- What the OHC Certification Actually Is
- The Path: Course, Practicums, and Written Exam
- How the Written Exam Works
- The Eleven-Heading Exam Blueprint
- The Two Practicums Most Candidates Underestimate
- Sequencing Your Preparation Around the Blueprint
- Attempts, Retakes, and Registration Mechanics
- Five-Year Validity and Recertification
- Where the Credential Is Used
- Frequently Asked Questions
- CAOHC issues the Occupational Hearing Conservationist certification, which awards the COHC designation after an approved course, two practicums, and a written...
- The initial course must be a minimum of 20 hours; there are no course-enrollment prerequisites.
- The written exam is four-option, single-best-answer multiple choice with a 75-minute timer and a 70% minimum score.
- Certification is valid for five years from course completion; renewal needs an 8-hour course, both practicums, and a 30-question exam.
What the OHC Certification Actually Is
The Occupational Hearing Conservationist credential is issued by the Council for Accreditation in Occupational Hearing Conservation (CAOHC). Earning it awards the COHC designation. It certifies that a person can carry out the practical, day-to-day tasks of a workplace hearing conservation program: performing screening audiometry, fitting hearing protection, counseling workers, and keeping the records that regulators and auditors expect to see.
It helps to be precise about scope. This article covers initial Occupational Hearing Conservationist certification. It does not cover the separate Course Director certification or other CAOHC roles. If you are still sorting out terminology, our explainers on what OHC certification is and what OHC stands for cover the basics, and the OHC requirements guide goes deeper on eligibility.
The Path: Course, Practicums, and Written Exam
Initial certification has three components, and all three are required:
- An approved course of at least 20 hours. The 20 hours is the minimum course length. It is not the exam time limit, a confusion that trips up first-time readers.
- Satisfactory audiometric and hearing-protection-fitting practicums. These are demonstrated skills, not written questions.
- The written exam. Details follow in the next section.
There are no course-enrollment prerequisites. You do not need a prior credential to sign up for an approved course. That said, "no prerequisites to enroll" is not the same as "no preparation required to pass." Our difficulty guide explains where candidates tend to struggle.
Tuition and course registration are handled through the Course Director who runs your class, and administration of the exam runs through the CAOHC Learning Center with the Course Director or an approved proctor. Because pricing is set by the individual course provider, check the OHC certification cost breakdown for what to ask before you register.
How the Written Exam Works
| Feature | Initial OHC Written Exam |
|---|---|
| Question style | Four-option, single-best-answer multiple choice |
| Timer | 75 minutes; cannot be paused |
| Minimum passing score | 70% |
| Languages | English or Spanish |
| Navigation | Questions can be flagged and revisited |
| Maximum attempts | Three |
The question-count discrepancy
You will see two different numbers in CAOHC's own materials. The handbook references 55 questions, while the online exam guide references 50. The published sources do not explain how those figures relate, for example whether some items are unscored, so this article does not commit to a single count. The practical advice: confirm the current format with your Course Director before test day, and pace yourself against the 75-minute timer rather than against a fixed question count.
What "single best answer" means for your approach
Because every item offers four options and only one is the best answer, questions often include two plausible choices. The skill being tested is judgment: which action is most consistent with accepted hearing conservation practice. When two options both sound reasonable, ask which one a practicing conservationist would do first, or which one stays within the scope of the role.
Since the timer cannot be paused, use the flag feature strategically: answer what you know, flag what you do not, and return to flagged items with the time that remains. Details on how the score threshold works are in our passing score guide, and we discuss what is and is not known about outcomes in the pass rate article.
The Eleven-Heading Exam Blueprint
CAOHC's handbook lists eleven headings as the OHC exam blueprint. The percentages are omitted, so there is no supported way to say which domain carries the most weight. Treat all eleven as fair game. Below are the headings with what each one demands in practice. For a longer treatment, see the complete domains guide.
Domain 1: Hearing Conservation (Overall)
The big picture: why programs exist and how the pieces fit together.
- Components of a complete hearing conservation program
- The conservationist's role relative to the rest of the team
- Why prevention of noise-induced hearing loss drives every other task
Domain 2: Anatomy, Physiology and Diseases of the Ear
Know the outer, middle, and inner ear well enough to explain hearing loss to a worker in plain language.
- Structures of the ear and the path sound takes through them
- How noise damages the inner ear
- Conductive versus sensorineural loss, and conditions that warrant referral
Domain 3: Hearing and the Physics of Sound and Performing and Explaining a Hearing Test
Sound fundamentals paired with the ability to explain testing to the person being tested.
- Frequency, intensity, and the decibel concept
- Clear test instructions and how you communicate them
Domain 4: Federal and State Regulations Related to Occupational Noise-Induced Hearing Loss
The regulatory framework behind workplace programs.
- What federal requirements mandate and how state rules may add to them
- Employer obligations tied to monitoring, testing, and protection
Domain 5: Audiometer and Testing Environment
Equipment and room conditions that make a test valid or invalid.
- Audiometer function, calibration, and daily checks
- Ambient noise in the test space and why it corrupts results
Domain 6: Audiometric Techniques and Testing
The procedure itself, done correctly and consistently.
- Test sequence and threshold-finding technique
- Headphone placement and recognizing unreliable responses
Domain 7: Audiometric Review and Evaluation
Reading results against baselines and recognizing when action is needed.
- Comparing current tests to a baseline
- Identifying changes that call for retesting or referral
Domain 8: Noise Measurement and Control
Where the noise comes from and what can be done about it.
- Sound level measurement and dosimetry concepts
- The preference for engineering and administrative controls before relying on protection alone
Domain 9: Hearing Protection Device (HPD) Fitting
Selecting, fitting, and verifying protection that actually works for the individual.
- Types of devices and how fit affects real-world protection
- Teaching correct insertion and use
Domain 10: Counseling and Training
Motivating workers to protect their hearing.
- Explaining results and risk without alarming or dismissing
- Delivering effective training and handling resistance
Domain 11: Recordkeeping and the Hearing Conservation Team
Documentation and collaboration.
- What must be recorded, retained, and protected
- Roles of the audiologist or physician, employer, safety staff, and employees
The Two Practicums Most Candidates Underestimate
Many people focus entirely on the written exam and treat the practicums as a formality. That is a mistake, because satisfactory audiometric and hearing-protection-fitting practicums are required for certification regardless of how well you score on the written test.
- Audiometric practicum: You demonstrate that you can set up, instruct, and administer a hearing test correctly. Rehearse your verbal instructions until they are clear and consistent, since Domains 3 and 6 reward precision.
- Hearing-protection-fitting practicum: You demonstrate selecting and fitting devices and coaching proper use. Practice with the actual device types your course provides.
Hands-on competence also feeds the written exam: candidates who have physically fit earplugs and run a test tend to find Domains 6 and 9 questions far more intuitive. For a broader look at the course experience, see our OHC training overview.
Sequencing Your Preparation Around the Blueprint
Rather than generic scheduling advice, here is one way to order your review to match how the content builds. Adjust it to your course dates; the full approach is laid out in the OHC study guide.
Foundations
- Domain 1 overview, then Domain 2 ear anatomy and disease
- Domain 3 sound physics, since later technical domains depend on it
Testing Chain
- Domains 5, 6, and 7 together: equipment, technique, and review
- Pair each with hands-on practice from your course
Protection and People
- Domains 8, 9, and 10: measurement, fitting, counseling
- Domain 4 regulations and Domain 11 recordkeeping to close the loop
Timed Practice
- Take timed sets against the 75-minute limit and practice flagging
- Skim a one-page review such as our OHC cheat sheet
Because the blueprint omits weights, do not skip a domain on the theory that it is minor. Use the practice test site to find your weak headings early and give those the extra time.
Attempts, Retakes, and Registration Mechanics
You get a maximum of three attempts at the written exam. If you need a retake, it is arranged through your Course Director and must occur within 30 days of the preceding attempt. Proctoring fees may apply to retakes, so ask your Course Director about them in advance.
Scheduling is also handled locally rather than through a fixed national testing calendar, since the exam is administered through the Course Director or an approved proctor. Our exam dates guide explains how to plan around course schedules.
Key Takeaway
With three attempts and a 30-day window between each, a failed first try is recoverable but compressed. Ask your Course Director which domains your score report flags, and spend the 30 days on those headings instead of re-reading everything.
Five-Year Validity and Recertification
Certification is valid for five years from course completion. To renew, you need:
- A minimum 8-hour refresher course
- Both practicums, again
- A separate recertification exam of 30 questions in 45 minutes
If you may miss your window, request an extension at least 30 days before your certification expires. Waiting until the last week removes that option. Put the expiry date in your calendar the day you pass.
Where the Credential Is Used
Hearing conservationists are typically found wherever employers must run noise-exposure programs: manufacturing, construction, mining, transportation, utilities, and similar settings, as well as occupational health clinics and mobile testing companies that serve many employers. Some roles are dedicated hearing conservation positions; others are added to existing safety, nursing, or industrial hygiene duties. Because the work sits inside a team that includes a reviewing audiologist or physician, the credential often complements rather than replaces those roles.
For current openings and the kinds of employers recruiting, see our OHC jobs page. Earnings vary widely by industry, region, and whether the role is full-time or bundled with other duties, so rather than quoting a figure here, review the salary guide and weigh it using our worth-it analysis.
Frequently Asked Questions
The Council for Accreditation in Occupational Hearing Conservation (CAOHC). Passing the requirements awards the COHC designation for initial certification.
There are no course-enrollment prerequisites. You do, however, need to complete a minimum 20-hour approved course, pass both practicums, and pass the written exam to become certified.
The initial exam has a 75-minute timer that cannot be paused, uses four-option single-best-answer questions, and requires a minimum score of 70%. It is offered in English or Spanish.
CAOHC's handbook and its online exam guide cite different counts (55 and 50), and the sources do not reconcile them. Confirm the current format with your Course Director.
You may attempt the exam up to three times in total. Retakes are arranged with your Course Director within 30 days of the previous attempt, and proctoring fees may apply.
Five years from course completion. Renewal requires an 8-hour course, both practicums, and a separate 30-question, 45-minute recertification exam, and extension requests should be made at least 30 days before expiry.
For an overview of the credential's role and how it fits your career plans, revisit what OHC is, then test your readiness with timed questions on the OHC practice exam site.