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Matt Fitzpatrick

Defra clean air strategy

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21 minutes ago, swinny said:

What meter is that please woodworks?

 

Old Protimeter. Comes with a calibration thingy but it's never needed adjusting

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6 hours ago, Woodworks said:

Two major points firstly as I am always banging on about 20% is too low for those of us in the wetter humid regions of the UK. 

Can you give a reason for this?

6 hours ago, Woodworks said:

 

  Secondly the you can sell wet logs if larger quantities than 2m3. The snag with this is 2m3 of fresh wet logs is around 1 tonne so above the payload of most pickups.

Also I couldn't tell from the paper whether the 2m3 was a solid measure or bulk measure.

 

2m3 of solid hard wood at 20%mc wwb  would weigh about 1 tonne or am I missing your point?

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7 hours ago, openspaceman said:

Can you give a reason for this?

Also I couldn't tell from the paper whether the 2m3 was a solid measure or bulk measure.

If the average RH is above 90% logs wont dry to below 20%. It's not exactly 90% and varies a bit with temp but close enough. Here is a table for woods moisture content for any given RH https://www.woodworkerssource.com/shop/mois.html and secondly some weather data for the average humidity but bare in mind you could be in a dry area but if we have a damp spell and with wood being hydroscopic it will take up moisture again. This is live data but pretty much everywhere in SW is above the 90% RH mark. https://wow.metoffice.gov.uk/  Also you can see my moisture reading on that log and you have seen how I dry them. Do you think there is much more we could without a kiln?

7 hours ago, openspaceman said:

 

2m3 of solid hard wood at 20%mc wwb  would weigh about 1 tonne or am I missing your point?

Yes my point was the rules will allow loads of more than 2m3 for people to do their own drying. 2m3 of fresh cut beach and oak logs will weigh about a tonne and the load has to be more than 2m3 to fit the rules. Most pickups have load capacity of less than a tonne.

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2 hours ago, Woodworks said:

If the average RH is above 90% logs wont dry to below 20%. It's not exactly 90% and varies a bit with temp but close enough. Here is a table for woods moisture content for any given RH https://www.woodworkerssource.com/shop/mois.html and secondly some weather data for the average humidity but bare in mind you could be in a dry area but if we have a damp spell and with wood being hydroscopic it will take up moisture again. This is live data but pretty much everywhere in SW is above the 90% RH mark. https://wow.metoffice.gov.uk/  Also you can see my moisture reading on that log and you have seen how I dry them. Do you think there is much more we could without a kiln?

Yes I see where you are coming from, even if you dry during the summer your logs would gain moisture prior to sale in winter, BigJ said much the same with Scotland. Comparing a few dates in Summer my location has RH some 30%age points lower than yours.

 

The other salient point is that even if the equilibrium moisture content  indicates 20% with RH of 90% if the log is above 20% it will hardly be losing any water.

 

I wonder how they derived the figure of 20%, it may have come from stoves manufacturers testing their offerings with wood at that mc.

 

I've pointed out in the past that the water content of wood doesn't affect the energy content much  but it does affect the completeness of combustion IF the firebox loses too much heat. Stubby recently said his stove had a double glazed door in order to maintain a high firebox temperature, so in the right stove there is no reason a high water content cannot be burned cleanly but in a simple metal box it may well be that 20% is needed.

 

Your protimeter tells the story but it would be interesting to run an experiment with Lascar temperature and RH loggers in one of your covered loads and a similar one under a cover with no drying logs in parallel plus sample weigh both a log being dried from green and a bone dry log over a full year in your conditions.

 

The paper also states that air seasoned wood needs 2 years (which I read as 2 summer seasons as little drying occurs October to April). I cut my own logs (from timber mostly care of Jonny Burch this year) and have no space to store 2 years worth under cover. Though I have shown I can get individual logs down to below 20% in a couple of summer months I know conditions are not that favourable in my stack and hence probably burn some logs at 30% or more if that bit of the stack has poor air flow. As my Jotul 602 is just a simple metal box I intend to upgrade to an "ecodesign" stove with an insulated firebox but have yet to find anything that sits in my fireplace with plenty of room at the sides and back like the Jotul does.

 

2 hours ago, Woodworks said:

Yes my point was the rules will allow loads of more than 2m3 for people to do their own drying. 2m3 of fresh cut beech and oak logs will weigh about a tonne and the load has to be more than 2m3 to fit the rules. Most pickups have load capacity of less than a tonne.

I see, but you are still not addressing my point of the interpretation of 2m3, whether it means solid wood or a bulk volume.

 

BTW with your approach to your firewood I'm confident in your furniture making skills should you revert to your old trade.

 

As a naughty aside, I worked with an old lag who would buy a fine piece of antique furniture and strip it down to its parts, he would replicate all the parts and reassemble two pieces each with half new parts and half old and pass them off as the original genuine number. It was a shame he (and his boss) were so greedy as he was genuinely skilled and knowledgeable about antiques.

 

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I suspect the draft strategy/paper has lots of errors.  2 years to dry wood is one.  Unfortunately it varies massively.... Soft wood, split small, good conditions, dry to well below 20% in a few summer months, well dry in a few winter months.  Other end of the scale, big splits of Oak in poor conditions.... Never dry.

 

I have to raise an eyebrow at the diagram top of page 5,. The big difference between old stoves and modern..... Are they really comparing apples and apples?  I suspect it may be worst case figures for old stoves, best case for new.

 

Out of interest, what do you gents think the certified scheme would add to the cost of 1m3 of wood? 

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Reading the paper again there are some lines which strongly suggest to me that a few lines from an industry body can go a long way.   For example,

 

and ensuring that chimneys are regularly swept by a professional 
or registered chimney sweep all make a big difference.

 

Errr. ..I sweep my own chimney, is a certified sweep going to make the air cleaner?

 

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Can everyone who sells firewood please complete the yuogov survey online and have an imput because defra is going to recommend to government restrictions on small volume sales of firewood  including dumpy bag deliveries  this  will impact on all small businesses. Don't be complacent on this because -  CPL , Whitehorse energy, fuel express ,certainley wood ,wholesale wood etc will have their way . 

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17 minutes ago, Matt Fitzpatrick said:

Can everyone who sells firewood please complete the yuogov survey online and have an imput because defra is going to recommend to government restrictions on small volume sales of firewood  including dumpy bag deliveries  this  will impact on all small businesses. Don't be complacent on this because -  CPL , Whitehorse energy, fuel express ,certainley wood ,wholesale wood etc will have their way . 

Do you have a link? 

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