AWTA Raw Wool are frequently approached by brokers, wool growers and others who have specific questions about the Company, its services and many other matters which relate to the Wool Industry.
A broad selection of questions are available below:
Why should I measure my wool?
Why is sampling supervision necessary?
What is the difference between a Test Report and a Test Certificate?
How quickly does AWTA provide results?
How do I query a test result?
How long does AWTA retain core samples for check testing?
Does AWTA have a test for chemical residues in wool?
Can AWTA test other fibres?
What are the main benefits of Staple Length & Strength Measurement?
For Staple Measurements how is the Position of Break calculated?
What is Laserscan?
What is Comfort Factor?
What is the precision (repeatability) of wool testing?
Why are there 4 different Yield results on my Certificates and in the catalogue?
Why are small changes in micron so important in determining the price of fine wool?
What is Dark and Medullated Fibre Contamination?
What problems do Dark and Medullated Fibre Contamination cause?
The questions above are by no means comprehensive. If you cannot find the answer to your question here or if you want more comprehensive information, please email [email protected]
Australian Wool Testing Authority (AWTA) Ltd is a Public Company, Limited by Guarantee.
AWTA Ltd was established in 1957 by the Commonwealth Government of the day in response to requests from the Australian wool industry. The statutory AWTA was privatised in 1982 and AWTA Ltd was established as a Public Company, Limited by Guarantee. This is a special kind of company structure, commonly used for not-for-profit organisations.
The Member Guarantors, who appoint the Board, are also representative of all sectors of the industry, including wool growers, wool selling brokers, wool exporters, private treaty merchants, and wool processors.
AWTA Ltd is effectively owned by the wool industry. Each sector of the wool industry appoints a director to AWTA Ltd's Board. The Member/Guarantors constituting the Company are:
AWTA has laboratories located in Melbourne, Fremantle and regional offices in many wool growing areas. Please refer to the contact section of our web site or contact us for further information.
Registered sampling sites are located in wool brokers stores in the major capital cities or in regional centres. Registered sampling sites are Licenced by AWEX, and all wool that is sold at an AWEX auction must be sampled at a registered sampling site.
Objective test information allows processors of Australian wool to better predict the processing capabilities of the wool.
Processing trials conducted over many years have established relationships which allow the Yield, Diameter and Fibre Length (Hauteur) of the processed product to be predicted from the objective measurements of Yield, Vegetable Matter, Mean Fibre Diameter and Staple Length & Strength taken on greasy wool.
Objective measurement also enables growers to receive equitable payment for their wool and provides important management information to woolgrowers.
Objective measurements facilitate the exchange of ownership of wool, and improve the accuracy of predicted processing performance. Wool sellers, buyers and processors now rely intimately on certified data.
This reliance is built upon the confidence of the industry in the integrity of the Certificates. Critical to this is confidence in the integrity of the samples and the sampling process.
Independence of the sales transaction, and impartiality on the part of the test house, is also critical to maintaining this confidence.
Sampling supervision ensures the integrity the industry requires. If the laboratory receives a sample that is not representative of the bales from which it was drawn, the test result will not be accurate. AWTA sampling supervision provides buyers of Australian wool with confidence in the integrity of the Certificates upon which they purchase that wool.
For more information see Sampling Supervision: Guaranteeing the Integrity of the Certification of Australian Wool.
In terms of testing procedures, there are no differences. AWTA applies the full IWTO Test Specifications in both cases, and the same quality control systems are also used.
The sole difference between a Report and a Certificate is that the wool submitted for the certification process has been sampled under AWTA supervision. An AWTA employee ensures that the sample is taken correctly and that the bale markings are recorded correctly and bale weights are accurate and also recorded correctly.
Therefore, users of AWTA Certificates can be confident of the integrity of the samples and of all the data recorded at the time of sampling. The existing wool pipeline relies completely on this confidence, as AWTA Certificates are the basis for exchange of ownership.
For Test Reports, samples are not taken under AWTA supervision. Generally they are taken by the seller or by another party. Where exchange of ownership occurs on this basis, it is by agreement between the buyer and the seller. AWTA will only guarantee the integrity of the testing of such samples. It does not guarantee the integrity of the sample or any associated data.
Although AWTA can provide Test Reports that include bale weights, and therefore processing yields, it is only in rare circumstances that the bale weights are actually provided by the client with the sample.
The availability of results depends on the type of test and/or the level of service requested. AWTA provides a range of service times tailored to meet specific customer requirements because the Company believes that customer service is equally important to accuracy and cost minimisation.
Customer service is viewed in terms of providing sampling services and test Certificates and Reports in a timely manner. To achieve this, when an IWTO Certificate is requested, the Company offers three levels of service:
These options enable each client to select a service that meets their own requirements. Certificates are deemed available once the client can collect the electronic version via the EDI system. Clients who subscribe to AWTA WOOLINK™ system, have direct access to the Company's test database and their Certificates are available the instant the last component is received in the central database and the necessary computations completed.
Where a Test Report is requested, the Express service is automatically supplied. However, the timing of the service commences from the date of receipt at the laboratory.
Likewise, the service time for Fleece Measurement samples also commences from the date the samples are received. In this instance AWTA will complete the testing and despatch the results within 7 days.
To assist in maintaining confidence in certification, AWTA encourages wool growers to query their test results if they suspect an error has occurred. For this reason it is important that they ensure that they peruse the results before their wool is sold. However, it is also important that queries are raised only when genuine errors are suspected.
If you suspect an error has occurred then ask your broker to contact the AWTA laboratory and request a check test on your behalf. AWTA is unable to identify individual grower lots without the unique reference number (usually called a weight note number) supplied by the broker.
After the initial testing process, AWTA places unused core sample material into a container and stores it in case it is needed for later use.
The length of storage before the sample is discarded is dependent on workload as only 40,000 tests are stored at any one time. Usual storage times range from 4 to 6 weeks. If a check test is requested after the sample has been discarded, then the bales must have a new core sample taken from them by the wool broker under AWTA's supervision.
Grab samples, used for staple measurements, are generally returned to secured storage areas in wool brokers stores. They can be recovered and retested if required.
AWTA does provide a test service for chemical residues at its Agrifood Technology laboratory. Tests are best performed on core sample material taken from bales of wool at the time of sale.
The test was originally developed by CSIRO in Geelong.
A range of tests are available for specialty fibres such as Mohair, Cashmere and Alpaca (see AWTA's Fees list). However, these industries are not as technically advanced in the use of objective measurement as the wool industry, and consequently in most cases standard test methods do not exist. Consequently, in such cases AWTA generally issues Test Reports.
The overall benefit of objective measurements to the wool industry is difficult to accurately quantify. What is certain is that objective measurements have transformed the way the industry operates, and the entire industry is now critically dependent upon the measurements now available.
This transformation has largely been driven by economic benefits made possible by objective measurements. In part the value of measurements is also reflected in the premiums and discounts that are now paid based on these measurements. They enable the market to better determine the value of individual farm lots. In doing so they reduce risk. In the long term, and everybody, including wool growers, benefits from this.
In particular, staple measurements provide wool buyers and processors with a much improved capability to predict processing performance, thereby reducing risk. In turn, the price signals that are consequently generated better inform wool growers of the characteristics of their wool that determine the price they obtain, opening up the opportunity to develop better farm management systems.
The measurement of Staple Strength involves measuring the force required to break approximately 55-60 staples, selected at random from the grab sample, which is displayed on the show floor. When each staple is broken, the two portions are collected and weighed.
The Position of Break (POB) of each staple is calculated from the weights of the two portions, with corrections applied to allow for grease, wax, suint, dirt and vegetable matter contamination. The POB can then be estimated from the ratio of the corrected weights.
POB is reported as the percentage of all staples measured that break in the Tip, Middle and Base regions of the staple.
The Laserscan machine is AWTA's standard method for measuring fibre diameter. It uses a laser beam, advanced electronics and computer software to provide precise measurements of:
The Laserscan instrument was developed by CSIRO with the assistance of research funds provided by The Woolmark Company via the wool research levy.
Comfort Factor is the percentage of fibres less than 30 micron and is determined when measuring the fibre diameter distribution of a sample using LASERSCAN or OFDA. The importance of Comfort Factor relates to the feel of a fabric on a wearer's skin. Fabric made from wool with a high Comfort Factor (>95%) will have less rigid fibres that bend more easily and therefore feel less "prickly".
However, wool growers need to be careful not to place too much emphasis on Comfort Factor when selecting rams.
The precision of an individual test result is usually expressed as Confidence Limits. Normally, the precision of a test result is defined in terms of 95% Confidence Limits, i.e., the limits on either side of the "true" result within which you can expect 95% of any repeat measurements to lie.
For example the 95% Confidence Limit for Laserscan measurement of Mean Fibre Diameter is ± 0.37 microns for wools less than 26 microns and ± 0.66 microns for wools 26 micron and greater. The 95% Confidence Limit for Staple Length is ± 4.8 mm for fleece wool and ± 5.4 for non-fleece wools. For Staple Strength, the 95% Confidence Limit is ± 5.9 N/Ktex for both fleece and non-fleece wools.
Detailed information about precision is included in all IWTO Specifications. In some cases the precision varies with the magnitude of the parameter being measured (e.g. Woolbase, Vegetable Matter Base and Mean Fibre Diameter). For the LASERSCAN instrument (IWTO-12) the 95% Confidence Limits for Mean Fibre Diameter (MFD) of greasy cores are expressed in 5 micron increments as follows:
As a guide, if you need yield and fibre diameter, we suggest about 30-50 grams. This represents a good-sized handful. However, if you only require fibre diameter (LASERSCAN) then half this quantity will suffice.
It is important to realise that the greatest variation in fibre diameter is along fibres and between fibres within a staple.
Therefore the sample must include several staples to ensure that a reasonably representative measurement is obtained.
Fleece samples must be labelled clearly and unambiguously.
Ideally, contact AWTA before taking the samples and we will provide identification cards for labeling. Otherwise ensure that identification of each sample is clear, and that each tag will remain with the bag throughout transport. The best way is to put the sample and label together in a sample bag, which is sealed with a rubber band.
Remember you may be making decisions about individual animals on the measured characteristics. It is critically important that the data you associate with each animal is correct. Otherwise the measurements have no value. The first step in ensuring that this will occur is the sample identification, which is totally under your control.
This depends upon the request. If a Yield is requested then a washing yield is provided.
In all cases, AWTA also provides:
A range of selection indices can be provided upon request. Greasy Fleece Weights (GFW) and Body Weights (BWT) can also be entered where this data has been provided.
Other tests, such as Length & Strength and Colour can also be requested.
The report includes a summary of all the results, and individual fibre diameter distribution histograms for each sample.
The Yield predicts the amount of useable fibre available for the processor. As wool is processed in different ways, there are four different Yield calculations as follows:
The price of wool of a specified micron is determined by supply and demand. It is hardly surprising that the price increases with decreasing micron, as the supply also decreases with decreasing micron.
However, it is not unusual to see a large step change in price for a change of 0.1 microns. When this occurs it is usually the result of mill specifications that demand that no lot within a consignment should exceed a specific micron value. If there are a number of orders for the same specification then this can dramatically increase competition between buyers, thereby driving up the price over very narrow range of variation.
Medullated fibres are characterised by a medulla or a hollow core. This may extend for a considerable length along the fibre or may consist of a number of discrete hollow areas along the fibre. Medullated fibres appear chalky because light is reflected from the inner wall. They are a problem in fabrics because their dye update is different from non-medullated fibres and as a consequence they cause a visible defect in the fabric.
The degree of medullation is usually characterised by estimating the percentage of the fibre occupied by the hollow medulla.
Types of medulla that can occur in wool fibres are:
(a) fragmental, (b) interrupted and (c) continuous.
Dark and Pigmented fibres occur in all sheep, but generally in well bred white merino sheep the numbers are very low. The colour of the fibre is caused by a chemical called melanin, produced by cells called melanocytes in the skin of the sheep. The genes controlling melanin production are able to regulate pigmentation in white Merino sheep, at least in part, by controlling the location and activity of melanocytes within the wool-bearing skin. However, the gene responsible for active melanin production is not absent - it is recessive. Consequently white merinos can produce lambs with pigmented patches. Part of the animal husbandry practices of Australian Merino wool produces is to cull such lambs from their flocks.
Pigmentation can also be produced by fecal or urine stains, particularly around the breech of the sheep. Management of this type of stain involves crutching sheep before shearing.
Dark, pigmented and urine stained fibres also cause fabric defects as they take dye differently from non-pigmented or stained fibres.
Both dark and medullated fibre contamination cause problems for the manufacturer. A single dark fibre in a white/pastel fabric will appear as a thin dark line if lying on the surface of the yarn or as a dark smudge if it lies within the yarn structure. In fabrics that are coloured, medullated fibres give a different (often white) appearance when dyed. This problem is generally more pronounced as the depth of colour increases. As a rule of thumb, the commercial limit for dark fibre contamination in tops destined for a white or pastel end-use is less than 100 dark fibres per kilogram (df/kg), with lower levels required for ultra-high quality products (less than 50 df/kg).
Wool growers declare “Mulesing Status” information along with other details pertaining to Dark & Medullated Fibre Risk to their broker or selling agent through the National Wool Declaration scheme.
This data is then passed on to AWTA where it is published on our Test Certificates and stored in our Central database. This process occurs for virtually all wool which is presale tested and hence AWTA can collate and report mulesing status information to the industry.
Information is now published on the AWTA website which shows the total quantity of non-mulese (NM), ceased mulesed (CM) and pain relief (PR) wool tested each month.