Which of the following is NOT listed as something to protect the infrared tester from?

• A. Electromagnetic Fields
• B. Static Electricity
• C. Thermal Shock
• D. Water Immersion

Answer: (D)

Infrared testers are precision devices whose measurements can be affected by electric and thermal conditions, so the guidance focuses on protecting the instrument from factors that directly interfere with its sensors and electronics. Electromagnetic fields can couple into delicate circuits and distort readings, so you keep the tester away from strong EMI sources. Static electricity is a discharge risk that can damage the sensor elements or create calibration drift, so you handle the device with proper grounding and anti-static precautions. Thermal shock—rapid, large temperature changes—can stress components, seals, and the sensor window, leading to calibration shifts or mechanical failure, so you avoid sudden temperature transitions and store or move the instrument gradually.

Water immersion isn’t listed as a protective measure because, rather than a condition you guard against in normal operation, it’s typically treated as a misuse or hazard to avoid. Unless the device is explicitly rated for immersion, you protect it by keeping it dry rather than by applying a protective measure for immersion.