Explosion Models

RiskWare includes two different explosion models:

the TNT (equivalency) charge blast model
a multi-energy fuel-air charge blast model.

The models are based on the algorithms described in Chapter 5, Vapour cloud explosions (Mercx, W.P.M. and van den Berg, A.C.) of the Yellow Book (3rd edition), Methods for the Calculation of Physical Effects, Part 2, CPR14E, Committee for the Prevention of Disasters, The Hague, 1997.

The Explosion Scenario

The explosion scenario is a scenario object similat to the generic scenario object described in:

The data structure consists of a Header that describes the identity (name and ID), and location (georeference) of the explosion complex, which is usually

a container in an industrial area or chemical plant,
a hazardous goods transportation vehicle, or a
segment of a pipeline.

This is followed by two mandatory LISTs which specifies model properties (model_specifications ) and source properties (sources_specifications ).

A mandatory TABLE which contains the reference point for all explosion sources, number of sources, the identy (name and ID) and explosion data for each source (explosion_sources).

The next mandatory LIST specifies properties for the output raster (output_specifications) and contains links to pressure raster data.

The main EXPLOSION SZENARIO TEMPLATE is defined as follows:

#######################################################################
### The Explosion Szenario Template
#######################################################################
#
# The data in this template is cooked up for explanation only
#
##### BEGIN HEADER  ###################################################
# Max length of ANY line in header is 96 characters
# Max no. of editable ME lines via user interface = 3

NA  Example Chemical Plant             # object name
ID  SITE1                              # unique ID
ME  Meta Information 1                 # meta information 1
ME  Meta Information 2                 # ...
ME  Meta Information n                 # meta information n
AU  patel   Thu Feb 23 12:45:55 1997   # automatically inserted
                                       # when created or changed
#######################################################################
OT EST                # Type of Object: Explosion Szenario Template

GX 124400.0          # latitude / reference X
GY 488700.0          # longitude/ reference Y
EL 25.5              # masl
HY chemicalplant.exp
PI objects/sources/gifs/plant9.gif    #hypertext (map, picture) file
##### END HEADER ######################################################
#
# Note: all coordinates are related to georeference point 
# of the explosion complex 

TABLE methods
E	icon	# this is a trigger
E	method
D       1 blast_model
D       2 tnt_model  
END_TABLE

LIST model_specifications
D model: origin x-coordinate      # origin in lower left 
D model: origin y-coordinate      # corner of model area
D model: number of colums
D model: number of rows
D model: cell size x direction
D model: cell size y direction
D model indicator                # 0 -> multy energy  1-> TNT  2->both
END_LIST

LIST sources_specifications
D sources: origin x-coordinate    # origin for all specified sources  
D sources: origin y-coordinate    # in the table
D number of sources           
END_LIST
# note: sources must not be within the output or model area!
#  even when specific data is not needed to compute pressure
#  for specific model (energy/TNT) you have to fill in dummy values! 

TABLE explosion_sources
E source_name               # links to a plant, container,                
E source_ID                 # vehicle, or pipeline segment.
E x-coordinate                    
E y-coordinate                     
E available combustion energy   # [J]
E explosion strength       
E ambient pressure             # [Pa]
E TNT equivalency              # TNT equivalency based on energy
D  hydrogen_pisa1    1h    50.  60.  500000.  100000.  0.2
.
.
D  gasoline_pisa1    2g    55.  70. 1000000.  100000.  0.4  
END_TABLE

LIST output_specification
E output: origin x-coordinate     # origin located in the 
E output: origin y-coordinate     # lower left corner of output area
E output: number of colums
E output: number of rows
E output: cell size x-direction
E output: cell size y-direction             
E explosion data link      #data link (multy energy model)
E TNT explosion data link  #data link (TNT model)
END_LIST
#######################################################################