- Which IAQ-T This Sheet Covers
- The Exam at a Glance: Numbers to Memorize
- Domain Weights: Where the Points Live
- HVAC Systems (24%): What to Know Cold
- Instrumentation (19%): Tools, Calibration, Records
- Testing and Visual Inspection (27%)
- Air Contaminants in Construction (12%)
- Documentation (18%)
- Reference Standards Named in the Knowledge Base
- Eligibility, Fees, and Scheduling Mechanics
- Retakes, Validity, and Renewal
- A Domain-Ordered Review Plan
- Quick-Fire FAQ
- The exam has 75 items: 70 scored, 5 unscored beta. You need at least 53 of the 70 scored items.
- Testing and Visual Inspection (27%) and HVAC Systems (24%) together account for just over half the exam.
- Initial and renewal fees are USD 0 for eligible technician applicants, but ICB must still approve your eligibility.
- Certification lasts two years; renewal needs 4 accepted CEUs, where one training hour equals one CEU.
Which IAQ-T This Sheet Covers
Several credentials in the building-air world shorten to similar letters, so start by locking in the right one. This cheat sheet covers the Indoor Air Quality Technician (IAQ-T) issued through the International Certification Board (ICB), the Sheet Metal Industry International Certification Board. ICB also describes it as the IAQ Technician / Ventilation Verification credential. It is not an IAQA, IICRC, ACAC, EPA, or state-specific program, and nothing here transfers from those.
The scope comes from the Indoor Air Quality Technician Knowledge Base in the ICB Certification Manual (cover version 241024, approved October 24, 2024). If you want the plain-language background first, see What Is IAQ-T? and What Does IAQ-T Stand For?.
The Exam at a Glance: Numbers to Memorize
| Item | Fact |
|---|---|
| Total items | 75 (70 scored + 5 unscored beta items) |
| Passing threshold | At least 53 of 70 scored items |
| Format | Written, proctored; online or paper delivery |
| Administration | ICB-designated proctor and site, arranged through your local JATC/training-center coordinator |
| Practical exam? | No separate IAQ-T practical exam verified; TABB is the credential with written plus practical testing |
| Time limit | No national numeric limit in current issuer material; a SMART Local 2 notice (April 2026) described a 2.5-hour ICB testing event |
| Fees (initial and renewal) | USD 0 for eligible Technician applicants per the ICB Fee Schedule |
| Validity | Two full years from the last day of the quarter in which you certify |
| Test window | Written testing must occur within one year of application approval |
Two cautions. First, older ICB manual versions add a rounded "75%" label to the 53/70 threshold; the current benchmark to memorize is 53 of 70 scored items. Second, the 2.5-hour figure comes from a local event listing and an older externally hosted exam-details document, so it is supporting evidence rather than a guaranteed national timer. For deeper reading, see IAQ-T Passing Score 2026 and IAQ-T Exam Dates 2026.
Domain Weights: Where the Points Live
The five domains are official weighted objectives, and they total 100%. They are not course modules, so a training class may spend time differently than the exam does.
| Domain | Weight | Priority |
|---|---|---|
| Domain 3: Testing and Visual Inspection | 27% | Highest |
| Domain 1: HVAC Systems | 24% | High |
| Domain 2: Instrumentation | 19% | Medium-high |
| Domain 5: Documentation | 18% | Medium-high |
| Domain 4: Air Contaminants in Construction | 12% | Smallest, still scored |
Documentation at 18% is the domain candidates most often under-study, because it feels like paperwork rather than technical content. On a 70-item scored section where you can miss only 17 items, a neglected domain can sink you. The full breakdown lives in IAQ-T Exam Domains 2026.
HVAC Systems (24%): What to Know Cold
Domain 1: HVAC Systems
This domain tests whether you understand how the air-handling system you are verifying actually works, since you cannot judge ventilation without knowing how air is moved, mixed, filtered, and exhausted.
- Outside-air intake, return air, supply air, and mixed-air relationships, including how outside-air percentage is derived from measurements
- Air changes per hour and how airflow relates to room volume
- Filtration basics and how filter rating relates to ASHRAE 52.2-2017
- Operating modes (occupied, unoccupied, economizer, minimum outside air) and how each changes ventilation delivery
- Building automation system (BAS) trends, setpoints, and sensor behavior
- Exhaust, pressurization, and how mechanical systems affect pressure relationships between spaces
Expect scenario-style reasoning, such as spotting why a measured outside-air fraction might not match design intent, or what an operating-mode change does to delivered ventilation. Practice the arithmetic by hand, because calculator permission was not verified for this exam.
Instrumentation (19%): Tools, Calibration, Records
Domain 2: Instrumentation
Know what each instrument measures, when it is the right choice, how it is verified, and what makes a reading defensible.
- Matching instruments to measurements: airflow, temperature, humidity, carbon dioxide, particulates, and pressure
- Calibration, zeroing, and verification before use, and why calibration status belongs in the record
- Sensor placement, averaging, and the effect of poor technique on a reading
- Recognizing when a reading is implausible and the instrument or method, rather than the building, is at fault
Testing and Visual Inspection (27%)
This is the heaviest domain, which is why it belongs at the top of your study order. It covers the hands-on work of verifying ventilation in a real building: walking the system, inspecting components, taking measurements, and comparing what you find against what the design and the referenced standards call for.
Domain 3: Testing and Visual Inspection
- Visual inspection of intakes, dampers, coils, filters, drain pans, ductwork, and the surroundings of outside-air openings
- Verifying ventilation airflow against design and applicable standards (ASHRAE 62.1-2019 for commercial buildings, 62.2-2019 for residential)
- Checking thermal comfort conditions in light of ASHRAE 55-2017
- Healthcare-facility ventilation considerations touching ASHRAE 170-2017
- Following safe work practices around energized equipment, with NFPA 70E-2018 named in the knowledge base
- Identifying discrepancies between as-built conditions, design intent, and current building use
A recurring theme is that a building's use can change after the design was set. A space converted from storage to dense occupancy changes the ventilation picture, and a good technician notices and reports it. Our difficulty guide explains why scenario questions here feel harder than definitional ones.
Air Contaminants in Construction (12%)
Domain 4: Air Contaminants in Construction
The smallest domain is still worth roughly one in eight scored items. Focus on how construction and renovation activity affects indoor air and how that is controlled.
- Common construction-phase contaminants such as dust, fumes, and moisture-related problems, and where they travel
- Protecting HVAC equipment and ductwork during construction and what happens if it is skipped
- Source control, containment, pressure relationships, and ventilation as mitigation strategies
- Why verification before occupancy matters after dusty or wet work
Documentation (18%)
Documentation is where a technician's work becomes useful to someone else. The exam expects you to understand what a clear, complete field record contains and why.
Domain 5: Documentation
- Recording measurements with location, date, conditions, instrument, and calibration status
- Writing field reports that state discrepancies plainly and separate observation from interpretation
- Noting building-use changes and operating mode at the time of testing
- Keeping records traceable so another professional could reproduce or review the work
Key Takeaway
If a question asks what to do after finding a problem, the answer almost always includes documenting it accurately and completely. Do not treat Documentation as a throwaway domain at 18% of the blueprint.
Reference Standards Named in the Knowledge Base
The knowledge base lists specific editions. Study those editions, not whatever is newest, because the published outline is what the exam is built from.
| Standard (edition in outline) | Where it shows up |
|---|---|
| ASHRAE 62.1-2019 | Ventilation for acceptable indoor air quality, commercial and institutional buildings |
| ASHRAE 62.2-2019 | Ventilation and acceptable indoor air quality, residential buildings |
| ASHRAE 55-2017 | Thermal environmental conditions for human occupancy |
| ASHRAE 170-2017 | Ventilation of health care facilities |
| ASHRAE 52.2-2017 | Testing and rating of general ventilation air-cleaning devices (filters) |
| NFPA 70E-2018 | Electrical safety in the workplace |
Listing an edition here does not mean it is the latest published version. It means it is the edition the outline names. Do not silently swap in newer editions when studying. Pair this table with the walkthrough in our IAQ-T study guide.
Eligibility, Fees, and Scheduling Mechanics
Who can apply
General Technician eligibility under the manual's section 3.2 covers one of these routes:
- A person for whom NEMIC contributions are payable
- A person doing sheet-metal industry work under a SMART-accepted building-trades collective bargaining agreement with NEMIC contributions
- A temporarily unemployed, non-retired worker last employed in such work who remains available for it, or who is temporarily unable to work through sickness or disability
- A person temporarily employed to organize a sheet-metal employer
ICB must approve eligibility. The IAQ-T scheme adds no universal degree requirement, experience-year minimum, training-hour minimum, reference count, or prerequisite certification. That absence of prerequisites does not waive the general ICB eligibility above. Details are in IAQ-T Requirements 2026.
What it costs
Initial and renewal certification fees are USD 0 for eligible Technician applicants under the ICB Fee Schedule. "Fee-free" is not the same as "open to everyone," and separate training, travel, or local charges and deposits were not verified as universal costs. Some local training centers publish their own class charges, so ask your coordinator. See IAQ-T Certification Cost 2026 for the full picture.
How you actually get scheduled
Your local JATC/training-center coordinator is the key contact for local training requirements, digital-manual access, and exam scheduling. ROC-P is ICB's account and application portal, not a third-party exam vendor. For preparation, NEMI points candidates to ITI's Ventilation Verification for Indoor Air Quality course and the current ICB Knowledge Base. ITI's online enrollment now runs through an iTi ID and Learning Portal, though older materials still use Moodle wording, so check current ITI access instructions.
Retakes, Validity, and Renewal
If you do not pass
| Attempt | Wait before the next attempt |
|---|---|
| First retest | 30 days |
| Second retest | 60 days |
| Subsequent attempts | 90 days |
Remember that written testing must happen within one year of application approval, so a string of long waits can eat into your window. Build your plan around the dates in our scheduling guide.
Keeping the credential
Certification runs two full years from the last day of the quarter in which you certify. Renewal requires:
- Continued eligibility and Code of Conduct compliance
- Applying before your credential expires
- 4 accepted CEUs earned during the certification period
ICB defines one training hour as one CEU, and the 4 accepted units cover all technician certifications you hold, so you do not need 4 per credential. The renewal fee for eligible technicians is USD 0.
A note on pass rates: no pass rate was found in the reviewed official sources, so any specific percentage you see online is unverified. What is verifiable is the passing standard of 53 of 70 scored items. Our pass-rate article explains how to think about that distinction.
A Domain-Ordered Review Plan
Rather than a generic schedule, sequence your review by exam weight and by how each domain builds on the last. Foundations first, then the heavy domains, with documentation woven through.
HVAC Systems (24%)
- Airflow paths, outside-air percentage math, operating modes
- Read the filtration and ventilation standards listed above
Instrumentation (19%)
- Match each instrument to its measurement and failure modes
- Practice spotting implausible readings and calibration issues
Testing and Visual Inspection (27%)
- Work scenarios: inspection findings versus design intent
- Revisit ventilation verification against 62.1 and 62.2
Contaminants (12%) and Documentation (18%)
- Construction-phase controls and pre-occupancy checks
- Draft sample field reports, then run a full timed practice set
Place the biggest domain after you have the system and instrument vocabulary, because inspection questions assume both. For fuller tactics, see the complete study guide, and test your recall with free practice questions.
Quick-Fire FAQ
There are 75 items in total: 70 scored and 5 unscored beta items. You cannot tell which are unscored, so treat every item as if it counts.
At least 53 of the 70 scored items. Older manuals add a rounded 75% label, but the exact threshold to remember is 53 of 70. More detail is in our passing score guide.
Testing and Visual Inspection at 27%, followed by HVAC Systems at 24%. Instrumentation is 19%, Documentation 18%, and Air Contaminants in Construction 12%.
No separate IAQ-T practical exam was verified. ICB and NEMI distinguish the IAQ-T written exam from TABB, which has both written and practical exams.
Initial and renewal fees are USD 0 for eligible Technician applicants, though ICB must approve eligibility and local training or travel costs may apply. See the cost breakdown and weigh the value in Is the IAQ-T Certification Worth It?.