Oklahoma HVACR Unlimited Contractor Exam Book Package

Prepare for the Oklahoma HVACR Unlimited Contractor examination with a focused collection of technical reference books and tools covering mechanical codes, fuel gas requirements, refrigeration and air conditioning, commercial load calculations, duct sizing, trade mathematics, and construction safety.

The Oklahoma HVACR Unlimited Contractor Exam Book Package includes a Ductulator, International Mechanical Code, 2018, International Fuel Gas Code, 2018, Modern Refrigeration and Air Conditioning, 22nd Edition, Manual N - Commercial Load Calculation for Small Commercial Buildings, 5th Edition, Mathematics for Plumbers and Pipefitters, 8th Edition, and Code of Federal Regulations - 29 CFR Part 1926 (OSHA).

The Oklahoma HVACR Unlimited Contractor classification is intended for contractors performing qualifying heating, ventilation, air conditioning, refrigeration, sheet metal, natural gas piping, and related process piping work without the equipment-capacity limitations placed on Oklahoma's HVACR Limited Contractor classification.

Because the technical contractor examination is open book, candidates should become familiar with the references they plan to use before test day. Effective preparation combines HVACR trade knowledge with the ability to determine which reference applies to a question and locate the appropriate code section, table, formula, definition, or technical explanation efficiently.

Exam Details

The Oklahoma HVACR Contractor Unlimited examination evaluates a candidate's knowledge of installing, maintaining, repairing, fabricating, altering, and extending air conditioning, refrigeration, heating, and ventilation systems within the unrestricted HVACR contractor classification.

• Exam: Oklahoma HVACR Contractor Unlimited
• Testing Provider: PSI
• Number of Questions: 90
• Time Allowed: 240 minutes
• Passing Score: 70%
• Passing Raw Score: 63 correct answers
• Exam Format: Open book

The examination addresses several major areas of HVACR trade knowledge. These include Electrical Knowledge and Controls, Natural Gas, Air Distribution Systems, Refrigeration and Air Conditioning Systems, Heating Systems, and Safety.

Air Distribution Systems is a significant part of unlimited contractor preparation. Candidates should understand duct sizing and design, duct materials, installation, hangers and supports, insulation, ventilation, exhaust systems, fire and smoke control, testing and balancing, and system plans and symbols.

Refrigeration and Air Conditioning Systems preparation should include refrigeration theory, refrigerants, system components, piping, equipment sizing and design, installation, system operation, maintenance, and troubleshooting.

Heating Systems review should include heating theory, equipment, combustion air, vents and chimneys, equipment sizing, installation, hydronic systems, operation, troubleshooting, and maintenance. Natural Gas preparation includes piping, valves, connectors, supports, sizing, materials, testing, appliances, venting, and combustion air.

Electrical Knowledge and Controls can involve electrical theory, motors, circuits, and controls as they apply to HVACR equipment. Safety preparation should include construction-industry practices and OSHA requirements relevant to HVACR work.

Open Book Test

The Oklahoma HVACR Contractor Unlimited examination is an open book test. Candidates may use approved reference materials according to PSI's examination-center rules.

Open-book testing still requires substantial preparation. Candidates should not plan to search every reference from the beginning for every question. A more efficient approach is to understand the technical subject first, identify the correct reference, and then locate the applicable information when needed.

The International Mechanical Code can support questions involving mechanical installations, ventilation, duct systems, equipment requirements, refrigeration systems, combustion air, exhaust, chimneys, and vents.

The International Fuel Gas Code can support questions involving fuel gas piping, materials, sizing, valves, connectors, appliance installation, combustion air, venting, and testing.

Modern Refrigeration and Air Conditioning provides broader technical information covering refrigeration, heating, air conditioning, electrical concepts, controls, equipment, installation, system operation, maintenance, and troubleshooting.

Manual N supports preparation for commercial heating and cooling load calculations, while the Ductulator supports air-distribution and duct-sizing practice. Mathematics for Plumbers and Pipefitters provides trade-math review, and 29 CFR Part 1926 supports preparation for construction safety questions.

Candidates should practice reference navigation before the examination. Choose a subject, identify the correct book, and locate the chapter, section, table, formula, or technical explanation that applies. Repeated practice helps connect HVACR knowledge to the references used during open-book testing.

Licensing Steps

1. Gain qualifying mechanical trade experience. Build verifiable HVACR experience appropriate to the unlimited contractor classification.
2. Meet journeyman-level qualifications. Oklahoma contractor applicants must satisfy the applicable requirements for mechanical journeyman licensing before progressing to contractor-level qualification.
3. Gain additional contractor experience. Oklahoma requires contractor applicants to have additional qualifying mechanical trade experience beyond the journeyman level.
4. Qualify for the Unlimited classification. Experience for the unlimited HVACR category must demonstrate work appropriate to the unrestricted scope of the license.
5. Submit the contractor license application. Apply for the HVACR Unlimited Contractor classification through the Oklahoma Construction Industries Board.
6. Receive examination eligibility. The state reviews the application and determines whether the applicant is qualified to proceed with testing.
7. Schedule the required examination. Approved candidates schedule testing through PSI.
8. Complete the contractor licensing process. After meeting examination requirements, complete the applicable requirements for active contractor status.

Exam preparation is one part of the licensing process. Applicants should also understand the experience, application, and active-license requirements associated with becoming an Oklahoma HVACR Unlimited Contractor.

State Requirements

The Oklahoma HVACR Unlimited Contractor classification authorizes qualifying work involving cooling products, systems, or equipment, including process piping, without the tonnage limitation applied to the HVACR Limited Contractor license.

The classification also covers heating equipment and associated process piping without the limited category's heating-input restriction. It includes qualifying sheet metal, natural gas piping, refrigeration, and related HVACR work within the unrestricted classification.

Oklahoma requires mechanical contractor applicants to meet the same general qualification requirements applicable to a journeyman and obtain an additional year of mechanical trade experience.

A mechanical contractor must also be a permanent employee, owner, partner, or officer of the mechanical firm. Candidates should understand that passing the exam does not by itself complete the contractor licensing process.

The Oklahoma Construction Industries Board oversees mechanical licensing and determines examination eligibility. Applicants should complete the licensing process for the appropriate classification and meet the requirements associated with operating under an active mechanical contractor license.

Reference Books

• Ductulator
  A practical air-distribution tool used for duct-sizing calculations. It supports preparation involving airflow, duct dimensions, velocity, friction, and other relationships used in HVAC duct design and air distribution.
• International Mechanical Code, 2018
  Covers mechanical installations, equipment, ventilation, duct systems, exhaust systems, refrigeration, combustion air, chimneys, vents, and related mechanical requirements. Candidates can use this code when preparing for installation and system-requirement questions.
• International Fuel Gas Code, 2018
  Covers fuel gas piping, materials, valves, connectors, sizing, appliances, testing, combustion air, venting, and related fuel gas requirements. It supports preparation for Natural Gas and heating-related questions.
• Modern Refrigeration and Air Conditioning, 22nd Edition
  Provides comprehensive technical coverage of refrigeration principles, refrigerants, air conditioning, heating, electrical fundamentals, motors, controls, equipment, installation, system operation, maintenance, service, and troubleshooting.
• Manual N - Commercial Load Calculation for Small Commercial Buildings, 5th Edition
  Supports commercial heating and cooling load-calculation preparation. Candidates pursuing an unrestricted HVACR contractor classification can use Manual N to strengthen their understanding of load calculations and commercial equipment-sizing concepts.
• Mathematics for Plumbers and Pipefitters, 8th Edition
  Provides trade-oriented mathematical instruction covering measurements, formulas, conversions, area, volume, piping mathematics, and other calculations relevant to mechanical work.
• Code of Federal Regulations - 29 CFR Part 1926 (OSHA)
  Contains federal construction-industry safety standards. It supports preparation involving workplace hazards, personal protective equipment, fall protection, ladders, scaffolds, employee protection, and other construction safety requirements.

Each reference supports a different part of preparation. Mechanical and fuel gas codes help candidates research installation requirements. Modern Refrigeration and Air Conditioning supports broader technical understanding. Manual N and the Ductulator address load calculations and air distribution, while the mathematics and OSHA references support calculations and safety.

Exam Room Approved Books

The technical references associated with the Oklahoma HVACR Contractor Unlimited examination include the Ductulator, International Mechanical Code, International Fuel Gas Code, Modern Refrigeration and Air Conditioning, Manual N, Mathematics for Plumbers and Pipefitters, and 29 CFR Part 1926.

The specified code editions in this package are the 2018 International Mechanical Code and the 2018 International Fuel Gas Code. Candidates should practice using these code books throughout preparation so they become familiar with chapter organization, indexes, definitions, and tables.

Modern Refrigeration and Air Conditioning, 22nd Edition is permitted under the current PSI reference schedule beginning August 13, 2026.

Reference books are most useful when candidates already know how they are organized. Work directly with the books during practice questions rather than treating them only as test-day materials.

Test Information and Study Materials

A productive Oklahoma HVACR Unlimited Contractor study plan should combine technical review, code navigation, commercial load calculations, air-distribution practice, mathematics, and safety preparation.

Begin with the major HVACR systems. Review refrigeration theory, refrigerants, components, piping, equipment sizing, system operation, installation, maintenance, and troubleshooting. Use Modern Refrigeration and Air Conditioning throughout these study sessions.

Heating preparation should include equipment, combustion air, venting, chimneys, hydronic systems, sizing, installation, operation, and troubleshooting. Natural gas preparation should include piping, connectors, valves, supports, materials, sizing, combustion air, appliances, testing, and venting.

Air-distribution preparation should include duct sizing, design, installation, materials, supports, insulation, ventilation, exhaust systems, fire and smoke requirements, testing and balancing, and plans and symbols.

Use the Ductulator during duct-sizing practice instead of waiting until the end of your preparation. Repeated use can help you become more familiar with airflow, velocity, friction, and duct dimensions.

Manual N should be incorporated into commercial load-calculation preparation. The unlimited classification includes work beyond the capacity restrictions of the limited category, so commercial HVAC knowledge is an important part of a well-rounded study plan.

Code-navigation practice should also be deliberate. Choose a subject such as ventilation, combustion air, duct installation, fuel gas sizing, or equipment requirements and practice finding the appropriate information in the correct code.

Trade mathematics should be practiced by solving problems involving measurements, formulas, conversions, area, volume, and other mechanical applications. Safety preparation should involve direct use of 29 CFR Part 1926 so candidates become familiar with how OSHA information is organized.

Mixed-reference practice can help create a realistic open-book study routine. Work through questions from several different subject areas during the same session. Before opening a reference, decide which book or tool should contain the information.

This approach helps candidates develop both subject recognition and reference-navigation skills. Instead of searching randomly, the candidate learns to connect each type of question with the most appropriate source.

How 1 Exam Prep Helps You Reach Your Goal

1 Exam Prep supports Oklahoma HVACR Unlimited Contractor candidates through organized study guidance, trade-focused review, practice-oriented preparation, reference navigation, and confidence-building study structure.

The Oklahoma HVACR Unlimited Contractor examination covers a broad range of trade knowledge. Candidates may need to work with refrigeration, heating, electrical controls, natural gas, air distribution, commercial load calculations, mechanical codes, mathematics, and construction safety.

1 Exam Prep encourages candidates to work directly with their reference materials throughout preparation. Using the books while answering practice questions, reviewing technical subjects, completing calculations, and locating code requirements helps build familiarity with both the content and organization of the references.

Reference-navigation practice can also reveal areas that need additional attention. A candidate with extensive refrigeration experience may need more practice with Manual N, duct sizing, fuel gas requirements, electrical controls, or OSHA regulations. Another candidate may be comfortable with installations but need additional code-navigation or mathematics practice.

Organizing preparation around these technical areas can create a more balanced study routine. The goal is to help candidates develop stronger familiarity with the examination subjects and reference materials while building confidence through consistent preparation rather than relying on last-minute memorization.

FAQ Section

What is included in the Oklahoma HVACR Unlimited Contractor Exam Book Package?

The package includes a Ductulator, International Mechanical Code 2018, International Fuel Gas Code 2018, Modern Refrigeration and Air Conditioning 22nd Edition, Manual N 5th Edition, Mathematics for Plumbers and Pipefitters 8th Edition, and 29 CFR Part 1926 OSHA.

Is the Oklahoma HVACR Unlimited Contractor exam open book?

Yes. The Oklahoma HVACR Contractor Unlimited examination is open book and allows approved reference materials under PSI testing rules.

How many questions are on the Oklahoma HVACR Unlimited Contractor exam?

The technical examination contains 90 questions. Candidates receive 240 minutes to complete the exam.

What score is required to pass?

The passing score is 70 percent, which corresponds to 63 correct answers on the 90-question examination.

What does the Oklahoma HVACR Unlimited Contractor license cover?

The unlimited classification covers qualifying cooling systems, heating equipment, sheet metal, natural gas piping, refrigeration, and related process piping without the equipment-capacity limitations applied to the HVACR Limited classification.

Does the package include Manual N?

Yes. Manual N - Commercial Load Calculation for Small Commercial Buildings, 5th Edition is included to support commercial heating and cooling load-calculation preparation.

Does the package include a Ductulator?

Yes. A Ductulator is included to support duct-sizing and air-distribution preparation.

Why is the International Mechanical Code included?

The International Mechanical Code supports preparation involving mechanical equipment, ventilation, duct systems, refrigeration, exhaust, combustion air, chimneys, vents, and other installation requirements.

Why is the International Fuel Gas Code included?

The International Fuel Gas Code supports natural gas preparation involving piping, sizing, materials, appliances, combustion air, venting, testing, and related requirements.

How should I prepare with this book package?

Use the references alongside technical study and practice questions. Learn which reference applies to each subject and practice locating chapters, code sections, tables, formulas, calculations, and safety requirements efficiently.

Should I wait until exam day to use the books?

No. Use the books throughout your preparation so you become familiar with their organization and can connect different HVACR subjects with the appropriate reference.