What does the containment domain cover on the AMRT exam?
It covers the engineering controls that keep contamination inside the work area: containment type selection, critical barriers, HVAC isolation, negative pressure, decontamination chambers and the machines that make it all work. This is the largest single block of questions in our bank, and it is where the arithmetic shows up.
Know that required airflow is containment volume multiplied by target air changes per hour and divided by sixty, and that a machine's rated CFM is not what it delivers once ducted and loaded with filters. Know why air flows from clean to dirty, how the pressure differential is verified with a manometer, and what a decontamination chamber is for. Our free ACH and negative air calculator runs the same math the exam asks you to do on paper.
Where do candidates lose points on containment questions?
The unit conversions. Candidates who know the formula still fumble the divide-by-sixty step, or size a machine off floor area instead of volume. Work every calculation question in cubic feet, write the formula down before you plug in numbers, and check that the answer is a plausible CFM for a machine you have actually pushed through a doorway.
The other repeat offender is containment selection. A small, isolated area of growth does not need a full containment with an airlock, and a whole-house Condition 3 job cannot be handled with a bag over a stud bay. Match the control to the size and location of the contamination, and remember that running air movers over growth without containment aerosolizes spores into clean space.
How should you study containment and negative air?
Do the math by hand until it is boring, then check yourself with the calculator. Take three rooms in whatever building you are in, measure them, pick a target ACH, and size the equipment. Repeat until you can do it without the formula in front of you.
Then work the Containment & Engineering Controls module, read the S520 summary on our standard page for how containment fits the wider remediation principles, and use the flashcards for the equipment vocabulary. Take this quiz last, under time pressure, because on exam day the calculation questions are the ones that eat your clock.