PSI - Issue 11

Gabriela Lotufo Oliveira et al. / Procedia Structural Integrity 11 (2018) 242–249 Gabriela Lotufo Oliveira, Fabiana Lopes de Oliveira, Sérgio Brazolin / Structural Integrity Procedia 00 (2018) 000–000

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Table 2. Australian Use Categories. Use Category

Service Conditions

Deterioration Agents

H1

completely protected from the weather, well ventilated and protected from termites

borers

H2

protected from wetting, no leaching

borers and termites

H3

periodic moderate wetting and leaching

moderate decay, borers and termite severe decay, borers and termites

H4

severe wetting and leaching non-critical applications

H5

extreme wetting and leaching, critical application

very severe decay, borers and termites

H6

prolonged immersion in sea water

marine wood borers

In Brazil, standard ABNT NBR 16143:2013 – Preservação de madeiras – Sistema de categorias de uso (ABNT, 2013c), presents six categories based on the exposure of the wood component, similarly to those from Australia. The main difference between the Brazilian and Australian Use Categories is that the first one considers three types of termites and three types of fungi. One of the types of termite is also a possible deterioration agent in the first Use Category. The bigger amount of decay agents considered in the Brazilian preservation standards indicates more favorable conditions for decay to occur in this country, as Scheffer’s climate index. However, just four preservatives are registered for pressure treatment of wood in Brazil (Creosote, CCA, CCB and CA-B (Copper Azole Type B)). In the USA, more than twenty preservatives are standardized by ASTM. Creosote, CCA-C, Alkaline Copper Quaternary Type A (ACQ-A), pentachlorophenol, CA-B, Ammoniacal Copper Zinc Arsenate (ACZA) and many others are among them. As for Australia, the registered preservatives are: CCA, ACQ, Copper Azole (CA), Creosote and Boron. One of the explanations for that occurrence is the minor use of wood as structural component in the Brazilian The use of CLT, made of pinewood, has recently begun in Brazil, typically for high-standard residences. The Brazilian use category system standard (ABNT, 2013c) establishes the need of quality control, measuring two parameters for pressure treatment: retention, or the quantity of active ingredient introduced into the dry wood (below 30%), expressed as kg/m³, and penetration of the preservative in the permeable portion of wood. Therefore, as a case study, samples of Pinus sp. , which could be used as raw material for CLT production, were submitted to testing to identify the penetration and the retention of the preservative. Thus, twenty-one pinewood boards were randomly selected from a timber establishment, and a sample with approximate dimensions of (15 x 15 x 2) cm was cut from each of them. According to the producer, the timber was from the south region of Brazil and was treated with CCB. Retention of the preservative was determined using an atomic absorption spectrophotometer and penetration, by means of a colorimetric test, as described in the ABNT NBR 6232:2013 (ABNT, 2013a) standard. To determine penetration, the blue color in the tested samples indicates the presence of the preservative, according to the following classification: NP – non-penetration of the preservative; IP - irregular penetration; TP - total penetration in the permeable portion of the wood. Table 1 shows the results of the tested parameters (penetration and retention) in the samples of Pinus sp. Figure 4 illustrates the penetration tests. construction sector, mostly for cultural reasons. 4. Case study: CLT treated with CCB in Brazil