Advanced Evaluation of Fire Resistance in Spruce Wood (Picea abies spp.) Treated with Innovative Surface Coatings

Redžo Hasanagić ¹

Selma Mujanić ¹

Eli Keržič ²

Leila Fathi ³

Mohsen Noghani Dokht Bahmani ³

Mohammad Dahmardeh Ghalehno ⁴

Boštjan Lesar ²

Miha Humar ²

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Department of Wood Science and Technology, Faculty of Technical Engineering, University of Bihać, 77000 Bihać, Bosnia and Herzegovina |

Department of Wood Science, Biotechnical Faculty, University of Ljubljana, 1501 Ljubljana, Slovenia |

Department of Wood and Furniture Industry Engineering, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord 64164478, Iran

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Department of Wood and Paper Sciences and Technology, University of Zabol, Zabol 9861335856, Iran

Publication type: Journal Article

Publication date: 2025-03-21

MDPI

Journal: Fire

scimago Q1

wos Q1

SJR: 0.566

CiteScore: 3.1

Impact factor: 3

ISSN: 25716255

DOI: 10.3390/fire8040120

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Abstract

This study investigates innovative surface coatings’ effectiveness in enhancing spruce wood’s fire resistance (Picea abies spp.). Spruce wood samples were treated with various agents, including oils, waxes, boric acid, commercial coatings, and fire-retardant agents. The evaluation was conducted using the small flame method (EN ISO 11925-2:2020), surface roughness analysis, hyperspectral imaging (HSI), and contact angle measurements. The results demonstrated significant improvements in fire resistance for samples treated with specific coatings, particularly the Burn Block spray and Caparol coating, which effectively prevented flame spread. The analysis revealed that the Burn Block spray reduced the average flame height to 6.57 cm, while the Caparol coating achieved a similar effect with an average flame height of 6.95 cm. In contrast, untreated samples exhibited a flame height of 9.34 cm, with boric acid-treated samples reaching up to 12.18 cm. Char depth measurements and the surface roughness analysis revealed a clear correlation between the type of treatment and the thermal stability of the wood. Hyperspectral imaging enabled a detailed visualisation of surface degradation, while contact angle measurements highlighted the impact of hydrophobicity on flammability. This research provides in-depth insights into the fire-retardant mechanisms of spruce wood and offers practical guidelines for developing safer and more sustainable wood materials for the construction industry.