Offshore Safety

11

MASTER HSE & Q MASTER HSE & Q -- M7 M7 -- Industrial Industrial SafetySafety

MASTER MASTER HSE&QHSE&Q -- M7 Industrial M7 Industrial SafetySafety

HSE in OFFSHORE HSE in OFFSHORE Oil&GasOil&Gas and and PetrochemicalPetrochemical ProjectsProjects

INTRODUCTIONINTRODUCTION

5 FEBRUARY 20095 FEBRUARY 2009


TABLE OF CONTENTTABLE OF CONTENT

MODULE 0MODULE 0 -- INTRODUCTIONINTRODUCTION-- GeneralGeneral conceptsconcepts-- SafetySafety in Design (Offshore)in Design (Offshore)

MODULE 1MODULE 1 -- DROPPED OBJECT STUDYDROPPED OBJECT STUDYMODULE 2MODULE 2 -- MARINE HAZARD ANALYSIS (SHIP MARINE HAZARD ANALYSIS (SHIP

IMPACT / COLLISION STUDY)IMPACT / COLLISION STUDY)MODULE 3MODULE 3 -- ESCAPE, EVACUATION AND RESCUE ESCAPE, EVACUATION AND RESCUE

ANALYSIS (EERA)ANALYSIS (EERA)MODULE 4MODULE 4 -- TEMPORARY REFUGE (T.R.) INTEGRITYTEMPORARY REFUGE (T.R.) INTEGRITYMODULE 5 (EXTRA)MODULE 5 (EXTRA) -- HAZARDOUS AREA HAZARDOUS AREA

CLASSIFICATION (HAC)CLASSIFICATION (HAC)

22


Oil&GasOil&Gas, , ChemicalChemical, , PetrochemicalPetrochemicalOnshoreOnshore and Offshore and Offshore PlantsPlants::

HazardousHazardous??


FireFire

HazardsHazards

33


ExplosionExplosion

HazardsHazards


DispersionDispersion of of ToxicToxic SubstancesSubstances

HazardsHazards

44


WhereWhere doesdoes the the hazardhazard originate?originate?

HazardsHazards


Example of Check List for identification of HazardsHazardsHazards

55


In broad terms, we can identify two types of Hazards:In broad terms, we can identify two types of Hazards:

-- Occupational HazardsOccupational Hazards (impact on the health of the worker/s)(impact on the health of the worker/s)

-- ““MajorMajor”” HazardsHazards (possible impact on population, environment, (possible impact on population, environment, asset)asset)

Major Major HazardsHazards

HazardousHazardous SubstancesSubstances

HazardsHazards


NFPA NFPA DiamondDiamond

Hazardous SubstancesHazardous Substances

66


EuropeanEuropean SymbolsSymbols (Dir 67/548)(Dir 67/548)

Hazardous SubstancesHazardous Substances


Release of Hazardous substance can cause: Release of Hazardous substance can cause: Flammable materialFlammable material

-- Jet FireJet Fire

-- Pool FirePool Fire

-- BLEVEBLEVE

-- UVCE/CVEUVCE/CVE

Toxic MaterialToxic Material-- Toxic DispersionToxic Dispersion

But also: Release of Energy/PressureBut also: Release of Energy/Pressure

-- Physical explosionPhysical explosion

Hazard ScenariosHazard Scenarios

77


HowHow anan accidentaccident scenario scenario isis generatedgenerated??((ExampleExample EventEvent TreeTree))

Hazard ScenariosHazard Scenarios


HowHow are are hazardshazards controlledcontrolled??

RiskRisk Control Control LegislationLegislation

88


Incidents that define Process SafetyIncidents that define Process Safety

WHEN WHERE WHAT FATALITIES• 1966 Feyzin, France LPG Bleve 18• 1974 Flixborough, UK Cyclohexane 28• 1976 Seveso, Italy Dioxin 1• 1979 Bantry Bay, Ireland Crude ship 50• 1982 Ocean Ranger, Canada Platform 84• 1984 Mexico LPG Bleve 600+• 1984 Bhopal, India Methyl isocyanate 20000+• 1986 Challenger Space shuttle 7• 1986 Chernobyl, USSR Nuclear powerplant 100+• 1986 Sandoz, Bale, Switzerland Warehouse 0• 1987 Texas City, USA HF 0• 1987 Grangemouth, UK HCK HP/LP interface 1• 1988 Piper Alpha Platform 167• 1988 Norco, USA Propane FCCU 7• 1989 Pasadena TX, USA Ethylene/isobutane 23• 1992 La Mède, France Gasoline/LPG FCCU 6• 1994 Milford Haven, UK FCCU feedstock 0• 1998 Longford, Australia LPG, brittle fracture 2• 2001 Toulouse, France Ammonium Nitrate 30• 2001 Petrobras Platform 11• 2003 Columbia Space shuttle 7• 2004 Skikda, Algeria LNG 27• 2005 Texas City, US Gasoline ISOM 15• 2005 Buncefield, UK Gasoline 0• 2005 Bombay High, India Platform 13

REGULATIONSFirst LPG prescriptive regulationsEU Seveso I Directive1982US Chemical Emergency Preparedness Program 1985US Emergency Planning and Community Right-to-Know Act 1986US Chemical Accident Prevention Program 1986 US Chemical Safety Audit Program 1986EU Seveso I Directive update 1987US Clean Air Act Amendments 1990

UK HSE Offshore Installations (Safety Case) Regulations 1992US OSHA 1910-119 Process Safety Management 1992US EPA Risk Management Program1996

EU Seveso II Directive 1996UK Control of Major Accident Hazard Regulations 1999EU Seveso II update 2002 (SEVESO III)

UK HSE Offshore Installations (Safety Case) Regulations 2005

API RPs on occupied buildings and vents

OSHA Refinery National Emphasis Program


HowHow isis PlantPlant SafetySafety ensuredensured in a Project?in a Project?

HSE ManagementHSE Management

99


“GOOD” DESIGN

LOW RISKS (FOR POPULATION,

OPERATORS, ENVIRONMENT)

2

PROBLEMS: How can we demonstrate ‘safety’ of design?How “good”? (i.e. up to which point the system shall be

optimized?)

HIGH PRODUCTIVITY

Safety in Design Safety in Design -- HSEHSE


Integrated HSE

Management

To assess the level of safety wrt exposed people

SAFETY

To identify and certify the machinery systems

according to the provisions of the EU Directive

To verify, in all phases of production process, the correct implementation of Rules,

Standards and SE requirements

To assess the level of productivity of plant

To assess the level of reliability required to Safety Loops

To assess the level of safety towards environment

ENVIRONMENT

RELIABILITY

HAZARDOUS AREAS CLASSIFICATION

SIL

PRESSURE EQUIPMENT CERTIFICATION

(PED, EU)

F&G DETECTION

MACHINERY CERTIFICATION (EU)

AUDITS/REVIEW

To certify safety of pressure equipment

Optimisation of Localisation of detectors

Control of explosion risk


1010


HSE MANAGEMENT FLOW CHART

HSE DESIGNREVIEW

PROCEDURE

CONTRACT & LAWREQUIREMENTS

CONTRACTOR’SHSE POLICY

APPLICABLECODES & STANDARDS

PROJECT GENERALHSE PLAN

HSE PLAN FORENGINEERING & PROCUREMENT

HSE PLAN FORWORKS AT SITE

HSE DESIGNCRITERIAHSE DESIGN

CRITERIAHSE DESIGNCRITERIA

HSE STUDYPROCEDUREHSE STUDY

PROCEDUREHSE STUDYPROCEDURE

CONTRACTOR’SHSE AUDIT

PLANS

HAZOPQRA

EIASIL STUDY

ETC.(STUDIES)

PLOT PLAN

ESD

GAS DET.

FIRE PROT.

ETC.(REVIEWS)

ENGINEERING &PROCUREMENT

PROJECTMOC

PROCEDURE

HSE REVIEWOF CHANGES

CONTRACTOR’SHSE

AUDITCONTRACTOR’S

HSEAUDITCONTRACTOR’SHSE

AUDIT

APPROVED

CHANGES

REV IEWFEED BACK

INPU

T TO

DES

IGN

DOC

S TO

REV

IEW

INPUT TODESIGN

PROPOSED CHANGES

DESI

GN W

ORK

S

PRE-STARTUPREVIEW

PROCEDURE

HSE STUDYPROCEDURE

HSE STUDYPROCEDURE

HSE STUDYPROCEDURE

WORK ENV. STUDYJOB HAZARD

ANASLYSISETC.

(STUDIES)

SITE HSE MANUAL

COMMISSIONING &STARTUP

PRE-STARTUPHSE REVIEW

CONSTRUCTION

HSE WORKINGPROCEDUREHSE WORKINGPROCEDUREHSE WORKINGPROCEDURE



OFFSHORE PLANTS

Safety in Design Safety in Design -- OffshoreOffshore

1111


Specific Hazards in offshore environment?

• Hazardous substances (as onshore);

• External events:collisions (ship, helicopter..),extreme weather;

• Worsening factors:equipment congestion;process/safety/living areas on same structure in close proximity;repair/escape and rescue is difficult;mitigation is difficult.




1212


Explosion Risk Analysis3.6

Fire Resistance Analysis3.5

Fire Risk Analysis3.4

Fire Protection Analysis3.3

Hazardous Inventory Report3.2

Hazard Register3.1

FORMAL SAFETY ASSESSMENTS3.

SIL (Safety Integrity Level) Analysis2.5

HAZOP Review - Vendor Package2.4

HAZOP Review - Utility Systems2.3

HAZOP Review - Process Systems2.2

HAZID Review2.1

HAZARD IDENTIFICATION2

HSE/Risk Assessment Plan1.1

PROJECT HSE MANAGEMENT1

ACTIVITY

Safety in Design Safety in Design –– Offshore Offshore –– Example of HSE PlanExample of HSE Plan


Operational Safety Case5.2

Design Safety Case5.1

SAFETY CASE5.

RAM for Safety Critical Elements4.3

Performance Standards for SCEs4.2

Safety Critical Element (SCE) List4.1

PERFORMANCE STANDARDS4.

Dropped Object Study3.16

Exhaust Gas Dispersion Study3.15

Smoke and Gas Dispersion Study3.14

Quantified Risk Assessment (QRA)3.13

Temporary Refuge Impairments Assessment (TRIA)3.12

Occupational Risk Assessment3.11

Ship Collision Risk Analysis3.10

Emergency Systems Survivability Analysis (ESSA)3.9

Escape, Evacuation and Rescue (EER) Study3.8

Explosion Resistance Analysis3.7


1313


Safety Sign Layouts7.8

Fire-fighting Equipment Layouts7.7

Safety and Lifesaving Equipment Layouts7.6

Escape Way Layouts7.5

Hazardous Area Classification Report & Layout7.4

Fire and Gas Detection Layout7.3

Vent Dispersion and Radiation Study7.2

Flare Radiation and Dispersion Study7.1

DESIGN SAFETY ACTIVITIES7.

Noise/Vibration Criteria6.4

Project Environmental Criteria6.3

Fire and Gas Detection Philosophy6.2

HSE/Safety/Loss Prevention Philosophy6.1

DESIGN CRITERIA & PHILOSOPHIES6.



Material Handling Review9.5

Material Handling Philosophy9.4

Human Factors Verification9.3

Human Factors / 3D Model Review9.2

Human Factors Philosophy9.1

HUMAN FACTORS & MATERIAL HANDLING9.

Reliability, Availability and Maintainability (RAM) Study8.3

Failure, Modes & Effects Analysis (FMEA)8.2

HIPPS Reliability Study8.1

RELIABILITY, AVAILABILITY AND MAINTAINABILITY STUDIES8.


1414


API RP 14J Compliance Review11.2

Hazardous Area Class. Compliance Review11.1

VERIFICATION DOCUMENTS11.

Field Abandonment Report10.4

Noise Study10.3

Emissions List10.2

Environmental Impact Study10.1

ENVIRONMENTAL ACTIVITIES10.



1. Skelton B., “Process Safety Analysis - An Introduction”, IChemE, UK.

2. F.P. Lees, “Loss Prevention in the Process Industries”, Butterworth-Heinnemann.

3. "Guidelines for Quantitative Risk Assessment“, CPR 18E Purple Book, 1999, TNO The Netherlands.

4. AIChE Center for Chemical Process Safety (CCPS), 1992, "Guidelines for Hazard Evaluation Procedures", USA, 2nd edition.

5. ISO “Petroleum and natural gas industries – Offshore production installations – Guidelines on tools and techniques for hazard identification and risk assessment”

6. Vinnem, J. E., “Offshore Risk Assessment . Principles, modelling and Applications of QRA studies” – Springer, 2007

7. ….. and many others

Some References

1515


Headquarters:

Via San Nazaro, 19 - 16145 Genova – Italy

National Offices:

Via Martiri di Cefalonia, 2 - 20097 San Donato Milanese

Largo C. Salinari, 18/19 - 00142 Roma

Via S. Pasquale a Chiaia, 62B - 80121 Napoli

SS 7 km 7,3 c/o Cetma - 72100 Brindisi

Via S. Maria dell’Arco, 19 - 98121 Messina

URL: www.dappolonia.it

11


Module 1Module 1

Dropped Object StudyDropped Object Study

5 February 20095 February 2009




DROPPED OBJECT STUDY1. The concept of Dropped Object Analysis,2. The Best Practices,3. The methodologies,4. Examples of results.

Module 1 - TABLE OF CONTENT

22


Dropped Object (DO) analysis is aimed at the evaluation Dropped Object (DO) analysis is aimed at the evaluation of the risk associated to a load falling onto sensitive of the risk associated to a load falling onto sensitive objects.objects.

DO analysis is mainly applied to offshore platforms to DO analysis is mainly applied to offshore platforms to assess the risk from dropped crane/monorails loads onto assess the risk from dropped crane/monorails loads onto equipment (on the platform decks) and onto pipelines equipment (on the platform decks) and onto pipelines ((subseasubsea, risers, onboard). A result of the study is the , risers, onboard). A result of the study is the identification of protections required to mitigate the risk.identification of protections required to mitigate the risk.



MethodologyThe Dropped Object Analysis is done to assess the risk of damage to process areas, subsea pipelines and safety critical elements due to falling objects.

The approach for the Dropped Object Analysis is typically as follows:

- Review crane facilities and operations associated with the facilities;- Identify the main hazards associated with the cranes and their operations and define the expected scenarios associated with these hazards;- Undertake frequency analysis and assess the associated impact energy and subsequently determine the expected risk associated with the hazards identified;- Discuss the risk associated with dropped objects and subsequently identify engineering and operational safeguards that are in place to either control or mitigate them;- Determine if protection is required for the topside equipment, subseapipelines and structures.


33


Dropped Object (DO) is essentially a very specialized Dropped Object (DO) is essentially a very specialized "Risk Analysis" where:"Risk Analysis" where:

LikelihoodLikelihood of the Event is given by the expected of the Event is given by the expected Frequency of the Dropped Load,Frequency of the Dropped Load,

ConsequenceConsequence of the Event is given by the expected of the Event is given by the expected damage to equipment following the Impact with the damage to equipment following the Impact with the dropped object.dropped object.



Frequency is typically evaluated by applying Frequency is typically evaluated by applying international standardized methods (e.g. DNVinternational standardized methods (e.g. DNV--RPRP--F107) F107) and engineering considerations. and engineering considerations.

Consequence is evaluated by assessing the type of Consequence is evaluated by assessing the type of damage to the pipeline (again by the application of DNVdamage to the pipeline (again by the application of DNV--RPRP--F107 methodology or similar).F107 methodology or similar).


44



HAZARD IDENTIFICATIONHAZARD IDENTIFICATION


• Platform configuration (operational, drilling, work-over)• Platform crane(s) location, characteristics and lifts/year• Barge crane (if any) location, characteristics and lifts/year• Assisting barge dimension and location• Platform and jacket layouts and sections• Topsides configuration and process data• Bathymetry• Sealine data (route, mechanical data, transported fluid

composition and operational data)

Dropped Object Study Dropped Object Study -- INPUT DATAINPUT DATA


55


• Loads divided in load classes as applied in DNV RecommendedPractices.

• Dropped object frequency as in DNV RP:

2.2x10-5 drops/lift, for loads less than 20 tons3.0x10-5 drops/lift, for loads greater than 20 tons

• Lift frequencies given by load classes.• Definition of Initial drop points.• Definition Receptor points on the seabed.• The objects excursions on the seabed are normal distributed

with angular deviations (gliding angle).• Jacket is considered as a solid obstacle due to the low

probability of objects passing through the legs .• The presence of a barge on the boat landing side is considered

as an obstacle for the objects to drop into the sea .

ASSUMPTIONS (1/3)ASSUMPTIONS (1/3)



ASSUMPTIONS (2/3)ASSUMPTIONS (2/3)


66




Dropped Object Study for Dropped Object Study for SealinesSealines-- ASSUMPTIONS (3/3)ASSUMPTIONS (3/3)Dropped Object StudyDropped Object Study

77


• For each drop point vertical projection onto the sea bed, a normal distribution of the load is given, as follows:

• The probability that a sinking object will hit the seabed within a distance r from the vertical line through the drop point is :

• The probability of impacting on the seabed within two circles around the drop point with inner radius rj-1 and outer radius rj is:

• This probability may be expressed per m2 by dividing the value on the actual circle area:

FREQUENCY (1/6)FREQUENCY (1/6)

2

2

2x

e2

1)x(p δ⋅−

⋅δ⋅π⋅

=

∫−

⋅=≤r

r

dx)x(p)rx(P

)rx(P)rx(P)rxr(P 1jjj1j −− ≤−≤=≤<

j,1j

j1jj1j A

)rxr(P)rxr(P

−

−−

≤<=≤<





•The breadth of each ring is taken at a constant value interval.

88


• For the considered load class LC, the frequency FLC, with which the associated dropped objects hits the sea bottom, can be evaluated as (drop/year/m2):

fd dropped object frequency (drop/lift);fl lift frequency (lift/year); pdi probability that the object drops on the vertical of the dropped point i; pij probability per m2 that the object drops into the j-th annular ring with “i” as

centre point.

• Pdi is considered the same for each dropped point detected.• The frequency FLC is evaluated on the sea bottom for a discrete

number of points (receptor points equally spaced and sealinesimulating points).


)pp(ffFi j

ijdildLC ∑∑ ⋅⋅⋅=





99


For the considered load class LC, the frequency FLC, with which the associated dropped objects hits the deck, can be evaluated as (drop/year/m2):

where:fd=dropped object frequency (drop/lift);fl=lift frequency (lift/year);ALC=area (m2) of the footprint of the crane trajectory over the deck, during the movement of objects belongs to load class LC.



LC

ldLC A

ffF

⋅=


FREQUENCY (6/6) FREQUENCY (6/6) -- example on a 10" condensate lineexample on a 10" condensate line


1010


• Kinetic energy for each drop points and for each load class LC is evaluated with the formula of objectsdropping in air (first) and into water (after) and compared with the kinetic energy capable to produce a sealine OR topside Equipment damage.

• Kinetic energy that could damage pipeline is evaluatedaccording to DNV-RP-F107 :

and damage criteria is expressed by DNV as:

CONSEQUENCE (1)CONSEQUENCE (1)

23

21

21

9216 ⎟

⎠⎞

⎜⎝⎛⋅⎟

⎠⎞

⎜⎝⎛⋅⋅⎟

⎠⎞

⎜⎝⎛ ⋅⋅=

DD

tDmE pD

δπ



Each level shall be compared with the applicable RiskManagement Standard criteria!

SEE EXAMPLE OF ACTUAL CALCULATION FOR DO KINETIC ENERGY

CONSEQUENCE (2)CONSEQUENCE (2)


1111


EXAMPLESEXAMPLES


Dropped Objects:


EXAMPLESEXAMPLES


Platform North

0m 5m 10m 15m 20m

SCALE

Deck +19.500

Jacket

1E-007

3E-007

5E-007

7E-007

9E-007

1.1E-006

1.3E-006

1.5E-006

1.7E-006

1.9E-006

2.1E-006

2.3E-006

2.5E-006

Impact Frequency:

1212


EXAMPLESEXAMPLES


4'' gas lift sealine

deck +24.000

jacket

6'' oil sealine12'' separation gas sealine

Platform North

0m 5m 10m 15m 20m

SCALE2E-007

4E-007

6E-007

8E-007

1E-006

1.2E-006

1.4E-006

1.6E-006

1.8E-006

2E-006

2.2E-006

2.4E-006

2.6E-006

2.8E-006

3E-006


EXAMPLESEXAMPLES


0m 5m 10m 15m 20m

SCALE

Deck +3.400

1E-007

3E-007

5E-007

7E-007

9E-007

1.1E-006

1.3E-006

1.5E-006

1.7E-006

1.9E-006

2.1E-006

2.3E-006

Sealine

1313


EXAMPLESEXAMPLES



EXAMPLESEXAMPLES


11


Module 2Module 2

Marine Hazard AnalysisMarine Hazard Analysis(Ship Impact / Collision Study)(Ship Impact / Collision Study)5 February 20095 February 2009




Marine Hazard Analysis1. The concept of Marine Hazard,2. The main methodological approach,3. The calculations and Results,4. Examples.


22


MARINE HAZARDMARINE HAZARD

…………

ShipShip Impact / Impact / CollisionCollision StudyStudy

SHIPS IMPACTSHIPS IMPACT

SHIP COLLISIONSHIP COLLISION

HEAVY LIFTS/D.O.HEAVY LIFTS/D.O.

Are those Hazards related toAre those Hazards related toMarine and Vessel OperationsMarine and Vessel Operations

These Hazards have highThese Hazards have highpotential consequencespotential consequences


Methodology Methodology -- Ship impact studyShip impact studyThe Analysis is performed in the following steps:The Analysis is performed in the following steps:

1.1. Identify the risks associated to the facilities due to Identify the risks associated to the facilities due to marine activities e.g. ship collision with the platforms, marine activities e.g. ship collision with the platforms, fishing vessels and other traffic hazards to pipelines fishing vessels and other traffic hazards to pipelines and supporting vessels;and supporting vessels;

2.2. Quantify the expected frequency of occurrence of Quantify the expected frequency of occurrence of these events;these events;

3.3. Assess the expected consequences, on the basis of Assess the expected consequences, on the basis of the applicable severity classification given in the the applicable severity classification given in the Project Risk Criteria.Project Risk Criteria.


33


Typical Input DataTypical Input DataInput data needed for the Marine Hazard Analysis are:Input data needed for the Marine Hazard Analysis are:

1.1. Platform and field layouts;Platform and field layouts;2.2. Data on the commercial marine traffic in the area;Data on the commercial marine traffic in the area;3.3. Data on the fishing traffic in the area;Data on the fishing traffic in the area;4.4. Operational Data and Frequencies of the Plant;Operational Data and Frequencies of the Plant;5.5. Typical Typical MeteoMeteo--marine data (wind intensity and marine data (wind intensity and

direction, marine currents, direction, marine currents, ectect.)..).



METHODOLOGY FOR FREQUENCY ASSESSMENTMETHODOLOGY FOR FREQUENCY ASSESSMENTThe expected frequency of occurrence of collision events The expected frequency of occurrence of collision events are calculated starting from the available maritime traffic are calculated starting from the available maritime traffic data. data. The models used in the analysis consider the real intensity The models used in the analysis consider the real intensity of the ship traffic in the area, the time of exposure to the of the ship traffic in the area, the time of exposure to the hazard of collision and the real interaction between vessels hazard of collision and the real interaction between vessels and installation.and installation.Two cases are typically considered:Two cases are typically considered:

••vessel impact with vessel impact with fixed obstaclesfixed obstacles (vessel/platform);(vessel/platform);••vessel impact with vessel impact with moving obstaclesmoving obstacles (vessel/vessel).(vessel/vessel).


44


Impact of moving vessel with Fixed ObstaclesImpact of moving vessel with Fixed ObstaclesThe following scenarios are typically considered to The following scenarios are typically considered to evaluate the expected frequency of collision between with evaluate the expected frequency of collision between with a fixed object such as the platform (or a moored vessel a fixed object such as the platform (or a moored vessel such as a FPSO) and a moving vessel:such as a FPSO) and a moving vessel:

•• impact of powered passing vessels;impact of powered passing vessels;•• impact of drifting vessels;impact of drifting vessels;•• impact of dedicated/supporting vessels.impact of dedicated/supporting vessels.



The model is based on a geometric approach and on two The model is based on a geometric approach and on two premises:premises:a) ships normally travel in predictable "lanes";a) ships normally travel in predictable "lanes";b) vessels normally keeps an effective monitoring of the b) vessels normally keeps an effective monitoring of the movements (also visual) which shall avoid collision with an movements (also visual) which shall avoid collision with an obstacle unless there is an emergency situation. However obstacle unless there is an emergency situation. However it is not totally excluded that a certain fraction of vessels it is not totally excluded that a certain fraction of vessels could fail to keep an effective monitoring.could fail to keep an effective monitoring.

There will be reasonable navigation uncertainties as well There will be reasonable navigation uncertainties as well as the effect of wind and waves on the vessels: these will as the effect of wind and waves on the vessels: these will possibly cause vessels to stray from the lanes centerline. possibly cause vessels to stray from the lanes centerline. Vessels traveling on a lane will be normally more likely to Vessels traveling on a lane will be normally more likely to be near the centre line but a distribution of vessel traffic be near the centre line but a distribution of vessel traffic across the lane must be defined.across the lane must be defined.


55




Collision Frequency for Powered Passing VesselsCollision Frequency for Powered Passing VesselsThe collision probability between powered passing vessels The collision probability between powered passing vessels (commercial vessels, fishing boats, pleasure crafts) along a shi(commercial vessels, fishing boats, pleasure crafts) along a shipping pping lane and a fixed obstacle is evaluated considering standard navilane and a fixed obstacle is evaluated considering standard navigation gation conditions and a standard level of instrumental assistance. Witconditions and a standard level of instrumental assistance. With these h these assumptions, the frequency of collision with the Platform/mooredassumptions, the frequency of collision with the Platform/mooredvessel for each ship class is:vessel for each ship class is:

FpiFpi = = ΣΣNiNi××ff ×× P1i P1i ×× P2i P2i ×× P3iP3iwhere:where:FpiFpi = annual collision frequency for a class "i" powered vessel (ev= annual collision frequency for a class "i" powered vessel (event/year);ent/year);Ni = total vessel traffic in the shipping lane for a class i vesNi = total vessel traffic in the shipping lane for a class i vessel (vessel movement/year);sel (vessel movement/year);f = fraction of vessels in direct collision route with the obstaf = fraction of vessels in direct collision route with the obstacle;cle;P1i = Planning failure factor: Probability that a vessel fails tP1i = Planning failure factor: Probability that a vessel fails to plan its approaching route o plan its approaching route adequately so as to avoid an obstacle;adequately so as to avoid an obstacle;P2i = P2i = WatchkeepingWatchkeeping failure factor: Probability that in the vessel it is not kept failure factor: Probability that in the vessel it is not kept an an adequate monitoring of the movements (so to recover in time a baadequate monitoring of the movements (so to recover in time a bad maneuvering);d maneuvering);P3i = Obstacle initiated recovery factor: Probability that exteP3i = Obstacle initiated recovery factor: Probability that external monitoring (e.g. from rnal monitoring (e.g. from the "obstacle" point of view) fails to take some action to recovthe "obstacle" point of view) fails to take some action to recover the failures and/or er the failures and/or prevent a collision.prevent a collision.


66


Collision Frequency for Drifting VesselsCollision Frequency for Drifting VesselsThe frequency of collision between drifting vessels (passing vesThe frequency of collision between drifting vessels (passing vessels or sels or fishing boats or pleasure crafts) and a fixed obstacle is evaluafishing boats or pleasure crafts) and a fixed obstacle is evaluated ted using the following formula:using the following formula:

where:where:j = is the considered "block" or "section" of the shipping lane;j = is the considered "block" or "section" of the shipping lane;I = is the vessel class;I = is the vessel class;FdiFdi = annual collision frequency for a class i drifting vessel (ev= annual collision frequency for a class i drifting vessel (event/year);ent/year);FdijFdij = annual collision frequency with an obstacle for a class i dri= annual collision frequency with an obstacle for a class i drifting vessel whose fting vessel whose initial location is block j (event/year);initial location is block j (event/year);NijNij = number of class i vessels per year in block j (vessel/year);= number of class i vessels per year in block j (vessel/year);PwjPwj = probability that wind from block j is directed towards the ob= probability that wind from block j is directed towards the obstacle;stacle;PfiPfi = failure probability for vessels of class i causing vessel to = failure probability for vessels of class i causing vessel to drift drift -- (events/vessel);(events/vessel);Di = collision diameter of a class i vessel;Di = collision diameter of a class i vessel;LjLj = is the length of block j.= is the length of block j.


∑ ∑ ⋅⋅⋅==j j j

ifiwjijdijdi L

DPPNFF


Collision Frequency for Dedicated/Supporting VesselsCollision Frequency for Dedicated/Supporting VesselsDedicated and supporting vessels could be considered both powereDedicated and supporting vessels could be considered both powered d passing and drifting vessels. Therefore the collision frequencypassing and drifting vessels. Therefore the collision frequency of of these vessels against an obstacle is given by the sum of the colthese vessels against an obstacle is given by the sum of the collision lision frequency of drifting vessels plus the collision frequency of pofrequency of drifting vessels plus the collision frequency of powered wered passing vessels. passing vessels.

FcFc = (Fc1+Fc2) = (Fc1+Fc2) ×× PredPredFc1 = N Fc1 = N ×× Pr Pr ×× Pc/r Pc/r ×× PnaPna

Pc/r = Pc/r = αα/2/2ππ = 1/= 1/ππ ×× arcsin[(D1+D2)/2L]arcsin[(D1+D2)/2L]Fc2 = N Fc2 = N ×× Pf Pf ×× Pc/f Pc/f ×× PnaPna


H2

DDL 21 ++

=

77


FcFc = (Fc1+Fc2) = (Fc1+Fc2) ×× PredPred;; Fc1 = N Fc1 = N ×× Pr Pr ×× Pc/r Pc/r ×× PnaPnaPc/r = Pc/r = αα/2/2ππ = 1/= 1/ππ ×× arcsin[(D1+D2)/2L];arcsin[(D1+D2)/2L];

Fc2 = N Fc2 = N ×× Pf Pf ×× Pc/f Pc/f ×× PnaPna


H2

DDL 21 ++

=

number of vessels per year (vessel/year);=N

reduction factor for approaching vessels supported by assistance vessels;=Pred

annual collision frequency with a fixed obstacle for drifting vessels (event/year);=Fc2

annual collision frequency with a fixed obstacle for powered passing vessels (event/year);=Fc1

annual collision frequency with a fixed obstacle for dedicated and powered passing vessels (event/year);=Fc

probability that the route leads to collision with the fixed obstacle conditioned to propulsion loss.=Pc/f

is the failure probability for vessels with the potential to cause vessel to drift (events/vessel);=Pf

is the average distance between vessel and the obstacle (m);=L

is the net distance between the vessel and the fixed obstacle (m);=H

equivalent diameters (obstacle/vessel) meters;=D1,2

is the collision angle;=α

probability of failure of safety procedures to avoid impact;=Pna

probability that the route leads to collision with the fixed obstacle conditioned to the entrance inside the MSOD zone, it is calculated using geometrical models;

=Pc/r

probability of uncontrolled navigation inside Minimum Safety Operational Distance MSOD;=Pr



88


Impact of moving vessel with Moving Obstacles Impact of moving vessel with Moving Obstacles (vessel/vessel)(vessel/vessel)The carrier approach routes are subdivided into two or The carrier approach routes are subdivided into two or more parts. It is then assumed that the ship movements more parts. It is then assumed that the ship movements along each route fraction are developed with a simplified along each route fraction are developed with a simplified profile with the vessel axis constant within each portion of profile with the vessel axis constant within each portion of the route. For each selected position, the same the route. For each selected position, the same methodology reported for fixed obstacles shall be applied methodology reported for fixed obstacles shall be applied considering, as reduction factor, the fraction of time spent considering, as reduction factor, the fraction of time spent in a year by the vessel to cover the relevant route fraction.in a year by the vessel to cover the relevant route fraction.



METHODOLOGY FOR CALCULATION OF EXPECTED METHODOLOGY FOR CALCULATION OF EXPECTED IMPACT ENERGYIMPACT ENERGYThe effect of a potential collision between a ship and a The effect of a potential collision between a ship and a Platform, or between ships has been analyzed in the Platform, or between ships has been analyzed in the literature with structural simulations of impacts under the literature with structural simulations of impacts under the most serious conditions, namely for perpendicular impacts most serious conditions, namely for perpendicular impacts (most severe impact).(most severe impact).

From previous studies, the "limit" for serious damages can From previous studies, the "limit" for serious damages can be identified for different conditions, vessels and be identified for different conditions, vessels and structures, in terms of Maximum Impact Energy (MJ).structures, in terms of Maximum Impact Energy (MJ).


99


The expected impact energies, as a function of the tonnage The expected impact energies, as a function of the tonnage of the striking vessel and for different speed of impact, can of the striking vessel and for different speed of impact, can be calculated (e.g. with the following formula):be calculated (e.g. with the following formula):


( )1000000

0.514v1000M21E

2Tot ⋅⋅⋅

⋅=

vessel speed (knots).=vvessel total mass (tons);=MTot

expected impact energy (MJ);=E

The calculated impact energies can be compared for each The calculated impact energies can be compared for each ship class with the "limit" available from literature or from ship class with the "limit" available from literature or from projectproject--specific data.specific data.


ShipShip Impact / Impact / CollisionCollision StudyStudy( )

10000000.514v1000M

21E

2Tot ⋅⋅⋅

⋅=

vessel speed (knots).=vvessel total mass (tons);=MTot

expected impact energy (MJ);=E

SuezmaxSuezmax TankerTanker

Typical DWT: 150,000 TonsTypical DWT: 150,000 TonsTypical Service speed: 15 knotsTypical Service speed: 15 knots

Expected Impact Energy isExpected Impact Energy is……

Approximately: 5,000 MJApproximately: 5,000 MJ

1010



5000Suezmax impact 150,000 DWT - 15 knots2000Earthquake Ritcher Scale 3.041851 Ton of TNT0.004Hidraulic Hammer (per stroke)0.001Electrical Energy In 1 AA Battery132Chemical Energy In 1 Gallon Of Gasoline

5000Typical Lightning Bolt6.28E+07"Little Boy" Nuclear Bomb1.90E+12Mt. St. Helens Eruption Of 1980

Energy (MegaJoule)Event



Example of calculated Impact Energy for Vesselsin Function of Tonnage and Speed

7,4124,1721,84976247315554140,00054,2352,3841,057436270893180,0004768432192794916614,500315989401610313,000253301353101,0001

20 kn15 kn10 kn6.5 kn5 kn2.9 kn1.7 kn

Energy (MJ)(a)Total Mass(b)

(tons)ShipClass

(a) the impact energies expected to have the potential to cause a loss of integrity for perpendicular collision are highlighted.(b) Total Mass is calculated as ship dwt plus ship weight.

1111


References:References:•• TechnicaTechnica, 1987, Report, "RABL , 1987, Report, "RABL -- Risk Assessment of Buoyancy Risk Assessment of Buoyancy

Loss, Project PP4, Assessment of Module Collision Loss, Project PP4, Assessment of Module Collision Frequencies", London, U.K.Frequencies", London, U.K.

•• PitbladoPitblado, 2004, , 2004, ““Consequences of LNG Marine IncidentsConsequences of LNG Marine Incidents””, CCPS , CCPS Conference, June 2004.Conference, June 2004.

•• SikteCSikteC, 1987, Report, , 1987, Report, ““ZeepipeZeepipe Riser Platform, Ship Collision Riser Platform, Ship Collision StudyStudy””, Trondheim, Norway, Trondheim, Norway

11


Module 3Module 3

Escape, Evacuation and Rescue Escape, Evacuation and Rescue Analysis (EERA)Analysis (EERA)5 February 20095 February 2009




Escape, Evacuation and Rescue Analysis1. Why EERA,2. The main methodological approach,3. The Analysis and Results,4. Examples.


22


To ensure that offshore installations be To ensure that offshore installations be as safe as safe as reasonably practicableas reasonably practicable (ALARP) for personnel (ALARP) for personnel in the event of a situation which requires in the event of a situation which requires abandonment of the installation.abandonment of the installation.

EERAEERA

WHY EERA ?WHY EERA ?


The overall objective of the EERA is to assess The overall objective of the EERA is to assess the potential for impairment of the Plant Escape, the potential for impairment of the Plant Escape, Evacuation and Rescue (EER) arrangements and Evacuation and Rescue (EER) arrangements and associated goals and objectives.associated goals and objectives.

EERA is performed on the basis of the results EERA is performed on the basis of the results arising from QRA and, together with thearising from QRA and, together with theEmergency Systems Survivability Assessment Emergency Systems Survivability Assessment (ESSA), assesses in detail the potential for key(ESSA), assesses in detail the potential for keysafety related arrangements to be impaired by safety related arrangements to be impaired by the major accident hazards, hence potentiallythe major accident hazards, hence potentiallyresulting in escalation of an event.resulting in escalation of an event.

EERAEERA

33


DEFINITIONSDEFINITIONS

EERAEERA

Escape = Movement of personnel from their location at the time of the alarm to a Temporary Safe Refuge (TSR).

Evacuation = Movement from the TSR to a lifeboat or other safety craft, and its launch and movement to a safe distance from the installation.

Rescue = Transfer of personnel from safety craft, water, or platform to a safe haven.


EERA focuses on assessing the vulnerability of EERA focuses on assessing the vulnerability of emergency response related arrangements (e.g.emergency response related arrangements (e.g.escape routes, muster points etc)escape routes, muster points etc)

EERAEERA

Steps:- Identification of scenarios (MAE, Major Accidental Events)

- Identification of the systems/equipment required for E, E & R

- Definition of performance criteria for E,E & R systems

- Analysis of the mechanisms that can impair the E, E & R systems/ functions

44


EERAEERA


EERAEERA

IDENTIFICATION OF MAJOR ACCIDENT HAZARDS

Essentially the MAEs are:

Hydrocarbon jet fires and pool fires;Explosions and flash fires;Gas (flammable / toxic) and Smoke dispersion;Non-hydrocarbon fires (e.g. Electrical);Dropped objects;Helicopter crash onto facility (helideck);Ship or boat collision;

55


EERAEERA



EERAEERA


66


EERAEERA

IMPAIRMENT CRITERIA


EERAEERA

IMPAIRMENT CRITERIA (CONTINUATION)

77


EERAEERA

Overview of EER Process 1.0Alarm

Major Incident

2.0Access

3.0Muster

4.0Egress

5.0Evacuation

6.0Escape

7.0Rescue

Place of Safety

PATH 1PATH 1PATH 2PATH 2PATH 3PATH 3PATH 4PATH 4


EERAEERA

IMPAIRMENT CRITERIA (CONTINUATION)

Top Level Hierarchical Task Analysis

0.0 EER PROCESS

1.0 ALARM

2.0 ACCESS

3.0 MUSTER

4.0 EGRESS

5.0 EVACUATION

6.0 ESCAPE

7.0 RESCUE

1.1 Detect Alarm

1.2 Interpret alarm

1.3Act

accordingly

2.1 Choose

Access Route

2.2 Move Along

Access Route

3.1 Register at Muster Point

3.2 Communicate with“Cellule de Crise”

3.3 Receive Instructions

4.1ChooseEgressRoute

4.2Move Along

Egress Route

5.1 Evacuate ViaBridge Link

5.2Evacuate byhelicopter

5.3Evacuate bySea

6.1Escapeby Sea

6.2Escape directly

into sea

7.1 Approachsurvivors

7.2Help Survivors

to Board

88


The study is typically performed in the following steps:- The Evacuation, Escape and Rescue (EER) arrangements and facilities are

described (considering both existing CPP and new facilities);- The loss of integrity criteria for the EER arrangements is defined, in

accordance to Client Criteria (and EERA ToR).

- Identification of MAEs that could potentially affect the EER devices (derived from QRA);

- Assessment of escape means availability during MAE occurrence.

EERA (Evacuation, Escape and Rescue) Analysis

The EERA Report demonstrates that the impairment of the key EER arrangements is within Client criteria.


Typical EERA Results (top events)

example of EERA results

NNPPPPPPPPNN99NNPPPPPPNNNN55NNNNNNPPNNNN44NNPPPPPPPPNN11

Emergency Emergency GatesGates

NNPPPPPPPPNN99NNPPPPPPPPNN55NNPPPPPPPPNN44NNPPPPPPPPNN11

Escape Escape routesroutes

Overall EER Goal Overall EER Goal ImpairedImpaired

FlammaFlammable Gasble Gas

Flash Flash FireFire

Heat Heat RadiationRadiation

Flame Flame ImpingemImpingem

entent

OverpressOverpressureure

Top Top EventsEvents

EER EER ArrangementArrangement

99


References:References:•• A methodology for hazard identification on EER Assessments A methodology for hazard identification on EER Assessments ––

OTH 95 466 OTH 95 466 –– RM Consultants RM Consultants –– Health and Safety ExecutiveHealth and Safety Executive•• SOLAS International Maritime Organization (IMO). Consolidated SOLAS International Maritime Organization (IMO). Consolidated

text of the IMO international convention for the Safety Of Life text of the IMO international convention for the Safety Of Life At At Sea (SOLAS) 2004 and subsequent amendmentsSea (SOLAS) 2004 and subsequent amendments

•• ISO 13702:1999 Petroleum and Natural Gas Industries ISO 13702:1999 Petroleum and Natural Gas Industries –– Control Control and Mitigation of Fires and Explosions on Offshore Production and Mitigation of Fires and Explosions on Offshore Production Installations Installations –– Requirements and GuidelinesRequirements and Guidelines

11


Module 4Module 4

Temporary Refuge (T.R.) IntegrityTemporary Refuge (T.R.) Integrity





Temporary Refuge Integrity1. Definition of T.R.2. The main issues.


22


Temporary Refuge (TR):Temporary Refuge (TR): (Also: Temporary Safe (Also: Temporary Safe Refuge Refuge -- TSR):TSR):

One or more locations where personnel are One or more locations where personnel are adequately protected from explosion, fire, heat, adequately protected from explosion, fire, heat, smoke, toxic gas, or fumes while an emergency smoke, toxic gas, or fumes while an emergency incident is brought under control or the decision incident is brought under control or the decision is made to abandon the facility.is made to abandon the facility.

T.RT.R..

T. R. T. R. -- TEMPORARY REFUGETEMPORARY REFUGE


•• to be accessible,to be accessible,•• to provide physical protection for personnel to provide physical protection for personnel

from the immediate effects of the emergency from the immediate effects of the emergency incident,incident,

•• to maintain its structural integrity,to maintain its structural integrity,•• to allow communication with people outside to allow communication with people outside

involved in controlling the incident or involved in controlling the incident or organisingorganising rescue services, andrescue services, and

•• to provide egress to the means of evacuation.to provide egress to the means of evacuation.

T.RT.R..

The TR needs:The TR needs:

33


This applies offshore to temporary refuges and This applies offshore to temporary refuges and in general to any facilities that need to operate during in general to any facilities that need to operate during an emergency. In the context of MAE, four main types an emergency. In the context of MAE, four main types of failure need to be considered:of failure need to be considered:

•• Loss of structural supportLoss of structural support (collapse of jacket or (collapse of jacket or supporting structure; loss of buoyancy or stability supporting structure; loss of buoyancy or stability of floating unit; collapse of walls or roof or floor; of floating unit; collapse of walls or roof or floor; etc)etc)

•• Loss of availability of means of evacuationLoss of availability of means of evacuation

T.RT.R..


•• Deterioration of conditionsDeterioration of conditions at temporary refuge at temporary refuge locations ingress of smoke, fumes, gas, or heat; locations ingress of smoke, fumes, gas, or heat; lack of oxygen; toxic fumes generated internally; lack of oxygen; toxic fumes generated internally; effects of internal fire; etc) to the point where this effects of internal fire; etc) to the point where this may be expected to lead to loss of life or other may be expected to lead to loss of life or other serious harm to the workforceserious harm to the workforce

•• Loss of command functionsLoss of command functions (communications; (communications; power; control systems; lighting; etc) which will power; control systems; lighting; etc) which will effect the information available for decisioneffect the information available for decision--making, and the capacity to mitigate or fight the making, and the capacity to mitigate or fight the incident and/or incident and/or organiseorganise safe evacuation if safe evacuation if appropriateappropriate

T.RT.R..

44


T.RT.R..


T.RT.R..

There are two main Risk drivers to TR impairmentThere are two main Risk drivers to TR impairment•• Risk of Gas ExplosionRisk of Gas Explosion

the overpressure could damage platform the overpressure could damage platform protection systems, damage escape routes and protection systems, damage escape routes and ultimately damage the integrity of the T.R.ultimately damage the integrity of the T.R.

•• Risk of smoke and Gas ingressRisk of smoke and Gas ingressSmoke and Gas could impair the systems that Smoke and Gas could impair the systems that maintain the quality of environment inside the maintain the quality of environment inside the T.R.T.R.

55


•• Failure of firewalls, allowing entry of fire, smoke, Failure of firewalls, allowing entry of fire, smoke, flammable flammable vapoursvapours, toxic fumes or flood water, toxic fumes or flood water

•• Fire inside the TR (Fire inside the TR (modelledmodelled as a separate event)as a separate event)•• ExplosionExplosion•• Deterioration of internal conditions due to Deterioration of internal conditions due to

external fire, smoke, gases or floodingexternal fire, smoke, gases or flooding•• Structural, foundation or buoyancy failureStructural, foundation or buoyancy failure•• Loss of command support and communications Loss of command support and communications

systems (this should be covered by a systems (this should be covered by a separate separate emergency systems survivability assessmentemergency systems survivability assessment))

•• Escape from the TR is prevented at all exits due Escape from the TR is prevented at all exits due to a deterioration of external conditionsto a deterioration of external conditions

T.RT.R..

The TR impairmentsThe TR impairments


A riskA risk--based approach shall be set out in the Temporary based approach shall be set out in the Temporary Refuge Impairment Analysis (TRIA) in which the Refuge Impairment Analysis (TRIA) in which the impairment criteria shall be assessed for hazards impairment criteria shall be assessed for hazards identified by all credible Major Accident Events (identified by all credible Major Accident Events (MAEsMAEs) ) discussed in the following;discussed in the following;

•• Fire and Explosion Analysis (FERA);Fire and Explosion Analysis (FERA);•• Toxic Gas Dispersion Analysis;Toxic Gas Dispersion Analysis;•• Escape, Evacuation and Rescue Analysis (EERA);Escape, Evacuation and Rescue Analysis (EERA);•• Smoke and Gas Ingress Analysis (SGIA);Smoke and Gas Ingress Analysis (SGIA);•• Emergency Systems Survivability Analysis (ESSA);Emergency Systems Survivability Analysis (ESSA);•• Impact analysis (Dropped object, Boat impact and Impact analysis (Dropped object, Boat impact and

Missile impact);Missile impact);•• Environmental analysis (Seismic and Extreme Environmental analysis (Seismic and Extreme

weather conditions).weather conditions).•• helicopter crashhelicopter crash

T.RT.R..

The TR impairmentsThe TR impairments

66


References:References:•• A methodology for hazard identification on EER Assessments A methodology for hazard identification on EER Assessments ––

OTH 95 466 OTH 95 466 –– RM Consultants RM Consultants –– Health and Safety ExecutiveHealth and Safety Executive•• ISO 13702:1999 Petroleum and Natural Gas Industries ISO 13702:1999 Petroleum and Natural Gas Industries –– Control Control

and Mitigation of Fires and Explosions on Offshore Production and Mitigation of Fires and Explosions on Offshore Production Installations Installations –– Requirements and GuidelinesRequirements and Guidelines

•• ISO15544:2000 Petroleum and natural gas industriesISO15544:2000 Petroleum and natural gas industries--Offshore Offshore production installationproduction installation--Requirements and guidelines for Requirements and guidelines for emergency responseemergency response

11


MASTER PROGETTAZIONE IMPIANTI MASTER PROGETTAZIONE IMPIANTI OIL&GASOIL&GAS

HSE in HSE in Oil&GasOil&Gas and and PetrochemicalPetrochemical ProjectsProjects

Module 5 (Extra)Module 5 (Extra)

Hazardous Area ClassificationHazardous Area Classification



A life without adventure is likely to be unsatisfying, but a life in which adventure is allowed to take whatever form it will, is likely to be short.

— Bertrand Russell

Safety EngineeringSafety Engineering

In the latest years, design and operating procedures to eliminate or control process hazards have evolved and been incorporated into codes and standards. The sequence and series of control tools and techniques normally applied in a modern Process Project is referred to as "Safety Engineering".

One of the most widely used and important (for its influence in the design) technique is the Hazardous Area Classification (HAC).

22


Hazardous Area Classification1. The concept of Hazardous Area. Purpose of the classification,2. The main standards for HAC: API, European Standards,3. The methods for the definition of the extension of classified area,4. Workshop.



Hazardous Area Classification (HAC) is a method of Hazardous Area Classification (HAC) is a method of analysing and classifyinganalysing and classifying the environment where the environment where explosive gas atmospheres may occur to allow the explosive gas atmospheres may occur to allow the proper selection of electrical apparatus to be installed in proper selection of electrical apparatus to be installed in that environment. that environment.

There are several kind of methods to determine the There are several kind of methods to determine the hazardous area according to different national regulation.hazardous area according to different national regulation.Among all:Among all:

•• API 500 / 505API 500 / 505•• IEC 60079IEC 60079--1010


33



These recommended practices are applicable to many These recommended practices are applicable to many type of Plant (e.g. Chemical Plant, Refinery, Oil&Gas type of Plant (e.g. Chemical Plant, Refinery, Oil&Gas Plant, Offshore Installations, etc), with exception for Plant, Offshore Installations, etc), with exception for mines (none is applicable), explosives plant (IEC is not mines (none is applicable), explosives plant (IEC is not applicable), hospitals and houses (IEC is not applicable).applicable), hospitals and houses (IEC is not applicable).



References:References:•• API Recommended Practice 505, API Recommended Practice 505, ““Recommended Practice for Recommended Practice for

Classification of Locations for Electrical Installations at Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Zone 0, Zone 1, and Petroleum Facilities Classified as Class I, Zone 0, Zone 1, and Zone 2Zone 2””, First Edition, November 1997., First Edition, November 1997.

•• IEC EN 60079IEC EN 60079--10. Electrical Apparatus for Explosive Gas 10. Electrical Apparatus for Explosive Gas Atmospheres Atmospheres -- Part 10 Part 10 -- Classification of Hazardous Areas. Classification of Hazardous Areas. --Fourth Ed. 2002 Fourth Ed. 2002 -- 6.6.

44



Explosive Gas AtmosphereExplosive Gas Atmosphere: A mixture with air, under : A mixture with air, under atmospheric conditions, of a flammable material in the atmospheric conditions, of a flammable material in the form of gas or vapour in which, after ignition, the form of gas or vapour in which, after ignition, the combustion spreads throughout the unconsumed mixturecombustion spreads throughout the unconsumed mixture..Hazardous AreaHazardous Area: A three: A three--dimensional space in which an dimensional space in which an explosive gas atmosphere explosive gas atmosphere is presentis present, or may be expected , or may be expected to be present, in quantities such as to require special to be present, in quantities such as to require special precautions for the construction, installation and use of precautions for the construction, installation and use of apparatuses.apparatuses.NonNon--hazardous Areahazardous Area: A three: A three--dimensional space in which dimensional space in which an explosive gas atmosphere an explosive gas atmosphere is not expected to be is not expected to be presentpresent, in quantities such as to require special , in quantities such as to require special precautions for the construction, installation and use of precautions for the construction, installation and use of apparatuses.apparatuses.



Grades of ReleaseGrades of Release::Continuous (C): A release which is continuous or is Continuous (C): A release which is continuous or is

expected to occur for long periods, or that expected to occur for long periods, or that occurs frequently and for short periods. occurs frequently and for short periods.

Primary (P):Primary (P): A release which can be expected to occur A release which can be expected to occur periodically or occasionally during normal periodically or occasionally during normal operation.operation.

Secondary (S): A release which is not expected to occur Secondary (S): A release which is not expected to occur during normal operation and if it does during normal operation and if it does occur, it is likely to do so only occur, it is likely to do so only infrequently and for short periods.infrequently and for short periods.

Normal OperationNormal Operation::The situation when the equipment is operating within its The situation when the equipment is operating within its design parameters.design parameters.

exampleexample

55



ZonesZones: Hazardous areas are classified into zones on the : Hazardous areas are classified into zones on the basis of the frequency of the occurrence and duration of basis of the frequency of the occurrence and duration of an explosive gas atmosphere, as follows:an explosive gas atmosphere, as follows:

•• Zone 0Zone 0: An area in which an explosive gas atmosphere : An area in which an explosive gas atmosphere is present continuously or for long periods. is present continuously or for long periods.

•• Zone 1Zone 1: An area in which an explosive gas atmosphere : An area in which an explosive gas atmosphere is likely to occur in normal operation.is likely to occur in normal operation.

•• Zone 2Zone 2: An area in which an explosive gas atmosphere : An area in which an explosive gas atmosphere is not likely to occur in normal operation and, if it does is not likely to occur in normal operation and, if it does occur, it is likely to do so only infrequently and will occur, it is likely to do so only infrequently and will exist for a short period only.exist for a short period only.



Type of VentilationType of Ventilation::Natural (N):Natural (N): This is a type of ventilation, which is This is a type of ventilation, which is

accomplished by the movement of air accomplished by the movement of air caused by the wind and/or by temperature caused by the wind and/or by temperature gradients.gradients.

Artificial (A):Artificial (A): The air movement required for ventilation is The air movement required for ventilation is provided by artificial means, for example provided by artificial means, for example fans or extractors.fans or extractors.

66



Availability of VentilationAvailability of Ventilation::Good (G):Good (G): Ventilation is present virtually continuously.Ventilation is present virtually continuously.Fair (F):Fair (F): Ventilation is expected to be present during Ventilation is expected to be present during

normal operation. Discontinuities are normal operation. Discontinuities are permitted, provided they occur infrequently permitted, provided they occur infrequently and for short periods.and for short periods.

Poor (P):Poor (P): Ventilation which does not meet the standard Ventilation which does not meet the standard of fair or good and whose discontinuities are of fair or good and whose discontinuities are however not expected to occur for long however not expected to occur for long periods.periods.



Degree of VentilationDegree of Ventilation [1]:[1]:High ventilation (VH):High ventilation (VH): Can reduce concentration at the source of Can reduce concentration at the source of

release virtually instantaneously, resulting in a release virtually instantaneously, resulting in a concentration below the lower explosive limit concentration below the lower explosive limit (LEL).(LEL).

Medium ventilation (VM):Medium ventilation (VM): Can control the concentration, resulting in a Can control the concentration, resulting in a stable situation in which the concentration stable situation in which the concentration beyond the zone boundary is below the LEL beyond the zone boundary is below the LEL whilst release is in progress and where the whilst release is in progress and where the explosive atmosphere does not unduly persist explosive atmosphere does not unduly persist after the release has stopped. after the release has stopped.

Low ventilation (VL):Low ventilation (VL): Cannot control the concentration whilst the Cannot control the concentration whilst the release is in progress and/or cannot prevent release is in progress and/or cannot prevent undue persistence of a flammable atmosphere undue persistence of a flammable atmosphere after the release has stopped.after the release has stopped.

77





Fluid CategoryFluid Category::Fluid Category AFluid Category A: A flammable liquid that, on release, : A flammable liquid that, on release,

would vaporize rapidly and substantially. would vaporize rapidly and substantially. This category includes:This category includes: ..

a) Any liquefied petroleum gas or lighter flammable liquid.b) Any flammable liquid at a temperature sufficient to

produce, on release, more than about 40% vol vaporization with no heat input other than from the surroundings.

Fluid Category BFluid Category B: A flammable liquid, not in Category A, : A flammable liquid, not in Category A, but at a temperature sufficient for the but at a temperature sufficient for the boiling to occur on release.boiling to occur on release.

Fluid Category CFluid Category C: A flammable liquid, not in Category A : A flammable liquid, not in Category A or B, but which can, on release, be at a or B, but which can, on release, be at a temperature above its flashpoint, or form a temperature above its flashpoint, or form a flammable mist or spray.flammable mist or spray.

88



Temperature ClassesTemperature Classes: According to the auto: According to the auto--ignition ignition temperature, for every flammable fluid is associated a temperature, for every flammable fluid is associated a Temperature ClassTemperature Class


Hazardous Area Classification Hazardous Area Classification –– API 505API 505

The procedure to classify the plant is as follow:The procedure to classify the plant is as follow:•• Identify the hazardous materials;Identify the hazardous materials;•• Identify for each material, its chemicalIdentify for each material, its chemical--physical physical

properties, such as LFL, UFL, Flash Point, Autoproperties, such as LFL, UFL, Flash Point, Auto--ignition ignition Temperature;Temperature;

•• Identify the Emission Sources and their probability of Identify the Emission Sources and their probability of occurrence;occurrence;

•• Evaluate the availability of ventilation;Evaluate the availability of ventilation;•• Apply the typical examples present on the standard to Apply the typical examples present on the standard to

each emission source identified according to the each emission source identified according to the ventilation and the plant layout.ventilation and the plant layout.

99


Hazardous Area Classification Hazardous Area Classification –– API 505 API 505 –– Example Example

Example:Example: Launching Trap of an Offshore PlatformLaunching Trap of an Offshore Platform

INPUTINPUTMax air temperature: 38°CRelative Humidity: 77%Environment: Open structure, naturally ventilatedMaterial: Natural Gas (99,47% mol CH4)Chemical-Phisical Properties:Boiling point: -162°C Density gas/air: 0,694LEL: 5,3 Ignition Temperature: >500°CGroup: IIA Temperature Class: T1Vapour Pressure: N/A (gas) Flash Point: N/A (gas)



OUTPUTOUTPUT

1,5 m

Zone 1 Extension

3,0 m

Zone 2 Extension

34

Op. Temp °C

Fig. 49NaturalGasMain Deck10.6.6.2.14

Hazardous Zone ref. to examplesMaterialLocationExampleNo

Launching Trap Launching Trap –– Example Example

1010




Hazardous Area Classification Hazardous Area Classification –– IEC 60079IEC 60079--1010

The procedure to classify the plant is as follow:The procedure to classify the plant is as follow:•• Identify the hazardous materials;Identify the hazardous materials;•• Identify for each material, its chemicalIdentify for each material, its chemical--physical properties, physical properties,

such as LFL, UFL, Flash Point, Autosuch as LFL, UFL, Flash Point, Auto--ignition Temperature;ignition Temperature;•• Identify the Emission Sources and their probability of Identify the Emission Sources and their probability of

occurrence, evaluating the type of release (Continuous, occurrence, evaluating the type of release (Continuous, Primary, Secondary);Primary, Secondary);

•• Evaluate the availability of ventilation;Evaluate the availability of ventilation;•• Evaluate the hole dimension according to the standard;Evaluate the hole dimension according to the standard;•• Apply the all the equations given in the standard in order to Apply the all the equations given in the standard in order to

evaluate the Flow rate of emission (evaluate the Flow rate of emission (QgQg), the Hazardous ), the Hazardous Volume (Volume (VzVz) and the Hazardous Distances () and the Hazardous Distances (dzdz))

The IEC standards provide also the rules for classifying the areThe IEC standards provide also the rules for classifying the areas as with flammable powder and dust substances.with flammable powder and dust substances.

1111


Hazardous Area Classification Hazardous Area Classification –– IEC 60079IEC 60079--1010

Hazardous VolumeMinimum ventilation flowGas emission flow rateTwo-phase emission flow rateCryogenic emission flow rateLiquid emission flow rateHazardous distance (high velocity of emission)

Hazardous distance (low velocity of emission)Explosive VolumeAverage concentration


Hazardous Area Classification Hazardous Area Classification –– IEC 60079IEC 60079--10 10 –– Example Example

4.43 %vol(0.0327kg/m3)LEL

482°CAutoignitionTemperature

IIAGroup

Natural GasMaterial

T1Temperature Class

17.77 kg/kmolMW

1.31Cp/Cv

<0°CFlash Point

Example:Example: Pressure Safety ValvePressure Safety Valve

25.013*E05 PaOperating Pressure

293 KOperating Temperature

OPENEnvironment

313 KT external

101325 PaP atm

1Efficiency of Ventilation

GOOD, NATURAL, MEDIUM

Ventilation (type, availability, degree)

1.127 kg/m3Air density

50%Max. Initial Gas Concentration

K = 0.35Kdz = 0.35

Safety Coefficient

0.5 m/sWind Speed

1212



Primary Grade EmissionPrimary Grade Emission

withwith , , (sonic release)(sonic release)

a = aa = a11 = = ddzz ~ 1 m~ 1 m



1313


Secondary Grade EmissionSecondary Grade Emission


withwith , , (sonic release)(sonic release)

with Kwith K00=1=1

a = aa = a22 = = ddzz ~ 10 m~ 10 m


440

0.506

Vz m3

0.416

2.27*E-3

Qg kg/s

IIA, T126410 m2° Grade

IIA, T10.1771 m1° Grade

Group, Temp. Class

Vexm3aiResults


1414


Hazardous Area Classification Hazardous Area Classification –– IEC 60079IEC 60079--10 10 –– Exercise Exercise

EMISSION FROM FLANGESEMISSION FROM FLANGES(Secondary Grade Emission)(Secondary Grade Emission)



4.43 %vol(0.0327kg/m3)LEL

482°CAutoignitionTemperature

IIAGroup

Natural GasMaterial

T1Temperature Class

17.77 kg/kmolMW

1.31Cp/Cv

<0°CFlash Point

25.013*E05 PaOperating Pressure

293 KOperating Temperature

OPEN (Kz=1)Environment

313 KT external

101325 PaP atm

1Efficiency of Ventilation

GOOD, NATURAL, MEDIUM

Ventilation (type, availability, degree)

1.127 kg/m3Air density

50%Max. Initial Gas Concentration

K = 0.35Kdz = 0.35

Safety Coefficient

0.5 m/sWind Speed

INPUT DATAINPUT DATA

0.6K , Kdz

25 mm2A (leak area)

0.8C (leak coefficient)

1515



Results:Results:

a = 0.2 a = 0.2 mm



1616



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Offshore Safety