Keep only one working day of forge fuel, 30-50 kg of charcoal, in a stone or metal bin at least 3 m from the fire, and hold the bulk store in a separate roofed, ventilated, raised outbuilding at least 10 m from any other building. The reason is that fuel is the part of a smithy that can burn for days: sparks land in it, warm charcoal sealed up can heat itself, and a smouldering heap in a closed store makes carbon monoxide.
Part of Workshop & Forge Design
Forge fuel storage is the arrangement of charcoal or coal into a small working supply near the fire and a larger reserve kept apart from it, dry, ventilated and clear of other buildings.
A Day’s Fuel At The Forge, The Rest Somewhere Else
The workshop guide stores coal or charcoal in the smithy but at least 3 m from the forge, keeps a day’s supply near the forge in a stone or metal bin, and puts bulk storage outside or in a separate outbuilding, because sparks can ignite fuel. The forge fuel guide asks for dry, covered, ventilated storage, raised off the ground, at least 2 m from the forge (Forge Fuel). The fire guide asks for 10 m between any building and fuel storage, doubled for combustible walls (Fire Prevention in Settlements).
These figures answer different questions and do not conflict if read in tiers. The 2 m and 3 m are the sparks distance between the fire and the day bin; take the larger. The 10 m is the radiant-heat distance between a burning store and the next building (Fire Breaks & Building Spacing). One related guide, on siting workshops, says never to store fuel inside a workshop that also has an open fire (Industrial Zone Workshops); the workshop guide’s day bin is a working quantity, not storage, and this article keeps the two apart: the day bin is the minimum, and it is what the next paragraph sizes.
Worked Example: How Much, And What It Takes To Make
Inputs: general forging uses 4-6 kg of charcoal an hour; a working day is 8 h; a pit makes 15-25% of the wood weight as charcoal (Charcoal Basics).
- Day’s fuel = 4 × 8 = 32 kg to 6 × 8 = 48 kg, which matches the forge fuel guide’s 30-50 kg.
- Wood needed to make 40 kg of charcoal: 40 ÷ 0.25 = 160 kg to 40 ÷ 0.15 = 267 kg.
- Heat in the day bin, taking charcoal at about 30 MJ per kg (a standard figure recalled, not read from this corpus): 40 × 30 = 1,200 MJ. At 5 kg an hour the fire burns 5 × 30 = 150 MJ per hour, or about 42 kW, so the bin holds eight hours of that fire.
What You Need
- A day bin of stone or metal, with a lid, 3 m or more from the fire and out of the line of the sparks
- A bulk store: roofed, ventilated, with a raised floor or rack, sides open to the air (a sealed shed is wrong)
- Breathable containers: baskets, burlap sacks or wooden bins with gaps
- A barrel of water and a bucket of sand at the store, the same kit as at the forge (Fire Safety & Suppression)
Method: Fill, Rotate And Check
Step 1: Let new charcoal cool completely before it is sacked or binned. The charcoal safety guide warns that incompletely cooled charcoal can reignite in a pile (Charcoal Safety Practices).
Step 2: Fill the day bin each evening from the bulk store, so the quantity near the fire is never more than a day’s.
Step 3: Use the oldest stock first and keep it dry. Wet charcoal wastes heat and can make the fire spit.
Step 4: Walk the bulk store daily in the first week after filling and weekly after that. Feel for warmth and sniff for smoke, from the open side.
Step 5: Keep coal apart from charcoal. Raw coal brings sulfur into the iron and needs coking first (forge fuel guide). Fine coal stored in an enclosed space can heat itself through slow oxidation (Coal Surface Mining), so keep coal in a lower, ventilated heap and do not pile it deep.
Common Mistakes
- Stacking the fuel beside the forge. Sparks land in it. The 3 m is a minimum.
- A sealed, shut-up fuel shed. Warm charcoal sealed up can heat itself and a smouldering heap gives off carbon monoxide.
- Charcoal dust. The charcoal safety guide notes that daily dust exposure damages lungs; mist it before breaking and break it outdoors.
- Putting the bulk store against the smithy wall. A fire in the store then exposes the smithy at close range.
Safety
Smouldering fuel makes carbon monoxide
Do not enter a closed fuel store that is warm or smells of smoke. Open the doors from the side, stand back and let it ventilate before going in; carbon monoxide has no smell and a heap can smoulder for days. Do not put water on a deep smouldering heap in a closed space; spread it thinly in the open air and watch it until it is cold. Never leave a bulk store unwatched in dry, windy weather: embers from the forge chimney can reach it.
What’s Next
- Learn next: Fire Safety & Suppression — what to do when the store does burn
- Combine with: Charcoal Production — where the fuel comes from