The structural reuse of Pinus Radiata in New Zealand

<p>Masses of used Copper chromium arsenic (CCA) treated timber is deposited into landfill from light timber framed building deconstruction every year. This research explores the structural integrity of CCA treated timber and the feasibility of its re-use within the construction industry. To answer this question an appropriate methodology has been designed to achieve quality results. The first part of the methodology was to identify the profit margin for pinus radiata through communicating with individuals in the current market. This market all works around the concept that to reuse there needs to be a significant buying community as it needs to generate MONEY. Through doing this it was identified that only a few companies in New Zealand reuse CCA treated timber and the ways of which it is re-used varies greatly between companies. Some firms pull the nails out due to health and safety reasons, while others leave them in due to the overall cost of the sale. This gives a good understanding on what everyone is doing across the country and allows for the sale market to be set at $2.00 a meter, which if done correctly comes in at around $0.16 a meter of profit. The next part of the methodology required a physical assessment of material itself in order to establish its structural integrity and identify other potential barriers to its reuse. This section covered all other possibilities to pinus radiata focusing on the different timber which have the same properties, and focus on separate treatments which will also conduct the same issues as CCA. This all found that there is much research to consider, which placed New Zealand in an area of profit, as any of these documents could be the focus point and all could eventually relieve CCA from the industry. Existing research identifies how the use of CCA treated timber can be prevented, but does not consider the diversion of existing treated timber being deposited into landfill. The lack of research into the re-use of CCA treated timber is the main barrier found in this thesis. This required the series of events which occur between building deconstruction and deposition into landfill to be clearly defined, before they could be changed. The changes to how CCA treated timber is processed after deconstruction has the potential to divert the material from landfill for re-use. The primary addition to this process was an assessment of the strength which it holds. To accomplish this a three point bending test was carried out on each member, finding the alternate strength and the modulus of elasticity (MOE). These two figures could then be directly compared to NZS 3603:1993 timber structural standards allowing their long term history of testing to be the comparative point (New Zealand Government, 1993). With the two figures it was found that all of this material strength was 91% above the minimum strength grading of SG6, and 55% above the next area of SG8, which is the most commonly used framing timber. Although through doing this there was hope for the material to present themselves with a way of finding the general strength with minimal tools, this is not present in the research. The most important finding of this research is that CCA treated timber is strong enough to be placed straight back into the construction industry and re-used for light timber frame construction. Future research is needed into the additional education required of builders in order for them to confidently re-use the timber in construction.</p>

The structural reuse of Pinus Radiata in New Zealand

<p>Masses of used Copper chromium arsenic (CCA) treated timber is deposited into landfill from light timber framed building deconstruction every year. This research explores the structural integrity of CCA treated timber and the feasibility of its re-use within the construction industry. To answer this question an appropriate methodology has been designed to achieve quality results. The first part of the methodology was to identify the profit margin for pinus radiata through communicating with individuals in the current market. This market all works around the concept that to reuse there needs to be a significant buying community as it needs to generate MONEY. Through doing this it was identified that only a few companies in New Zealand reuse CCA treated timber and the ways of which it is re-used varies greatly between companies. Some firms pull the nails out due to health and safety reasons, while others leave them in due to the overall cost of the sale. This gives a good understanding on what everyone is doing across the country and allows for the sale market to be set at $2.00 a meter, which if done correctly comes in at around $0.16 a meter of profit. The next part of the methodology required a physical assessment of material itself in order to establish its structural integrity and identify other potential barriers to its reuse. This section covered all other possibilities to pinus radiata focusing on the different timber which have the same properties, and focus on separate treatments which will also conduct the same issues as CCA. This all found that there is much research to consider, which placed New Zealand in an area of profit, as any of these documents could be the focus point and all could eventually relieve CCA from the industry. Existing research identifies how the use of CCA treated timber can be prevented, but does not consider the diversion of existing treated timber being deposited into landfill. The lack of research into the re-use of CCA treated timber is the main barrier found in this thesis. This required the series of events which occur between building deconstruction and deposition into landfill to be clearly defined, before they could be changed. The changes to how CCA treated timber is processed after deconstruction has the potential to divert the material from landfill for re-use. The primary addition to this process was an assessment of the strength which it holds. To accomplish this a three point bending test was carried out on each member, finding the alternate strength and the modulus of elasticity (MOE). These two figures could then be directly compared to NZS 3603:1993 timber structural standards allowing their long term history of testing to be the comparative point (New Zealand Government, 1993). With the two figures it was found that all of this material strength was 91% above the minimum strength grading of SG6, and 55% above the next area of SG8, which is the most commonly used framing timber. Although through doing this there was hope for the material to present themselves with a way of finding the general strength with minimal tools, this is not present in the research. The most important finding of this research is that CCA treated timber is strong enough to be placed straight back into the construction industry and re-used for light timber frame construction. Future research is needed into the additional education required of builders in order for them to confidently re-use the timber in construction.</p>

Atmospheric Monitoring of PM₂.₅, PM₁₀₋₂.₅, PM₁₀, Arsenic and Carbonaceous Aerosol at Wainuiomata

<p>Air pollution is harming our health and that of our children and parents. Air pollution causes many harmful effects, ranging from premature death, to headaches, coughing and asthma attacks. Previous studies (2008-2009) of particulate matter at Wainuiomata, Lower Hutt showed that biomass burning was primarily responsible for peak PM₂.₅ and PM₁₀ concentrations and exceedances of the National Environmental Standard (NES) and the New Zealand Ambient Air Quality Guidelines (NZAAQG). Arsenic was also found to be associated with biomass burning sources during winter at Wainuiomata. The source of arsenic was considered to be due to the use of copper chromium arsenate (CCA) treated timber as solid fuel for fires for domestic heating. While particulate matter pollution from domestic fires itself presents a health risk for the exposed population, the addition of arsenic to the mix enhances the potential risk. The use of CCA treated timber was unlikely to be used on a regular basis hence the peak arsenic concentrations did not always coincide with peak contributions from domestic fires and that the use of CCA – treated timber is more intermittent and opportunistic. This work compared several different analytical methodologies for the determination of arsenic in air particulate matter. The primary purpose was to use a standard analytical method as recommended by the NZAAQ guidelines and compare those results with the Ion Beam Analysis (IBA) and X-ray Fluorescence Spectroscopy (XRF) methods used to determine arsenic concentrations in previous studies. Through this collaborative research with GNS Science and GWRC, it was found that annual PM₁₀ and PM₂.₅ averages were well within the NZAAQG values of; 20 μg m⁻³ and 10 μg m⁻³ respectively. There was a much correlated seasonal and temporal variations observed for black carbon (BC), PM₂.₅ and arsenic concentrations. The overall concentrations of BC, PM₂.₅ and PM₁₀ have decreased significantly in the Wainuiomata airshed compared to previous studies as reported in 2009 with fewer exceedances of the NES and NZAAQG on a 24 hour daily average. The overall weighted mean arsenic concentration as measured by GF-AAS was 6.3 ± 0.8 ng m⁻³ and that measured by XRF and IBA was 3.8 ± 2.0 ng m⁻³ and 3.1 ± 5.9 ng m⁻³ respectively. The XRF and IBA arsenic concentrations were consistently lower than that of GF-AAS. The two annual arsenic averages (GF-AAS) were 6.5 ± 0.9 ng m⁻³ and 5.9 ± 0.7 ng m⁻³ respectively, for the entire sampling period. In both the cases the NZAAQG value of 5.5 ng m⁻³ were exceeded. The exceedance in the second year of sampling was not statistically significant as the guideline value 5.5 ngm⁻³ falls within the given uncertainty of the measured annual averages for arsenic. However, it is definitely an area of concern as the overall arsenic concentrations during winter periods was 12.2 ± 1.0 ng m⁻³. Moreover, burning CCA treated timber is effectively banned through regional plan rules and the problem presents itself as one of enforcement and/or public education. The inter-method comparison showed that IBA technique can be used for “screening” purposes due to high limit of detection (LOD) and analytical noise. While XRF can still be used interchangeably with GF-AAS but with Teflon or thinner filter membrane, for long term environmental monitoring of arsenic and other elemental compositions. Given the excellent recoveries of 99.2 ± 0.8% for duplicate spiked analysis and 102.7 ± 0.9% for lab blank filters spiked analysis, at 95% confidence intervals, GF-AAS method is highly reproducible and should be used in the determination of arsenic in ambient air for the purpose of comparing with the NZAAQG values.</p>

Atmospheric Monitoring of PM₂.₅, PM₁₀₋₂.₅, PM₁₀, Arsenic and Carbonaceous Aerosol at Wainuiomata

<p>Air pollution is harming our health and that of our children and parents. Air pollution causes many harmful effects, ranging from premature death, to headaches, coughing and asthma attacks. Previous studies (2008-2009) of particulate matter at Wainuiomata, Lower Hutt showed that biomass burning was primarily responsible for peak PM₂.₅ and PM₁₀ concentrations and exceedances of the National Environmental Standard (NES) and the New Zealand Ambient Air Quality Guidelines (NZAAQG). Arsenic was also found to be associated with biomass burning sources during winter at Wainuiomata. The source of arsenic was considered to be due to the use of copper chromium arsenate (CCA) treated timber as solid fuel for fires for domestic heating. While particulate matter pollution from domestic fires itself presents a health risk for the exposed population, the addition of arsenic to the mix enhances the potential risk. The use of CCA treated timber was unlikely to be used on a regular basis hence the peak arsenic concentrations did not always coincide with peak contributions from domestic fires and that the use of CCA – treated timber is more intermittent and opportunistic. This work compared several different analytical methodologies for the determination of arsenic in air particulate matter. The primary purpose was to use a standard analytical method as recommended by the NZAAQ guidelines and compare those results with the Ion Beam Analysis (IBA) and X-ray Fluorescence Spectroscopy (XRF) methods used to determine arsenic concentrations in previous studies. Through this collaborative research with GNS Science and GWRC, it was found that annual PM₁₀ and PM₂.₅ averages were well within the NZAAQG values of; 20 μg m⁻³ and 10 μg m⁻³ respectively. There was a much correlated seasonal and temporal variations observed for black carbon (BC), PM₂.₅ and arsenic concentrations. The overall concentrations of BC, PM₂.₅ and PM₁₀ have decreased significantly in the Wainuiomata airshed compared to previous studies as reported in 2009 with fewer exceedances of the NES and NZAAQG on a 24 hour daily average. The overall weighted mean arsenic concentration as measured by GF-AAS was 6.3 ± 0.8 ng m⁻³ and that measured by XRF and IBA was 3.8 ± 2.0 ng m⁻³ and 3.1 ± 5.9 ng m⁻³ respectively. The XRF and IBA arsenic concentrations were consistently lower than that of GF-AAS. The two annual arsenic averages (GF-AAS) were 6.5 ± 0.9 ng m⁻³ and 5.9 ± 0.7 ng m⁻³ respectively, for the entire sampling period. In both the cases the NZAAQG value of 5.5 ng m⁻³ were exceeded. The exceedance in the second year of sampling was not statistically significant as the guideline value 5.5 ngm⁻³ falls within the given uncertainty of the measured annual averages for arsenic. However, it is definitely an area of concern as the overall arsenic concentrations during winter periods was 12.2 ± 1.0 ng m⁻³. Moreover, burning CCA treated timber is effectively banned through regional plan rules and the problem presents itself as one of enforcement and/or public education. The inter-method comparison showed that IBA technique can be used for “screening” purposes due to high limit of detection (LOD) and analytical noise. While XRF can still be used interchangeably with GF-AAS but with Teflon or thinner filter membrane, for long term environmental monitoring of arsenic and other elemental compositions. Given the excellent recoveries of 99.2 ± 0.8% for duplicate spiked analysis and 102.7 ± 0.9% for lab blank filters spiked analysis, at 95% confidence intervals, GF-AAS method is highly reproducible and should be used in the determination of arsenic in ambient air for the purpose of comparing with the NZAAQG values.</p>

Arsenic in Hair as a Marker of Exposure to Smoke from the Burning of Treated Wood in Domestic Wood Burners

Timber treated with the anti-fungal chemical copper chrome arsenate is used extensively in the New Zealand building industry. While illegal, the burning of treated timber is commonplace in New Zealand and presents a health risk. Outdoor ambient monitoring of arsenic in airborne particulate matter in New Zealand has identified levels that exceed the maximum standards of 5.5 ng m−3 (annual average) at some urban locations. In this study, two-week-old beard hair samples were collected during the winter months to establish individual exposure to arsenic using Inductively Coupled Plasma-Mass Spectrometry. These results were then compared with questionnaire data about wood burner use for the two weeks prior to sampling, and spatial trends in arsenic from ambient monitoring. Results suggest that the burning of construction timber that may contain arsenic is associated with a higher level of arsenic in hair than those who burn logs or coal exclusively. There is no association between the area-level density of wood burners and arsenic levels but a significant correlation with individual household choice of fuel as well as the smell of wood smoke in the community, suggesting very localised influences. Strategies are needed to raise awareness of the risks of burning treated timber and to provide economically-viable alternatives.

Timber modification by radio wave technology

<p>The following paper describes how radio wave thermal modification at temperatures above 160°C can improve the durability of timber. It also broadens possible applications in areas where the timber decays faster under natural conditions. During the process, cellulose areas are modified to absorb less water. The treated timber is more resistant to decaying fungi. The heat required for this process is generated by polarization at a molecular level, similar to a microwave oven. However, the frequency of the radio and microwaves are different. (The frequency of radio and microwave are 13.56MHz and 2.45GHz respectively.) Radio waves have an advantage of higher permeability by several meters whereas microwaves can only heat a few centimeters. It is also possible to generate temperatures greater than 100°C, due to the frequency of radio waves polarizing water molecules and achieving ionic polarization. Therefore, it is possible to heat dry materials. The modified timber samples are analyzed for mechanical und hygric properties. The results show a positive influence on hydrologic properties by improving durability.</p>

Potential contaminants in rainwater after a bushfire

Using roof harvested rainwater held in domestic rainwater tanks is a common practice in Australia, particularly in rural areas. This rainwater might become contaminated with ash and other contaminants during or after a bushfire. Current advice from Australian Health Departments can include the recommendation that landholders drain their tanks after a bushfire, which can cause additional distress to landholders who have already been through a traumatic event. This study created artificially contaminated water, spiked with chemicals likely to be associated with bushfires, including chromated copper arsenate-treated timber ash and firefighting foam to determine the possibility of contamination. The authors also tested two readily available filter systems and found that they removed some but not all contaminants. The artificially created contaminated water fell within guidelines for nonpotable uses such as irrigation and stock watering. This suggests that advice to landholders should be that tank water following a bushfire is likely to be safe for use for purposes apart from drinking. Landholders should be encouraged to retain and use their water for recovery purposes, but not for potable use.