ROC experience requirements.
3. Determine whether an exam waiver applies.
4. Complete or plan for the Arizona SRE.
5. Download the current PSI C-74 content outline.
6. Obtain the exact approved code references.
7. Separate allowed books from study-only references.
8. Prepare approved references with permanent tabs and highlighting.
9. Make boilers one of your strongest subjects.
10. Spend significant time on all three piping categories.
11. Review burners and controls together.
12. Practice fuel-gas and mechanical-code lookups.
13. Study the solar reference before examination day.
14. Focus heavily on solar principles, loops, installation, and piping.
15. Practice calculations using an approved-style calculator.
16. Complete timed 120-minute trade practice exams.
17. Complete timed 75-minute solar practice exams.
18. Review every missed question before scheduling the real examination.

Arizona C-74 and CR-74 Exam Prep Resources

The C-74 examination covers a lot of material, but the official outline gives you a clear roadmap.

Boilers are the biggest individual category. Piping is the largest combined subject. Burners and controls are important. Code navigation matters. Solar requires its own focused preparation.

When you are ready to prepare, explore the Arizona contractor exam prep resources from Contractor Exam Preps. The right references, a good tabbing system, strong boiler and piping knowledge, focused solar study, and timed practice can make the C-74 or CR-74 exam much easier to handle.