ISO 9229 defines the vocabulary used in the field of thermal insulation, including terms for heat transfer, materials, and performance.
Why a vocabulary standard
Heat-recovery specs mix terms such as conductivity, resistance, effectiveness, and recuperation. ISO 9229 fixes their meaning so a supplier and buyer mean the same thing.
Useful terms for our field
| Term | Meaning |
|---|---|
| Thermal resistance (R) | Resistance to heat flow |
| Thermal transmittance (U) | Heat flow per area per temperature diff |
| Effectiveness | Actual / max possible transfer |
Effectiveness vs efficiency
In recovery, "effectiveness" is the correct term; "efficiency" is often misused. ISO 9229-aligned wording avoids the ambiguity.
Practical value
Citing standardized terms in your specification reduces disputes over whether a quoted "efficiency" means sensible effectiveness or total effectiveness.