Firewood is made of locally supplied Lithuanian timber. The wood species we use to make firewood are: Ash, Oak, Birch, Alder, Pine and Fir. Each log can be cut into pieces of 25, 30 or 45 cm, split 4-6 times for 8-15 cm diameter and stacked into 1m³, 1,8m³, 2m³ or 2,2m³ boxes or bags of 9.5 L, 21 L, 30 L, 40 L or 60 Liters.
Basically, the timber has similar calorific value, only difference is the density. There are 3 categories for calorific value. This value is the energy (expressed in kcal or Kilowatts), released by burning exactly 1m³ solid timber.
Firewood calorific value groups
|Firewood group||Calorific value (kcal)||Heat energy (KW)|
|Group I: Ash, Oak, Birch||2250 - 2500||2,65 - 2,93|
|Group II: Pine, Alder||1800 - 1900||2,15 - 2,21|
|Group III: Fir, Aspen||1500 - 1700||1,87 - 2,10|
Timber weight and volume ratio
|timber||1m3 weight (kg)||1000 kg volume (m³)|
The firewood is packed into easy-access wooden boxes. If packed into bags, then the bags are stacked into boxes. Boxes are the best way to manipulate and transport firewood. The basic limitations are the weight of cargo – its 24 tons and the space inside the trailer. The volume is rarely a limitation (except for sea container) and the number of boxes depends on box size, timber species and humidity of firewood.
The different schemes for loading firewood into the truck are provided in the table:
Firewood boxes in truck
|Stère / Raum meter||Fresh-cut firewood||Dried firewood|
|2 RM (2 cubic meters)||22-24||25-26|
|1,8 RM (1,8 cubic meter)||25-26||28|
|1 RM (1 cubic meter)||48-56||52-60|
1 RM = 1.17 x 0.92 x 0.93 m
1.8 RM = 1.12 x 0.8 x 2.0 m
2 RM = 1.13 x 0.93 x 1.9 m
Length of logs and volume in a box
|Log length:||Multiplier coefficient|
For the production in bags, Biodela™ specializes in 40 L bag production. Standard-conforming bag is 50 x 72 cm and weighs 14.5 -15.5 kg for Kiln dried firewood. Other popular sizes are 21 L or 60 L. Another popular product is the kindling sticks. The fire starters (kindling sticks) are 10-12 cm long ~2cm diameter tiny pieces of dry firewood (the humidity 10-15%). The sticks are packed into 9.5 Liter (3 - 3.5 kg) or into 30 L (5 - 5.5 kg) bags. Bags are stacked onto pallets. The 9.5 L bags are packed onto ~1m³ box (96 bags per pallet); the 30 L bags are stacked into 2m³ boxes (78 bags).
The most important for firewood are obviously the box quality and residual moisture (if it is dried). Ideal firewood box has strong side boards and well attached straps to endure the transfer and loading works.
The side boards must be ~5 cm width and correct rectangular shape. The 3 sides of the box are closed, the frontal part open for convenient access of logs. The box should have at least 2 straps around between top and bottom. The logs must be split at least into half, mostly in 4 or 6 pieces diagonally. The box shall contain only the firewood logs (no timber remaining or waste wood). Logs have to be mold-free.
The moisture of firewood measurement rule: because there is no way to dry the whole log equally, one must refer to the average of the moisture level. The applied rule is fully quoted below.
“Firewood humidity measurement method: an average size firewood log (from center of box) shall be split and left for 30 min indoor to evaporate. Then 3 measures shall be taken: a) center of outer side of log, b) end of log, b) center of split log inner side. The average of 3 measures is the humidity content. Dry firewood is considered to be of no more than 25% humidity content, unless agreed other. No limits apply for fresh firewood humidity content.”
Warehousing of firewood: the key steps, to avoid problems with firewood, are: 1. Protect from moisture absorption, 2. Protect from direct rain and 3. Protect from mold formation in poor ventilation. The best place to keep the firewood is outside in the open wind under cover/roof. This way it gets good ventilation and there’s no potential for mold to grow. Other option is in a warehouse if one can make sure the firewood gets sufficient 360° ventilation.
When the fresh firewood is stored outside, it would dry faster if there’s direct sunlight. In such case we recommend to cover the boxes with the plastic transparent tops to protect from rain.
The birch is very special type of firewood. Thanks to its good burning features and pleasant odor, it is most appreciated in Norway, Malta and in number of other countries as well. Birch is not only valuable heating fuel, but also perfect to use in private and business for Pizza Ovens, Steak Grill etc., picnics, camping, Sauna and so forth. For dry birch firewood, packed in bags, the Norsk Standard 4414 - special requirements for quality - is applied:
NS4414 Standard requirements for the dry birch firewood.
NS4414 (Norsk Standard 4414) requirements
|Class I||Class II||Class III||Class IV|
|Species||Selected Birch||Hardwood: birch, oak, ash, maple, rowan||All species||All species, incl. sapwood & demolition wood|
|Cannot be mixed||Cannot be mixed||Can be mixed||Can be mixed|
|Allowance for fast decay||Not tolerated||Up to 10% of logs||Up to 15% of logs||maximum 10% may have loose rot|
|Size of largest log||Min 8 cm Max15 cm||
Min 4 cm / Max 18 cm Max 20% of logs<8cm or >15 cm
Min 4 cm / Max 18 cm. Max 20% of logs<8cm or >15 cm
|Max 18 cm|
|Splitting||All logs are split||90% logs are split||Round logs max 8cm diameter allowed||Not required for logs <18 cm|
|Lengths acceptable||20 cm - 30 cm - 60 cm - 300 cm|
|Lengths deviation||+/- 1 cm||+/- 2 cm||+/- 10%||+/- 10%|
|Humidity||Max 20%||Max 22%||Max 25%||Max 25%|