ISO 9869-3:2023

Overview

ISO 9869-3:2023 - "Thermal insulation of building elements - In-situ measurement of thermal resistance and thermal transmittance - Part 3: Probe insertion method" specifies a practical, in-situ screening method to assess insulation performance of plane building elements (exterior walls, floors, ceilings). The standard describes the probe insertion method, combining a borescope visual inspection with a rod-shaped temperature sensor placed in a small-diameter borehole to obtain the temperature distribution through the wall. The procedure supports both a qualitative (no heat flow measurement) and a quantitative (with heat flow measurement) approach for determining local thermal resistance and diagnosing insulation issues.

Key topics and requirements

• Scope & limitations: Applicable to plane building components with light heat capacity (e.g., frame-structure dwellings). Results describe local performance at measurement points - not whole-panel U-value including thermal bridges (studs).
• Two measurement modes:
  • Without heat flow measurement: visual inspection with a borescope + temperature profile from the probe to evaluate installation quality or degradation.
  • With heat flow measurement: adds a heat flow meter at the indoor surface to calculate thermal resistance R = ΔT / heat flow.
• Probe and borehole: Borehole diameter is approximately 1 mm (document notes borehole ~