HCA (Method 1)

Summary

HCA (Method 1) performs a High Consequence Area (HCA) analysis workflow from start to finish per 49 CFR §192.903(1), using Class Location ranges output by the Class Location Calculation tool.

HCA (Method 1) is implemented as a ModelBuilder model tool, using the tools from the Prepare and Process toolsets in the Gas HCA Tool Python toolbox. It imports required source data into an existing Gas HCA Tool project geodatabase (created during the prerequisite Class Location analysis), performs data conditioning and intermediate calculations, and calculates final HCA ranges by method 1.

Usage

HCA (Method 1) implements G2-IS’ best practices for HCA analysis. However, because it is implemented as a ModelBuilder model tool, you are free to make a copy of the tool and modify it to suit your own needs.

HCA (Method 1) assumes that all feature classes and tables imported into the project geodatabase by, and/or created by the Class Location analysis workflow are present in the project geodatabase and stored under their default names. The tool further assumes that you have utilized your identified sites as qualifying areas/buildings in your Class Location analysis. The tool only imports into your project geodatabase the additional data needed to complete the HCA method 1 analysis.

The following tools are used in HCA (Method 1). They are listed in their order of execution within the HCA (Method 1) tool; the heading for each section below is a hyperlink to the detailed help for the tool. Please note that while the tools HCA (Method 1) uses are listed in order in which they are executed, the HCA (Method 1) tool parameters are shown in association with the tools that expose them, not necessarily in the order in which HCA (Method 1) lists them:

1) Prepare Pipe Segment and MAOP Features

Prepare Pipe Segment and MAOP Features copies your pipeline database pipe segment and Maximum Allowable Operating Pressure (MAOP) features (or records) to the PIPESEGMENT and MAOP tables, respectively in the project geodatabase.

  • Input Pipe Segment Features – Typically, your input pipe segment features/records correspond to discrete lengths of pipe with common attributes stored on your pipeline centerlines. Your input pipe segment features/records must contain the following attributes (your field names need not match, but fields containing this information must be present):
      • Pipe Segment Centerline Identifier Field – This field uniquely identifies the centerline feature on which the pipe segment feature/record occurs. This field will be mapped to and compared with ORIGNIAL_ROUTE_ID field in CENTERLINE layer.
      • Pipe Segment Begin Measure Field – A field that represents the begin measure of the pipe segment.
      • Pipe Segment End Measure Field – A field that represents the end measure of the pipe segment.
      • Pipe Segment Outside Diameter Field – A field that represents the diameter of the pipe segment in inches.
  • Input MAOP Features – Typically, your input MAOP features/records correspond to centerline segments with common MAOP values. Your input MAOP features/records must contain the following attributes (your field names need not match, but fields containing this information must be present):
      • MAOP Centerline Identifier Field – This field uniquely identifies the centerline feature on which the MAOP feature/record occurs. This field will be mapped to and compared with ORIGNIAL_ROUTE_ID field in CENTERLINE layer.
      • MAOP Begin Measure Field – A field that represents the begin measure of the MAOP segment.
      • MAOP End Measure Field – A field that represents the end measure of the MAOP segment.
      • MAOP Field – A field that the MAOP value (in PSI) of the segment.

2) Create Centerline PIR Buffers

Create Centerline PIR Buffers creates centerline Potential Impact Radius (PIR) segments on your centerline features, and then creates centerline PIR segment buffer polygons. The output features are stored in the following feature classes in the project geodatabase: HCA_PIR_SEGMENT and HCA_PIR_SEGMENT_BUFFER.

  • PIR Factor – The PIR combustion factor varies based on product type. 0.69, the factor for ‘dry’ natural gas, is the default value. 0.73 is the factor for ‘wet’ natural gas.
  • Additional PIR Tolerance (Feet) – This parameter enables you to specify an additional tolerance (in Feet) to add to the PIR, to account for uncertainty in the spatial location of your centerline, BIHO and identified site features.

3) Create Structures and Site PIR Buffers

Create Structure and Site PIR Buffers creates PIR buffer polygons on your BIHO and identified site features and then generates centerline PIR BIHO and identified site segments by intersecting the buffer polygons for BIHOs and identified sites with your centerline features. The output features are stored in the following feature classes in the project geodatabase: HCA_STRUCTUREBUFFER and HCA_STRUCTURESEGMENT.

HCA-MCA (Method 1) exposes none of this tool’s parameters.

4) HCA Calculation (Method 1)

HCA Calculation (Method 1) performs the final step in the analysis workflow, calculating your HCA ranges by method 1. This tool also produces dynamically segmented HCA segments that retain much useful attributes from the analysis process. The output features are stored in the following feature classes in the project geodatabase: HCA_RANGE_M1 and HCA_SEGMENT_COUNT_M1.

  • Class Type – When set to ‘Class Clustered,’ the tool uses ‘clustered’ Class Location features in the calculation. When set to ‘Class Unclustered,’ the tool uses unclustered Class Location features in the calculation.

Syntax

HCAMethod1GasHCAToolsDotClass (Input_Pipe_Segment_Features, Pipe_Segment_Centerline_Identifier_Field, Pipe_Segment_Begin_Measure_Field, Pipe_Segment_End_Measure_Field, Pipe_Segment_Outside_Diameter_Field, Input_MAOP_Features, MAOP_Centerline_Identifier_Field, MAOP_Begin_Measure_Field, MAOP_End_Measure_Field, MAOP_Field, PIR_Factor, {Additional_Tolerance_for_PIR__Feet_}, Class_Type)

Parameter Explanation Data Type
Input_Project_Database

Dialog Reference

Select the Gas HCA Tool project geodatabase you created while performing the prerequisite Class Location analysis. The output from this tool is stored in this workspace by default.

There is no Python reference for this parameter.

Workspace
Input_Pipe_Segment_Features

Dialog Reference

Specify your input pipe segment features/records.

There is no Python reference for this parameter.

Table View
Pipe_Segment_Centerline_Identifier_Field,

Dialog Reference

Specify the field that uniquely identifies the centerline segment on which the pipe segment feature/record occurs.

There is no Python reference for this parameter.

Field
Pipe_Segment_Begin_Measure_Field

Dialog Reference

Specify the field containing the begin measure value of the pipe segment feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field
Pipe_Segment_End_Measure_Field

Dialog Reference

Specify the field containing the end measure value of the pipe segment feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field
Pipe_Segment_Outside_Diameter_Field

Dialog Reference

Specify the field that stores the outside diameter (in inches) of the pipe segment feature/record.

There is no Python reference for this parameter.

Field
Input_MAOP_Features

Dialog Reference

Specify your input MAOP features/records.

There is no Python reference for this parameter.

Table View
MAOP_Centerline_Identifier_Field,

Dialog Reference

Specify the field that uniquely identifies the centerline segment on which the MAOP feature/record occurs.

There is no Python reference for this parameter.

Field
MAOP_Begin_Measure_Field

Dialog Reference

Specify the field containing the begin measure value of the MAOP feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field
MAOP_End_Measure_Field

Dialog Reference

Specify the field containing the end measure value of the MAOP feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field
MAOP_Field

Dialog Reference

Specify the field that stores the MAOP value (in PSI) of the MAOP feature/record.

There is no Python reference for this parameter.

Field

 

 

PIR_Factor

Dialog Reference

Enter the PIR combustion factor for the PIR calculation. 0.69, the factor for ‘dry’ natural gas, is the default value.

There is no Python reference for this parameter.

Double

 

Additional_Tolerance_for_PIR__Feet_

(Optional)

Dialog Reference

Enter an additional tolerance (in feet) to add to the PIR, if desired. The default value is 0 feet.

There is no Python reference for this parameter.

Double

 

Class_Type

Dialog Reference

Specify the desired class output calculation. The available options are ‘ Class Clustered’ and ‘Class Unclustered’.

There is no Python reference for this parameter.

Field

Code sample

The following script demonstrates how to use the HCA (Method 1) master tool with file geodatabase data.

# Import GasHCA Library
import hcapy
# improt Gas HCA Tools
arcpy.ImportToolbox(“C:\Python27\ArcGIS10.6\Lib\site-packages\hcapy\esri\Toolboxes\GasHCA Master Tools (Desktop)
.tbx”)
Input_Project_Database = r”C:\projects\GasHCA_Enhancements\A_DOTCLass_Test6.gdb”
Input_Pipe_Segment_Features = r”C:\projects\GasHCA_Enhancements\Test.gdb\PipeSegment”
Pipe_Segment_Centerline_Identifier_Field = “RouteEventID”
Pipe_Segment_Begin_Measure_Field = “BEGIN_MEASURE”
Pipe_Segment_End_Measure_Field = “END_MEASURE”
Pipe_Segment_Nominal_Diameter_Field = “Outsidediameter”
Input_MAOP_Features = r”C:\projects\GasHCA_Enhancements\Test.gdb\MAOP”
MAOP_Centerline_Identifier_Field = “RouteEventID”
MAOP_Begin_Measure_Field = “BEGIN_MEASURE”
MAOP_End_Measure_Field = “END_MEASURE”
MAOP_Field = “ActualPressure”
PIR_Factor = 0.69
Additional_PIR_Tolerance__Feet_ = 0

Class_Type = “Clustered”

# Execute Tool
HCAMethod1 (Input_Project_Database, Input_Pipe_Segment_Features, Pipe_Segment_Centerline_Identifier_Field, Pipe_Segment_Begin_Measure_Field, Pipe_Segment_End_Measure_Field, Pipe_Segment_Nominal_Diameter_Field, Input_MAOP_Features, MAOP_Centerline_Identifier_Field, MAOP_Begin_Measure_Field, MAOP_End_Measure_Field, MAOP_Field, PIR_Factor, Additional_PIR_Tolerance__Feet_, Class_Type)

Environments

Current Workspace, Scratch Workspace, Default Output Z Value, M Resolution, M Tolerance, Output M Domain, Output XY Domain, Output Z Domain, Output Coordinate System, Extent, Geographic Transformations, Output has M values, Output has Z values, XY Resolution, XY Tolerance, Z Resolution, Z Tolerance

Licensing information

This tool requires a valid Gas HCA Tool user license or subscription. Please see the Request License and Register License tool help topics for details on obtaining and registering a Gas HCA Tool software license.

Related topics

Tags

High Consequence Area, HCA, centerline, pipe segment, diameter, maximum allowable operating pressure, MAOP, potential impact radius, PIR, class location, clustered, unclustered.

Credits

Copyright © 2016-2020 by G2 Integrated Solutions, LLC. All Rights Reserved.

Use limitations

HCA (Method 1) does not currently include calculation of Moderate Consequence Area (MCA) ranges. You may use the Esri Overlay Route Events tool to overlay method 1 and method 2 results, and thereby update method 1 HCA results with MCA ranges identified with the HCA Calculation (Method 2) tool.