OK-MECH Certification

Scope of the Unlimited Classification: The "Unlimited" designation in HVACR Contractor Unlimited signals that a licensee can work on larger commercial systems, not just residential-scale equipment. Applicants must document qualifying experience on equipment rated above 25 tons and 500,000 Btu/h to prove they can handle that scope.

Who Needs the HVACR Contractor Unlimited Credential

This exam is built for people who intend to operate or hold a supervisory technical role within a licensed mechanical contracting firm in Oklahoma - not entry-level technicians. The CIB requires that applicants be an owner, partner, officer, or permanent employee of a mechanical firm before they can even sit for the trade exam. In practice, this credential targets:

• Journeyman-level HVAC/R technicians moving toward a contractor license
• Business owners who want to legally bid and pull permits for unlimited-tonnage commercial HVACR work
• Mechanical firm employees being positioned as the company's qualifying agent

Anyone weighing whether this path fits their career goals should also review OK-MECH Jobs and Is the OK-MECH Certification Worth It? Complete ROI Analysis 2026 before committing time and testing fees.

Exam Format, Timing, and Fees

The HVACR Contractor Unlimited trade exam consists of 90 computer-based questions to be completed in 240 minutes, with a required score of 70% to pass. PSI may embed up to 10 additional unscored, experimental questions used to test future exam content - you won't know which items are experimental, and the time to answer them does not count against your 240-minute clock.

Separately, license applicants must also pass the Business and Law examination: 50 questions, 120 minutes, also scored at a 70% threshold. Both exams must be passed within three years of eligibility approval under CIB rules.

Exam Component	Questions	Time Limit	Passing Score	Fee
Trade Exam (HVACR Contractor Unlimited)	90	240 minutes	70%	$92
Business and Law Exam	50	120 minutes	70%	$92

Beyond the per-attempt exam fees, the initial CIB application and licensing payment totals $330 - $30 for the application and $300 for the license itself. For a full accounting of every dollar involved, including bonding and insurance costs, see OK-MECH Certification Cost 2026: Complete Pricing Breakdown. If you want the exact scoring mechanics spelled out question-by-question, OK-MECH Passing Score 2026: Exactly What You Need to Pass covers that in detail.

The Six Trade Exam Domains

The 90 scored questions on the trade exam are distributed across six subject areas, weighted 15, 12, 25, 20, 15, and 3 items respectively. Air Distribution Systems is the single largest domain. Understanding this weighting is the foundation of any efficient prep plan - trying to study all six domains equally wastes time on the lighter-weighted areas at the expense of the heavyweight ones.

For deeper topic-by-topic breakdowns of each domain, the dedicated OK-MECH Exam Domains 2026: Complete Guide to All 6 Content Areas guide expands on likely question styles within each area, and How Hard Is the OK-MECH Exam? Complete Difficulty Guide 2026 discusses which domains candidates tend to find most challenging.

Eligibility and Experience Requirements

Before you can register for the trade exam, the CIB requires that you:

• Be at least 18 years old
• Meet the mechanical journeyman experience requirements, plus one additional year of qualifying experience
• Be an owner, partner, officer, or permanent employee of a mechanical firm
• Document work specifically on equipment above 25 tons and 500,000 Btu/h to qualify for the Unlimited classification

The standard route relies on four total years of qualifying experience, though approved education can reduce the journeyman experience component. Experience certifications and applicable school records must be submitted to support your application. Once licensed and active, contractors must also maintain a $5,000 surety bond and $50,000 commercial general liability insurance to keep the license in good standing.

A complete eligibility checklist - including how education credit interacts with the experience requirement - is available in OK-MECH Requirements 2026: Eligibility, Prerequisites & How to Qualify.

Open-Book References Allowed at the Testing Center

Unlike many licensing exams, the OK-MECH trade exam permits a defined set of open-book references at the testing center. Per the current PSI bulletin (effective August 31, 2026), allowed materials include the specified mechanical and fuel-gas codes, a refrigeration textbook, an OSHA reference, ACCA Manual N, Mathematics for Plumbers and Pipefitters, and an ACCA ductulator.

Candidates need to pay close attention to edition timing, because references are being updated on a rolling schedule:

• The 2024 IMC and IFGC become usable starting September 14, 2026; the 2018 editions are no longer allowed after December 14, 2026.
• Modern Refrigeration and Air Conditioning, 22nd edition, became usable August 13, 2026; the 20th edition and the previously listed Refrigeration and Air Conditioning Technology, 5th edition, stop being allowed on November 1, 2026.

You are allowed to pre-highlight your references and use permanent tabs to speed up navigation during the exam - but handwritten notes in the margins are prohibited. A PSI-compliant non-programmable calculator is also permitted for the math-heavy portions, especially within Air Distribution Systems.

Building a Domain-Focused Study Plan

Because Air Distribution Systems (25 questions) and Refrigeration and Air Conditioning Systems (20 questions) together make up nearly half of the trade exam, your prep schedule should weight time accordingly rather than splitting effort evenly across all six domains. A short weekly structure built around domain weight, not generic study theory, tends to work best.

Practicing under real time pressure matters as much as reviewing content, since 240 minutes across 90 questions still demands pacing discipline, especially on the calculation-heavy Air Distribution items. Try a full-length simulated run on our practice test platform before your scheduled date so the format itself isn't a surprise. For a structured, week-by-week prep framework built specifically around this exam's fee and retake rules, see OK-MECH Study Guide 2026: How to Pass on Your First Attempt.

Retakes, Bonding, and Annual Renewal

If you don't pass on your first attempt, you must wait 30 days before retesting. Any subsequent failure requires a 90-day wait before the next attempt. Remember that both the trade exam and the Business and Law exam must be passed within three years of your eligibility approval - plan retakes with that window in mind.

Once licensed, renewal is annual and falls in your birth month, with a $200 contractor renewal fee. Continuing education requires six approved hours every 36 months, though there is an initial three-year exemption from that requirement right after initial licensure. Scheduling specifics, including how testing windows are structured throughout the year, are covered in OK-MECH Exam Dates 2026: Testing Windows, Deadlines & Scheduling.

For a condensed, at-a-glance reference of every number in this article - fees, timing, domain weights, and renewal figures - bookmark the OK-MECH Cheat Sheet 2026: One-Page Review of Must-Know Facts and keep it handy in the days before your test.

Frequently Asked Questions