[Stoves] NESCAUM created a contextual stove test method that has been approved by the EPA

Tue Mar 2 16:45:19 CST 2021

Dear Friends

This just arrived in the Alliance for Green Heat newsletter.

Focus on Test Methods
Integrated Duty Cycle test method for wood stoves<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fr20.rs6.net%2Ftn.jsp%3Ff%3D001nS047ylYVTu19M0lFBm18u2-n6hPJm8mjz4If5cN2ByxQ4_R4uYa9lN7EES44-OZlj8nrPdnQfkpswdhFn3KJgTM5W88NezZUg0gHfZmfboqzZTcvqOYWIswtGtPuk3LjcGUMdA7sDYdrQaoCSzt1mtjbp7ZGCzJZbM44AcRdFF4946_fal4a2ZItMs5oTHGxrBGsW7buSbKLDARVL-W5Rr8jaIKBiyc3b6wQaThrjYGbRVJAW4xsOm6zjg6zXrCMMxRs6092XE%3D%26c%3Dk5iAelLeAR0vLSgruf65h6D-mTkJDfJ0bGYCPi8MSK1mFxvSTlRf7A%3D%3D%26ch%3Dinq7piMgGPDs3KfbjYsLqMOXkfHaftqrxyFpdQ5YTX3JRRcrbupsOA%3D%3D&data=04%7C01%7C%7C7011c22afce847f3a51b08d8ddab660c%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637503075516114554%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=YngUt1bZNnOc5t52yaOsefP1Np7jvOIXQDWGz5EpZNw%3D&reserved=0>
NESCAUM released an interim report on the Integrated Duty Cycle (IDC) test method. The IDC incorporates typical operating situations, including start-up, reload, and transition from various heat output loads. The single-day test allows for replicate testing without increasing certification test costs. It has also just been recognized as a "broadly applicable" method by the EPA, meaning that any wood stove can use it to become certified.

An integrated duty cycle is a contextual test. It explores how a stove reacts to various changes in power and duration of same.  It is supposed to represent use.  It is similar to a “drive cycle” used to rate car fuel mileage.

What is interesting is that this approach is widely used by the EPA for heating stoves, vehicles, factories and so on, but does not support it for cooking stoves at the international level.  From day 1 of the “Lima Consensus”, the IWA 11:2012 and the ISO standards, the EPA has always promoted either the WBT or some variation of a fixed, irrelevant (de-contextualized) power sequence.  For the ISO it is really incorrect to use the term “sequence” because the ISO test is three different tests at three power levels.

The hostility to an ISO contextual test is evidenced by the killing of the document ISO 19867-2 – Contextual Testing.  You will notice that there is a 19867-1 and a 19867-3 but no 19867-2.  The idea was to have a stove test that represented reality so predictions could be made about what the performance would be in the field.  This is exactly what NESCAUM prepared and which was just adopted by the EPA.

What is happening in the field now, is countries wanting to use the ISO Standard are having to develop their own contextual test, ignoring the published one.  Genuflection is the order of the day.

The 19867-1 document has some text giving a nod to idea of a contextual (realistic) test but that led to a problem: the wording is such that you can do pretty much anything you want, without guidance, controls and replicability, and produce a “performance result” agreeable to you, that may not be relevant to anything in particular.

You may have seen recent newsletter from Aprovecho discussing the performance of a stove with air blown under the fire at various flow rates.   In the early videos provided, the “fuel” was machined rectangular pieces of very dry Douglas Fir about 1 x 1.5 cm.  In the latest video it is what appears to be 5 x 5 cm square billets of the same material.   The attendant claim is that the air blower causes the stove to emit very little PM in the exhaust. The question that comes to mind is, “Why didn’t the fuel remain the same as in the earlier tests?”  The answer is, I suspect, that the performance was not very good with the smaller fuel so they changed it.

This is legal according to the ISO.  You can change the fuel and report the result.  There is freedom to change the fuel until you get what you want as a result.  This is called “fuel-shopping”.   I am not sure what to call “shape-and-size-shopping”.   We are free to do that as well. The results are pointless, meaningless, irrelevant.  Despite all that work, we don’t know how it will perform burning real wood, of any kind.

A contextual test would provide a set of defined restraints on how all it is to done.  Thus, the content of the NESCAUM protocol.  The way the test sequence was developed is what should have been in ISO 19867-2: Contextual Stove Test Method.

I wonder if the current action to write an institutional stove test will end up as 19867-2 to fill the gap and hide the contextual absence.

Regards
Crispin

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