The Emergency Response Guidebook (ERG2008) is used by firefighters, police, and other emergency services personnel who arrive at the scene of a transportation incident involving a hazardous material. The guidebook was developed jointly by the US Department of Transportation, Transport Canada, and the Secretariat of Communications and Transportation of Mexico (SCT).
When some people see the output of the ERG, the first thought is “It looks just like a circle and a rectangle….why isn’t this a plume?”. The ERG is actually a widely used standard and is a “keep-out” protocol similar to a plume but requires less rigorous inputs. It lets first responders determine an area of concern without over complicating a situation that may already be difficult to respond to. When first responders arrive at an emergency their first two priorities are scene safety to protect responding personnel and saving the lives of victims involved in the incident. For that initial response they need quick results that will help them achieve these goals. The ERG tool is well suited to fit that mission.
More information on the ERG can be found here:
A PDF of the Guidebook can be found here:
The guidebook itself lists hundreds of hazardous chemicals. For each chemical, recommended safe distances described as “Initial isolation distances” and “Protective action distances” are listed. The “Initial Isolation Distance” is a distance within which all persons should be considered for evacuation in all directions from the actual spill/leak source. The “Protective action distances” represent areas in which first responders could evacuate people to preserve safety.
ArcGIS Geoprocessing tools were created to put a spatial context to the ERG workflow process. The Geoprocessing tools take all input parameters that the ERG requires to calculate the “Initial Isolation Zone” and “Protective Action Zone”. The output of the geoprocessing tools create a feature class with polygons representing those zones.
The geoprocessing tools were built as custom .Net Geoprocessing tools. These tools can be executed from ArcMap, or put into a Geoprocessing Model and published via ArcGIS Server to be leveraged in web mapping applications or ArcGIS Explorer. The tools can be downloaded from the ESRI Resource Center in the Emergency Management COP template or the Geoprocessing Resource Center.
These tools provide a great example of how geoprocessing based upon standards such as the ERG can be incorporated into a custom geoprocessing tool. Making custom geoprocessing tools allow the tool to be flexible to run in both ArcGIS Desktop and ArcGIS Server applications. More information on building custom geoprocessing tools can be found here:
The download comes with two toolboxes. The “ERGTools –Generic Tools” are the core geoprocessing tools. The inputs allow you to upload a feature class as input. Most people will use the “ERGModels – Generic Tools” toolbox which allows the user to interactively define a point on the map that represents a hazardous material spill.
There are also two Geoprocessing tools included: “ERG By Chemical” and “ERG By Placard”. The “ERG By Chemical” lists all chemicals represented in the guidebook as a parameter. In some cases someone may call in to report an incident, but not know the chemical, but saw the placard on the vehicle that spilled in which case you can run the “ERG By Placard”.
When you open the Geoprocessing tools, you will see all the parameters required. The first parameter represents the input point. The next parameter represents the Material or Placard depending on the tool you run. There are additional parameters for the time and size of the incident that the guidebook defines that will impact the size of the “Initial isolation distances” and “Protective action distances” . The distances change from daytime to nighttime due to different mixing and dispersion conditions in the air. Spills that involve releases of approximately 200 liters (300 kg for solids)or less are considered Small Spills, while spills that involve quantities greater than 200 liters (300 kg for solids) are considered Large Spills.
The output feature class contains three polygons with an ERGZone attribute. Zone 1 represents the Isolation Distance. Zone 2 Represents the Protective Action zone. Zone 3 is a combination of Zone 1 and Zone 2 and is used for GIS purposes such as defining road blocks, etc.
The attributes of the output feature class indicate which Zone each polygon represents, as well information about the origin of spill, chemical type, date and Guide Number in the ERG Guidebook.
The install package includes more detailed information about installing and using the ERG tool. The ERG Geoprocessing tools are supported on ArcGIS 9.3 or higher.