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This project is funded by the European Union
Projekat finansira Evropska Unija
HAZARD IDENTIFICATION
METHODS /Part 1
Antony Thanos
Ph.D. Chem. Eng.
[email protected]
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
Hazard
• State, action or physical-chemical characteristic
with potential of harm to equipment, human health
or the environment
• Examples:
 Work at height – Hazard of fall
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Hazard examples : (cont.)
 Toxic material handling (e.g. production of NH3)
o Toxic release (e.g. failure of pipe)
o Dispersion of released NH3 to the
atmosphere
o Toxic effects to human via inhalation of toxic
substance
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Hazard examples : (cont.)
 Flammable material handling (e.g. storage of
gasoline)
o Release of substance (e.g. hole in tank wall)
o Subsequence ignition leading to fire or
explosion (vapour ignition in congested
space –” certain circumstances”)
o Effects to human and equipment due to :
heat radiation (cause of burns or
equipment failure) for fire
overpressure/missiles for explosion
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Hazard source examples:
 Failures of control systems, such as :
o instrument failure, e,g. LIT (Level Indicator
Transmitters) stuck to place failing to show
overfilling of tank
o level controller (LC) failure
o control valve failure, e.g. LCV (Level Control
Valve) failure lead to overfill and
overpressure with failure of pipe/pressure
vessel
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Hazard source examples
 Failures of control /protection systems
PRV
FI
LC
LIT
HV
LCV
This Project is funded
by the European Union
Ομάδα
Project implemented by Human
Dynamics Consortium
• Hazard source examples : (cont.)
 Failures of protection/“emergency” systems,
such as :
o Pressure Relief Valve (PRV) failure, e,g. valve
fails to open in high pressure case, leading
to vessel failure
 Mechanical failures, e.g. corrosion, weld
defects, human error in design
 Operator errors, e.g. hand operated valve (HV)
closes when pump is in operation
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Hazard source examples : (cont.)
 External sources, e.g. earthquakes, missiles
from accidents in other equipment
 Management failures, as lack of operating /
maintenance procedures
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Accident : The event that leads to harm to human,
environment or equipment
• Consequence : The outcome (effect) of an
accident, as for example:
 Injury from fall from height
 Pulmonary damage due to inhalation of
released NH3
 Burns from thermal radiation of fire in gasoline
tank
• Consequence analysis : the procedure applied for
calculation of the extent of accidents effects
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Hazard Identification : Use of techniques for
identifying hazards, causes of accidents and
effects
 Techniques do not automatically reveal
hazards, but facilitate the systematic
examination of hazards, taking into advantage
of existing knowledge of systems examined
 “Few accidents occur because the design team
lack knowledge; Most errors in design occur,
because the design team fail to apply their
knowledge”, Trevor Kletz
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Hazard Identification (cont.)
 Not all hazards or causes/effects are
guarantied to be found
 Results quality are strongly dependent on
personnel experience
 High subjectivity in hazard importance
evaluation
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Hazard Identification (cont.)
 Team work leads to higher quality in results
 The prudent application of Hazard Identification
Techniques can identify important accidents,
their causes and effects
 Do not consider Hazard Identification only as
requirement for Legislation compliance, but as
essential tool for safety improvement
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Safety reviews/audit/inspections
 Evaluation of information from :
o Visits to workplaces
o Review of drawings, operation procedures
o Interviews with personnel (defensive
response ?)
o Records of events
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Safety reviews/audit/inspections (cont.)
 Advantages :
o Very simple
o Applicable during the whole lifecycle of
establishment
o Allows compliance checks with company
procedures/practices
 Disadvantage :
o Not strictly formed technique
 Not to be considered as suitable for Safety
Reports
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists
 Written list of questions (usually require
answers in YES/NO form)
 Response to questions via :
o Document review
o Walk-arounds (verification of actual situation
–existing installations)
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Level of detail strongly depends on author
experience on process examined
o Minimal : Too generic, easily applied in
different processes within a company
o Very detailed:
focusing in a specific process only
not applicable in other type of processes
(e.g. LPG checklists not suitable to Heavy
Fuel Oil depots)
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Typical areas to be addressed :
o Storage/handling of materials
o Process equipment, procedures
o Control and emergency provisions
o Sampling facilities
o Personnel protection
o Maintenance
o Emergency response
o Wastes management
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Example :
o Is there quality control on raw materials ?
o Are SDS available for raw materials ?
o Are there incompatible materials in close
areas ?
o What is the flash point of raw/intermediate
materials, products ?
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Examples :
o Are there shift hand-over procedures ?
o Are there equipment isolation procedures ?
o Are there reactions with runaway
characteristics ?
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Examples for safety valves :
o Are there available and valid test certificates
for each safety valve ?
o Are there the required marking on each
safety valve ?
o Are all safety valves depicted in P&IDs?
o Do all safety valve discharge to safe
location?
o Are there isolation valves in safety valves
limiting their operation ?
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Examples for pumps :
o Are there dry-run protection provisions for
pumps ?
o Can pump shut-off pressure exceed
downstream pipe design pressure ?
o ……. Please contribute……
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Examples for pumps : (cont.)
o Are there strainers at suction ?
o Are there check valves at discharge to
prevent back flow ?
o Are there protection guards at pump/motor
couplings ?
o Is there minimum flow recirculation line ?
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Examples for furnaces :
o Is there protection for acid dew point
corrosion ?
o Are there fail-closed valves at fuel supply
lines ?
o ……. Please contribute……
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Examples for furnaces : (cont.)
o Is manual reset required for fail-closed fuel
supply lines ?
o After failure in ignition of burners are there
interlocks for sufficient purging air before reignition ?
o Are there fast acting blow-off panels in
furnace ?
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Advantages
o Very useful in compliance checking with
standards, legislation requirements etc.
o Can be used by non-experience personnel
o Adaptable to analysis depth desired
o Minimal time requirements (in the order of 7
days for large processes)
o Known hazards are fully explored
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Checklists (cont.)
 Disadvantages
o No info for causes, consequences,
prevention/mitigation
o Not effectively applicable to novel processes
(as checklist heavily rely on past experience)
o Hazards not foreseen by questions cannot
be identified
o Not to be considered as suitable for Safety
Reports
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Preliminary Hazard Analysis
 Applied usually in initial design of layout
planning
 Examines basic characteristics for :
o Raw materials, intermediates/final products,
wastes
o Equipment: high pressure systems, reactors
o Factors causing accidents and safety
equipment
o Procedures for operation, control,
maintenance
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Preliminary Hazard Analysis (cont.)
 First step for further refinement of hazard
identification by more detailed technique when
project is more mature
 Rather experienced personnel on safety is
required, as judgment is necessary
 Hazard attributed to ranking scheme, such as :
o I, Insignificant
o II, Limiting
o III, Critical
o IV, Catastrophic
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Preliminary Hazard Analysis (cont.)
 Results presented usually in sheet form
Example of results for LPG road tanker
Hazard
Cause
Flammable 1. Hose rupture
release due to tanker
movement
This Project is funded
by the European Union
Effects
Cat. Mitigation/Prevention
measures
Uncontrolled leak, III
potential off-site
consequences
a. Procedures require
handbrake on
during loading
Project implemented by Human
Dynamics Consortium
• Preliminary Hazard Analysis (cont.)
 Advantages:
o Rather limited information and time (in the
order of 12 days for large processes)
o Applicable even in early stage of design
permits interventions for risk control with
minimum cost, e.g. identification of
intermediate products with special
hazards (Bhopal accident),
permits examination of different
production process
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Preliminary Hazard Analysis (cont.)
 Disadvantage :
o Not strictly defined technique. Information
collected within discussions without
systematic structure
 Not to be considered as suitable for Safety
Reports (design is expected to be fixed and
mature when Safety Report is submitted)
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking
 Calculation of qualitative or quantitative index
of hazard, based on characteristics of
hazardous processes (quantities, operating
conditions etc.)
 Examples :
o DOW F&EI (Fire and Explosion Index)
o DOW CEI (Chemical Exposure Index)
o MOND Toxicity index
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking (cont.)
 Examples of required information:
o Material properties
o Process conditions/characteristics
o System design and construction
o Support systems
o Purging, ventilation, cooling, heating etc
o Equipment fire proofing, layout, corrosion resistance
etc
o Operation, training
o Maintenance, inspection
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI
 Index calculation
F&EI= MF*(1+GPH)*(1+SPH)
MF: Material factor, based on NFPA flammable and
reactivity ranking, or calculated on physicochemical
properties (at ambient conditions)
GPH : General Process Hazard
SPH: Specific Process Hazard
GPH, SPH : Calculated as Sum of penalties of partial
values available in tables
GPH=ΣGPHi, SPH=ΣSPHi
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
 MF table values adjusted, if necessary,
depending on process conditions (e.g. material
used at temperature over flash point)
 GPHi cases :
o Exothermic reactions
o Endothermic reactions
o Material handling and transfer
o Enclosed or Indoor process units
o Access
o Drainage and Spill control
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
 Example GPHi values for Exothermic Reaction :
o Mild exotherms : GPH=0.3 (isomerisation,
hydrogenation)
o Moderate exothems : GPH=0.5 (alkylation)
o Extremely sensitive exotherm reactions :
GPH=1.25 (nitration)
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
 Example GPHi values for indoor units :
o Dust filters in enclosed area : GPH=0.5
o LPGs, or flammables above flash point :
GPH=0.6 (in case of quantity over 1000 gal,
GPH=0.9)
o For mechanical ventilation GPHs reduced by
50%
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
 SPHi cases :
o Toxic materials
o Vacuum conditions
o Operation near flammable range
o Dust explosion
o Pressure
o Low temperature
o Quantities of flammable/unstable material
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
 SPHi cases : (cont.)
o Corrosion/erosion
o Leakage (joints-packings
o Fired equipment
o Hot-Oil heat exchangers
o Rotating equipment
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
 Examples of SPHi values for pressure :
o 1000 psig, SPH=0.86
o 2500 psig, SPH=0.98
o >10000 psig, SPH=1.5
 Quantity of flammable material : graph based
on potential heat release
 Fired equipment : graph based on distance
from flammables leakage locations (SPH max =1
for flammables heated in fired equipment)
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
 Examples of SPHi values for leakage :
o Process with regular leakage problems at
pumps, compressors, flanges, SPH=0.3
o Abrasive slurries with sealing problems,
along with rotating shafts (i.e. pumps)
SPH=0.4
o Use of sight glasses, expansion joints,
bellows assemblies, SPH=1.5
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
 DOW F&EI values :
1-60, Light
61-96, Moderate
97-127, Intermediate
128-158, Heavy
159, Severe
And then ???
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
 DOW F&EI method is supplemented by similar
calculation of :
o Exposure area (function of DOW F&EI value)
o Base Maximum Property Damage
o Loss Control Factor using credits for
prevention/mitigation measures, such as :
Emergency power, Cooling, Computer
control, Isolation features
o Actual Maximum Property Damage and
Maximum outage time expected
o and finally Business interruption loss
(capital units)
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking - DOW F&EI (cont.)
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking in legislation
 Italian legislation for LPGs and for very
flammable and toxic storage
 Incorporation of safety measures in ranking
calculation
 Result (classes) used in risk acceptance
criteria
• TNO subselection method for scenarios
selection (used in Netherlands within
legislation requirements for Safety Reports –
RIVM Reference Manual BEVI Risk
Assessments)
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking
 Advantages of Risk Ranking techniques:
o Strictly defined (easy to apply)
o Rather limited data required
o Limited time requirements (in the order of
10 days for large processes)
o Can be applied even (and preferably) by 1
person
o Scalable (application in either Unit or Site
level)
o Applicable in early design phase
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking (cont.)
 Advantages of Risk Ranking techniques : (cont).
o Very useful in evaluation/comparison of :
alternative processes and sitings,
comparison of different sites,
ranking of hazardous areas within a Site
o Effective decision making and screening tool
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
• Relative Ranking (cont.)
 Disadvantages :
o Strong dependence of outcome from
penalties/equations used and assumptions
used
o Procedural issues not prorely taken into
account
o Not to be considered as suitable for Safety
Reports for other than screening purposes
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
END OF PART 1
This Project is funded
by the European Union
Project implemented by Human
Dynamics Consortium
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