CPR Thermal Imaging & Moisture Meters 2 — Questions and Answers
Question 1: What is the minimum recommended temperature differential (Delta T) between indoor and outdoor conditions for effective thermal imaging during a moisture inspection?
- 5°F (3°C)
- 10°F (6°C) (Correct answer)
- 20°F (11°C)
- 30°F (17°C)
Correct answer: 10°F (6°C)
A minimum Delta T of 10°F (6°C) between interior and exterior is generally required to create enough thermal contrast for moisture anomalies to appear on an IR camera.
Question 2: A thermal image shows a cool, irregularly shaped pattern on a ceiling near a plumbing stack. The MOST likely cause is:
- HVAC cold air leak
- Active moisture intrusion from above (Correct answer)
- Thermal bridging from a structural beam
- Pest activity inside the cavity
Correct answer: Active moisture intrusion from above
An irregular cool pattern near a plumbing stack on a ceiling strongly indicates active or recent moisture intrusion, since wet materials lose heat more quickly than dry ones.
Question 3: Which building material has the HIGHEST emissivity value and is therefore easiest to image accurately with a thermal camera?
- Polished aluminum
- Galvanized metal ductwork
- Unpainted drywall (Correct answer)
- Glass windows
Correct answer: Unpainted drywall
Unpainted drywall has a high emissivity (~0.90–0.95), making it an ideal surface for accurate thermal imaging without significant emissivity correction.
Question 4: When using a thermal camera to detect moisture in a floor assembly, the technician should scan:
- Only from above with lights off
- From below (crawlspace) with the subfloor heated from above (Correct answer)
- Only after applying water to confirm the pattern
- With the camera held at a 45-degree angle to the surface
Correct answer: From below (crawlspace) with the subfloor heated from above
Scanning from below while the upper floor is heated creates a thermal gradient that reveals moisture-laden areas as cooler anomalies in the subfloor.
Question 5: A restoration technician notices a warm spot on an exterior wall during a winter inspection. What does this MOST likely indicate?
- Moisture accumulation in the wall cavity
- Missing or compressed insulation (Correct answer)
- Active mold colony generating heat
- Elevated ambient temperature outside
Correct answer: Missing or compressed insulation
Warm spots on exterior walls in winter most often indicate missing or compressed insulation allowing conditioned air to pass through, not moisture.
Question 6: Which of the following BEST describes the term 'apparent temperature' in thermal imaging?
- The actual surface temperature measured by contact probe
- The temperature displayed by the IR camera based on emissivity and reflected temperature (Correct answer)
- The ambient air temperature at the time of inspection
- The dew point temperature of the surface being scanned
Correct answer: The temperature displayed by the IR camera based on emissivity and reflected temperature
Apparent temperature is the value displayed by the IR camera, which accounts for emissivity and reflected ambient radiation and may differ from the true surface temperature.
Question 7: A thermal camera image shows cold spots at regularly spaced intervals along a wall. The MOST probable explanation is:
- Moisture trapped behind each stud bay
- Thermal bridging through wall studs (Correct answer)
- Multiple plumbing supply lines running vertically
- Evaporative cooling from surface mold colonies
Correct answer: Thermal bridging through wall studs
Regularly spaced cold spots in winter (or warm spots in summer) along a wall are the classic thermal signature of thermal bridging through wood or metal studs.
CPR Thermal Imaging & Moisture Meters 2
What is the minimum recommended temperature differential (Delta T) between indoor and outdoor conditions for effective thermal imaging during a moisture inspection?