Why does EPA require stoves to test under 1 Kg/hr?

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John Ackerly

Burning Hunk
I couldn't find any post on this but its been a big deal for HPBA and others. HPBA argues that the minimum burn rate should be raised from 1 kg/h to 1.15 kg/h. Shouldn't stoves simply be required to test at their lowest possible air setting? I think the confusion was over whether a consumer could burn a stove at 1 kg/h, but it only had to be tested at 1.15. That should never be allowed. But as long as the stove is successfully tested as low as it can burn, why should it have to burn at any particular rate? Is it because otherwise you couldn't compare weighted grams per hour if stoves are tested a different burn rates? Anyone know ins and outs of this issue?
 
Stove tests should be an average of all their settings. Some folks run them low and slow, some run them high and hot.
 
The new proposals are to test at the lowest and highest burn rates for compliance with emission limits. As opposed to the current weighted average of the four burn rates. They are also considering phasing in cordwood for tests as well as the current crib testing. As far as if they are looking at using 1 gm/hr or 1.15 gm/hr. I haven't heard the reasoning behind the limits they will set for the low burn rate. I do know they are going to do away with different rates for cat and non-cat stoves, both will have to comply with the same rate.
 
The new proposals are to test at the lowest and highest burn rates for compliance with emission limits. As opposed to the current weighted average of the four burn rates. They are also considering phasing in cordwood for tests as well as the current crib testing. As far as if they are looking at using 1 gm/hr or 1.15 gm/hr. I haven't heard the reasoning behind the limits they will set for the low burn rate. I do know they are going to do away with different rates for cat and non-cat stoves, both will have to comply with the same rate.

What John is referencing is not the gr/hr. Rather the kg/hr. Test method 28 permits a manufacturer to replace the inability to run a category 1 run (low burn below .80 kg/hr) with two category 2 burns. Even if the manufacturer's product is unable to burn on the crib based test fuel below .80 kg/hr, they may still manufacture the product to do so.

John is looking for an explanation as to why manufacturers are permitted to make stoves one way but test them another....at least that is what I take from this.

By redefining in the method category 1 burn up to 1.15 kg/hr, the stoves would be able to better burn the fuel load and not fail the test. So long as the stoves cannot burn lower than they are tested, we support HPBA in redefining the Category 1 run to be up to 1.15 kg/hr.
 
Chris - thanks for clarifying what I was trying to say! I reread some of the HPBA material on this, and they don't make it clear whether the stove could be manufactured to run at 1 kg/hr but only test at 1.15 kg/hr. I would also agree with HPBA if they can confirm that the stove has to be successfully tested at its lowest air setting, then it should not have to burn under 1 kg/hr. This is another barrier to innovation. Why force manufacturers to make stoves that can burn on really low burn rates as long as they can meet the emission standards? I think the gram per hour weighting is still important.
 
As a consumer, I ask that you please do not impose a testing scenario that forces or rewards the manufacturers to reduce the stove's ability to burn at a low low burn rate. Ideally, newer stoves are more able to burn cleanly at very very low kg/hr as well as high kg/hr. Consumers want a spread and to get more stoves into more homes I would expect the HPBA to give consumers what they want.
 
As a consumer, I ask that you please do not impose a testing scenario that forces or rewards the manufacturers to reduce the stove's ability to burn at a low low burn rate. Ideally, newer stoves are more able to burn cleanly at very very low kg/hr as well as high kg/hr. Consumers want a spread and to get more stoves into more homes I would expect the HPBA to give consumers what they want.

HPBA is advocating for faster burn rates, by lobbying EPA to raise the minimum low burn rate from 1 kg/hr to 1.15 kg/hr. The irony is that the EPA has rebuffed HPBA on this one, and is forcing stoves to burn at lower, i.e. dirtier burn rates (at least for non-cats). So I don't understand why EPA would not agree to raise it to 1.15 kg/hr unless they, like many others, felt HPBA was arguing that stoves could be made to burn very low but not tested at the lowest rate. I agree with you: let's not force or reward stoves to burn slower or faster. Let's leave that up to the manufacturer and just make sure that they are tested at the lowest and highest burn rates that they are capable of.
 
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This sounds like it could end up just like the schools where the student are not taught to learn, but how to pass a test. The end result is a poorly educated student. The same thing with a dumb stove. That doesn't help the consumer or the industry IMO.

I'm intrigued by the Australian stove testing standards. They appear to be more rigid and hardwood based instead of cribwood. It was very interesting to see how an American stove like the Lopi Liberty was adapted to meet the Australian standard by removing two burn tubes and increasing the size of the remaining tube at the rear of the firebox. I'd love to see this version tested in November at Brookhaven.
 
This sounds like it could end up just like the schools where the student are not taught to learn, but how to pass a test. The end result is a poorly educated student. The same thing with a dumb stove. That doesn't help the consumer or the industry IMO.

I'm intrigued by the Australian stove testing standards. They appear to be more rigid and hardwood based instead of cribwood. It was very interesting to see how an American stove like the Lopi Liberty was adapted to meet the Australian standard by removing two burn tubes and increasing the size of the remaining tube at the rear of the firebox. I'd love to see this version tested in November at Brookhaven.
BeGreen,

Hope you are well. There are very complex issues related to testing.

First, it should be acknowledged crib fuel based testing was NEVER meant to be representative of how a stove performs in the real world burning cord wood. The crib fuel based testing was done so to establish an apple to apple comparison between various product designs.

Second, these crib fuels have been Douglas Fir based. Regulators in the east wish to know how the stoves sold in their part of the country do based upon hard woods. Whether that be cribs or cord wood.

Third, when EPA suggested cord wood testing with hard wood, our (yours and mine) states objected in that they will no longer know how the stoves perform on the soft woods of the NW. We do not want different, mostly redundant tests that drive up costs.

You are correct and what ever test method is found to be the most effective and also satisfies as many regulators as possible, should not force the design and engineering of stoves that are diffuclt to operate in the field.

I would invite you to come visit me (as I have done in the past) in the middle of September and sit and answer phone calls. It might suprise you how many folks do not understand how their wood stove (of any brand) is supposed to work and be operated.

Many folks read about our products and claim they want one to replace their 2-3 year "X" brand stove. After 20 minutes of intro to wood burning, they set about using their other brand and finding it works just fine. As many have said in our industry, we have designed stoves to burn the fuel we test with. And standards have been also established based on the premise.

Cord wood testing will not come easy.

Stay cool on the other side!
 
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Agreed. In Sept-Oct. most of the dozens of posts we deal with daily are about "my stove doesn't work". It takes a lot of persuading to convince some that they are not running the stove correctly, that the wood is damp or the flue is too short. As my dad used to say, the most important nut in a car is the one behind the wheel.
 
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I talked to some folks involved in the first NSPS, and they say a main reason EPA requires stoves to burn really low and slow is because so many homeowners will try everything they can imagine to get the stoves to operate at low burn rates, even to the point of physical altering the air stops and/or adding dampers in the flue so that the fire will last all night. So, if stoves are made to burn at 1.15 kg/hr, it will lead to more consumers tampering with their stoves.

Question to all you experts out there: What percentage of homeowners do something to their stoves to get them to burn slower? That would include adding a flue damper, or actually altering something on air inlet or damper control. Could it be as high as 5%? Some folks mess with pollution control devices on their autos, but it seems like such a small number of people that you can't build cars just to outwit those few folks. Do we really need to build stoves just to outwit the few folks who alter their stoves? Even if 10% of folks added a flue damper, should we make manufacturers build stoves to really low burn rates?
 
What should happen is that stoves should have adjustments to what is now unrestricted primary and secondary air inputs that authorized dealer personnel can adjust to compensate for the fact that everybody does not have a 15-16 foot chimney that the regs force stove manufacturers to design to for the test.

http://www.gulland.ca/florida_bungalow_syndrome.htm

And yes, the primary and secondary intakes in my stove are modified to compensate for the fact that I have a 25, not 15, foot chimney. And don't like a runaway stove in my family room.
 
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We get thousands of folks reading posts here so it wouldn't surprise me at all to see >5% of users with a damper in the pipe. Some will have it to solve a problem like strong draft, some will have it to be miserly, some will have it from a previous install and others will have it as a safety device to slow down a runaway stove.
 
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Internal combustion engines are allowed adjustment for things like altitude. Stoves have issues that need the same ability.
 
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I can't possibly imagine even 1% of stove owners deliberately modifying their stoves to get them to burn slower. 1% of users here, sure, but not the population as a whole.
I did modify my air inlet, but only for the purpose of completely closing the air during the summer months, with a benefit that it could be used for runaway fire. I retained my old "closed" position for normal use.

TE
 
Key dampers in stove pipes are as old as the hills. And tons of people leave them in the pipe when they get a new stove or add one when they have an "oh chit" moment with the new stove.
 
Agreed. In Sept-Oct. most of the dozens of posts we deal with daily are about "my stove doesn't work". It takes a lot of persuading to convince some that they are not running the stove correctly, that the wood is damp or the flue is too short. As my dad used to say, the most important nut in a car is the one behind the wheel.
I agree. I speak with numerous people during the burn season who say " I had my last stove 20 something years and been burn wood 30+ years and this new stove don't work" explaining the differences in newer EPA stoves is a large pecentage of calls in my world. Love your Dad's saying BTW.

Question to all you experts out there: What percentage of homeowners do something to their stoves to get them to burn slower? That would include adding a flue damper, or actually altering something on air inlet or damper control. Could it be as high as 5%? Some folks mess with pollution control devices on their autos, but it seems like such a small number of people that you can't build cars just to outwit those few folks. Do we really need to build stoves just to outwit the few folks who alter their stoves? Even if 10% of folks added a flue damper, should we make manufacturers build stoves to really low burn rates?

I would say from what I see at my job 5% would be a good conservative number and it may be slightly higher.
Internal combustion engines are allowed adjustment for things like altitude. Stoves have issues that need the same ability.

Very Good Point
 
In the long run, stove manufacturers may not be able to avoid adding microprocessor-controlled air supply which adjusts depending on draft and temperature. That's how we cleaned up other heating sources and cars. Designs like the Mulciber may just be the beginning.
I speak with numerous people during the burn season who say " I had my last stove 20 something years and been burn wood 30+ years and this new stove don't work" explaining the differences in newer EPA stoves is a large pecentage of calls in my world.

I have said it before but would it really be so difficult to make a few video tutorials on how to properly operate an EPA wood stove, burn them on a DVD and add it to the stove manual? Maybe the HBPA could do something for their actual customers instead of just lobbying to get out of inconvenient regulations.
 
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I have said it before but would it really be so difficult to make a few video tutorials on how to properly operate an EPA wood stove, burn them on a DVD and add it to the stove manual? Maybe the HBPA could do something for their actual customers instead of just lobbying to get out of inconvenient regulations.

Great Idea. We have numerous videos on our website. BUT So many of them don't even read the OM. <>
 
Thanks for all those perspectives. So it sounds like increasing the minimum burn rate for 1 kg/h to 1.15 kg/hr will make it easier & cheaper for manufacturers to make stoves, but it will cause more problems with a percentage of homes that are susceptible to runaway conditions. How common are runaway stoves? My chimney is probably only 15 feet and I have never experienced it. A neighbor definitely has the problem though. I don't think EPA would ever, ever allow retailers to adjust stoves. I wonder if a company could design and advertise a version of one of their stoves that operates better with long chimneys and strong drafts? How much does altitude impact draft. If you install a stove at 9,000 feet, how differently does it operate?
 
How common are runaway stoves?

John - stick around here when fall turns into winter. Lots of posts show up about high operating temps.

I agree with BroB about the ability to "adjust" the stove to a permanent setting during initial setup based off of the specific install. This would be quite easy to accomplish with pretty basic tools (manometer) and an acceptable range stated by the MFG. Get it set - lock it in place. Essentially a "fine tuning" for the specific install.
 
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Does a magic heat count?

A heat reclaimer on these newer EPA stove is a con in my opinion. The stoves are designed to optimize the flue temps and anything that that pulls heat away for the chimney can cause unwanted results...IMHO.

. So it sounds like increasing the minimum burn rate for 1 kg/h to 1.15 kg/hr will make it easier & cheaper for manufacturers to make stoves, but it will cause more problems with a percentage of homes that are susceptible to runaway conditions. How common are runaway stoves? My chimney is probably only 15 feet and I have never experienced it. A neighbor definitely has the problem though. I don't think EPA would ever, ever allow retailers to adjust stoves. I wonder if a company could design and advertise a version of one of their stoves that operates better with long chimneys and strong drafts? How much does altitude impact draft. If you install a stove at 9,000 feet, how differently does it operate?

Not really sure how much changing from 1 kg/hr to 1.15 kg/hr would effect that, but it's a question I too am interested in the answer. Most of the overfiring I see are results of bad installs and/or incorrect operation. I always recommend a Barometric Damper over a Key/hand damper on newer EPA stoves to eliminate "operator error". Key dampers are better for pre epa and exempt (35:1) stoves...IMO. I've seen many of the pros on here say (and I agree) learn your stove and your setup and how they work in different conditions. Draft gauges are a great way to do that.
 
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Thanks for all those perspectives. So it sounds like increasing the minimum burn rate for 1 kg/h to 1.15 kg/hr will make it easier & cheaper for manufacturers to make stoves, but it will cause more problems with a percentage of homes that are susceptible to runaway conditions. How common are runaway stoves? My chimney is probably only 15 feet and I have never experienced it. A neighbor definitely has the problem though. I don't think EPA would ever, ever allow retailers to adjust stoves. I wonder if a company could design and advertise a version of one of their stoves that operates better with long chimneys and strong drafts? How much does altitude impact draft. If you install a stove at 9,000 feet, how differently does it operate?
I've had a few conflagrations that some would call runaways. Actually they were very robust burn offs of wood gas that took the stove close to overfire territory. I tend to stay calm but alert during these events, but a new burner would not. The stove has a 20ft chimney. To halt these blooms of fire in the Castine sometimes I would open the stove door to flood the firebox with cooler air. Eventually I just avoided loads of small splits. With the T6 I tested and found the EBT (version A) was supplying too much air at the base of the fire right as a large fuel load took off. This would happen with very dry loads of doug fir (with high oil content). I ended up blocking the EBT, thus effectively cutting off the boost manifold air. Since doing that the stove has never flared up regardless of loading. PE has since changed the EBT design to function more like a barometric damper on the secondary air only. That is a much better design IMO and I probably would not touch it.

I modified the old style EBT by blocking primarily because I am not the only one running the stove. My concern was that a flare-up would happen when my wife or son was running the stove and they would panic.
 
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I think simply put:

Please correct me if i am wrong on any of this.
Looks like non-cats are going to have a hard time meeting the new standards especially at the Category 1 lowest burn rate requirement of 1 gram per hour. Currently meeting emissions was a weighted average of all 4 burn rate categories and the new proposal stoves will be required to meet the standard at all 4 categories with no averaging it all together.

Its a given that at the lowest setting non-cats have trouble as they rely more heavily on the heat built up in the firebox to burn cleanly. At the lowest burn rates heat built up in the firebox is less thus lower efficiency. Where as the Cat stoves can burn at lower rates efficiently, as the cat once fired can maintain its operation as its generating its own heat from burning the smoke gases.

So it looks like increasing from 1.0 to 1.15 g/h burn rate will make it more realistic for non-cat stoves to meet emissions.

I also see that its being said in these postings that there should not be a certain specification for Category 1 lowest burn rate. That the stove design should dictate what the lowest burn rate is and that the only requirement is that the stove meet emissions at its designed lowest burn rate.

As far as people modding their stoves, I think one of the most important aspects to consumers using wood stoves is waking in the morning to a warm house. So they try and get the stove to burn for a longer period of time. An important aspect of this is that burn times include the time during the coal stage. The coal stage still giving off heat but not as much as when there is still active flames a going. This coal stage occurs during the coldest part of the night in the wee hours of the morning so the house temps will drop. Plus people dont like waking to a cold house. So its only natural they would like to increase the burn times of the stove.
 
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