- What This Sheet Covers (and What It Doesn't)
- Exam Format Facts at a Glance
- The Eleven Blueprint Headings, Compressed
- Numbers You Should Have Memorized
- Registration, Tuition and Proctoring Mechanics
- Attempts, Validity and Renewal
- Common Traps on Four-Option Questions
- A Domain-Ordered Review Schedule
- Frequently Asked Questions
- The initial written exam runs 75 minutes, four-option single-best-answer, with a 70% minimum score.
- The handbook says 55 questions while the online guide says 50, so confirm the count with your Course Director.
- Certification needs a minimum 20-hour approved course, two practicums, and the written exam.
- The blueprint has eleven headings with no published percentages, so no domain can be called "highest weight."
What This Sheet Covers (and What It Doesn't)
This page is a compressed review for the Occupational Hearing Conservationist credential issued by the Council for Accreditation in Occupational Hearing Conservation (CAOHC). Passing earns the COHC designation. The scope here is initial certification only. It does not cover Professional Supervisor/Audiologist (CPS/A) certification or Course Director certification, which are separate tracks with their own requirements.
The official scope source is the OHC Handbook and Instructions (revised February 2023, pages 6-8), which lists eleven headings and explicitly labels them an exam blueprint. We built this cheat sheet around those headings and the current administration rules. For a slower, week-by-week plan, pair it with the OHC study guide; for deeper treatment of each content area, see the complete guide to all 11 OHC content areas.
Exam Format Facts at a Glance
| Item | What to Know |
|---|---|
| Issuer | Council for Accreditation in Occupational Hearing Conservation (CAOHC) |
| Designation earned | COHC (initial Occupational Hearing Conservationist certification) |
| Question style | Four-option, single-best-answer multiple choice |
| Minimum passing score | 70% |
| Initial exam timer | 75 minutes |
| Initial question count | Handbook says 55; online exam guide says 50 (confirm locally) |
| Language | English or Spanish |
| Timer behavior | Cannot be paused; questions can be flagged and revisited |
| Administration | Through the CAOHC Learning Center by the Course Director or an approved proctor |
The question-count discrepancy is worth understanding rather than glossing over. The handbook and the online exam guide give different numbers, and nothing in the published materials explains whether the difference reflects scored versus unscored items or simply an outdated figure. Don't assume either way. Ask your Course Director which version applies to your session, and prepare for the longer one. For more on how the cut score works in practice, see what you need to pass.
The 75-minute clock is not the 20-hour course
Candidates sometimes blur two different numbers. The 20-hour figure is the minimum length of the approved course. The 75-minute figure is the timer on the initial written exam. Because the timer can't be paused, practice pacing: flag a stubborn item, move on, and return to it before submitting.
The Eleven Blueprint Headings, Compressed
The handbook publishes eleven headings without percentages. That means you cannot responsibly claim any single area is weighted most heavily. Treat all eleven as fair game, and give extra time to areas where you personally score lowest. If you're wondering how this plays into difficulty, our difficulty breakdown covers it.
1. Hearing Conservation (Overall)
The big-picture frame: why programs exist and how their parts fit together.
- Know the major program elements: noise measurement, audiometric testing, hearing protection, training, and recordkeeping
- Understand the OHC's role relative to the program's supervising professional and the rest of the team
2. Anatomy, Physiology and Diseases of the Ear
The biological foundation for everything you'll explain to workers.
- Outer, middle, and inner ear structures and the path sound takes through them
- Conductive versus sensorineural loss, and how noise-induced damage differs from other causes
- Common ear conditions that should prompt a referral rather than a routine retest
3. Hearing and the Physics of Sound and Performing and Explaining a Hearing Test
Sound science paired with the ability to explain a test to a worker.
- Frequency, intensity, and the decibel scale (and why it is logarithmic)
- How to describe the test to an employee in plain language before you begin
4. Federal and State Regulations Related to Occupational Noise-Induced Hearing Loss
The legal backbone of hearing conservation programs.
- Know which regulatory requirements drive monitoring, testing, protection, and recordkeeping
- Remember that state rules may add requirements beyond federal ones
5. Audiometer and Testing Environment
Equipment and room conditions that make or break a valid test.
- Why background noise in the test space matters and how it affects thresholds
- Basic audiometer components, calibration concepts, and daily function checks
6. Audiometric Techniques and Testing
The hands-on procedure, which also appears in the practicum.
- Earphone placement, instructions to the employee, and the threshold-seeking sequence
- Recognizing unreliable responses and knowing when to reinstruct or retest
7. Audiometric Review and Evaluation
Reading results and deciding what happens next.
- Comparing a current test to a baseline and recognizing significant change
- Knowing when results trigger retesting, follow-up, or referral
8. Noise Measurement and Control
Quantifying exposure and reducing it at the source.
- The purpose of sound level measurements and personal dosimetry
- The control hierarchy: engineering and administrative controls come before reliance on protection devices
9. Hearing Protection Device (HPD) Fitting
Selection, fitting, and checking real-world protection.
- Common HPD types and the tradeoffs among them
- Proper insertion or wearing technique, and why a poor fit defeats a high rating
10. Counseling and Training
Motivating workers to actually use what you've taught them.
- Explaining results and risks without jargon
- Adult-learning basics: relevant examples, demonstration, and checking understanding
11. Recordkeeping and the Hearing Conservation Team
Documentation and who is responsible for what.
- What records a program maintains and why accuracy matters
- The roles on the hearing conservation team and how the OHC coordinates with them
Numbers You Should Have Memorized
The exam tests concepts, but a handful of published program numbers belong on a single index card. Everything below comes from CAOHC's own materials.
- 20 hours: minimum length of the approved initial course
- 75 minutes: initial written exam timer
- 70%: minimum passing score
- 3: maximum number of attempts
- 30 days: window after a prior attempt to arrange a retake with the Course Director
- 5 years: certification validity, counted from course completion
- 8 hours: minimum renewal course length
- 30 questions / 45 minutes: the separate recertification exam
- 30 days: minimum lead time to request an extension before expiry
Key Takeaway
Notice that "30 days" appears twice with different meanings: one is the retake-arrangement window after a failed attempt, the other is the minimum notice before expiry for an extension request. Write them on separate lines so they don't blur together.
Registration, Tuition and Proctoring Mechanics
CAOHC certification is built around the course, not a stand-alone test window. There are no course-enrollment prerequisites, so you don't need prior credentials to sign up. See the requirements breakdown for the full eligibility picture. To certify you need three things: a minimum 20-hour approved course, satisfactory audiometric and hearing-protection-fitting practicums, and the written exam.
Tuition and course registration are handled by the Course Director who runs your course, which means pricing varies by provider. For what to budget and which line items to ask about, read the cost breakdown. The written exam is delivered through the CAOHC Learning Center under the Course Director or an approved proctor. The current administration source is the Course Director Policies and Procedures Manual (revised November 2025), and the candidate-facing instructions are in the Certification Exam Instructions document.
Attempts, Validity and Renewal
If you don't pass
You get a maximum of three attempts. Retakes are arranged with your Course Director within 30 days of the preceding attempt, and proctoring fees may apply. Don't treat the retake window as a casual suggestion; if you wait past it, you may complicate your path.
Keeping the credential current
Certification is valid for five years from course completion. Renewal is not a re-exam of the whole blueprint. It requires a minimum 8-hour course, both practicums again, and the separate recertification exam: 30 questions in 45 minutes. If you can't complete renewal in time, request an extension at least 30 days before expiry. Details live on CAOHC's recertification and FAQ pages.
| Element | Initial Certification | Recertification |
|---|---|---|
| Course | Minimum 20 hours | Minimum 8 hours |
| Practicums | Audiometric and HPD fitting | Both practicums |
| Written exam | 75 minutes; handbook 55 vs. guide 50 questions | 30 questions, 45 minutes |
| Validity afterward | Five years from course completion | Five-year cycle continues |
Common Traps on Four-Option Questions
Single-best-answer items mean more than one option can look defensible. The exam is asking for the best one, usually the answer that matches the program's standard procedure or protects the worker most directly. A few patterns come up repeatedly for this credential:
- Scope-of-role traps. Some options have the OHC making a diagnosis or medical judgment. Interpreting the cause of a hearing problem is generally outside the OHC's role; flagging a concern and referring appropriately is inside it.
- "Hearing protection first" traps. If an option jumps straight to handing out earplugs when noise control at the source is on the table, remember the control hierarchy from Domain 8.
- Test-validity traps. When a result looks inconsistent, the best response usually addresses the testing conditions or the instructions (Domains 5 and 6) before concluding the worker's hearing changed.
- Counseling traps. The best answer in Domain 10 is typically the one that engages the worker with relevant, understandable information rather than reciting rules or assigning blame.
- Records traps. In Domain 11, favor the option that keeps documentation complete, accurate, and accessible to the people who need it.
A Domain-Ordered Review Schedule
You don't need a generic study system for this exam; you need an order that follows how the concepts build. Foundations first, then the hands-on skills your practicums reinforce, then the program-level material that ties it together. If your course is compressed, collapse these into fewer days but keep the sequence.
Foundations: Domains 2 and 3
- Ear anatomy, types of hearing loss, and sound physics come first because every later domain assumes them
- Practice explaining a hearing test aloud in plain language
Testing Skills: Domains 5, 6 and 7
- Equipment, environment, technique, and result review are one connected chain, so study them together
- Rehearse the steps you'll demonstrate in the audiometric practicum
Exposure and Protection: Domains 8 and 9
- Measurement, the control hierarchy, and HPD selection and fitting
- Pair with the fitting practicum so the knowledge becomes procedure
Program Layer: Domains 1, 4, 10 and 11
- Regulations, counseling, recordkeeping, and team roles tie everything together
- Finish with full-length timed practice at 75 minutes
Scoring lowest on a given domain is your signal to double its time, since the blueprint gives no weights to lean on. The OHC practice tests let you see which areas drag your results down, and our pass-rate discussion explains why published figures should be read cautiously.
Where the Credential Gets Used
Occupational Hearing Conservationists work where noise exposure creates a regulatory and health obligation: manufacturing plants, construction and heavy industry, utilities, mining and similar operations, plus the occupational health clinics and mobile testing companies that serve those employers. The credential signals that you can run the testing and fitting side of a hearing conservation program under appropriate professional oversight. For hiring trends, see the OHC jobs overview; for earnings context, the salary guide; and for the bigger question, whether the certification pays off.
Frequently Asked Questions
CAOHC's published sources conflict: the handbook says 55 and the online exam guide says 50. No published explanation reconciles them, so confirm with your Course Director and prepare for the longer version. The timer is 75 minutes either way.
That can't be answered from the published materials. The handbook lists eleven blueprint headings but omits percentages, so no domain can be identified as highest weight. Study all eleven and spend extra time where your practice scores are weakest.
No. The timer cannot be paused. You can flag questions and return to them, so use that feature to keep moving rather than stalling on one item.
You may attempt it up to three times in total. Retakes are arranged through your Course Director within 30 days of the preceding attempt, and proctoring fees may apply.
Certification is valid for five years from course completion. Renewal requires a minimum 8-hour course, both practicums, and the separate 30-question, 45-minute recertification exam. If you need more time, request an extension at least 30 days before your certification expires.
There are no course-enrollment prerequisites. To become certified, though, you must complete a minimum 20-hour approved course, pass both the audiometric and hearing-protection-fitting practicums, and pass the written exam. Tuition and registration go through the Course Director.