- TN-CMC is the Full Mechanical Contractor classification issued by the Tennessee Board for Licensing Contractors, covering both plumbing and HVAC.
- The Prov exam has 100 questions, is open-book, computer-delivered, and requires a 73% passing standard.
- Prov takes over exam scheduling on July 1, 2026; appointments already booked with PSI remain valid through September 2026.
- Domain 11, Air Distribution and Vents, carries 18 of 100 items - the single largest content area.
What Is a TN-CMC, Exactly?
TN-CMC stands for the Tennessee Full Mechanical Contractor (CMC) Exam, a licensing credential administered under the Tennessee Board for Licensing Contractors. It is not a niche add-on certificate - the "Full" designation means the classification covers both plumbing and HVAC scopes of work under a single mechanical contractor license. If you plan to bid, contract, or supervise mechanical work in Tennessee at a scale that touches both trades, this is the exam that unlocks that authority.
This article breaks down what the credential actually is, how the exam is structured, what it costs, and what happens after you pass. For a deeper dive into the exact terminology and how people commonly describe this credential, see What Is TN-CMC? and TN-CMC Meaning. If you're still untangling the abbreviation itself, What Does TN-CMC Stand For? covers that ground directly.
Who Issues the Credential and Who Needs It
The Tennessee Board for Licensing Contractors owns the CMC classification. The Board sets eligibility rules, collects preapproval and licensing fees, and issues the license itself. The actual exam delivery, however, is handled by a testing vendor - Prov - which took over new exam scheduling starting July 1, 2026. If you already had an appointment booked through PSI (the prior vendor) before that transition, that appointment is still honored through September 2026, so there's a short overlap window candidates should be aware of when planning their test date.
Anyone intending to independently contract on mechanical projects - plumbing, HVAC, or both - generally needs this license once project values cross the Board's licensing threshold. Tennessee law requires a license before bidding or contracting on covered projects of $25,000 or more, which makes the CMC a practical requirement for most commercial and many residential mechanical contractors operating at scale.
Exam Format, Fees, and Scheduling
The TN-CMC exam is computer-delivered and open-book, which changes how you should prepare compared to closed-book trade exams. You're allowed to bring approved reference material into the session, but the rules on what counts as "approved" are specific:
- Advance highlighting in your code books and manuals is permitted.
- Permanent tabs are allowed.
- Handwritten reference notes, loose papers, and movable tabs are not allowed.
- A simple four-function calculator is permitted - nothing programmable or scientific.
The exam draws from a defined outline: the June 15, 2026 Prov CMC blueprint lists 100 questions spread across 13 domains, with a 73% passing standard. Testing is available at physical test centers or through Examroom.ai remote proctoring, giving candidates flexibility in how they sit for the exam.
| Item | Detail |
|---|---|
| Prov exam fee (per attempt) | $53 |
| Board CMC preapproval fee | $50 |
| Initial contractor-license fee | $250 |
| Biennial renewal fee | $200 |
| Passing score | 73% |
| Total questions | 100 |
For a complete line-item walkthrough of every fee a candidate encounters from preapproval through renewal, see TN-CMC Certification Cost 2026: Complete Pricing Breakdown. And if scheduling logistics around the Prov/PSI transition are your main concern right now, TN-CMC Exam Dates 2026: Testing Windows, Deadlines & Scheduling lays out the timeline in more detail.
Key Takeaway
Because the exam is open-book, memorization matters less than knowing exactly where information lives in your IMC 2021, IFGC 2021, and HVAC Basics for Contractors references. Tab your books early and practice retrieving answers quickly under timed conditions.
The 13 Exam Domains
The CMC blueprint organizes content into 13 domains with fixed item counts. Understanding the weighting is the single most useful thing you can do before building a study plan, because it tells you exactly where your time pays off.
| Domain | Name | Items |
|---|---|---|
| 1 | General Knowledge | 6 |
| 2 | Code Requirements | 5 |
| 3 | Fuel Gas Systems | 8 |
| 4 | Safety | 8 |
| 5 | Controls | 4 |
| 6 | Electrical Concepts | 4 |
| 7 | Piping | 8 |
| 8 | Load Calculations | 5 |
| 9 | Equipment | 10 |
| 10 | Refrigerants and Oils | 10 |
| 11 | Air Distribution and Vents | 18 |
| 12 | Fire Protection | 4 |
| 13 | Sprinkler Systems | 10 |
Domain 11: Air Distribution and Vents
At 18 of 100 questions, this is the largest domain by a wide margin - nearly one-fifth of the entire exam. Candidates who under-prepare here put their overall score at serious risk.
- Duct sizing and layout principles
- Venting requirements tied to combustion appliances
- Airflow balancing concepts referenced in the IMC and HVAC Basics for Contractors materials
Domains 9, 10, and 13: The Secondary Heavyweights
Equipment, Refrigerants and Oils, and Sprinkler Systems each carry 10 questions apiece - together representing nearly a third of the exam alongside Air Distribution and Vents.
- Equipment: installation, sizing, and application knowledge
- Refrigerants and Oils: handling, compatibility, and code-driven restrictions
- Sprinkler Systems: layout and coordination basics relevant to a full mechanical scope
For a domain-by-domain breakdown with study priorities mapped to each content area, see TN-CMC Exam Domains 2026: Complete Guide to All 13 Content Areas. If you want a single condensed reference sheet covering the outline, allowed materials, and passing threshold, bookmark TN-CMC Cheat Sheet 2026: One-Page Review of Must-Know Facts.
Eligibility and Preapproval
Before you can even schedule the exam, the Board requires preapproval. The core eligibility requirements are:
- Candidate must be 18 years or older.
- Candidate must document three years of plumbing experience.
- The Board's preapproval form accepts specified alternative documentation in place of direct experience, including qualifying engineering-degree documentation.
The person who sits the trade exam - the qualifying agent - can be an owner, officer, or full-time employee of the contracting business. New contractor applicants also have to pass a separate Tennessee Business and Law examination, and notably, the person who handles that business-and-law exam doesn't have to be the same individual who qualifies on the trade side. This split is useful for companies where one partner handles operations knowledge and another handles the technical trade qualification.
A full breakdown of every prerequisite, acceptable documentation type, and how the preapproval form works in practice is covered in TN-CMC Requirements 2026: Eligibility, Prerequisites & How to Qualify.
From Passing Score to Active License
Passing the exam is a milestone, not the finish line. Exam results are typically accepted for two years, so there's a window to complete the rest of the licensing process without retesting. Beyond the trade exam itself, the Board requires:
- Financial qualification documentation
- Business and reference documentation
- General-liability insurance
- Workers-compensation coverage, or a documented applicable exemption
One notable change: beginning July 1, 2026, the Board permits a contractor surety bond as an alternative to a CPA-reviewed or CPA-audited financial statement. That gives newer or smaller contracting operations another path to satisfy the financial requirement without commissioning a full CPA review.
Licenses renew every two years. It's worth noting that the eight-hour continuing-education requirement applicable to certain residential classifications does not apply to a CMC-only license, which simplifies renewal for contractors holding only the full mechanical classification. Details on the renewal cycle and fee are covered alongside the rest of the cost structure in TN-CMC Certification Cost 2026: Complete Pricing Breakdown.
Key Takeaway
Because passing results are valid for two years, candidates who fail on a first attempt still have runway to retake the exam and complete the remaining licensing steps without starting the preapproval process over - assuming they stay within that window.
Building a Domain-Weighted Study Plan
Given that the exam is open-book, your prep should split between two goals: understanding the material well enough to reason through scenario questions, and organizing your reference books so you can locate answers fast during the actual session. A simple way to sequence this across several weeks is to move from the heaviest domains to the lightest, so your highest-value content gets the most repetition.
Air Distribution and Vents, Equipment
- Work through duct sizing, venting, and airflow concepts from IMC 2021 and HVAC Basics for Contractors
- Tab your books permanently for equipment installation and sizing references
Refrigerants and Oils, Sprinkler Systems
- Review refrigerant handling and code restrictions
- Study sprinkler layout basics as they intersect with a full mechanical scope
Fuel Gas Systems, Safety, Piping
- Work IFGC 2021 sections tied to fuel gas systems
- Cover safety protocols and piping standards together, since both carry 8 items each
General Knowledge, Load Calculations, remaining lighter domains
- Finish General Knowledge, Code Requirements, Controls, Electrical Concepts, and Fire Protection
- Run full-length, domain-weighted timed simulations mirroring the current Prov bulletin
This sequencing is only a starting framework - for a more detailed week-by-week strategy tied specifically to this exam's structure and open-book format, see TN-CMC Study Guide 2026: How to Pass on Your First Attempt. If you're trying to gauge realistically how much prep time you need, How Hard Is the TN-CMC Exam? Complete Difficulty Guide 2026 and TN-CMC Passing Score 2026: Exactly What You Need to Pass both address that question from different angles. You can also start practicing against realistic domain-weighted questions right now on our TN-CMC practice test platform.
Who Hires CMC-Licensed Contractors
Because the Full Mechanical Contractor classification covers plumbing and HVAC together, license holders are positioned for a broader range of contracting work than someone limited to a single trade. This matters most on projects that blend both scopes - new construction, commercial mechanical retrofits, and larger residential builds where a single qualifying agent covering both plumbing and HVAC reduces the number of subcontractors a general contractor needs to coordinate.
Businesses often structure their qualifying agents strategically: one licensed individual holds the CMC trade qualification while another team member handles the Business and Law exam, letting the company scale its bidding capacity on projects at or above the $25,000 licensing threshold. If you're evaluating whether pursuing this license makes sense for your career or business, Is the TN-CMC Certification Worth It? Complete ROI Analysis 2026 and TN-CMC Salary Guide 2026: Complete Earnings Analysis dig into the practical upside. For active listings and how licensed contractors typically find work, see TN-CMC Jobs.
New to the field and wondering how training programs line up with this specific license? TN-CMC Training covers preparation paths, and What Is TN-CMC Certification? and TN-CMC Certification round out the foundational picture if you're arriving at this topic for the first time.
Frequently Asked Questions
It refers to the Tennessee Full Mechanical Contractor (CMC) Exam, administered under the Tennessee Board for Licensing Contractors. The "Full" classification covers both plumbing and HVAC scopes under one license.
The exam has 100 questions based on the current Prov outline, and candidates need a 73% passing standard to pass.
Yes, it's open-book. Prov permits advance highlighting and permanent tabs, plus a simple four-function calculator. Handwritten notes, loose papers, and movable tabs are not allowed.
Prov handles new exam scheduling starting July 1, 2026. Appointments already booked through PSI before that date remain valid through September 2026.
Three years of plumbing experience is the standard requirement, but the Board's preapproval form accepts specified alternative documentation, including qualifying engineering-degree documentation, in place of direct experience.