10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The CMR exam has 100 questions and runs 3 hours.
These 10 free CMR questions are organized by exam domain, so you can see how each part of the Council-certified Microbial Remediator blueprint is tested. Reveal the answer and explanation under each question.
An electric heater raises a drying chamber from 70°F to 85°F. Relative humidity falls from about 65% to 40%, while the measured dew point stays near 58°F. A technician records this as evidence that water vapor has been removed. What do these readings actually establish?
Correct answer: D - The lower RH reflects warming, not demonstrated water removal.
A containment enclosure measures 20 ft by 18 ft by 10 ft. Its project specification requires at least six exhaust air changes per hour. A HEPA exhaust unit rated at 500 cfm delivers a measured 250 cfm through its installed duct. A separate 600-cfm HEPA unit recirculates air entirely inside the enclosure. What is the smallest listed additional measured exhaust flow that satisfies the specification?
Correct answer: C - 150 cfm
A client asks an ACAC certificant to assess a mold problem and then perform the remediation. Considering ACAC's Code of Conduct alone, rather than any separate state licensing restriction, which description of this arrangement is accurate?
Correct answer: D - ACAC strongly discourages it but does not categorically prohibit it.
Wind-driven rain enters a second-floor room through a broken window during a hurricane. A contractor assigns Category 3 solely because S500 mentions hurricanes among its examples. Which interpretation should govern the restoration plan?
Correct answer: A - The water's contamination must be evaluated; the hurricane alone does not establish its category.
Eight hours after a clean potable-water supply-line break, an uninsulated gypsum-board wall is wet but firm, without swelling or opened seams. There is no visible mold. The source is controlled, and the cavity can be ventilated while the assembly is dried promptly. Which is the least destructive disposition consistent with EPA's clean-water guidance?
Correct answer: A - Retain it for monitored in-place drying with cavity ventilation.
Opening a wall after a long-standing leak reveals mold throughout the gypsum board's paper facing, which has separated from the core. The exposed wood studs have surface mold but remain structurally sound and accessible for cleaning. The leak has been repaired. To preserve materials that can be effectively remediated, select the material-specific scope of work.
Correct answer: B - Remove the affected gypsum board; clean and dry the sound studs.
For removal of moldy ceiling tiles, a crew installs polyethylene walls from the floor to the suspended-ceiling grid. Room registers are sealed, and HEPA-filtered exhaust produces inward airflow at the entry. Above the tiles, a shared return-air plenum connects to occupied offices. How should this uncontained pathway be eliminated?
Correct answer: B - Extend the barrier to the structural deck and seal plenum penetrations.
A sheet-metal supply duct has an internal fiberglass liner that is wet and visibly moldy. An HVAC contractor proposes drying the liner, vacuuming its face, and coating it so the duct can remain in service. Which treatment should replace that proposal?
Correct answer: C - Remove and replace the affected liner after correcting the moisture source.
A project's drying criterion requires each affected framing location to return to the 12%-15% moisture range measured in comparable unaffected wood. Repeat readings at four marked locations are 12%, 12%, 13%, and 19%, using the same calibrated meter, species setting, and probe depth. Room relative humidity is 42%. Which closeout decision meets the criterion?
Correct answer: B - Keep drying the 19% location until it meets the agreed criterion.
Minutes after a basement remediation crew increases its exhaust airflow, combustion gases begin spilling from a natural-draft gas water heater into the work area. Two workers develop headache and dizziness despite wearing P100 respirators. What takes priority now?
Correct answer: A - Evacuate to fresh air and call emergency medical services.
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