Risk-Informed Land Use Planning Familiarization Material

For Pipelines and Informed Planning Alliance (PIPA)

# Purpose

To meet the requirements of the Pipeline Safety Improvement Act (PSIA)
of 2002, PHMSA contracted with the Transportation Research Board (TRB)
to conduct a study of land use practices, zoning ordinances, and
preservation of environmental resources with regard to pipeline
rights-of-way and their maintenance. As a result of this study, [TRB
Special Report 281](http://onlinepubs.trb.org/onlinepubs/sr/sr281.pdf),
PHMSA/OPS formed the Pipelines and Informed Planning Alliance (PIPA) to
develop risk-informed land use guidance for application by stakeholders.
This paper summarizes the concepts of risk and risk management
strategies, the risk characterization practices in the pipeline
industry, the TRB recommendations for risk-informed land use guidance,
and the role of risk in land use decision-making near transmission
pipelines.

# Concepts of Risk and Risk Management Strategies

What is risk?

Risk is a concept used to characterize the magnitude of negative
consequences and the likelihood of the consequences occurring. The
mathematical expression for risk is:

Risk = Likelihood x Consequence

As described in the TRB report, sound risk assessment practice attempts
to answer the following questions:

-   What can go wrong?

-   How likely is it?

-   What are the consequences?

Because of the complexity of precise calculation of risk, the results of
the risk assessment process are often termed "risk insights," which are
often used to *inform* decision making by operators and regulators.

Terms related to risk assessment that can lead to confusion include
"hazard" and "threat". *Hazard* means a material or condition that could
produce an adverse health or safety impact ([e.g.]{.underline}, natural
gas in a pipeline under pressure) and *threat* means a physical process
that could cause the hazard to produce such an effect
([e.g.]{.underline}, severe corrosion of the pipeline, careless
excavation that could damage the pipeline).

What are the elements of risk management?

Risk management process involves the following elements:

-   *Identify* threats to the pipeline system and pipeline locations
    where failure would have the greatest consequences,

```{=html}
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-   *Assess* and quantify risks

    -   Assemble data about the pipeline system susceptibility to the
        threats,

    -   Integrate data in a risk model,

-   *Evaluate* results to make and implement risk-informed decisions

    -   Rank pipeline segments by risk,

-   *Mitigate risk* - Identify, evaluate and implement additional
    prevention and mitigation measures to reduce risk,

-   *Monitor* the effectiveness and modify the risk management process
    as needed.

To learn more about risk management, [*Ctrl click
here\>\>\>*](http://riskipedia.riskreports.com/display/RPA/Risk+Management+-+General+Principles%2C+History)

Why is risk a useful metric?

Operators of transmission pipelines must comply with regulatory
requirements developed to assure that the pipelines are maintained and
operated safely. Over the last sixty plus years, improvements have been
made in pipe materials, fabrication and installation techniques, and
post-installation operating and maintenance practices. These diverse
pipeline systems have varied susceptibility to threats to their
integrity which at times lead operators to employ practices in excess of
the regulations. As a result of Integrity Management regulations for
transmission pipelines, operators collect extensive data about the
characteristics of the pipe, the environment near the pipe, historical
practices and the concentration of people near the pipeline. Combining
the data collection process and institutional knowledge, an operator
knows the system and can develop an objective method to determine how
and where to focus enhanced practices and which practices are the most
effective. Risk is the best, perhaps only, metric to enable an operator
to consolidate information on the pipeline characteristics in support of
decisions on allocating resources to address recognized diverse safety
issues on its system.

# The Risk Characterization Practices in the Pipeline Industry

What do we know about the causes of pipeline failure - What are the
implications to land use near pipelines?

Threats considered "beyond the operator's control" include third party
excavation damage and damage from natural force ([e.g.]{.underline},
wind, rain, floods, lightening, and earth movement). Together they make
up the largest category of incidents (the term used to describe
reportable events for gas transmission pipelines) and accidents (the
term used to describe reportable events for liquid transmission
pipelines). Threats within the operator's control also can contribute
significantly to the occurrence of reportable events. If only incidents
and accidents *leading to fatalities* are considered over the period
from 2000 to 2005, excavation damage contributes 62.5% to hazardous
liquid accidents and 50.0% to gas incidents.

**[2000- 2005 Percent of Transmission Pipeline Events by
Threat]{.underline}**

  -------------------- ------------------------- -------------------------
  Threat               Gas Transmission          Liquid Transmission
                       Pipelines Incidents       Pipelines Accidents

  Excavation Damage    19.3                      **14.8**

  Natural Force Damage 16.1                      **7.1**

  Corrosion            23.0                      **26.9**

  Human Error          2.3                       **5.4**

  Material Failure     20.4                      **27.9**

  All Other Causes     18.9                      **17.8**
  -------------------- ------------------------- -------------------------

Land use planning near pipelines can influence the amount of third party
excavation damage. Increased land use near a pipeline can adversely
impact the safety of the pipeline.

What decisions do existing integrity management regulations require
operators to make using a characterization of pipeline risk?

The [Integrity Management](http://primis.phmsa.dot.gov/iim/) regulations
require pipeline operators to develop and maintain a program that
assesses pipeline risk and uses risk information as part of the effort
to ensure pipeline integrity and to protect [high-consequence
areas](http://primis.phmsa.dot.gov/comm/FactSheets/FSHCA.htm) (HCAs)
adjacent to pipelines. Provisions of these rules include:

-   Establishing risk-based schedules to conduct integrity assessments
    on highest risk segments first.

-   Evaluating segment risks to identify the interval for periodic
    integrity assessment (with maximum intervals prescribed in the
    regulations).

-   Integration of information that can impact the risk to a pipeline's
    integrity and the consequences of pipeline failure.

-   Performing risk analyses of pipeline segments to evaluate the need
    for additional preventive and mitigative actions to protect HCAs.
    The analysis of the effectiveness of the additional actions requires
    assessment of the magnitude and nature of risks along different
    pipeline segments and the effect of the actions on risk.

-   Evaluating the need (in Hazardous Liquid Systems) for Emergency Flow
    Restriction Devices (EFRDs) and enhanced Leak Detection Systems.

The concept of "Class Locations" is another example of how population
densities and surrounding land uses are incorporated in some existing
pipeline safety regulations. 49 CFR 192.5 defines area classifications
on the basis of population density in the vicinity of a natural gas
pipeline and specifies more conservative operating constraints as human
population density increases.

Each of these Class Locations has requirements on the depth of cover of
the pipe, and the maximum stress level it is allowed to operate. In
practice, operators periodically survey their pipelines to identify
areas where new development has occurred, and determine whether the
development has produced a change in the class location. Where a change
in class location has occurred, the operator either lowers the pressure
in the pipe to meet the required stress level, or replaces the pipe with
thicker pipe.

What approaches do operators use in characterizing pipeline risk?

Pipeline operators currently employ four basic types of risk analysis
models in order to evaluate and rank pipeline segments.

All models require location specific pipe characteristic data related to
the threats to be collected. This typically includes the design,
operation, and maintenance variables that are thought to affect the
likelihood of failure. Data is also collected about variables that
reflect conditions surrounding the line ([e.g.]{.underline}, population
density, or sensitive environmental resources) that relate to the
potential consequences of failure of a segment.

In quantitative models, algorithms using this data are used to estimate
risk. Other models are qualitative and use company expert opinion.
Models may incorporate both.

Most models provide a relative measure of risk (how the risk of
different segments compare) rather than an actual quantitative measure.
They are used to determine which pipeline segment poses the highest
risk. The numerical representation of risk from a relative model at one
company does not correspond to the same degree of risk at another
company. A relative risk model does not estimate actual risk such as the
annual risk of death to an individual residing near the pipeline.

*Number range CHAPTERIndex Models*

Index models are quantitative tools and provide operator specific,
relative risk ranking. They are the most frequently used risk models.

Operator specific numerical scores are assigned to the model variables
based on the known pipeline characteristic data. These numerical scores
are then combined according to a subjective assessment of their
importance using weighting factors and an index or score is calculated.
The scores characterizing the relative likelihood of a failure are
combined with those relating to consequences to arrive at a score
representing the relative risk by each section.

*Risk Estimation Models*

Risk estimation models are quantitative methods that use the
characteristics of sections of the pipeline and the surrounding area to
derive an estimate of the actual risk for each pipe segment. In risk
estimation models, the likelihood is estimated as the expected
probability of failure along the segment over a year's time.
Consequences are estimated in categories such as economic loss,
fatalities, and/or residual spill volume after clean-up (as an indicator
of long term environmental damage). Risks associated with each threat
for a section are calculated as the product of the likelihood of a
failure and the expected consequences from that failure. The total risk
for each section is estimated as the sum of risks from individual
threats over all threats and subsections. The model output is an actual
measure of risk.

*Scenario-Based Approaches*

Scenario models are qualitative and use an inductive approach to develop
accident sequences (or scenarios). A particular occurrence or initiating
event that has the potential to result in a leak or failure is assumed,
and possible scenarios that could evolve are then developed. Scenario
approaches allow the time-sequencing of events and accident progression
following a pipeline failure to be clearly described; index models do
not.

In a scenario-based approach, probabilities are qualitatively estimated
for the initiating event and each of the successive events in the
scenario to derive likelihood estimates for the scenario. Consequences
are qualitatively estimated to reflect the conditions resulting from the
sequence of events in the scenario. The numbers of scenarios that are
produced depend on the level of detail employed in the model.

Scenario-based approaches employ the same type of data as index and risk
estimation models but the data are typically used in conjunction with a
group evaluation process, rather than a model algorithm. The result is a
relative risk ranking of pipeline segments.

*Subject Matter Expert Approaches*

Similar to scenario-based approaches, subject matter expert (SME)
approaches utilize a panel of senior level personnel having in depth
knowledge of the pipeline system to identify various threats to pipeline
integrity and the associated consequences in high consequence areas from
pipeline operations. The SME process may also be used to provide inputs
to one of the other types of risk assessments.

For the SME approach to be effective, these "expert individuals" must
represent the major areas of pipeline activities such as operations,
engineering, cathodic protection, and assessment/testing. To be
effective, this method requires that data related to pipeline integrity
and the potential consequences of failure be readily available to
support characterization of the identified threats and consequences. A
process to rank the threats according to the collective judgment of the
panel is followed and a basis for the judgment is documented. The result
is a relative risk ranking of pipeline segments.

What do operators know about the range of impact (consequences) of
potential ruptures in their pipelines?

In the case of hazardous liquid pipelines, the regulations require
operators to identify the pipe segments that "can affect"
pre-established high consequence areas (HCAs). These pre-established
areas include populated areas, areas unusually sensitive to
environmental damage and commercially navigable waterways. In most
cases, operators have performed "can affect" analysis that takes into
account at a minimum: a spectrum of leak sizes, their detection
capability, their ability to mitigate the effects of spills, and the
terrain between the pipeline and the HCA.

In the case of gas pipelines, operators are required by the integrity
management regulation to evaluate their entire pipeline to determine
which segments, if they were to rupture, would impact areas having
prescribed population characteristics. The extent of impact of a
pipeline rupture is described by an equation that determines the
"potential impact circle". While a circle is used to estimate the range
of impact of a pipeline rupture, the actual observed burn area is
typically elliptical, and the application of the circle in identifying
HCAs is defined to address this difference.

The integrity management regulation requires changes in land use to
trigger a reevaluation of potential HCA's. This ensures that pipelines
near new high impact locations are incorporated into an operator's
integrity management program.

How does a gas pipeline fail and what is the potential impact?

The impact of a [gas pipeline
failure](http://66.102.1.104/scholar?hl=en&lr=&q=cache:NqojiUQhnaQJ:www.advanticatechinc.com/Library_Items/Technical_Papers/Papers/papers/ready%2520for%2520site/Development%2520and%2520Implementation%2520of%2520Risk%2520Assessment%2520Methods%2520for%2520Natural%25)
is influenced by the length, depth and type of defect and whether the
pipeline fails by puncture or rupture. It is dependent on the pipe
diameter, wall thickness, material properties and the operating
pressure. At failure, the surrounding soil will be expelled leaving a
crater. A mushroom shaped cap is formed which increases in height above
the release point and is fed by the gas jet and entrained air from the
plume which follows. In addition to entrained air the release can also
result in entrainment of ejected soil into the cap and plume. Eventually
the cap will disperse and a plume will remain.

Ignition can occur at any time during the release. If ignition occurs
immediately after rupture, a fireball will result. The fireball
typically lasts for up to thirty seconds and then the gas burns as a
large flame. There will not be a fireball if the release does not ignite
shortly after rupture. Depending on the failure mode, the gas can be
released with a wide range of different speeds and directions.

The levels of thermal radiation vary with time after rupture and with
distance from the release point. People can become casualties as a
result of receiving large doses of thermal radiation, and buildings can
be ignited by thermal radiation directly from the fire or from secondary
fires (e.g. from burning vegetation). A number of different criteria can
be used for predicting casualties which should also take account of the
distance from the pipeline and the availability of shelter.

The calculated consequence distances (potential impact circle) represent
the distance beyond which people would be expected to escape to safety
and the distance up to which houses would be predicted to catch fire.
These calculations take account of the time-dependent nature of the
event, and the variations due to the effects of parameters that cannot
be known in advance of the event, such as the prevailing weather
conditions or the crater source conditions, and range from a few meters
for vertical puncture releases to distances up to several hundred meters
for rupture releases, depending on the initial pressure assumed.

How does a liquid pipeline fail and what is the potential impact?

The consequences of a [liquid pipeline
failure](http://www.cde.ca.gov/ls/fa/sf/documents/v1protocolsec3.pdf)
depend on the product being transported, the manner in which the pipe
fails, pressure, and location. The major hazards associated with
products transported by pipeline are flammability and toxicity. Just as
with natural gas, petroleum liquid products are flammable and can result
in fire or explosions under certain conditions. In the case of liquid
releases, the area impacted can be a point some distance away from the
pipeline where liquid flowed and pooled before igniting. Chemicals such
as ammonia are toxic above certain airborne concentrations. Both of
these types of hazards can affect the safety of personnel in the
vicinity of the structural failure. A flammable vapor cloud can form
after a pipeline or tank fracture and, if an ignition source is present,
the cloud can detonate, or explode. In the case of a crude oil or gas
pipeline failure, a toxic cloud may also develop due to the presence of
hydrogen sulfide (H/sub 2/S). Even in low concentrations, inhalation of
H/sub 2/S may cause physical impairment or death.

What strategies can be used to reduce risk for existing pipelines?

The pipeline safety regulations, which are closely related to various
national consensus standards, are designed to require operators to carry
out preventive and mitigative activities for threats to integrity which
experience has shown to be important. As described above, the recent
integrity management regulations require operators to rigorously assess
the physical condition of pipe segments with the potential to impact
high consequence areas, and to remediate defects identified during these
assessments.

# TRB Recommendations for Risk-Informed Land Use Planning Guidance

TRB Special Report 281, *Transmission Pipelines and Land Use: A
Risk-Informed Approach*, recommendation states that risk-informed
guidance should address:

1.  Land use policies affecting the siting, width, and other
    characteristics of new pipeline corridors.

2.  The range of appropriate land uses, structures, and human activities
    compatible with pipeline rights-of-way.

3.  Setbacks and other measures that could be adopted to protect
    structures that are built and maintained near pipelines.

4.  Model local zoning ordinances, subdivision regulations, and planning
    policies and model state legislation that could be adopted for land
    uses near pipelines.

Such a risk-informed guidance system should include three interrelated
components:

1.  A decision framework informed by risk analysis.

2.  Guidelines based on the analysis.

3.  Alternative actions that could be taken on the basis of the
    guidelines.

The process for developing risk-informed land use guidance should:

1.  Involve the collaboration of a full range of public and private
    stakeholders (e.g., industry and Federal, state, and local
    governments);

2.  Be conducted by persons with expertise in risk analysis, risk
    communication, land use management, and development regulation;

3.  Be transparent, independent, and peer reviewed at appropriate points
    along the way; and

4.  Incorporate learning and feedback to refine the guidance over time.

What does TRB say about the important components in risk-informed land
use decisions?

A systems approach to risk management that uses quantifiable mitigation
measures (such as setbacks, warning signs, and alarm and evacuation
procedures) and prevention measures (such as design, inspection, and
maintenance of pipelines) would likely improve pipeline safety across
the nation. The TRB suggests that the methodology should involve the
following principal components:

1.  *A high-quality, national level risk assessment* that acknowledges
    various classes of pipelines, their risk profiles and the variety of
    conditions that exist in the field;

2.  *Simple and easy-to-use decision-guiding tools* with regard to risk
    levels associated with various extents of setbacks, rights-of-way,
    and procedures involved in maintenance, inspections, and mitigation
    in emergencies;

3.  A *management plan for implementation* that renders help to local
    communities according to need and incorporates feedback from use of
    the approach in the field;

4.  A *management plan for long-term communication* of risk and input
    from all stakeholders, especially pipeline operators, local
    officials, and the public; and

5.  A *management plan for integrating* all the preceding components and
    refining them on a continuing basis using actual experience.

# Overview of the Role of Risk in Land Use Planning - Risk-Informed Decision Making and Communication 

How has risk-informed land use planning near pipelines evolved and what
is the current state?

Land use planning near transmission lines is a subset of land use
planning near hazardous facilities which has its roots in the Seveso
Directive in 1982. The best-known consequence of the Seveso disaster was
an EC-wide regulatory framework for ensuring the safety of hazardous
installations. Prior to the Seveso Directive there was no requirement
for public information about major industrial hazards and appropriate
safety measures in the event of an accident. This was the first time
that the principle of \"need to know\" was enshrined in European
Community legislation. It expanded the scope of public information and
public participation in decision-making. Other results of the directive
were planning for off-site emergencies and multiple aspects of
industrial safety. It also equalized the burden of regulation on
industry across the EC.

In 1999, Seveso II Directive introduced the new requirements relating to
safety management systems, emergency planning, land-use planning and the
reinforcement of inspections. It was aimed at prevention of
major-accident hazards involving dangerous substances and at limiting
their consequences if they occurred. The document, [*Guidance on Land
Use Planning*](http://mahbsrv.jrc.it/downloads-pdf/Landuse2.pdf), was
released but is not legislation. The Directive excluded but required
further investigation of the transport of dangerous substances by
pipelines.

Canada followed the EC's path. In the late 1980\'s, increasing pressure
from citizens\' action groups and a growing body of regulatory
legislation encouraged Canadian industry to adopt a proactive approach
to disaster planning. In 1991, the Major Industrial Accidents Council of
Canada released a national standard on emergency planning for Canadian
industry followed by land use planning for in 1995 and [guidance for
land use near
pipelines](http://www.cepa.com/index.aspx?site_guid=20B417BE-EDD6-497C-AFCA-B0D26BFF93FE&page_guid=4E05CD71-929E-40D1-94E7-DB904C3942A1)
in 2004.

While highly structured quantitative risk characterization is mandated
as part of land use near hazardous facility decisions in the UK, Canada,
European Union, Australia and New Zealand, virtually no similar national
approaches exist in the US. Risk informed land use planning guidance
specific to pipelines exists in the UK, Canada, Israel, Netherlands and
the EU. Land use planning in the US is usually performed at the local
level and planners generally do not require risk-based or risk-informed
evaluations. They typically do not have experience evaluating risks
associated siting new developments near existing hazards. The California
Department of Education is an exception.

What examples exist of land use decisions related to pipeline siting and
development near existing pipelines in the US?

-   [California Department of Education
    (CDE)](http://www.cde.ca.gov/ls/fa/sf/protocol07.asp)

Support's school siting decisions, including comparison of alternative
sites, when an oil (crude or refined) or natural gas pipeline is within
1500 feet of the proposed school site. The decision making process
involves three sequential steps: screening analysis of candidate sites
to determine whether additional analysis is needed (Stage 1); detailed
estimation of the individual risk (IR) from the pipeline to a person at
the boundary of a proposed site (Stage 2); more detailed analysis needed
only to address factors such as diverse materials in the pipeline, the
presence of multiple pipelines, or physical features that may change the
nature of the risk such as the presence of storm drains (Stage 3). CDE
developed a spreadsheet to estimate risk called, [*Pipeline Risk
Analysis Protocol Total Individual Risk (TIR) Estimating
Aid*](http://www.cde.ca.gov/ls/fa/sf/protocol07.asp). The approach
requires considerable technical expertise for CDE.

-   [City of Austin Ordinance on Development Near Hazardous
    Pipelines](http://www.ci.austin.tx.us/news/02/pipeline_ord.htm)

This Ordinance applies to hazardous liquid pipelines 8 inches or greater
in diameter. A "use requiring evacuation assistance" (list provided) is
prohibited in a structure located within 500 feet of a hazardous
pipeline. Exceptions are possible for certain structures between 200 and
500 feet of the pipeline and require resolution of the city Council
based on a recommendation of the fire chief that the structure design
provides an adequate time period for evacuation. There may not be new
construction within 200 feet of a hazardous pipeline. Exceptions are
possible for certain structures based on determination by the fire chief
that the structure design provides a one hour period for evacuation. No
placement of structures or excavation is permitted in a restricted
pipeline area (within 25 feet of the hazardous pipeline) or within its
easement (limited exceptions listed). A residential lot of less than one
acre may not include a restricted pipeline area. A person may not place
a structure or excavate within a restricted pipeline area (exceptions
listed).

-   [Model Setback and Depth Requirements - Municipal Research &
    Services Center (MSRC) of
    WA](http://www.mrsc.org/subjects/PubSafe/PipeSafetyModel.aspx#Model)

MSRC is a non-profit that provides research, consultation and
information services to and is funded by counties, cities and districts
in Washington state. This model Ordinance applies to new hazardous
liquid and gas transmission pipelines. It is designed to avoid
encroachment on the pipeline right-of-way, thereby reducing the
likelihood of third-party damage. All new hazardous liquid and gas
transmission pipelines must be buried a minimum of three feet below
grade. A setback of at least 50 feet from the nearest edge of the gas
transmission pipeline corridor (including right-of-way and easements) is
required for general residential, commercial and industrial buildings.
This setback distance must be doubled for certain educational and
recreational facilities.

-   [Washington Utilities and Transportation
    Commission](http://www.wutc.wa.gov/webimage.nsf/1fd8daa538d4adba8825704d00643802/9fe01a11e8383ff888257097005d6218!OpenDocument)

These guidelines are designed to increase awareness of the need to
integrate land use decisions with understanding of the pipeline
right-of-way location. They apply to existing transmission pipelines
only. The guidelines seem to draw heavily on the material in the
Canadian Standards Association guidelines described above. The guideline
proposes a Consultation Process emphasizing early communication among
key stakeholders as part of any land use planning process. The
Consultation Process should be undertaken for any proposed development
based on the criteria established by local governments. The report
tabulates nine factors that should be considered in designating the
distance between a pipeline and a proposed development for which
consultation should occur. The position in an earlier draft that
development within 660 feet of the pipeline - called the "Consultation
Zone" - should be subject to consultation was eliminated from the final
draft because the extent of the zone of potential impact depends on the
nine factors now enumerated.

The WUTC in [Chapter
480-93-020](http://www.wutc.wa.gov/rms2.nsf/177d98baa5918c7388256a550064a61e/838687206275d9018825738300581186!OpenDocument)
defines allowable distances from buildings and future buildings to gas
pipelines operating at different pressures. A gas company must receive
commission approval prior to operating any pipeline within 500' at 500
psig or 100' between 250-500 psig to a building. Newly constructed
pipelines must adhere to these standards and their design must consider
possible future development near the pipeline. If they cannot meet the
requirement, they must demonstrate why an alternate route was not
practical.

-   [Edison Township Municipal Code, Section
    17.08.210](http://primis.phmsa.dot.gov/comm/publications/MunicipalCodeofEdisonTownship.pdf)

The code is prescriptive. No building or land disturbance shall be
permitted within seventy-five (75) feet of any distribution, gathering
or transmission line, as defined in subsection A of this section. No
building or structure or part thereof which is used for the
manufacturing, processing, generation or storage of corrosive, highly
toxic, oxidizing, pyrophoric, water-reactive, highly combustible,
flammable or explosive materials that constitute a high fire, explosion
or health hazard, including loose, combustible fibers, dust and unstable
material, shall be constructed within one hundred twenty-five (125) feet
of any distribution, gathering or transmission line.

*What does risk-informed land use planning look like?*

Where structured characterization of the risks related to development
exist, the typical *elements* of current risk-informed land use planning
include the following:

-   *Identify* hazards and screen for potential impact,

-   *Assess* and quantify risks

    -   More complex situations may require a quantitative assessment of
        actual risk ([e.g.]{.underline}, involving consideration of
        failure cause, failure mode, gas outflow, ignition, thermal
        radiation, thermal effects, risk calculations)

-   *Evaluate -* Make and implement risk-informed decision,

-   *Mitigate* - Include consideration of means to reduce risk
    ([e.g.]{.underline}, reducing amount of hazardous material,
    strengthening preventive or mitigative measures, strengthen
    emergency planning) Involve stakeholders in consultation,

-   *Monitor* hazard and related risk over time.

These elements closely parallel the elements in pipeline integrity
management. The risk management already performed by operators may have
the potential to provide information to support risk-informed land use
guidance as shown below in parentheses. However, inconsistencies in the
approaches operators take to modeling risk and the prevalence of risk
models that estimate relative rather than absolute risk would prevent
the use of existing models to support consistent land use decisions.

-   *Identify* hazards (The hazard is the failure of a natural gas or
    hazardous liquid transmission pipelines covered under 49 CFR 192 and
    195.),

    -   Screen for potential impact (Operators identify areas of
        potential impact area through HCA's and "can affect" pipeline
        segments. The criterion is based on population density but it
        does not require facilities be identified by other
        characteristic such as ability to evacuate quickly.)

-   *Assess* and quantify risks (Operators currently perform a risk
    assessment as previously described. Most do not currently determine
    actual risk. Operators currently are not required to share
    assessment data except with OPS or state Commissions.)

    -   More complex situations may require a quantitative risk
        criterion

-   *Evaluate -* Make and implement risk-informed decision

-   *Mitigate* - Including consideration of means to reduce risk
    (Operators currently are required to consider this as part of the
    IMP but there is not a target level of risk for operators to reach.)

    -   Involve stakeholders in consultation (Operators currently are
        required to have a communications plan that follows API RP 1162.
        It includes information that is required to be communicated to
        different stakeholder groups such as information on how to
        respond in the event of a leak or emergency.)

-   *Monitor* hazard and related risk over time (Operators are required
    to patrol pipelines and at least annually reassess risk.)

*Here are some key observations on existing risk-informed land use
planning practices:*

-   Limited experience exists with risk-informed land use planning
    specific to pipelines - both in the US and abroad,

```{=html}
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```
-   Most decision processes involve initial screening to determine
    whether more detailed risk evaluation is needed,

-   Many risk screening approaches consider only the consequences not
    the threats,

-   Some land use decisions include the option to reduce likelihood of
    failure - who is responsible for the cost of these preventive
    measures is an issue, primarily for development near existing
    hazardous facilities,

-   Regulations require minimum distance to pipeline. If the minimum
    distance cannot be met, [additional
    mitigation](http://ictaf.tau.ac.il/cff4.pdf) actions such as
    installing thicker walled pipe, increasing depth of cover or
    installing concrete barriers are required.

-   The use of formal decision criteria seems to drive toward greater
    complexity of analysis ([e.g.]{.underline}, evaluation against
    individual risk criteria requires performance of quantitative risk
    analysis),

-   Stakeholder involvement in decision process seems critical to the
    acceptability of land use decisions.

-   Regulations that restrict land use near a hazard can impact land
    value and may be subject to compensation requirements depending on a
    court's interpretation of [regulatory "takings" provision of the
    Fifth Amendment.](http://www.cato.org/pubs/regulation/reg16n3g.html)

*Characteristics that are distinctive to transmission pipelines that may
affect land use planning near pipelines include:*

-   Pipeline "site" is not localized -- expecting operators to acquire
    broad expanse of adjacent land to prevent or constrain development
    is not economically realistic,

-   Activity associated with land development and use can affect the
    safety of the pipeline ([i.e.]{.underline}, a major threat to
    pipeline integrity is excavation damage),

-   Operator must monitor land development and use activity near
    pipeline to minimize risks to public safety and supply interruption,

-   Operators must have access to land near pipeline to carry out
    maintenance activities.

What commonalities are there between risk-informed land use planning
programs?

*Decision Making Responsibility*

With the exception of the UK, the decision to allow or restrict
development is made by local officials who are able to weigh the local
risks associated with development against the local benefits derived
from the development. The information on which these decisions are made
may come from a variety of sources and may require considerable
technical sophistication. The needed analysis may be the responsibility
of the land developer. Where consistent input to the decision process is
desired, provisions are needed to communicate how the analysis is to be
performed, and the criteria against which the results of the analysis
are to be compared.

Some land use decisions made to preserve the environment
([e.g.]{.underline}, development restrictions near pristine shorelines)
or to protect the community from natural disasters ([e.g.]{.underline},
restrictions to development in flood plains) can strongly impact land
value and may therefore be subject to compensation requirements dictated
by court interpretations of regulatory "takings" provisions of the fifth
amendment.

*Identify Hazards and Screen for Potential Impact*

Hazards that are subject to land use restrictions vary from toxic or
flammable chemicals, including natural gas and petroleum products, to
natural hazards such as flooding and seismic. The discussion here is
focused on restrictions related to the presence of hazardous chemicals,
either in processing facilities or being transported in the vicinity of
the proposed development.

-   Many land use decision processes begin by conducting a simple
    screening for the presence and potential impact of hazards that
    might impact the proposed land use. The purpose of this analysis is
    to focus future consideration on situations where the risk is
    believed to be large enough either to warrant more detailed
    analysis, or to initiate a consultation process involving a spectrum
    of stakeholders in discussions intended to lead to a decision on
    land use ([e.g.]{.underline}, Washington Utilities and
    Transportation Commission). Typically this screening involves
    identification of the hazardous materials within some prescribed
    evaluation zone, and evaluating the potential for consequences if
    the materials were released. This screening could be as simple as
    determining whether an oil or natural gas pipeline is within 1500
    feet of the boundary of the proposed school (California Department
    of Education).

*Assess and Quantify Risk*

For situations in which the hazard is determined to be significant, some
decision processes require a more detailed assessment and quantification
of risk. Both "consequence based" and the "risk based" approaches were
used. Most included provisions to perform more complex analysis for more
complex situations. Generally high density areas had an acceptable
actual risk of 1 x 10^-6^ and 1 x 10^-4^ in low density areas for an
individual. Obtaining reliable data to determine failure probability was
reported as challenging. [California Department of Education has a
template](http://www.cde.ca.gov/ls/fa/sf/protocol07.asp) for their
rather complex analysis.

*Evaluate - Make and Implement Risk-Informed Decision*

Possibly involving a quantitative risk criterion ([e.g.]{.underline},
annual risk to an individual at the boundary of the development)

*Mitigate*

-   Including consideration of means to reduce risk ([e.g.]{.underline},
    reducing amount of hazardous material, strengthening preventive or
    mitigative measures, strengthen emergency planning)

-   Involving stakeholders in consultation

*Monitor Hazard and Related Risk over Time*

Prescriptive programs generally provide an approval or disapproval but
do not include additional actions to take to monitor the hazard. Both
the EC and UK have initiatives to collect data about pipeline failures
in order to improve their programs.

Links to risk-informed land base planning near transmission lines
programs outside of the US:

-   [Canada -- Land use planning for pipelines: A guideline for local
    authorities, developers, and pipeline
    operators](http://www.cepa.com/index.aspx?site_guid=20B417BE-EDD6-497C-AFCA-B0D26BFF93FE&page_guid=4E05CD71-929E-40D1-94E7-DB904C3942A1)

-   [Isreal - Choosing a Standard for Natural Gas Pipelines Design and
    Construction](http://ictaf.tau.ac.il/cff4.pdf)

-   [UK -- Procedure for Setting Land Use Planning Zones For Major
    Accident Hazard
    Pipelines](http://www.hse.gov.uk/foi/internalops/hid/spc/spctld10.pdf)

-   [UK - Standard IGE/TD/1 Edition
    4](http://lorien.ncl.ac.uk/ming/safety/pipeline/pipeline-codes.pdf)

-   [EU - Land Use Planning Policies & Good
    Practices](http://www.unece.org/env/teia/water/pipeline/haguepresentations/SessionIII-1MichaelStruckl.pps)

Links to QRA's examples:

-   [Pipeline Safety Assessment Schulte
    Road](http://www.ci.tracy.ca.us/city_council/meetings/agendas/2007/12/18/04.pdf)

-   [Independent Safety Review of the Corrib Gas
    Pipeline](http://www.dcmnr.gov.ie/NR/rdonlyres/4CA02A2D-8FA0-4F76-8372-1839D95FA773/0/AdvanticaPresentationonDraftReport.pdf)

Links to support material for developing the guidance program:

-   [Planning Public Forums: Questions to Guide Local
    Officials](http://www.cacities.org/resource_files/25304.ILG_PlanPubForums.pdf)

-   [An Ounce of Prevention: Best Practices for Making Informed Land Use
    Decisions](http://www.riskinstitute.org/PERI/PTR/Risk+Management_PTR_1144.htm)