Investigation of factors in the efflorescence of fire retardant woods

Kawarasaki, Masayuki; Hirabayashi, Yasushi

doi:10.5990/jwpa.40.17

Cited by 4 publications

(1 citation statement)

References 2 publications

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“…After long-term outdoor exposure, coating cracks and efflorescence followed by leaching of chemicals are common, and many of them originate owing to moisture absorption or desorption. (a) FRT absorbs more water than untreated wood [10],…”

Section: Introductionmentioning

confidence: 99%

Derivation From En927 Method for Evaluating Outdoor Durability of Coated Fire-Retardant-Treated Wood

Takase

Ishikawa

Kamikawa

2023

World Conference on Timber Engineering (WCTE 2023)

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Conducting an artificial weathering test using UV lamps and water spraying is necessary to predict the outdoor durability of coated fire-retardant-treated wood. This paper describes the results of prototypes derived from the EN927-6 methods, which are artificial weathering methods for coated wood. Modified tests using QUV demonstrated that testing conditions such as the duration of each spray or temperature have different effects on coatings. Thus, lowbuild coatings tend to be evaluated poorly under the standard cycle. Moreover, maintaining a high moisture content by raising the initial moisture content or lowering the testing temperature speeds up leaching from high-build coatings.

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Section: Introductionmentioning

confidence: 99%

Derivation From En927 Method for Evaluating Outdoor Durability of Coated Fire-Retardant-Treated Wood

Takase

Ishikawa

Kamikawa

2023

World Conference on Timber Engineering (WCTE 2023)

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Artificial-weathering test requirements for fire-retardant-treated wood to reproduce optimal chemical retention and moisture conditions

Takase,

Ishikawa,

Kamikawa

2024

J Wood Sci

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Despite the increasing outdoor use of fire-retardant-treated wood, methods for predicting its service life remain poorly established. With the aim of establishing a method to predict chemical losses from fire-retardant-treated (FRT) wood caused by humid atmospheres and rain outdoors, this study examined the preferable conditions for artificial-weathering tests and demonstrated the acceleration coefficients in these tests (i.e., the ratio of equivalent time to reach the same retention of chemicals in artificial weathering and outdoors) based on the EN927-6 standard. To determine the moisture absorption and desorption levels of FRT exposed to outdoor conditions, an outdoor exposure experiment was conducted. The moisture content was higher in the FRT wood than in untreated wood, regardless of the type of coating, and ranged between 11% (in March) and 50% (in September) of the untreated wood’s weight. EN927-6 artificial weathering tests were performed on two groups of specimens with initial moisture contents of 0% and 25%. Retention rates of fire-retardant chemicals after a 2520-h test were compared with those retrieved from 4-year outdoor exposure reported elsewhere. Comparison of these two experiments demonstrated that the acceleration coefficients were 4.1–11.3 in the case of specimens with 0% initial moisture content and 5.1–11.4 in the case of specimens with 25% initial moisture content. The higher initial moisture content produced a more uniform acceleration coefficient. Nevertheless, larger acceleration coefficients were derived from specimens with penetrating or semi-film-forming coatings in both cases. The relationships between the uniformity of this acceleration coefficient and the initial moisture content are discussed from the moisture absorption experiment under constant temperature and humidity and under condensation conditions.

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Influence of moisture absorption on the degradation of fire-retardant-treated and surface-coated wood

et al. 2020

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Investigation of factors in the efflorescence of fire retardant woods

Cited by 4 publications

References 2 publications

Derivation From En927 Method for Evaluating Outdoor Durability of Coated Fire-Retardant-Treated Wood

Derivation From En927 Method for Evaluating Outdoor Durability of Coated Fire-Retardant-Treated Wood

Artificial-weathering test requirements for fire-retardant-treated wood to reproduce optimal chemical retention and moisture conditions

Influence of moisture absorption on the degradation of fire-retardant-treated and surface-coated wood

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