High-Rise Bomb Threat Standoff & Evacuation Planner
Model physical IED blast standoff distances, glass hazard cordons, and vertical staged evacuation times for skyscrapers and commercial facilities based on DHS and NCTC tactical tables.
Tactical Standoff & Evacuation Model
DHS/NCTC Incident Command MatrixIncident Action Directive (IAP)
Operational Standoff Methodology
This operational planner operationalizes guidelines from the U.S. Department of Homeland Security (DHS), the National Counterterrorism Center (NCTC), and NFPA 1620 (Standard for Pre-Incident Planning).
In high-density high-rise environments like Midtown Manhattan, a bomb threat presents two conflicting physics challenges: immediate structural collapse / blast overpressure versus catastrophic secondary glass shard hazards across congested city blocks.
Why is Outdoor Blast Standoff larger than Building Evacuation Distance?
Reinforced concrete and modern core columns offer significant blast attenuation compared to open streets. Building evacuation distance represents the minimum safe distance inside or directly outside an unreinforced perimeter wall, whereas outdoor standoff accounts for open blast wave overpressure ($0.5\text{ to }1.0\text{ psi}$ threshold) and supersonic flying fragmentation.
How is High-Rise Staged Evacuation Calculated?
Total simultaneous evacuation of a 70+ story building creates catastrophic stairwell bottlenecking, trapping occupants in stairwells for hours. Modern life safety standards mandate priority egress for the Incident Floor, two floors immediately above, and two floors below ($F_t \pm 2$), while holding remaining floors sheltered in place behind closed fire-rated doors until primary corridors are clear.
Tactical Standoff Reference Reference
Official NCTC / ATF bomb threat safe standoff benchmarks implemented in this engine:
NCTC IED Safe Standoff Table
| Threat | Est. Explosive | Bldg Evac | Outdoor Standoff |
|---|---|---|---|
| Pipe Bomb | 5 lbs (2.3 kg) | 70 ft (21 m) | 850 ft (259 m) |
| Briefcase / Box | 10 lbs (4.5 kg) | 100 ft (30 m) | 1,850 ft (564 m) |
| Compact Sedan | 500 lbs (227 kg) | 320 ft (98 m) | 1,500 ft (457 m) |
| Cargo / Delivery Van | 4,000 lbs (1,814 kg) | 640 ft (195 m) | 2,750 ft (838 m) |
| Semi-Trailer | 30,000 lbs (13,608 kg) | 1,570 ft (479 m) | 7,000 ft (2,134 m) |
Stairwell Hydraulic Evacuation Rate Model
Calculations use the Pauls / Nelson-Mowrer empirical pedestrian flow model: flow rate $F = (1 - 0.266 D) \cdot k \cdot W_e$, where $W_e$ is effective stairwell width (deducting boundary layer sway) and specific flow caps out at approximately 1.0 to 1.3 persons per second per lane under organized evacuation drills.