On 15 Nov, 14:32, andrew wrote:
Tim Lamb wrote:
My use was feed racks for
housed cattle and, now this activity has finished, I am wondering how to
dispose of the residue.

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

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