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Supplies & Duration Planning

5 min read

Stock a safe room for the people it holds and the hours they stay, and note that the defensive-architecture guide’s 20 L of water per person for 48 hours is half the corpus’s 20 L per person per day. For 20 people over 48 hours that is 400 L against 800 L, and 800 L weighs 7.85 kN on the floor, so use the larger figure, add 112,000 kcal of food at 2,800 per person per day, and provide three 20 L buckets for the 60 L of urine that 20 people make.

Part of Safe Rooms & Refuge Points

Supplies and duration planning for a safe room is the calculation of water, food, sanitation, air and light needed for the number of occupants and the length of the stay.

The Guide Gives A Duration And A Water Figure That Disagree With The Corpus

The defensive-architecture guide asks a safe room to sustain occupants for 24-48 hours, and to hold a minimum of 20 litres of water per person for 48 hours, a bucket toilet with cover material, first aid, blankets and a light source. The emergency-shelter guide uses the corpus minimum of 20 L per person per day (Emergency Shelter Capability). Over 48 hours the guide’s figure is 20 ÷ 2 = 10 L per person per day, half of that. Drinking alone is far smaller: the trigger-criteria guide uses 2 L per person per day as the survival minimum (Trigger Criteria). So 10 L a day covers drinking five times over but not washing, cooking and cleaning a bucket toilet, which is the reason for the corpus’s larger figure.

Worked Example: Twenty People, Forty-Eight Hours

Inputs: 20 people; 48 hours, 2 days; food 2,800 kcal per person per day, the community average used in the shelter guide; grain at about 3,400 kcal/kg (a recalled figure for wheat, to be checked); urine about 1.5 L per person per day (recalled, typical 1-2 L); toilet buckets of 20 L (Toilet Designs); one toilet per 20 people, the Sphere figure quoted in the shelter guide.

  1. Water at the guide’s 20 L each: 20 × 20 = 400 L. At 20 L a day: 20 × 20 × 2 = 800 L. At 2 L a day: 20 × 2 × 2 = 80 L.
  2. Weight of 800 L: 800 kg, a force of 800 × 9.81 = 7,850 N = 7.85 kN, spread over the floor: four 200 L barrels. A kilonewton figure is a force; the kilograms are the mass.
  3. Food: 20 × 2,800 × 2 = 112,000 kcal. In grain, 112,000 ÷ 3,400 = 33 kg. A healthy adult can manage a day or two on much less; infants, the sick and the old cannot, so the food is stocked for them first.
  4. Toilets: 20 ÷ 20 = 1 toilet, but the buckets fill: urine 20 × 1.5 × 2 = 60 L, which is 60 ÷ 20 = 3 buckets, plus the solids and cover material. Plan a covered bucket for every 7 people.
  5. Air: one 10 cm vent per 9 people, 5 m³ of air each (Safe Rooms & Refuge Points): 20 people need three vents, and the floor area at 2 m² each is 40 m².
  6. Heat: 20 × 100 W = 2 kW from the occupants, enough to make a closed room hot in summer.

The water is the item that matters most and weighs most. Putting 800 L in barrels on the floor needs a floor that can take it and barrels that cannot be punctured or tipped.

What You Need

  • Water in sealed containers, covered, at least 40 L per person for 48 hours, rotated and checked
  • Food that keeps, for the infants, the sick and the old first
  • Covered buckets for sanitation, with ash, lime or earth as cover material, and hand-washing water
  • First aid and blankets (First Aid)
  • Light: the least flame possible; a single lamp on a fireproof surface only in a ventilated room
  • A list of who is expected, by name, and a count that is taken on entry

Method: Stock And Rotate

Step 1: Count the people the room is for.

Step 2: Multiply by the hours and by the per-person figures above.

Step 3: Store the water low and secure, not on a shelf, in containers that cannot be tipped.

Step 4: Rotate the stock each season and log the date.

Step 5: Test the vents and the sanitation with a full drill that lasts a few hours.

Step 6: Re-count after any change in the numbers of people or of rooms.

Common Mistakes

  • Using the 48-hour figure per person as a per-day figure, or the reverse.
  • No sanitation plan. Buckets fill, and a room with 20 people smells and spreads disease within hours.
  • Storing water above head height. A falling barrel is dangerous, and the weight is large.
  • Stocking food and forgetting the can opener or the knife.

Safety

No burning fuel in a closed room

A stove, brazier or candle bank in a safe room burns the air and makes carbon monoxide; at 2 kW of people the room is already warm. Keep one lamp, vented, and no stove. If anyone has a headache, drowsiness or nausea, leave by the second way out and ventilate before re-entering (Carbon Monoxide Risks). A room holding more than a handful of people exits outward by pushing; this one is small and has two ways out.

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