Background

Smoldering underground fires in peatlands are among the most persistent and destructive wildfire types, but resisting conventional suppression methods.

Aims

This study experimentally evaluates a heat-pipe-based underground firebreak concept as a passive cooling strategy to mitigate smoldering propagation in stratified peat profiles.

Methods

Laboratory-scale experiments were conducted with an upper dry peat layer overlying a saturated layer. Heat pipes of varying lengths, geometries and quantities were installed with the condenser section positioned at the dry–saturated interface.

Key results

Under these conditions, heat pipes reduced peak smoldering temperatures and, in some configurations, quenched combustion. The intervention expanded the high-moisture, non-combustible region (‘safe zone’) more than fivefold compared with control tests. Longer pipes and configurations with larger condenser surface areas demonstrated greater thermal suppression effects.

Conclusion

The results provides a laboratory-scale proof of concept that heat pipes can function as passive thermal sinks and promote moisture redistribution at the dry–saturated interface in peat columns.

Implications

These findings are limited to controlled laboratory experiments. Substantial additional experimental, modeling and field research are required before assessing real-world deployment potential.