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Crap at math need help


Just_me
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Hi all,

I’m trying to work out how many barrow bags I need to store my firewood. 
I received 26t of green softwood, looks like a mix of various species. The Forestry of England have kindly provided figures to convert into m3. Google says green wood is circa 40% wet. So once dried out I’ll have 16t in dry wood. Using FoE 1.38 conversion figure gives me 23 m3 of dry wood. The barrow bags I currently have are 0.19m3. Therefore 23 m3/0.19= 121 bags and I’ve doubled to allow for them being chucked in and not stacked inside the bags. According to my calculations I’ll only need 240 ish bags. But reality on the ground shows I might need as many as 500. Where have gone wrong? It’s not crucial but I’m struggle to fit 500 where I planned to store for a few years. 
I hope that all makes sense. 

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9 minutes ago, Just_me said:

Hi all,

I’m trying to work out how many barrow bags I need to store my firewood. 
I received 26t of green softwood, looks like a mix of various species. The Forestry of England have kindly provided figures to convert into m3. Google says green wood is circa 40% wet. So once dried out I’ll have 16t in dry wood. Using FoE 1.38 conversion figure gives me 23 m3 of dry wood. The barrow bags I currently have are 0.19m3. Therefore 23 m3/0.19= 121 bags and I’ve doubled to allow for them being chucked in and not stacked inside the bags. According to my calculations I’ll only need 240 ish bags. But reality on the ground shows I might need as many as 500. Where have gone wrong? It’s not crucial but I’m struggle to fit 500 where I planned to store for a few years. 
I hope that all makes sense. 

The only softwood I can think of that is below 51% mc wwb is european larch, next is douglas  at 52% but all the pines and spruces are above 60%.

 

Volume will shrink by about 10% on drying below 20% mc.

 

The problem with bags is they have lots of "edge effects" where in a stack the logs fill in all the gaps in a bag there are always spaces at the points the logs contact the bag, worse with solid containers that have no give.

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When wood dries it might half in weight but it won't half in volume.  I think that's where you have gone wrong.

 

I use bags and IBCs.  I'd advise buying way more bags than you think you'll need.  Bags rip and break a lot especially if you filling them mechanically.

 

Yes the wood won't dry well in bags, if thats what you are intending.

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Posted (edited)

Ah of course….so it’s 26t x 1.38 to get an ish volume. Thank you guys. I thought I was going nuts. Re not drying in bags. They’re vented barrow bags and the timber seems to dry fine last few years but it’s an incredibly windy spot (misses loves it coz she can dry clothes outside pretty much for 10 months sometime). But I’ve never had this volume before. I wasn’t planning on selling any but I may have too if it turns out I’ve 500 bags worth. And the locals have been asking. Once again thanks a lot. I’ve been thinking about turning my businesses’ heating into timber source rather than gas, hence why I’m experimenting with larger volumes. 

Edited by Just_me
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