Carbon Monoxide and the storage of pellets.

11/29/2012 - 09:12

I have just received a Health and safety bulletin regarding deaths from CO poisoning caused by the storage of pellets.It is common knowledge about the risk of death by CO absorption in the commercial sector by the storage of pellets but now there have been a few domestic case ( follow the link) below.http://annhyg.oxfordjournals.org/content/56/7/755.abstract?etocI bet the stored pellet problem will surprise a few.Rgds,Steve.

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Property

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... is it only pellets, what about wood piles inside or sansa (olive/nut waste)?

The answer is I really do not know, the HSE bulletin was only issued on the 5th of November as it is a newly identified problem within the domestic installation market. The bulletin is aimed at installers maintainers and storer's of pellets and systems, so as an installer I would make my clients aware of the possible danger of CO poisening. I think that wood stockpiles would be ok as I have not heard of any report of this sort of incident in saw mills and wood yards etc. Sansa like pellet is processed but stored in non sealed sacks unlike pellet, I buy sansa on a weekly basis rather than store as the freshly processed sansa burns better in my boiler and is always still quite warm when I load it into the van so I will test it with my flue gas analyser when I next buy sansa and get a reading. Here is the HSE link for further information http://www.hse.gov.uk/safetybulletins/co-wood-pellets.htm Rgds, Steve.

Thanks for the info SteveW. I just looked up the advisory on the HSE site and it was interesting, as there are many people using pellet systems here.

How do stored pellets produce CO? Or is it to do with blocking air vents for the boiler Steve? Ciao Billy

Bunter B wood (Trees) absorbs Carbon Dioxide from the air and give off Oxygen, so presumably as the drying process evolves CO is given off from the degenerating wood. I think it's safe to say these findings involve a vast amount of Pellets and I would not worry about the odd 20-30 bags in your ventilated cantina.

Mmmmmm. seems a bit odd.

Hope I'm not infringeing any copyright, but thought it worth posting a section of the academic article abstract that SteveW has posted the link to, at the start of this thread:- "Thirty kilograms of freshly produced pellets from two different manufacturers were stored for 16 days in airtight containers at 26°C with different relative humidities. CO concentrations between 3100 and 4700 ppm were measured in all containers. There were no notable differences between the wood pellet products or storage at different humidities. Emission of CO from wood pellets has already been described, but fatal accidents have previously been reported only in association with pellet transport on cargo ships or storage in silos. It is therefore a new finding that fatal accidents may also occur in the wood pellet storerooms of private households. We show that significant CO concentrations can build up even when these rooms are ventilated in accordance with the regulations" I was amazed that there's a problem with just 30kg - that's only a couple of sacks! There are other variables there which I would wonder about - can't imagine storing pellets at 26°C, but we've never bothered about ventilating the cantina....... All-in-all, worrying enough for me to warrant more investigation.

... our polythene sansa bags have a dimpled area that has breathable holes, perhaps this is enough to allow the CO2 to disperse gradually...

Or to look at it another way: If your gas fire was leaking any amount of CO into your room, would you be concerned? Since the poisoning can be gradual/cumulative, I'd certainly be concerned about it. At the very least, I reckon that a CO alarm wouldn't be a bad idea - no?

In all our years in Italy I have never come across or heard of anyone with a problem, including those businesses who sell pellets from large warehouses. Think the whole business a bit of H&S gone overboard AGAIN, given a certain scenario giving a certain result and Panic, it's not safe to store pellets. Bollix that's what I say.

Like AndyT has said, costs little to make sure... and you never know it may be something else it saves people from...

That said, production methods also change over the years and so the way things were manufactured and packaged and the age of said products in the past may have had a significant bearing on the risk issue previously. There's no denying that these accidents have occurred. Pellet use is at an all-time high in Europe and it stands to reason that the pellets you're using now are signicantly 'newer' than perhaps was the case in the past, where they may have released the majority of their CO whilst in storage silos. Who knows? I wouldn't be saying 'bollix' to it, if it were my pregnant wife who'd died however. Regardless, I don't have a pellet stove and neither will I ever have one ;)

Concentration Symptoms 35 ppm (0.0035%) Headache and dizziness within six to eight hours of constant exposure 100 ppm (0.01%) Slight headache in two to three hours 200 ppm (0.02%) Slight headache within two to three hours; loss of judgment 400 ppm (0.04%) Frontal headache within one to two hours 800 ppm (0.08%) Dizziness, nausea, and convulsions within 45 min; insensible within 2 hours 1,600 ppm (0.16%) Headache, tachycardia, dizziness, and nausea within 20 min; death in less than 2 hours 3,200 ppm (0.32%) Headache, dizziness and nausea in five to ten minutes. Death within 30 minutes. 6,400 ppm (0.64%) Headache and dizziness in one to two minutes. Convulsions, respiratory arrest, and death in less than 20 minutes. 12,800 ppm (1.28%) Unconsciousness after 2–3 breaths. Death in less than three minutes. CO nasty stuff!