[Stoves] TLUD stoves and tests

Fri Jul 27 20:25:18 CDT 2018

Dear Xavier

"Is there a way we could get our hands on the documents of the new ISO standard, and share it with everyone on the List?"

No.

The ISO, like other Standards bodies, generates it's income from the sale of documents. They are priced on a per-page basis.

When you buy a copy, it has your name on it. You are not allowed to make copies or post it on the Web. That is a condition of buying it.

It has to be read together with many other documents: the definitions, the voluntary performance targets (which have to be purchased) and many external ‎documents related to describing or preparing and operating the specified equipment.

The Standard is unusual in that it prescribes the equipment to be used, not just the measurements to be made and reported. This greatly raises the cost of performing a test, and I believe reduces its accuracy.

Those with access to the required documentation are free to comment on its merits and workings and publish them. Because it affects my work, I will be writing one and can share it.

The test method is novel, unpublished, ‎and not tested by national structures. Its intent is to make an 'international comparison' between stoves on a common reporting platform. As we are already aware, such comparisons are meaningless unless the context of use happens to coincide with the test sequence. The test sequence is 30 minutes of high power, 30 minutes of medium power, and 30 minutes of low power.

The only group I know personally that tried to follow the protocol from the instructions was unable to ‎get consistent results, largely because the ending of the measurement period(s) is unclear.

In a sense, it claims to be decontextualized, like the WBT or an EPA test, but also 'permits' what amounts to contextual tests, which was supposed to be covered by ISO 19867-2‎ which had clear guidelines on how to do that. It is very unlikely that document will ever see the light of day.

We are therefore left with ‎19867-1 which pretty much let's you do what you want. It is very easy to cheat (apply bias) which we presume will typically by applied in favour of one's own product.

The VPT numbers in 19867-3, about which many concerns were raised before and after the ISO exercise, were produced using a highly dubious process, which in part explains why they are in a separate document. I expect the numerical values will be challenged in the journals. One paper just published by Omar Masera and others already showed the targets are too low (for Mexico) by a factor of about 6. The actual exposure from the stove was 6-10 times less than the WHO single box model predicts it will be.

The implication is that a stove ISO-rated to be a Tier 2 is really a Tier 4 when it comes to the actual exposure the WHO says is going to be safe, or very low risk. Some Tier 3 stoves might actually be Tier 5. I will check that.

The major point is that the VPT's were created to promote LPG and the basis for that was 'health protective exposure levels' for PM2.5. Now it it turns out that 'protective' levels are achieved in typical kitchens ‎with stoves having a far higher emission rate. I have been pointing out the bad math here for ages. And not only here.

What do do? Let's discuss options.

Regards
Crispin

Xavier, Kirk and list

see below

On Jul 26, 2018, at 2:53 PM, <xvr.brandao at gmail.com<mailto:xvr.brandao at gmail.com>> <xvr.brandao at gmail.com<mailto:xvr.brandao at gmail.com>> wrote:

Dear Ron,

I don’t think the new ISO standard includes the WBT, I think you are the only person claiming that.

[RWL:  I guess you will trust what the South Africa group thinks on this subject.  They failed in a fight to remove the WBT.

 I could send a copy of what has been approved - but that would violate the agreement I made to be part of the process.

I assure you that I have plenty of company - and it will appear soon.

What Nikhil has is possibly/probably 99% of the final.

Until there exists reviews of the WBT protocol demonstrating it is valid, the « cites for inadequacy that are very old » (some are from 2016 and 2017) will be the only proofs there is.

« [RWL3:   Can you give cites on these three sentences?  Maybe from some group that treats char as waste? »
See the table from Riva and al., Fuzzy interval propagation of uncertainties in experimental analysis for
improved and traditional three – Stone fire cookstoves below, this is with the WBT:

<image001.png>
Some of the stoves tested were « Micro-Gasifier Stoves with FAN »

« [RWL4:   I have - and I recall no statements about TLUDs or char-making. »

RWL:  I agree that the word micro-gasifier was there.  They still were only arguing for more tests - that I still claim aren't worth the extra effort.  Too much depends on the operator of the test.   But that is not sufficient reason to drop the test.  Just be satisfied if you and other groups can get within a few percent.

Ron

See above.

« They want to do more testing to get an accuracy that is un-needed and wasteful of time and money. »
Only with the WBT I believe. I don’t think the CSI protocol needs more test sessions.

Everyone,
Is there a way we could get our hands on the documents of the new ISO standard, and share it with everyone on the List?
Could we crowdpay it for example, and leave it on a website or a server for everyone to see?

I think it is really a shame that the document is behind a paywall.

Best,

Xavier

De : Ronal W. Larson <rongretlarson at comcast.net<mailto:rongretlarson at comcast.net>>
Envoyé : jeudi 26 juillet 2018 21:33
À : Discussion of biomass <stoves at lists.bioenergylists.org<mailto:stoves at lists.bioenergylists.org>>; Xavier Brandao <xvr.brandao at gmail.com<mailto:xvr.brandao at gmail.com>>; Kirk Harris <kgharris at sonic.net<mailto:kgharris at sonic.net>>
Objet : Re: [Stoves] TLUD stoves and tests

List, Xavier and Kirk

                The main item not being discussed below is the recently approved (with a huge majority by a lot of stove experts - after years of debate) new ISO test procedures.  To me this proves conclusively that the WBT is fine.  Giving cites for inadequacy that are very old is no proof of anything.

On Jul 26, 2018, at 12:51 PM, <xav.brandao at gmail.com<mailto:xav.brandao at gmail.com>> <xav.brandao at gmail.com<mailto:xav.brandao at gmail.com>> wrote:

Dear Kirk,

“A well designed TLUD type stove will do well, whatever test it is given.”
                RWL1:   Kirk - I have to disagree.  There are tests (especially one used in China) that treat char as waste - and so don't measure the produced char.  I guarantee that TLUDs will look bad on those tests.

Will it for sure? I have not tested nor seen tests of TLUD stoves myself, nor read that much about TLUD testing.
                [RWL2:  I gave a cite yesterday to a paper by Jetter et al, that is on testing.  Clearly the best performing stoves there were TLUDs and fan-powered (also TLUD principles).  To repeat - see
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.648.7709&rep=rep1&type=pdf<https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fdownload%3Fdoi%3D10.1.1.648.7709%26rep%3Drep1%26type%3Dpdf&data=02%7C01%7C%7Ccd779a9e54f64b8b10ac08d5f420797b%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636683342662918792&sdata=xPDuZa%2BQGPdp3mvZ5c57xRdrFZ%2BOUMqRCkfH4%2Bmts2I%3D&reserved=0>

“A lesser performing type stove will accordingly do less well, whatever test it is given.”
No.
It might perform great sometimes with the WBT. Then terrible. Then great. Then quite ok.
Then it might perform great or terrible in the field.
There is too much variability and unreliability.
                [RWL3:   Can you give cites on these three sentences?  Maybe from some group that treats char as waste?

Have you read Fabio Riva and Francesco Lombardi papers?
                [RWL4:   I have - and I recall no statements about TLUDs or char-making.  They want to do more testing to get an accuracy that is un-needed and wasteful of time and money.

                I'll stop here - to give time on the above.

Ron

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