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100+ Free CRIE Practice Questions

Pass your ACAC Council-certified Residential Indoor Environmentalist (CRIE) exam on the first try — instant access, no signup required.

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Which is the appropriate response when a residential indoor environmental investigator finds a clothes dryer venting indoors?

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2026 Statistics

Key Facts: CRIE Exam

50

Exam Questions (ACAC official)

ACAC CRIE Candidate Handbook

70%

Passing Score

ACAC

2 hrs

Time Limit

ACAC

15 L/min

Air-O-Cell Standard Flow Rate

IICRC S520

4 pCi/L

EPA Radon Action Level

EPA

24-48 hrs

Water Damage Drying Window

ANSI/IICRC S500

The ACAC CRIE (Council-certified Residential Indoor Environmentalist) is an ACAC credential for residential indoor environmental investigators. The 50-question, 2-hour proctored exam (70% to pass) covers mold biology and sampling (Air-O-Cell at 15 L/min, indoor/outdoor comparison), ANSI/IICRC S500 (Category 1/2/3 water; Class 1-4) and S520 (Condition 1/2/3 mold, P100 PPE for Condition 3), 24-48 hour drying rule, residential IAQ contaminants (radon 4 pCi/L EPA action level, formaldehyde, CO OSHA 50 ppm PEL / EPA 9 ppm NAAQS, VOCs by TO-15/TO-17, lead via EPA RRP, asbestos referral, allergens, ETS), ASTM D7338 (fungal assessment), ASTM E1527 (Phase I ESA), ASHRAE 62.2 (residential ventilation 7.5 cfm/person + 3 cfm/100 sf), state licensing (NY Article 32, FL, TX), defensible documentation, IEP-vs-contractor separation per S520, and AIHA Position. Eligibility is current employment in the field of indoor environmental investigation; no specific degree or years required. Certification lasts 2 years with 40 recertification credits.

Sample CRIE Practice Questions

Try these sample questions to test your CRIE exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which industry standard is the primary U.S. consensus reference for professional mold remediation that a residential indoor environmentalist would cite in scope development?
A.ANSI/IICRC S520
B.OSHA HazCom (29 CFR 1910.1200)
C.EPA AP-42
D.ASHRAE 90.1
Explanation: ANSI/IICRC S520 (Standard for Professional Mold Remediation) is the U.S. consensus standard defining mold remediation protocols, including condition classifications (1, 2, 3) and PPE requirements. Residential Indoor Environmentalists cite S520 in scope development.
2ANSI/IICRC S500 is the primary consensus standard for which subject?
A.Mold remediation
B.Professional water damage restoration
C.Fire damage cleaning
D.Air duct cleaning
Explanation: ANSI/IICRC S500 (Standard for Professional Water Damage Restoration) is the U.S. consensus standard for water damage restoration. It defines Category 1/2/3 water contamination and Class 1-4 water intrusion classifications. CRIEs reference S500 when assessing water-damaged homes.
3Which ASTM standard guide addresses the assessment of fungal growth in buildings?
A.ASTM E1527
B.ASTM D7338
C.ASTM E84
D.ASTM E2418
Explanation: ASTM D7338 (Standard Guide for Assessment of Fungal Growth in Buildings) provides a framework for systematic fungal growth assessment. The CRIE references D7338 alongside ANSI/IICRC S520 in inspection methodology.
4Per ANSI/IICRC S520, an indoor environment with normal fungal ecology relative to outdoor reference is classified as which condition?
A.Condition 1
B.Condition 2
C.Condition 3
D.Condition 4
Explanation: ANSI/IICRC S520 Condition 1 (Normal Fungal Ecology) describes an indoor environment with no abnormal mold contamination relative to outdoor reference. No remediation is required. Condition 2 is settled dust reservoirs; Condition 3 is actual mold growth.
5Which is the primary water sample category requiring the most aggressive restoration response per ANSI/IICRC S500?
A.Category 1 (clean water)
B.Category 2 (grey water)
C.Category 3 (black water)
D.Category 4 (steam)
Explanation: ANSI/IICRC S500 Category 3 (black water) is grossly contaminated water (sewage, rising flood water, ground/surface water entering the structure). It requires the most aggressive response including PPE, containment, and typically removal of porous materials. S500 defines Categories 1, 2, and 3.
6Which Class of water intrusion per ANSI/IICRC S500 generally has the highest evaporation load?
A.Class 1
B.Class 2
C.Class 3
D.Class 4
Explanation: ANSI/IICRC S500 Class 3 has the highest evaporation load (water has soaked walls, insulation, ceilings, and floors). Class 4 is specialty drying (deep-pocket materials like hardwood). The Class affects dehumidification capacity required.
7Which mold species is the textbook indicator of prolonged saturation of cellulose materials such as drywall paper?
A.Cladosporium herbarum
B.Stachybotrys chartarum
C.Alternaria alternata
D.Aspergillus niger
Explanation: Stachybotrys chartarum is the classic indicator of prolonged saturation of cellulose materials such as drywall paper, OSB, and ceiling tiles. It is a slow-growing hydrophilic mold with high water activity requirements (aw > 0.9).
8What is the standard sampling flow rate for an Air-O-Cell spore trap cassette?
A.5 L/min
B.10 L/min
C.15 L/min
D.25 L/min
Explanation: Air-O-Cell spore trap cassettes are designed for 15 L/min flow rate. A standard 5-minute sample yields a 75 L volume that the lab uses to calculate spores/m^3.
9Which type of sampling is most appropriate for documenting visible mold growth on a wall surface for laboratory identification?
A.Tape lift (clear cellophane tape impression)
B.Air-O-Cell spore trap
C.ERMI dust sample
D.Bulk demolition
Explanation: Tape lift surface sampling (clear cellophane tape impression) is the standard for documenting visible mold growth and supports laboratory identification of genera/species. Swabs and bulk samples are alternatives.
10Which is the primary IICRC S520 PPE recommendation for a worker remediating a Condition 3 mold contamination of approximately 30 sq ft on drywall?
A.N95 respirator only
B.Half-face APR with P100 filters, gloves, and goggles
C.No PPE required for small areas
D.Surgical mask
Explanation: For Condition 3 mold remediation, ANSI/IICRC S520 recommends a half-face air-purifying respirator with P100 filters as minimum, plus gloves, goggles, and disposable outer garments. For very small areas EPA allows N95, but professional practice typically defaults to P100 for Condition 3.

About the CRIE Exam

The CRIE credential certifies competency in residential indoor environmental investigation including mold biology and sampling, water damage and moisture management (ANSI/IICRC S500/S520), residential IAQ contaminants (radon, formaldehyde, CO, VOCs, lead, asbestos referral, allergens, ETS), standards (ASTM D7338, ASHRAE 62.2), and defensible documentation for homeowner decisions, real estate transactions, and litigation.

Questions

50 scored questions

Time Limit

2 hours

Passing Score

70%

Exam Fee

$400 (approx., first term — verify with ACAC) (ACAC (American Council for Accredited Certification))

CRIE Exam Content Outline

~25%

Mold Biology & Sampling

Indicator molds, spore trap (Air-O-Cell at 15 L/min), tape lift, ERMI, indoor/outdoor comparison

~25%

Moisture & Water Damage (S500/S520)

ANSI/IICRC S500 (Cat 1/2/3, Class 1-4), S520 (Condition 1/2/3), 24-48 hr drying rule, moisture meters, IR camera

~20%

Residential IAQ Contaminants

Radon (4 pCi/L), formaldehyde, CO, VOCs (TO-15/TO-17), lead, asbestos, allergens, ETS

~15%

Standards, Regulations & Documentation

ASTM D7338, E1527, E2418, ASHRAE 62.2, state licensing, chain-of-custody, defensible reports

~15%

Professional Conduct & Investigation Methods

IEP-vs-contractor separation, conflict of interest, real estate, litigation, clinical referral, AIHA Position

How to Pass the CRIE Exam

What You Need to Know

  • Passing score: 70%
  • Exam length: 50 questions
  • Time limit: 2 hours
  • Exam fee: $400 (approx., first term — verify with ACAC)

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

CRIE Study Tips from Top Performers

1Memorize ANSI/IICRC S520 conditions: Condition 1 (normal), Condition 2 (settled dust reservoir), Condition 3 (active growth) — and corresponding PPE (N95 minimum for small Condition 3, P100 default for Condition 3 work)
2Master ANSI/IICRC S500 water Category 1 (clean), Category 2 (grey, significant contamination), Category 3 (black, sewage/flood) — and the 24-48 hour drying rule before microbial amplification
3Know the Air-O-Cell standard flow rate (15 L/min) and how to interpret indoor-to-outdoor comparison (elevated indoor with unusual genera = amplification)
4Memorize the EPA radon action level (4 pCi/L) and short-term vs long-term radon testing protocols
5Master ASHRAE 62.2 residential whole-dwelling rate (7.5 cfm/person + 3 cfm per 100 sf) and bath exhaust (50 cfm intermittent or 20 cfm continuous)
6Know state mold licensing requirements where you operate (NY Article 32, FL Chapter 468, TX Mold Assessor) and IEP-vs-contractor separation per S520

Frequently Asked Questions

What is the CRIE exam?

The CRIE (Council-certified Residential Indoor Environmentalist) is an ACAC credential for residential indoor environmental investigators. It tests competency in mold biology and sampling, water damage and moisture management per ANSI/IICRC S500/S520, residential IAQ contaminants (radon, formaldehyde, CO, VOCs, lead, asbestos referral, allergens), standards (ASTM D7338, ASHRAE 62.2), and professional documentation.

How many questions are on the CRIE exam?

The official ACAC CRIE exam contains 50 multiple-choice questions and is delivered electronically at Kryterion authorized testing centers. Candidates have 2 hours to complete the closed-book exam. (This practice exam offers 100 questions for additional preparation.)

What is the passing score for the CRIE exam?

ACAC requires 70% to pass the CRIE exam. The passing score is set by the CRIE certification board.

What are the prerequisites for the CRIE credential?

ACAC requires current employment in the field of indoor environmental investigation. There is no specific degree or years of experience required (unlike the CIE which requires 2 years experience). Candidates must agree to the ACAC Code of Ethics.

How does the CRIE differ from the CIE?

The CRIE (Residential Indoor Environmentalist) focuses on residential indoor environments and has the more accessible eligibility (current employment in the field, no specific years). The CIE (Indoor Environmentalist) requires 2 years experience (or 2-year degree + 1 year) and covers a broader scope including commercial buildings. Both are ACAC credentials.

How much does the CRIE exam cost?

ACAC publishes a general first-term fee structure of approximately $400 for vocational certifications (includes a $100 processing fee). Verify current CRIE pricing at acac.org/fees.

How long is the CRIE credential valid?

CRIE certification is current for 2 years from the date of issue. Certificate holders must accumulate 40 recertification credits during the 2-year cycle.

What topics should I prioritize when studying for the CRIE exam?

Focus on: (1) ANSI/IICRC S520 conditions (1 normal, 2 dust reservoir, 3 active growth) and PPE (P100 minimum for Condition 3); (2) ANSI/IICRC S500 water Categories 1/2/3 and Classes 1-4, plus 24-48 hour drying rule; (3) Air-O-Cell sampling at 15 L/min and indoor/outdoor comparison; (4) Indicator molds (Stachybotrys, Chaetomium, Aspergillus); (5) EPA radon action level (4 pCi/L); (6) ASHRAE 62.2 residential ventilation (7.5 cfm/person + 3 cfm/100 sf); (7) State mold licensing (NY Article 32, FL, TX); (8) IEP-vs-contractor separation per S520 and AIHA Position on Mold and Dampness.