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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear Crispin,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Perhaps lengthy but very well written and states the problems in rating stoves. All the work in the past (WBT etc.) were useful measures of a small part of the big picture. Starting with test methods that are simple and work on small units of the process are key. Then they need to work when used in the bigger lab scale of testing stoves. Then verified they represent what happen in the field.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>What would be useful is a list of the unit tests that need to be worked on. Then have labs suggest ideas for research and have money available for the research. Determining energy in ash-char mixes, carbon energy in particulates leaving the combustion box, and location of formation of these particles are a few I can think of. If we can develop simple methods that can be used by most labs that have been verified to work when correlated using costly lab equipment is a start.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>So much to do. Getting organized as to what needs to be done by posting a flow chart or tree. Then have a way to include all that want to contribute with suggestions of procedure etc. by e-mail directed to a sub-number of the tree. The ones making decisions can look at the list of all suggestions and move appropriately. But I am sure they have their own process. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Frank<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Frank Shields<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>42 Hangar Way<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Watsonville, CA 95076<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>(831) 724-5244 tel<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>(831) 724-3188 fax<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>frank@bioCharlab.com<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> stoves-bounces@lists.bioenergylists.org [mailto:stoves-bounces@lists.bioenergylists.org] <b>On Behalf Of </b>Crispin Pemberton-Pigott<br><b>Sent:</b> Thursday, March 01, 2012 9:59 PM<br><b>To:</b> 'Discussion of biomass cooking stoves'<br><b>Subject:</b> Re: [Stoves] PCIA den Haag<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear Tom and Everyone<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>There will no doubt be some immediate reactions to what flows from the PCIA/EPA/ISO meeting (hereinafter ‘at the Hague’) and then some longer messages interpreting and discussing the resolved document.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>So two things right away:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Otto, don’t worry, emissions are pre-eminent because it is fundamentally about health and safety, with fuel an interesting benefit. If a very clean stove was available that did not save fuel it would get a great deal of attention, OK?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div><div><div><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Tom, <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>“</span><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>It's starting at the very basics - VITA WBT 4.0 - but they wanted to start somewhere.<span style='color:#1F497D'>”<o:p></o:p></span></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>I think it will be seen shortly that what the agreement says is far more than ‘what test to use’ and in fact it does not say ‘use this test’, not even once, though to me had been was the intention at some time in the past. There are a lot of capable people involved in stove development and testing these days so there is no need to over-simplify the task at hand. It is a far better document than, ‘use this test and rate stoves based on the outcome’.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>There are many different types of stove, many foods to be prepared, spaces to be heated, fuels to be consumed. The IWA (International Working Agreement) is a cast-in-stone temporary measure which will be around for (probably) about 3 years while and ISO process is completed.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>The IWA is framed to ensure that any stove type can be dealt with, any fuel, any appropriate protocol can be applied, with the over-riding view that one cannot rate a stove into a performance ‘tier’ unless the test used to do so can be shown to have enough skill. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>The skill definition used is ‘1/3 of the width of the tier’. This means one might find it easy using a number of protocols to differentiate between a baseline and a modestly improved stove with 40% less emissions. It is far more difficult to guarantee that a stove performs 90% instead of 80% better than the baseline (i.e. stating clearly that it is 90 not 80). In order to place a stove in the 90% category, the test used would have to have enough precision and that precision is 1/3 of the 10%, meaning 3% total error. The WBT’s used to date cannot do that. They are not accurate enough. Getting ‘a number’ is not good enough when playing in this area. The answers have to be defended and there is a lot of money riding on the consequences. It is also worth mentioning that there are many different WBT’s and they do not all have the same accuracy.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>The framing of the wording is such that when rating a stove, the claim must be scientifically defensible, and there are formal methods for determining that. It is not a case of making ‘competing claims’. From now on, the claims have to be validated, not just for determining what the rating number is (that is obvious) but also for showing that, for example, placing a stove in a 4<sup>th</sup> (highest) tier position was done using a method that is skillful enough to do so.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>There is an important point regarding how the tiers were determined. There are performance tiers and they have numbers and they divide stoves into categories. No problem. What they are (the tier levels or performance improvements) is not all that important, actually. It is far more important that they be defensible when sitting court with a donor saying such and such a stove programme cheated and lied to them about the performance of the product they paid to roll out. No one wants that. The deception might be about durability, performance, cost, suitability for purpose – anything one might have contracted to do. This is not to say that the IWA will be used in court, only the contract is, but it is a flag waved that it matters what you claim and the methods that underwrite that claim has to be sufficient for the purpose. Both the stove provider and the buyer have a responsibility to see that the test method is capable of rating the stove. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>Back to the tiers: The tiers were established on the basis that we need them, and we have to have some way of proposing them, and that you have to start somewhere. So, by taking a look over years of testing using protocols that are known not to be all that accurate (WBT’s) some numbers were proposed. It does not matter that the tests used to generate these proposed tiers were not all that accurate, don’t get excited. It only matters that we have agreed the tiers are basically logarithmic in distribution, and that they will prevail for a time.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>Now, what the IWA does NOT say is that because the tiers were generated by using the Berkeley WBT3, WBT3.1 and the ETHOS Technical Committee’s WBT4 and WBT4.1 (which for an reason has been re-dubbed the “VITA WBT4.1” – I am pretty sure Don Johnson is unaware of the use of his organisations name) that it means only those tests can be used to place a stove, from this day forth, on a tier. No, not at all. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>A lot of care was taken to ensure that the wording does not make such a statement. The reason is this: it is well known that the accuracy and precision of these WBT’s is not great, and certainly not good enough to separate the better performing stoves. The tests give a number, but it is not a very accurate number.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>I cannot state with certainty what the accuracy of any of those protocols is because none of them has even been properly rated by an independent laboratory against a ‘real’ measurement. So the IWA states clearly that all the protocols have to be tested themselves to see whether or not they can actually meet the ‘one third of tier’ precision requirement. The responsibility for this is lies with the labs because the IWA is not able to create institutions or direct someone else’s expenditure.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>In other words, you cannot use a test with an accuracy of plus-minus 30% to say that one stove is 15% better than another because the error in making the measurements is larger than the difference sought. Repeating a test 100 times using a method that has built-in errors of 30% cannot give you a 15% resolution. ‘The signal is lost in the noise’, as they say.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>It was heartening to see the number of delegates who understood this implicitly and the importance it has for the development of this cooking stove industry. It means that going forward, facts trump opinion. Claims have to be justifiable, if not actually justified.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>To reiterate, the IWA is not an agreement that picks a stove test and that will be used by all to rate stoves. That did not and should not have happened. What happened is that a framework setting out performance tiers and how stoves will be rated has been drawn based on the outputs from old methods. The fact that the proposers of the tiers used old methods does not mean that all future testing must be conducted using those same methods. It was just used as a way to generate a starting point. The ISO standard will probably adjust the tiers when data with greater precision is generated.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>The way forward has also been described. The IWA is not limited to wood fuels, nor cooking stoves actually, it could be used as a guide for any stove type, any fuel, any pots, any foods, because it enshrines the principle that whatever the test method used, it has to be rated for its skill, and it has to be skillful <i>enough</i> to make a determination for that category.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>Following the GACC meeting on Thursday most of the labs had a representative at a discussion about meeting these new demands. We discussed the relative merits of a carbon balance approach to determining the PM and the velocity and volume method. Both are used and they have, in normal circumstances, similar accuracies. There is nothing really between them in most situations. Now we must determine if they are appropriate for <i>stoves</i>, not just as scientifically valid methods. That conversation will continue as it is far too early to make categorical statements about methods of PM measurement for baseline and highly improved stoves. The challenges are daunting, to say the least. Stoves are far more difficult to measure than vehicles, for example, and the reduction in PM for vehicles is ‘dry dust’ whereas for stoves (because of health considerations) it is all particles (including condensed, sticky balls of tar and creosote and formaldehyde etc). <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>What is clever about the IWA is that because we have zero chance to edit it (due to the nature of the ISO processes) there was still time enough and understanding enough to get unanimous agreement on how to go forward without anointing any one (unrated) test method. It was not possible to anoint one method because the accuracy of the protocols is unknown. One can’t pick blindly and hope. No. That is not how due diligence is practised. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>What little is in the literature about the accuracy of stove tests, read together with the need for tiers of performance, says we need better methods, basically. You cannot set and apply tiers of performance for stoves that the protocol cannot differentiate. That was stated early on. The absolutely minimum valid resolution needed is 1/3 of a tier width. I am sure you all understand that. If your ruler only has Feet marked on it, you can’t measure Inches. Measuring in Feet 3 times does not create Inch marks.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>One more thing to add is that we should all keep in mind the difference between a systematic error and an experimental error. This is said to avoid endless discussion about ‘repeat it and the accuracy will improve’. Suppose you have decided to remove and weigh charcoal and say it was not burned, so the heat was not yielded, so the thermal efficiency of the stove is such-and-such. This is part of the UCB-WBT’s. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>You will have a problem determining what is charcoal and what is not. Let’s suppose you make a perfect separation. Suppose the amount of wood burned was 1000 g and the remaining charcoal is 100g. Now you need to assign a heat value to this charcoal, but you do not know its real heat content. So you guess and say it is 29 MJ/kg or 29,000 kJ total in this example. The range of charcoal heat content might actually be anywhere from 12 to 32 MJ/kg – a very wide range, but you assign a value of 29,000. So there is an error bar needed to show that the value might really be anywhere between 12,000 and 32,000. You report that. OK, it is reported. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>This is an example of an error that is not removed by doing the test 3 or 300 times. If the heat content of the charcoal (per test) is a guess, the error is never removed. The value is always in doubt. That doubt has to be shown on the performance chart. What has happened to date is that the ‘final number’ of each of three tests is shown, perhaps on a graph with a bunch of other stove performance numbers. There are three dots showing the values from the three iterations. No problem. But that ‘range of performance’ or the ‘range of values’ is not represented by the three dots. Each has to have an error bar above and below that captures the sum of all the errors inherent in the test method. When these are plotted for each of the three dots, the total range of possible ‘truths’ is much larger than the range for the three dots alone. The total range shows the range of values of performance that could be true about that stove.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>If you repeated the test 100 times, and got 100 dots, they would tend to cluster (hopefully) around some point. That is a reduction in the experimental error, but it makes no impact on the systematic errors (for example the heat value of the charcoal which is still a guess). There are many such systematic errors in a UCB-WBT. I think this is well known. The same is true for all tests. What we need to do is to first quantify what these are so we can include them on the charts, and second, look for test methods that limit both sources of error (systematic and experimental).<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>It is quickly obvious that with such a range of products, fuels, pots and cooking styles, we need some deep reflection. The way engineers describe the performance of thermal devices is well established and the metrics and units agreed. The protocols for determining them, one by one or all at once (multivariate) are pretty well established too. We do not need to re-invent them if they are available. Some things about domestic stoves are unique and need special consideration. One problem is the accidental measurement of condensed water vapour in a system that is measuring PM using light scattering. Fog droplets are highly reflective and are read as ‘dust’. If you are burning damp fuel and have a boiling pot, there is a lot of water vapour going into the measurement system. The SABS stove test protocol includes steps to minimise the problem. The hood-based WBT’s do not. Another problem is variation in altitude and air moisture. These have a lot of effect on stoves so the reported results can be quite different from reality on the ground unless steps are taken to use the right method and reporting units.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>What might surprise stovers is the good accuracy that can obtained with quite simple methods that determine one thing at a time. It is possible that we will settle for a series of metrics that are individually known to be very accurate and which read together, categorise very well the predicted performance in the field. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>I look forward with anticipation to continuing the work on this. It is a cutting edge subject. The collegiality shown by the labs is admirable. The conversation is definitely focussed on proper scientific investigation, as it should be. We had delegates from 5 African National Standards groups, plus regional test centres and formal sector standards bodies. They were instrumental in crafting the wording to be performance-based and non-prescriptive, yet still provide a clear and well-grounded framework for the next three or four years.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>The ISO standards development process is highly structured. This was probably the last event at which you could just get on a plane and show up. The national bodies represented on the ISO will take the process forward (and no one else). There will of course be nominated methods and procedures with supporting documentation submitted for consideration and debate. It is possible a future agreement might specify a particular test method or make reference to one or more methods, or it may be entirely ‘performance based’, i.e. if it can be shown to be appropriate, you can use it. No one is guessing at this point. In general, standards are become more performance based and less prescriptive but that is not a guarantee of anything.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>There is a Safety Rating method included in the IWA. As there is not a lot of consensus about how have that conversation, the method was accepted as proposed because when it comes to funding, the purchaser may set very different targets for certain fuels (like kerosene of gas) or stability or surface temperature depending on local circumstances. The IWA method is a point system. Most National Standards use a pass-fail (checkbox) system. It is likely an ISO standard would be a combination of both approaches. At least there is something.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>Although this message is lengthy, it is only an early comment on the implications of the IWA. You will no doubt hear alternative interpretations of the Agreement which I look forward to analysing as well.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>For funders, the core methods for testing has been achieved – creating a valid due diligence pathway – and in only 2 days. I congratulate everyone involved. Round of applause, please.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>Best regards<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'>Crispin in the Hague<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></div></div></div></div></body></html>