CPR Infrared Thermography 2

Question 1

What does emissivity refer to in the context of infrared thermography?

Accepted Answer

A material's efficiency at emitting infrared radiation relative to a blackbody

Answer

Emissivity is a dimensionless value (0–1) describing how efficiently a material emits infrared energy compared to a perfect blackbody at the same temperature.

Question 2

Which emissivity value setting should a thermographer use when imaging a highly polished metal surface?

Accepted Answer

0.10–0.20

Answer

Polished metals have very low emissivity (typically 0.05–0.20), so the camera must be set accordingly to avoid inaccurate temperature readings.

Question 3

In building moisture investigations, infrared thermography detects wet areas primarily because wet materials exhibit:

Accepted Answer

A thermal mass difference causing evaporative cooling

Answer

Wet materials appear cooler in IR images during evaporation because evaporative cooling lowers the surface temperature relative to dry surroundings.

Question 4

What is the recommended minimum temperature differential (ΔT) between indoor and outdoor environments for effective building envelope IR scanning?

Accepted Answer

10°F (5.6°C)

Answer

A minimum 10°F (5.6°C) delta-T is generally required to create enough thermal contrast to reveal insulation defects and moisture patterns.

Question 5

Which type of IR camera detector does NOT require cooling and is most commonly used in field restoration work?

Accepted Answer

Microbolometer (uncooled FPA)

Answer

Microbolometer-based uncooled focal plane array detectors are rugged, affordable, and require no cryogenic cooling, making them ideal for field use.

(CPR) Certified Professional Restorer Practice Test

(CPR) Certified Professional Restorer Practice Test

CPR Infrared Thermography 2