incorporating inherently safer designs to improve ... · incorporating inherently safer designs to...
TRANSCRIPT
MMI Engineering
Eric Peterson, Ph.D.
Technical Process Safety and Risk Manager
www.mmiengineering.com
Date: 6 November 2013
Incorporating Inherently Safer Designs to
Improve Sustainability of Industrial
Facilities
Abstract
An increasing number of facilities across the globe are reaching a
significant age of maturity. Those facilities were constructed under
different regulations and guidelines than those used today. Renovations,
upgrades and retrofits are abundant in the oil, gas, and petrochemical
facilities and these new constructions must follow the current
regulations. The new guidelines will enhance the facility to become more
sustainable and inherently safer based on newer design and construction
practices. This paper discusses the coming challenges to facilities and the
need to incorporate inherently safer designs in the upgrades,
modifications to the facilities.
Requirements for Facilities
One question is: Are the older facilities grandfathered in under these
new regulations or must they comply. For safety concerns, they should
be required to perform safety assessments.
Being safety conscientious provides the facility a means to have
protocols in place to remove or reduce the cause (or provide mitigation
for the consequence) of an event whether this event is caused by human
error or faulty equipment in origin. Incorporating inherently safe
designs allow the facility to tolerate a consequence event while
maintaining the integrity of the surrounding structures and safety of
personnel to a reasonably practicable level.
Regulations vs. Industry Guidelines
– Recognized and Generally
Accepted Good Engineering
Practice (RAGAGEP) guidelines
• API RP-752/753
• CCPS publications
• ASME, ASCE codes
OSHA, Title 29 Code of Federal
Regulations (CFR) 1910.119
Encompassing Onshore Facilities
API Recommended Practice (RP)
752/753
ASME, ASCE
CCPS Guidelines for Facility Siting
and Layout
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Past Events at Aging Facilities
VCE which resulted in 28
employees killed and 36
injured with many of the
fatalities were in the
collapsed control room
building.
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Flixborough, UK on 1 June 1974
1989 Phillips disaster in Texas
A series of massive explosions
destroyed polyethylene facility resulting
in 23 on-site fatalities and another 130
were injured. The control room was
located very near to hazardous
operations. There were also inadequate
in firefighting capabilities.
Facility Siting Methods
Facility siting
– a high level (screening or using look-up tables),
– performing a consequence based, or
– risk based approach
– or a combination of the above
Hazards identification forms the cornerstone for any
facility siting study
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Hazard Identification Methods
Consequence based scenario selection
– desktop review of process safety information
• HMBs, PFDs, P&IDs, Layout, Receptor/Building Data
• Validation with a site visit to determine “select” scenarios in
various locations of the facility.
– The data utilized to perform this task is listed as followings:
The scenarios are based on the process area specific factors
such as equipment failure, process parameters data, and
design of the equipment in the process area, process stream
composition, operating conditions, and proximity to buildings.
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Hazard Identification Methods
Risk Based Approach, such as, such as quantitative
risk assessments (QRA) or semi-quantitative risk
analysis.
– This method is more rigorous and utilizes relevant company
and industry loss of containment data on similar types of
processes and equipment when selecting scenarios.
– This is in addition to the process safety information identified
in consequence based approach.
– This method requires a company to have or use (i.e.
assumption log) a risk criteria established.
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Hazard Identification Methods
Checklists can be too generic
– There is potential to not address all relevant issues:
• A hydrocarbon drift scenario to a utility area from truck
loading may not be captured in the utility system PHA or
HAZOP, and utility area may not be considered a higher
concern than proximity of process areas in truck loading
PHA or HAZOP.
– There is potential to be too generic:
• A corrosion leak is considered for loss of containment
and a severity rating applied in a HAZOP setting in a
global node without consideration for release locations is
not helpful for a facility siting.
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Proposed
Facility Siting Hazard Identification
Combining as basis for a comprehensive facility siting
study
– process hazard analysis checklists,
– process information and
– relevant event failure data
A formal facility study workshop
– Facility Siting HAZID or Facility Siting Risk Assessment (FSRA)
Workshop to review all reasonably sources of hazards
• From process design
• From hazards external to the process design
• From proposed changes to existing operations.
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The Benefits?
– A structured approach to capture specific concerns.
– Managing this process over the lifecycle of the facility.
– Justification of scenario basis for compliance and
– Demonstration for As-Low-As Reasonably-Practicable
(ALARP) principle also added benefits
Similar to upstream capital design industry - Major
Accident Events (MAE) workshop
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Proposed
Facility Siting Hazard Identification
Methodology (before workshop)
High severity loss of containment consequences
identified during a PHA or HAZOP should be given
special consideration
Model a sample applicable consequences analysis
– fire, toxic, asphyxiation, cryogenic, and explosion
– variation of parameters
• type of hydrocarbons available for release, the process
conditions, hole sizes, weather conditions, immediate ignition,
delayed ignition etc.
Modeling these scenarios would be a useful element to
a hazards identification workshop.
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• Inherently Safe Design
• Combination of Inherently Safe Designs and Process Control Systems
• Codes and Standards
• Safety Assessments
• Planning and Implementation of Engineering and Administrative Controls
Safety Management
Technical Safety
Risk Management
Overall Technical
Safety and Risk
Methodology(during workshop)
Defining potential hazard events
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– Toxic gas
– Asbestos
– Noise
– Flammable liquids
– Others
– Hydrocarbon under
pressure
– Elevated objects
– Working at height
– Moving vehicles
– Electricity
Once a hazardous event is defined, mechanisms for causes can
be defined and postulated scenarios can be further developed.
Author: David Sanderson
Date: 01 January 2011
CFD Modeling
Author: David Sanderson
Date: 01 January 2011
Heat transfer on Wall
Author: David Sanderson
Date: 01 January 2011
CFD Modeling of Mitigation Solutions
Methodology (during workshop)
Failure mechanisms identified
– Stress cracking
– Corrosion internal/external
– Fatigue
– Impact (dropped object, collision etc.)
Loss of containment (LOC) hazardous events
consequences should be defined
– Consequence analysis before the workshop would be helpful
to the team
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Methodology (during workshop)
Define prevention and consequence mitigation for
each area or system
Inherently safer design principles such as:
– Engineered controls – e.g. spacing, reduced inventory,
pressure vessel integrity, emergency shutdown valves,
pressure relief valves, etc.
– Procedural controls – e.g. technical operating procedures,
maintenance procedures, emergency response procedures,
etc. (not necessary to detail in the workshop)
– Management controls – e.g. responsibilities, competence
assurance, etc. (not necessary to detail in the workshop)
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Methodology (after workshop)
The structured approach can be represented in a
“bow-tie” format for each of the hazardous events.
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Note that the primary purpose of this discussion is to define hazardous
scenarios for facility siting and not to detail specific of a bow-tie methodology.
EVENT
H
A
Z
A
R
D
Barriers
C
O
N
S
E
Q
U
E
N
C
E
S
RecoveryPreparedness
Measures
Controlling the RiskRecovering from the
Realisation of the Risk
The optimization identifies the critical structural components which need to remain intact
during the identified fire scenarios in order to withstand the structural loads for a required
period of time so that the acceptance criteria are met.
The flow chart shows the assessment procedure for determining the optimum structural
protection scheme.
Assessment Procedure for Determining an Optimum PFP Scheme
PFP Optimization Procedure
CFD - Safety & Economic Benefit
Examples Conceptual: Facility plot layout possibilities (decrease incorrect solutions early
& the “re-”engineering resources)
Front End Engineering Design: New processing facilities (reduce plant footprint or increase efficiency of space available)
Detail Engineering Design: New production facilities (better estimate of required construction material)
Asset Acquisition: Evaluation of feasibility
Reserve Enhancement: Advance oil recovery (Method comparison)
Process Alteration: Change in process conditions (T, p, flowrate)
New Product Line Viability: (HMB’s, reactants, products)
HOW?!?!
Optimal Solutions Result In:
1. Increased Safety
– Deeper understanding of potential consequences
– Detailed knowledge of risk drivers
– Know efforts to optimally improve safety
– Better control of actual risk level
2. Reduced Cost
– Mitigation efforts may more easily be proven to not be required
– Material (steel) type & amount required for an acceptable level
– Reducing weight (both steel walls and passive fire protection)
Safety in Design using CFD (Computational Fluid
Dynamics) in Fire, Blast & Toxicology Assessments
Conclusions
The Facility siting studies have proven to be
invaluable in the quest to ensure safety in the oil, gas
and petrochemicals industry.
– The benefits of facility siting studies are realized through
fewer incidents, specifically those resulting in high
consequences such as multiple fatalities, associated
environmental and social costs, associated downtime and
privilege to operate.
This presentation has proposed developing a facility
siting hazards identification assessment plan as part
of the facility siting process
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Concluding Remarks
Employing CFD is Increasingly Important in Effective
Risk Management for Onshore & Offshore Facilities
Detailed Understanding of Potential Consequences Allow
for Improved Engineering Design, Mitigation Measures &
Procedures, for Enhanced Safety Performance &
Financial Results
Effective Means to Improve Insight of New Hazards &
Potential Consequences Where New Technologies are
Applied
Engineering a Safer World
For more information: Eric Peterson 281-810-5019 [email protected] www.mmiengineering.com