Page 15 - InnoRenew CoE International Conference 2022
P. 15
Reaction to fire characterisation of densified-processed
poplar and beech
Ulises Rojas-Alva1*, Nataša Knez2, Grunde Jomaas1,3, Lei Han3,4, Marica Mikuljan3,4, Andreja Kutnar3,4
1 Department for Fire-safe Sustainable Built Environment (FRISSBE), ZAG (Slovenian National Building and Civil Engineering Institute); Obrtna cona
Logatec 35, SI-1370 Logatec, Slovenia; ulises.rojas-alva@zag.si, grunde.jomaas@zag.si
2 Slovenian National Building and Civil Engineering Institute; Dimičeva 12, Ljubljana, Slovenia; natasa.knez@zag.si
3 Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, 6000 Koper, Slovenia;
lei.han@innorenew.eu, marica.mikuljan@innorenew.eu, andreja.kutnar@innorenew.eu
4 InnoRenew CoE, Livade 6a, 6310 Izola, Slovenia
* Corresponding author
There is a renewed interest in the densification of wood due to the need for utilising lower quality wood species
and utilisation of fast-grown woods (Sandberg et al., 2021). The densification process improves the mechanical
properties of wood that can then be used for advanced engineering (structures and other applications). However,
as with all cellulose products aimed at the built environment, the fire performance of the densified wood products
needs to be characterised. Therefore, cone calorimeter experiments, following the ISO 5660-1 standard (ISO,
2015), were carried out for a range of densified samples of Black poplar (Populus spp.) and European beech
(Fagus sylvatica L.) to assess the fire characteristics of densified wood. Densification was performed by thermo-
hydro-mechanical (THM) treatment in an open system at 170 ℃ - 200 ℃. Time to ignition and the heat release
rate (HRR) were measured during the testing campaign. Three groups of poplar were tested: (1) unmodified
specimens, (2) THM-densified specimens, (3) low-molecular-weight phenol-formaldehyde resin-impregnated
and THM-densified specimens, while the test on beech only included unmodified specimens and THM-densified
specimens. For poplar, the time to ignition increased by 5 times with resin impregnation (when exposed to 35 kW/
m²), whereas the influence on time to ignition from densification alone is less clear. The heat release rate (HRR)
of poplar was slightly decreased by densification, but the peak HRR increased somewhat by densification. This
falls in line with the fact that the mass loss rate of the poplar decreased by densification. More significant results
were obtained for beech, as the densification increased substantially by the HRR and mass loss rate. Interesting
observations were also made in the analysis of the combustion products. All in all, poplar with resin impregnation
and THM treatment is significantly less ignitable than untreated poplar, and densified beech burns at a lower
rate than untreated beech.
Keywords: wood densification, reaction to fire, heat release rate, Black poplar, European beech
REFERENCES
ISO. (2015). ISO 5660-1:2015 Reaction-to-fire tests -- Heat release, smoke production and mass loss rate --
Part 1: Heat release rate (cone calorimeter method) and smoke production rate (dynamic measurement).
Sandberg, D., Kutnar, A., Karlsson, O., & Jones, D. (2021). Wood Modification Technologies: Principles,
Sustainability, and the Need for Innovation. CRC Press.
17–18 NOVEMBER 2022 I IZOLA, SLOVENIA 15
poplar and beech
Ulises Rojas-Alva1*, Nataša Knez2, Grunde Jomaas1,3, Lei Han3,4, Marica Mikuljan3,4, Andreja Kutnar3,4
1 Department for Fire-safe Sustainable Built Environment (FRISSBE), ZAG (Slovenian National Building and Civil Engineering Institute); Obrtna cona
Logatec 35, SI-1370 Logatec, Slovenia; ulises.rojas-alva@zag.si, grunde.jomaas@zag.si
2 Slovenian National Building and Civil Engineering Institute; Dimičeva 12, Ljubljana, Slovenia; natasa.knez@zag.si
3 Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, 6000 Koper, Slovenia;
lei.han@innorenew.eu, marica.mikuljan@innorenew.eu, andreja.kutnar@innorenew.eu
4 InnoRenew CoE, Livade 6a, 6310 Izola, Slovenia
* Corresponding author
There is a renewed interest in the densification of wood due to the need for utilising lower quality wood species
and utilisation of fast-grown woods (Sandberg et al., 2021). The densification process improves the mechanical
properties of wood that can then be used for advanced engineering (structures and other applications). However,
as with all cellulose products aimed at the built environment, the fire performance of the densified wood products
needs to be characterised. Therefore, cone calorimeter experiments, following the ISO 5660-1 standard (ISO,
2015), were carried out for a range of densified samples of Black poplar (Populus spp.) and European beech
(Fagus sylvatica L.) to assess the fire characteristics of densified wood. Densification was performed by thermo-
hydro-mechanical (THM) treatment in an open system at 170 ℃ - 200 ℃. Time to ignition and the heat release
rate (HRR) were measured during the testing campaign. Three groups of poplar were tested: (1) unmodified
specimens, (2) THM-densified specimens, (3) low-molecular-weight phenol-formaldehyde resin-impregnated
and THM-densified specimens, while the test on beech only included unmodified specimens and THM-densified
specimens. For poplar, the time to ignition increased by 5 times with resin impregnation (when exposed to 35 kW/
m²), whereas the influence on time to ignition from densification alone is less clear. The heat release rate (HRR)
of poplar was slightly decreased by densification, but the peak HRR increased somewhat by densification. This
falls in line with the fact that the mass loss rate of the poplar decreased by densification. More significant results
were obtained for beech, as the densification increased substantially by the HRR and mass loss rate. Interesting
observations were also made in the analysis of the combustion products. All in all, poplar with resin impregnation
and THM treatment is significantly less ignitable than untreated poplar, and densified beech burns at a lower
rate than untreated beech.
Keywords: wood densification, reaction to fire, heat release rate, Black poplar, European beech
REFERENCES
ISO. (2015). ISO 5660-1:2015 Reaction-to-fire tests -- Heat release, smoke production and mass loss rate --
Part 1: Heat release rate (cone calorimeter method) and smoke production rate (dynamic measurement).
Sandberg, D., Kutnar, A., Karlsson, O., & Jones, D. (2021). Wood Modification Technologies: Principles,
Sustainability, and the Need for Innovation. CRC Press.
17–18 NOVEMBER 2022 I IZOLA, SLOVENIA 15
