CREATE CENTERLINE PIR BUFFERS

Summary

Create Centerline PIR Buffers buffers your centerline features based on the Potential Impact Radius (PIR), as defined in 49 CFR §192.903, using the PIR formula:

PIR = f _* (p _* d²)^0.5

where:

PIR is the radius of a circular area in feet surrounding the point of failure

f is the product-specific PIR combustion factor (0.69 for ‘dry’ natural gas)

p is the Maximum Allowable Operating Pressure (MAOP) of the pipe

d is the nominal diameter of the pipeline in inches

The PIR for HCA–MCA analysis is derived from the pipe diameter and MAOP attributes you import into the Gas HCA Tool project geodatabase using Prepare Pipe Segment and MAOP Features. Note that the PIR can vary along your centerline features. The tool creates PIR buffer features along the length of your centerline features, as needed. The centerline PIR buffers are subsequently used to select the Building Intended for Human Occupancy (BIHO) features and identified sites processed by the Create Structure and Site PIR Buffers tool.

Usage

Input Pipe Segment Features or Records – This tool requires as input the pipe segment records output by the Prepare Pipe Segment and MAOP Features Unless otherwise specified, the tool defaults this parameter to the PIPESEGMENT table in your selected Gas HCA Tool project geodatabase.
Input MAOP Features or Records – This tool requires as input the MAOP records output by the Prepare Pipe Segment and MAOP Features Unless otherwise specified, the tool defaults this parameter to the MAOP table in your selected Gas HCA Tool project geodatabase.
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. If your pipeline is transporting gas other than natural gas, please section 3.2 of ASME/ANSI B31.8S for additional information on how to calculate the PIR combustion factor.
Additional PIR Tolerance – 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.
Calculation Type – This parameter enables you to specify HCA-MCA calculation method. (The same method should be applied to all tools in a given HCA-MCA analysis workflow.) The Gas HCA Tool supports both method 1 and method 2 HCA-MCA calculations, as defined by 49 CFR §192.903(1) and (2), respectively.
Output Centerline PIR Segment Features – Unless otherwise specified, the default destination for the output centerline PIR segment features is the HCA_PIR_SEGMENT feature class in your selected Gas HCA Tool project geodatabase. This output stores the PIR segment features created along your centerline features.
Output Centerline PIR Segment Buffer Features – Unless otherwise specified, the default destination for the output centerline PIR segment buffer features is the HCA_PIR_SEGMENT_BUFFER feature class in your selected Gas HCA Tool project geodatabase. This output stores the PIR segment buffer polygons features created buffering the output PIR segment features using the PIR.

In a typical HCA-MCA analysis workflow, Create Centerline buffers is run after Prepare Pipe Segment and MAOP Features and before Create Structure and Site PIR Buffers.

Syntax

CenterlinePIRTool_hcapy (project_database, {pipe_segment_layer}, {maop_layer}, pir_factor, {pir_tolerance}, {tool_type}, pir_segment_out, {pir_segment_buffer_out})

Parameter	Explanation	Data Type
project_database	Dialog Reference Select a Gas HCA Tool project geodatabase created using the Initialize Database tool. The output from this tool is stored in this workspace, by default. There is no Python reference for this parameter.	Workspace
pipe_segment_layer (Optional)	Dialog Reference Specify your input pipe segment features. There is no Python reference for this parameter.	Table View
maop_layer (Optional)	Dialog Reference Specify your input MAOP features. There is no Python reference for this parameter.	Table View
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
pir_tolerance (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
tool_type (Optional)	Dialog Reference Select the calculation type. HCA Method 1 is the default value. There is no Python reference for this parameter.	String
pir_segment_out	Dialog Reference Specify the destination for your output centerline PIR segment features. There is no Python reference for this parameter.	Table View
pir_segment_buffer_out (Optional)	Dialog Reference Specify the destination for your output centerline PIR segment buffer features. There is no Python reference for this parameter.	Table View

Code sample

Create Centerline PIR Buffers

# Import GasHCA Library

import hcapy

# improt Gas HCA Tools

arcpy.ImportToolbox(“C:\Python27\ArcGIS10.6\Lib\site-packages\hcapy\esri\Toolboxes\Gas HCA Tools.pyt”)

project_database = r”C:\projects\GasHCA_Enhancements\A_DOTCLass_Test5.gdb”

pir_factor = 0.69

# Execute tool

arcpy.CenterlinePIR_hcapy(project_database, pir_factor = pir_factor)

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.

Credits

Use limitations

There are no access and use limitations for this item.