Planning a hidden life-support ecosystem

A continuity-of-government (COG) bunker is more than a secure room; it is a self-contained ecosystem designed to keep decision makers alive and productive when the surface world is compromised. The United States, the United Kingdom, Switzerland, and several other nations maintain hardened facilities that can shelter key officials through crises ranging from nuclear attack to pandemic. These shelters are stocked years in advance, but they cannot be packed infinitely with supplies. Storage, power, and logistics personnel must weigh trade-offs between rations, water, life-support hardware, and waste handling when they allocate precious cubic meters. The calculator above targets that planning problem. It combines the constraints that covert facility planners routinely evaluate—calories, water, carbon dioxide scrubbing capacity, waste storage, and emergency batteries—into a single snapshot of endurance. By entering your staffing assumptions and stockpile levels, you can see which resource will force an evacuation first and how much margin the shelter commander truly has.

COG bunkers often rely on pre-positioned MRE-style rations, powdered beverages, and freeze-dried entrees because they last five to ten years. Water is harder; either massive cisterns must be integrated into the rock, or engineers must reuse condensate from HVAC systems and treat groundwater. Air scrubbing is typically handled by lithium hydroxide or regenerable solid amine cartridges borrowed from submarine practice. Waste poses yet another challenge because the facility may not have a functioning municipal sewer connection after an attack. Planning for all of these streams simultaneously is far more complex than simply counting the number of meals in storage. A system-level calculator helps COG planners articulate the weakest link in the chain and update budgets accordingly.

Formulas underpinning the endurance estimate

The calculator treats each resource as a finite reservoir that is depleted linearly over time. For calories, the usable energy stockpile equals the ration mass multiplied by its caloric density. The number of days until the stockpile is exhausted is simply the total calories divided by the population’s daily requirement. In formal notation, if $N$ is the population, $\mathrm{C\_d}$ is the daily caloric need per person, $\mathrm{M\_r}$ is the total ration mass, and $\mathrm{\rho \_c}$ is the caloric density, then the food-limited endurance $\mathrm{T\_f}$ is

$\mathrm{T\_f}=\frac{\mathrm{M\_r}}{\times }N\mathrm{C\_d}$.

Water follows the same structure: stored liters divided by liters consumed per person per day. The script converts the daily consumption to total facility demand and then calculates days of supply. Carbon dioxide scrubbing is slightly different because it depends on metabolic output, not on a resource consumed. Crew respiration produces approximately one kilogram of CO₂ per person per day under moderate workloads. Scrubber cartridges have rated absorption capacity in kilograms. The endurance is therefore the total absorption capacity divided by daily production. Waste storage is modeled as a tank that fills based on daily excreta and gray water, again scaled by population. Electrical and thermal buffers, such as flywheels or phase-change thermal stores, are expressed in kilowatt-hours of stored energy. If the critical load is $P$ kilowatts and the buffer holds $\mathrm{E\_b}$ kilowatt-hours, then the autonomy in hours is $\frac{\mathrm{E\_b}}{P}$, which the tool converts into days so it can be compared directly with the other constraints.

After computing raw endurance for each resource, the calculator imposes a configurable reserve. COG doctrine typically requires commanders to retain between 10% and 20% of critical supplies to buffer uncertainties such as unscheduled guests or measurement error. The form’s “safety reserve” percentage reduces each resource’s usable endurance by the same proportion. The limiting sustainment window is then the minimum of all adjusted values. This approach makes the shortfall immediately visible: if water runs out in 18 days while food lasts 45 days, you know to prioritize a cistern expansion before buying additional MREs.

Worked example: sheltering the legislative branch

Imagine a scenario in which 120 staff members—including leadership, communications teams, and medical personnel—must shelter in a retrofitted mine. The logistics officer has acquired 30,000 kilograms of high-calorie rations and a half-million liters of potable water. The facility includes a bank of regenerative amine scrubbers rated for 150 kilograms of CO₂ before requiring thermal reactivation. A blackwater tank stores 25,000 liters, and emergency batteries provide 600 kilowatt-hours of backup power for communications and life support loads totaling 12 kW. Entering these figures with a 15% reserve shows that calories will last about 70 days, water will last 29 days, CO₂ scrubbers will saturate in 8.3 days, and the waste tank fills in roughly 58 days. Energy storage supports only two days at the current load. Once the reserve is applied, the true sustainment limit is the scrubbing system at just over seven days.

The example highlights how often overlooked the CO₂ removal system can be. Without regenerating cartridges or adding additional sorbent, leadership would be forced to rotate staff out of the bunker after a week even though they still have weeks of food and water remaining. Because the summary table surfaces each constraint, planners can make the case for redundant scrubbers or can explore lowering metabolic CO₂ output by reducing activity. Perhaps half the staff can move to a low-metabolism protocol or cycle to a secondary alcove with chemical scrubbers while engineers bake out the amine beds. The CSV export documents the baseline scenario so future exercises can compare improvements.

Scenario comparison table

The table below contrasts three upgrade options for the example facility. Scenario A adds sorbent cartridges, Scenario B expands water storage, and Scenario C includes both plus a power upgrade. The “Limiting resource” column shows which subsystem forces evacuation first after reserves.

These comparisons make trade-offs explicit. Extra sorbent triples the breathing window but reveals the battery system as the next bottleneck. The cistern retrofit extends water endurance by 16 days yet still leaves the scrubbers as the limiting constraint. The hybrid scenario delivers the most balanced posture, allowing leadership to ride out nearly three weeks underground while retaining reserves for a controlled extraction. Planners can use the calculator to update the table with their own figures and demonstrate the value of incremental upgrades.

Limitations and best practices

The calculator assumes steady consumption and does not account for ration degradation, microbial growth in water, or the fact that lithium hydroxide can lose capacity when exposed to humidity. Real COG facilities rotate stockpiles and track lot numbers so they can discard expiring items. The model also treats waste production as a fixed number, yet actual waste varies with diet and hydration. Designers should run multiple cases with higher waste-per-person numbers to ensure tanks do not overflow if gastrointestinal illness strikes. Energy modeling is similarly simplified. Actual facilities would consider generator fuel, air-handling power, and the efficiency of inverters that convert stored energy into usable electricity. You can approximate these effects by increasing the critical load entry.

Psychological stress, injuries, and mission demands add further uncertainty. Anxious staff may eat more calories or require heated water, both of which shorten endurance. Medical teams may need to incinerate biohazard waste, drawing additional power. Exercise programs designed to prevent muscle atrophy will raise CO₂ output and water consumption. For these reasons, doctrine emphasizes frequent drills and system testing. The calculator supports this mindset by making it easy to adjust parameters and record the results via CSV. Pair it with actual scrubbing cartridge measurements and water sampling logs to maintain a living readiness document.

Finally, any COG facility should plan for reconstitution phases. The tool does not track how long it takes to regenerate scrubbers, purify wastewater, or receive resupply from a surface convoy. Use the sustainment window as a trigger for those logistics. If the limiting resource is CO₂ scrubbing at seven days, then the operations plan should schedule cartridge reactivation every five days. If energy is the limiting factor, planners might add thermochemical storage or integrate small modular reactors. The calculator’s strength lies in revealing the weakest link so leaders can invest accordingly. By combining it with realistic training, cross-trained maintenance crews, and redundant life-support systems, governments can ensure that constitutional processes continue even under the direst circumstances.