Calling all wood burning stove owners

[oldhenwife]

Do you have any problems with modern fire-resistance-treated timbers?

Some of the noggins we've salvaged from new roofings haven't burned as well as we expected - and yes we did dry them thoroughly.

Mary

[tim....]

Is this for real?

tim

[d_s_or_j]

In message , tim.... writes

one would hope so

[Steve Firth]

The asbestos I tried to burn last week was a bugger to light.

[terry]

Yep those metal studs too. Hard on the hands bending em to fit in the stove. Seems like anything fire proof or fire treated is not supposed to burn!!!!! Wonder why?

[Bill]

In message , terry writes

Now there is a challenge..................

[NT]

When I burnt wood I often had hard to burn stuff, I forget what it was, but used to use it to line the bottom. The primary fuel thus burnt this stuff up gradually.

NT

[geoff]

In message , " [e-mail]" writes

But you're the wicked witch of the north

can't you cast a spell and ignite them with sparks from your broomstick ?

[Jules]

I dunno - use your noggins... :P

[Tim Lamb]

In message , " [e-mail]" writes

Yes:-)

When I last had a proper job... Maintenance staff had first call on surplus material heading for the dump. An overhead conveyor passage between two factory buildings had been taken down liberating a pile of clean pine (apart from pigeon droppings) in 8"x 3"x 6'. The boiler house man and I both vied for the spoils.

He wanted to split the wood and market it for fire lighting purposes. (this was 30 years ago). Unfortunately the wood had been impregnated with a salt which made it virtually fireproof. My use was feed racks for housed cattle and, now this activity has finished, I am wondering how to dispose of the residue.

regards

[oldhenwife]

It seems that not everyone here is familiar with joiners' expressions.

[The Natural Philosopher]

It seems that one person here isnt familiar with the concept of 'fireproofing', rather.

[andrew]

If it cannot be re used then land fill at a permitted facility or a fully WID compliant burner are the only two options I can think of, with the latter all the ash would be considered hazardous.

Most wood fire retardants seem to be simple salts of sodium potassium and boron and silica, rather than the bromine based stuff, so the products of combustion shouldn't be too bad. I guess they act by farminng a skin over the wood which prevents the air getting to char, which then is self limiting to an extent as char is a good insulator. So the wood self extinguishes in the same way a match does once the volatiles have burned off. Any such coating will fail if the wood it protects gets above ~270C, as one might expect in a good, hot wood burner.

AJH

[geoff]

However, if you sprayed it with WD40 ...

[Steve Firth]

Probably need an angle grinder as well...

[oldhenwife]

Thank you Tim and Andrew.

I don't know that the timber HAS been treated. Perhaps I should have put it more simply for some and asked if modern structural timbers are always fire-proofed, thus leading to problems with burning off-cuts in an efficient stove.

The suspect timber we harvested will burn but it takes time and a lot of heat to ignite - as NT suggested. It certainly isn't as 'burnable' as the hardwood logs we've split from trees we've cut ourselves and seasoned. What's more, the 'glass' window is sooty the morning after we've burned the off-cuts (we've done it twice).

What made me wonder about treatment was that there were green flames, indicating the presence of copper salts. That, I wouldn't have thought, have been used for flame retardation, more likely it would be against insect damage - but it's a long time since I've worked with such things and technology changes swiftly.

We have about two evening's worth of the bits left, I'll use those but would still like to know if it's worth collecting more from a similar source.

By the way, as I said these were from roofing timbers. Bags of noggins donated from a window supplier burned perfectly.

Thanks again,

Mary

[The Natural Philosopher]

Not fireproofed, but pressure treated against rot.

Split them to expose the inside.

Oh, its probably totally illegal to burn them as well.

[Steve Firth]

They contain arsenic and other nasties, so it's no sensible to burn them.

[Tim W]

Steve Firth wibbled on Monday 16 November 2009 12:57

Chromated copper arsenate was restricted in 2004 in the UK if my googling is correct. Banned in timber that may be used in kiddy areas, so I'm assuming it's unlikely you'd have found it in any common timber after that date.

Unless anyone says that's wrong (I thought it was banned a long time back, but there you go) it might help to guage if a random bit of wood is safe to burn or not...

[andrew]

It's still used in roofing timber so off cuts are readily available on building sites. It's an interesting exception (presumably allowed because the cost of re roofing is high) because a well made roof should stay dry enough not to need preserving from insect or fungus.

If burned my guess is that arsenic oxide will be in the smoke but I'm not sure how volatile the chromium species will be. Fixed in the wood the chromium is inert, the trivalent form, as a combustion product it becomes the hexavalent form which is more easily assimilated into the body, I'm told. Not only is it a heavy metal toxin but also believed to be a carcinogen. I wouldn't advocate burning it in any domestic fire.

In 1990 I lost an argument with the big white chief of a charitee I do work for to use chestnut stakes for a grazing project. Now he is replacing 3500 cca treated stakes that have rotted at ground level, such is the quality of pressure treatment. Chestnut would have lasted this long and not been a disposal problem. As it is I expect t0 see them burning the cca treated stakes and leaving the ash to contaminate the ground.

AJH