Test Planning, Placement, and Closed-House Conditions
Test Planning, Placement, and Closed-House Conditions
This domain tests the field conditions that make a result defensible.
Core rules
- Test the lowest livable level. A crawlspace or unfinished attic is not livable; a finished basement is.
- Place the detector in the breathing zone: at least 20 inches (50 cm) above the floor, 4 inches (10 cm) from walls, and at least 3 feet (1 m) from exterior doors, windows, and vents. Avoid kitchens, bathrooms, laundry rooms, closets, and direct HVAC airflow.
- Maintain closed-house conditions for at least 12 hours before and during a short-term test: keep exterior doors and windows closed and avoid whole-house or window fans that bring in outside air. HVAC may run normally for comfort.
- For real estate tests, follow the applicable state rule; many require 48 hours, while ANSI/AARST MAMF requires a 12-hour minimum. Document building configuration, HVAC operation, weather, and deviations.
Worked example
A homeowner opens a basement window 3 hours before a 48-hour CRM test. Because closed-house conditions were not met for 12 hours, the technician should not start the clock. Either delay deployment until 12 hours of closure or document the deviation and treat the test as invalid.
Traps
Testing a crawlspace; placing the detector near a return-air vent; starting immediately after a window was open; confusing “closed-house” with turning off HVAC; failing to note a whole-house fan.