Emergency Response Distance Calculator

Determine initial isolation and protective action distances per the DOT Emergency Response Guidebook.

Material Type

Container Size

Time of Day

Fire Involved

Tab to move between fields

Initial Isolation (ft)

200

Protective Action Distance (miles)

0.7

Protective Distance (ft)3,696

Evacuation Zone (acres)985.2

Downwind Distance (miles)1

Fire Distance Multiplier1

How to Use This Calculator

Select the Material Type (1=Toxic Gas, 2=Flammable Gas, 3=Poison, 4=Corrosive, 5=Oxidizer) based on the ERG guide for the substance involved.
Choose the Container Size (1=Small drums/cylinders, 2=Medium totes, 3=Large tanker/railcar) to reflect the release scale.
Set Time of Day (1=Day, 2=Night) since nighttime atmospheric stability increases downwind hazard distances.
Toggle Fire Involved (1=yes, 0=no) — a fire multiplies distances due to combustion products and pressure releases.
Review Initial Isolation (ft) to establish the hot zone perimeter around the release immediately.
Use Protective Action Distance (miles) and Evacuation Zone (acres) to guide shelter-in-place or evacuation decisions.

What each input means

Material Type: 1=Toxic Gas, 2=Flammable Gas, 3=Poison, 4=Corrosive, 5=Oxidizer.
Container Size: 1=Small (drums/cylinders), 2=Medium (totes/multiple drums), 3=Large (tanker/railcar).
Time of Day: 1=Day, 2=Night (night has more stable atmosphere).
Fire Involved: 1 if fire is involved, 0 otherwise.

Identify Input Parameters
4 parameters
Material Type = 1, Container Size = 2, Time of Day = 1, Fire Involved = 0 = 4 input(s) provided
Calculate Initial Isolation
Initial Isolation
200 = 200
Calculate Protective Action Distance
Protective Action Distance
0.7 = 0.7
Calculate Protective Distance
Protective Distance
3696 = 3696
Calculate Evacuation Zone
Evacuation Zone
985.2 = 985.2