Moisture meters, thermal cameras and other inspection tools

In plain English

R520 lists the instruments used to find and track moisture, along with the limits of each. A thermo-hygrometer records temperature and humidity; the same unit should be used throughout a project, because calibration differs between devices. Pin-type moisture sensors show where carpet or materials are wet but only respond above roughly 17% moisture content. Moisture meters give true percentages only on materials they are calibrated for; on concrete or insulation they show a relative reading that must be compared with a known dry reference.

Infrared cameras show surface temperature differences, not moisture. A cool spot may mean evaporating water, but it can also be an air-conditioning draft, missing insulation or a cold pipe. R520 says suspect spots should be confirmed with a meter and that IR operators should be trained. Borescopes let an inspector look inside a wall cavity through a small hole.

Laser particle counters measure total airborne particles, not mold specifically. Remediators use them as a quality check during cleaning and to test air filtration equipment. Manometers confirm that a containment is under negative pressure. Gas and oxygen monitors may be needed in confined spaces. None of these tools identifies mold species or measures exposure; that is the IEP's sampling work. Texas note: in Texas, moisture readings and mapping on a regulated project feed the licensed assessor's protocol and clearance, so a contractor's readings support the record but do not replace the assessment.

Key points

• Use one thermo-hygrometer for the whole job.
• Meter readings on concrete or insulation are relative, not percentages.
• A thermal camera finds temperature differences; confirm moisture with a meter.
• Metal, salts or urine can cause false moisture readings.
• Particle counters measure all particles, not just mold.

Official text

This topic is covered in our own words because the standard behind it is copyrighted; we cite it below rather than reproduce it.

Citations

• IICRC S520 Reference Guide, IICRC S520 Standard and Reference Guide for Professional Mold Remediation — Reference Guide — Ch. 5, pp. 50–54. Best practice

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