Australian Standard Method Research Articles

Green roof substrate physical properties differ between standard laboratory tests due to differences in compaction

Green roofs are expanding internationally due to the well documented benefits they provide for buildings and cities. This requires transferable knowledge of the technological aspects influencing green roof design, particularly substrate properties. However, this is made difficult due to differences in substrate testing methods referred to in green roof guidelines and standards. Therefore, we tested a green roof substrate using laboratory-based methods from European (FLL), North American (ASTM) and Australian (AS) green roof guidelines and standards to determine how these methods vary in characterising substrate physical properties (bulk density, water permeability and water holding capacity at field capacity (WHC)). Further, we compared the results from the laboratory-based methods with measures of bulk density and WHC in green roof platforms to determine whether standard methods accurately represent substrate properties in-situ. Results from the standard test methods varied due to differences in sample compaction. The standard test methods that employ Proctor hammer compaction (FLL and ASTM) had greater bulk density (at field capacity and dry) and lower water permeability than Australian standard methods that employ free-fall compaction. WHC did not differ among the standard methods. The Australian standard method better reflected bulk density at field capacity and WHC of the substrate under in-situ green roof conditions. For mineral based substrates, our results suggest that for the FLL and ASTM testing methods, a single Proctor hammer drop will produce a degree of sample compaction equivalent to the free-fall method (AS) and be more representative of bulk density in-situ. Subtle changes in testing procedures would allow for more direct comparison of substrate properties between standard methods and help enable the international transfer of knowledge for substrate design.

Reliability of new Australian test methods in predicting alkali silica reaction of field concrete

Two new Australian Standard methods to test alkali-silica reactivity (ASR) of aggregates – AS1141.60.1 accelerated mortar bar test (AMBT) and AS1141.60.2 concrete prism test (CPT) were published in September 2014. The methods adopted test procedures correspondingly from ASTMC1260 and ASTMC1293 with improved performance limits leading to a new class of slowly reactive aggregates. This paper examines the accuracy of these new testing methods in predicting the ASR of aggregates in field conditions based on international research data. AS1141.60.1 was found to be a relatively good accelerated test which correctly classified ‘slowly reactive’ and ‘reactive’ aggregates consistent with field performance with few exceptions. It is however a poorer screening test for non-reactive aggregates than ASTMC1260. Both AS1141.60.2 and ASTMC1293 concrete prism tests were found to be more reliable than AMBT as both correctly classified almost all 64 aggregates against known field performance.

Ultra-fine grinding is not essential for acid sulfate soil tests

Australian Standard methods for acid sulfate soils (ASS) require the grinding of soil to <0.075 mm. A ring-mill or similar grinding apparatus is therefore needed. We investigated whether ring-mill grinding is required for accurate and reproducible test results and associated calculations (such as acid–base accounting), or if more conventional fine-grinding (i.e. <0.5 mm) is sufficient to obtain acceptable results. An initial experiment (unreplicated) was conducted on 52 soils comparing ring-mill and fine-grinding treatments, and this information was used to formulate final, more detailed experimental work on five soils from the same dataset. Soils from an ASS survey in coastal central Queensland were chosen to reflect the range of chemical properties found in ASS. Soils were analysed by the Chromium and SPOCAS suite of tests for the two grinding treatments. For those tests that follow a relatively vigorous extraction carried out with heating [such as chromium-reducible S, peroxide-oxidisable S and acid-neutralising capacity by back titration (ANCBT)], results were similar for the two grinding treatments. However, for those tests that follow a relatively mild extraction without heating (such as KCl-extractable S, HCl-extractable S and titratable actual acidity), significantly higher values (P < 0.05) were obtained for ring-mill ground soil. There was no significant difference in calculated net acidity between ring-mill grinding and fine-grinding for soils without excess ANC. For self-neutralising soils, fine-grinding gave significantly lower values of ANC than ring-mill grinding. It is uncertain whether ring-mill grinding gives a true reflection of the ANC available in the natural environment.

A comparative evaluation of the sensitivity of Salmonella detection on processed chicken carcasses using Australian and US methodologies

To confirm the reliability and sensitivity of Salmonella testing of processed poultry in Australia. The detection of Salmonella in a whole carcass wash of 90 randomly selected processed broilers was compared using the Australian Standard method, an Australian industry method used by a major processor and the United States Department of Agriculture method published in the Federal Register. The sensitivity of each method was determined using a carcass wash containing a known number of Salmonella Typhimurium to determine the minimum concentration to be able to be identified as positive. The two Australian methods were found to be comparable with both the Australian methods detecting more positive carcasses than the United States Department of Agriculture (USDA) method. The Australian methods were sensitive at the level of 1-3 CFU ml(-1) and the USDA method was sensitive at 10-30 CFU ml(-1). The Australian Standard method and the Australian industry method were both able to detect Salmonella reliably even at a low level of contamination. This study gives a high level of confidence both to the operators of poultry-processing plants and to regulators dependent upon the outcome of Salmonella testing for process control in Australia.

ASM Affairs, March 2005

Standing Committee on Biosafety; Standing Committee on Clinical Microbiology; The role of the National Scientific Advisory Committee (NSAC) in ASM; Announcing a major review of Australian Standard Methods for Water Microbiology: the AS 4276 Series; ASM awards and prizes; Emerging Microbiologists

Evaluation of detection methods for Legionella species using seeded water samples

South African laboratories are currently using various methods in a non-standardised approach to detect Legionella species in environmental samples. In an attempt to provide guidelines for the development of a standard method, a number of currently available detection methods were evaluated, using seeded samples of sterile and non-sterile tap water, cooling water and make-up water. The samples were seeded with a type strain of L. pneumophila serogroup 1 (American Type Culture Collection 33152). The effect of sample concentration by centrifugation and membrane filtration followed by either vortex or sonication for resuspension of organisms was studied. Three currently available culture methods were evaluated: the International standard method (ISO/DIS 11731), the Australian standard method (AS 3896 - 1991) and a locally-developed adaptation of the most probable number method (MPN). In addition, the direct immunofluorescence test and a commercially available latex agglutination test kit were included in the evaluations. The usefulness of treatment with acid or heat prior to culture was also compared. Our results indicated that concentration by membrane filtration using nitro-cellulose filters with a pore size of 0.45 ?m, followed by sonication for 10 min, would be the most appropriate concentration and resuspension method for the samples. In the absence of sample pretreatment with acid or heat, organism recovery from sterile seeded samples on BCYE ranged from 85.9 - 98.7%. However, in the non-sterile samples, these figures dropped to 8.1 - 38.5%. Sample pretreatment resulted in a further loss of at least 50% of organisms in all the samples, regardless of the pretreatment method or culture medium used. In general, the ISO and AS methods were more appropriate than the MPN method for organism recovery from sterile seeded samples. However, for the nonsterile samples, the MPN method yielded better recovery. WaterSA Vol.27(4) 2001: 523-528

97/02439 New analytical methods for determining trace elements in coal

New and improved analytical methods, based on modem spectroscopic techniques, have been developed to provide more reliable data on the levels of environmentally significant elements in Australian bituminous thermal coals. Arsenic, selenium and antimony are determined using hydride generation atomic absorption or fluorescence spectrometry, applied to an Eschka fusion of the raw coal. Boron is determined on the same digest using inductively coupled plasma atomic emission spectrometry (ICPAES). ICPAES is also used to determine beryllium, chromium, cobalt, copper, manganese, molybdenum, nickel, lead and zinc, after fusion of a low temperature ash with lithium borate. Other elements of concern including cadmium, uranium and thorium are analyzed by inductively coupled plasma mass spectrometry on a mixed acid digest of a low temperature ash. This technique was also suitable for determining elements analyzed by the ICPAES. Improved methods for chlorine and fluorine have also been developed. Details of the methods will be given and results of validation trials discussed on some of the methods which are anticipated to be designated Australian standard methods.

AN ELECTRICAL TESTING METHOD FOR THE DETECTION OF LISTERIA SPECIES IN CONFECTIONERY PRODUCTS

An electrical testing method for the detection of Listeria spp. in confectionery products and associated raw materials was developed in which samples can be negatively screened within 48h. The method involves a 24h resuscitation in Listeria enrichment broth followed by a 24h test in a Bactometer M128 using a broth (Claremont broth) developed from Oxford agar. The comparative study involved analysis of 511 samples (chocolate, dairy, cereal, nut and fruit products) tested by the Interim Australian Standard method (AS) and the Bactometer method (BM). The sensitivity and specificity of the BM for samples §1 Listeria/g was 100% and 99.8%, respectively, when compared to the AS method. When samples containing < 1 Listeria/g sample were added to the analysis, the sensitivity and specificity marginally dropped (98.3% and 99.6%). The electrical capacitance method is rapid and easy to perform, with a negative result being available within 48h making it a viable tool in a positive release QA program in food manufacturing factories.

Precision of Colour Measurement on Wools Sampled in the Grease in Australia

Confidence limits are calculated for the precision of measurements of the yellowness of clean wool sampled in the grease by means of the draft Australian standard method. The difference between two tests made in different laboratories is estimated to be less than 1.9 units in more than 95% of cases.

Comparison of the An Bord Bainne method, the Australian Standard method and an automatic procedure for determining the heat‐coagulation time of 20% reconstituted milk

The An Bord Bainne method, the Australian Standard method and an automatic electromagnetic method for determining the heat‐coagulation time of 20% skimmed milk powder solutions have been examined for accuracy and comparability of the results, based on 50 samples. Nine representative samples were chosen from the classes ‘non‐heat‐stable’, ‘moderately heat‐stable’, and ‘highly heat‐stable’ and used for evaluating the standard deviation and the coefficient of variation of the respective procedures. The statistic correlation between the measured values was carried out by means of Spearman's coefficient of rank correlation (rs), whereby the calculation was done not only for all the 50 milk powder samples but additionally also for 14 samples classified as ‘highly heat‐stable’. In both cases the correlation was significant at the 5% level (α= 0.05).

Studies on the measurement of smoke propensity of UPVC

AbstractThe smoke propensity of plastics as measured in the NBS Smoke Chamber method has been rationalized in terms of the influence of specimen thickness and resolved in a relation between mass optical density (MOD) and mass loss, which gives two parameters for characterizing behaviour, a maximum MOD for thin specimens and an asymptotic MOD for thicker ones. Data have been obtained for unplasticized piolyvinylchloride formulations and compared to that obtained by the Arapahoe Smoke Chamber and the Australian Standard method (AS 1530 Part 3). Although correlation coefficients between the methods were generally poor, the same formulations were ranked as the best performers in each method and the improvement over a standard formulation was potentially important in terms of wider acceptance under Australian building regulations.