Details:

Alternative Title:
TTO Number 13;Integrity management program delivery order DTRS56-02-D-70036;OPS TTO13 - Potential Impact Radius formulae for flammable gases other than natural gas.;
Corporate Creators:
Michael Baker Jr., Inc.
Corporate Contributors:
United States. Office of Pipeline Safety
Subject/TRT Terms:
[+]
49 CFR 192 Flammable Materials Fuel Gas Gases
Publication/ Report Number:
TTO Number 13
Resource Type:
Tech Report
Corporate Publisher:
United States. Office of Pipeline Safety
Abstract:
This report was prepared in accordance with the Statement of Work and proposal submitted in

response to RFP for Technical Task Order Number 13 (TTO 13) entitled “Potential Impact Radius

Formulae for Flammable Gases Other Than Natural Gas.”

A key element of the Gas Integrity Management Rule (49 CFR 192, Subpart O) is the calculation of

the potential impact radius (PIR) of a circle within which the potential failure of a pipeline could

have significant impact on people or property.

The original derivation of the PIR formula referenced in 49 CFR 192 is contained in the Gas

Research Institute (GRI) report by C-FER Technologies (C-FER), “A Model for Sizing High

Consequence Areas Associated with Natural Gas Pipelines” (Stephens 2000). It must be recognized

that this formula was derived solely on the premise that thermal radiation from a jet/trench fire is the

dominant hazard related to pipe rupture and subsequent ignition. Since natural gas is non-toxic and

significantly lighter than air, this premise is valid.

However, there are certain pipeline operators transporting flammable gases other than natural gas

(e.g. hydrogen) that will be governed by the jet fire hazard, and thus there is a need for derivation of

PIR formulae for use in identifying high consequence areas for these pipelines. While the C-FER

report provides a basis for derivation of such formulae, the dimensionless values for emissivity

factor, release rate decay factor, and efficiency factor used in the original derivation of the PIR

formula have not been validated or optimized for flammable gases other than natural gas.

An introduction to this report is contained in Section 1, while Section 2 presents the more detailed

background on the reasoning and assumptions used in the development of the PIR formulae

presented in this report.

Section 3 documents the process utilized in identifying the various products that are known or

reasonably assumed to be currently transported by pipelines in the US. Four products were chosen

for PIR formula development: ethylene, hydrogen, rich natural gas and synthesis gas (syngas).

Section 4 comprises the majority of the report and describes the actual PIR formula development in

a logical progression. At each step, the underlying formulae are given with the required variables

presented and explained. This section concludes with a generalized methodology for use in

determining the PIR for flammable gas mixtures. The PIR formula for natural gas referenced in 49

CFR 192 is also presented to allow the reader to compare the results of this study with the earlier

work.

Section 5 describes the efforts conducted to validate the PIR formulae. These efforts were essentially

fruitless due to the lack of actual incident data for the products of interest. Section 6 presents a

commentary on the usage of constants for selected model factors that are in fact variables and would

be treated as such if a more rigorous modeling approach were to be employed. Section 7 summarizes

the results of the PIR formula development process. Finally, Section 8 presents a list of reference

documents cited throughout the report.

The information included in the report that was entirely compiled by C-FER Technologies is

contained in Appendix A.


Format:
PDF
Funding:
DTRS56-02-D-70036
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:9c3345490fb0bd7669b2116ce6f16f263afdc224468771dd683ab61db866c32d
Download URL:
https://rosap.ntl.bts.gov/view/dot/16991/dot_16991_DS1.pdf
File Type:

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