hse design engineering tutorial

© 2015 – Hervé Baron

HERVE BARON

Engineering Training

Welcome to this presentation.

It is part of a suite of Engineering training modules.

It shows the activities and deliverables of the Design Safety & Environment (HSE) discipline.

Comments are most welcome ([email protected]), which I will incorporate for the benefit of all.

Please download this file so that you can see my trainer’s notes in the top left corner – latest Acrobat Pro feature.

Hervé


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Engineering disciplines: activities and deliverables

PROCESS

PLANT LAYOUT

EQUIPMENT

SAFETY & ENVIRONMENT

CIVIL

PIPING

PIPELINE

INSTRUMENTATION

ELECTRICAL


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Design Safety

The “Design Safety” discipline is to safeguard against the PLANT hazards.

Where does PLANT hazard come from? Loss of containment

Which are the two ways Design Safety can safeguard against loss of containment?

Reduce possibility

Minimize effect

Give some examples of each


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Design Safety




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Design Safety




Reduce possibility

Minimize effect


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Design Safety




Reduce likelihood

Minimize effect

How?


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Design Safety




Reduce likelihood • QA and QC during design and construction • Detection of plant upsets • Overpressure protection • Pipes to be protected against mechanical failure as a result of vibration • Correct fail-safe position of control elements • Pipes to be sized to avoid hammering and surge • Minimize number of flanges • Explosion protection of Electrical Equipment and Instruments • Specify adequate Safety Integrity Level for Safety Automated Functions


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Design Safety




Reduce likelihood

Minimize effect

How?


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Design Safety




Reduce likelihood

Minimize effect • PLANT layout: isolation of ignition/leak sources, spacing between units

and equipment, bounding of liquid storage • Adequate personnel escape ways • Fire protection and fighting • Fire and Gas Detection and alarm • ESD system to isolate and depressurize


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Design Safety




Reduce possibility

Minimize effect

The different areas of involvement of Design Safety are defined in the Design Safety Philosophy, also called “Safety Concept”.


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Design Safety




Reduce possibility

Minimize effect

The different areas of involvement of Design Safety are defined in the Design Safety Philosophy, also called “Safety Concept”.

This presentation of the discipline will follow the table of content of this document


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Design Safety Philosophy / Safety Concept

HAZARD Identification

Risk assessment

PLANT Layout

Process Safety Systems

Fire protection & Fire fighting

Fire & Gas Detection

Hazardous area classification

Escape, Evacuation


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HAZARD Identification • General Hazards • Process related hazards


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How are PLANT general hazards identified?


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HAZard IDentification (HAZID)

A structured, key word based Qualitative risk identification and analysis methodology

Risk (to personnel safety, environment, assets) resulting from accident – normal operation excluded

Using check-lists enables a systematic screening.

Guided team brainstorming activity that benefits from the broad experience of a multidisciplinary team.

The result of the review is documented in a table where potential hazards, corresponding causes, consequences and associated safeguards are reported.

When necessary actions are formulated and followed-up


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HAZard IDentification (HAZID) GUIDEWORDS

Presenter

Presentation Notes

Vicinity of motorway = ignition source Plant near KAUST: built in a wady!


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HAZard IDentification (HAZID)

Presenter

Presentation Notes

Vicinity of motorway = ignition source Plant near KAUST: built in a wady!


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HAZard IDentification (HAZID) Output

Presenter

Presentation Notes

Other examples: leakage of product at bottom part of the column which is above its auto-ignition temperature Overpressure due to change of viscosity following loss of heat tracing Example of recommendation: DBB on toxic services


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How are process hazards identified?


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Hazard and Operability Review (HAZOP)

What is a HAZOP?


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What is a HAZOP?

A review of the possible deviations of the process from normal conditions


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What is a HAZOP?


What are these possible deviations?


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What is a HAZOP?



High/Low Pressure, High/Low Temperature, High/Low Flow, change in composition


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What is a HAZOP?




How does a HAZOP review proceed?


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What is a HAZOP?

A review of the possible process deviations from normal conditions



How does a HAZOP review proceed?

The plant is split in nodes. For each node, each deviation is reviewed.


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What type of failure are reviewed in HAZOP?


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What type of failure are reviewed in HAZOP? • Failure of process controls • Failure of equipment • Missoperation by operator


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HAZOP action and response sheet


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Action items follow-up

Presenter

Presentation Notes

Ask to whom shall this follow-up be assigned?


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Risk assessment

PLANT Layout





Escape, Evacuation


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Safety of Layout


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Safety of Layout

Where shall we locate the air-coolers electrical sub-station?

?


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Safety of Layout


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Risk assessment

PLANT Layout





Escape, Evacuation


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Risk assessment

PLANT Layout





Escape, Evacuation

There are 2 types of Fire protection: Active and Passive. Give an example of each…


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Fire Fighting

What type of fire fighting equipment uses water?


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Fire Water demand calculation

Presenter

Presentation Notes

Storage tank fire protection: rim seal (low expansion foam) + shell cooling by foam/water spray system (mechanical water/foam proportioner)+ bund foam pourers, all 3 systems are connected to the FW network for water supply + Fire curtain between furnace and process units


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Spray (deluge) system

What is the purpose of fixed water spray systems?

Presenter

Presentation Notes

Fire intensity control/Control of burning: application of water spray to equipment or areas where a fire can occur to control the rate of burning and thereby limit heat release from a fire until fuel can be eliminated or extinguishment effected Exposure protection: absorption of heat through application of water spray to structures or equipment exposed to a fire, to limit surface temperature to a level that will minimize damage and prevent failure


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What is the purpose of fixed water spray systems? Which equipment are concerned?

Presenter

Presentation Notes

These equipment are not defined in codes but project wise, according to Client requirements (sometimes coming from the Client’s insurer) or as per the Engineer’s choice, in the Job Specification for Design Active Fire Protection. Off-shore all equipment are deluged to cool down the equipment to limit the risk of fire escalation as equipment are very close to each other. On-shore fire fighting is much easier (access) and more space is provided between equipment. Hence a limited number of equipment are deluged. For instance: For fire intensity control: high hazard equipment that contain a severe fuel hazard with a high heat release rate thus requiring an immediate application of water, e.g., All vessels, columns, heat exchangers holding more than 5 m3 LPG type hydrocarbon – except equipment located at elevation of more than 8 meters. Pumps handling LPG HC close to their auto-ignition temperature Compressors handling flammable gases – deluged area shall extend to auxiliaries Exposure protection: e.g. “Equipment containing hydrocarbons which cannot be reached by firewater monitors.” Rk: rate of water spray for fire intensity control is twice that of water spray for exposure protection. Rates are defined by NFPA 15.


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Equipment to be protected by water spray system are not defined in codes but project wise, according to Client requirements if they exist or as per the Engineer’s choice, in the Job Specification for Design Active Fire Protection. Off-shore all equipment are deluged to cool down the equipment to limit the risk of fire escalation as equipment are very close to each other. On-shore fire fighting is much easier (access) and more space is provided between equipment. Hence a limited number of equipment are deluged. For instance: For fire intensity control: high hazard equipment that contain a severe fuel hazard with a high heat release rate thus requiring an immediate application of water, e.g., • All vessels, columns, heat exchangers holding more than 5 m3 LPG type hydrocarbon –

except equipment located at elevation of more than 8 meters. • Pumps handling LPG • HC close to their auto-ignition temperature • Compressors handling flammable gases – deluged area shall extend to auxiliaries

Exposure protection: e.g. “Equipment containing hydrocarbons which cannot be reached by firewater monitors.”

Presenter

Presentation Notes

Rk: rate of water spray for fire intensity control is twice that of water spray for exposure protection. Rates are defined by NFPA 15.


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Fire Fighting

How do we calculate the Plant Fire water equirements?


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Fire Fighting / Fire Zones


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Fire Water demand calculation

Presenter

Presentation Notes

Rate of deluge are specified in codes, e.g., rate of water spray for fire intensity control is twice that of water spray for exposure protection as per NFPA 15.


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Fire Water facilities


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Fire Water distribution


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Fire Water P&IDs


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Deluge system arrangements

Presenter

Presentation Notes

Deluge system design requirements are specified in codes, e.g., NFPA 15.


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Fire protection and Personnel protection drawing

Presenter

Presentation Notes

Why is this drawing called Personnel protection? Because there are the Safety showers


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Passive fire protection


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Presenter

Presentation Notes

How are Fire envelopes defined? A list of equipment creating a fire risk zone is drawn, generally, equipment containing more than 5m3 of liquid HC (as per codes, in, particular API 2218). This « list of source of hazard for PFP “ is not necessarily a deliverable, but an internal document Fire scenario envelopes around Equipment creating a Fire Hazard are drawn on a Plot Plan. Dimensions of envelopes are specified in the code (API 2218). Equipment inside the enveloppe are screened for requirement of Fire Proofing (criteria is that of code API RP 2218 ): flammable inventory or domino effect


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How are Fire envelopes defined? •A list of equipment creating a fire risk zone is drawn, generally, equipment containing more than 5m3 of liquid HC (as per codes, in, particular API 2218).

•This « list of source of hazard for PFP “ is not necessarily a deliverable, but an internal document

•Fire scenario envelopes around Equipment creating a Fire Hazard are drawn on a Plot Plan. Dimensions of envelopes are specified in the code (API 2218).

•Equipment inside the enveloppe are screened for requirement of Fire Proofing (criteria is that of code API RP 2218 ): flammable inventory or domino effect.


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Risk assessment

PLANT Layout





Escape, Evacuation

Presenter

Presentation Notes

Plant isolation and depressurisation philosophy


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Risk assessment

PLANT Layout





Escape, Evacuation

Where shall Emergency ShutDown Valves be provided?

Presenter

Presentation Notes

ESDVs shall be provided between Fire Zones


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Emergency Shutdown System (ESD)


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Risk assessment

PLANT Layout





Escape, Evacuation


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Fire & Gas detection layouts


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Fire & Gas Cause & Effects matrix


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Risk assessment

PLANT Layout





Escape, Evacuation


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Hazardous area classification drawings


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The referential must be defined, e.g.,

API RP 505 Recommended Practices for Classification of Locations for Electrical Installations at Petroleum Facilities classified as Class I, Zone 0, Zone 1 and Zone 2 (1997 Edition).

Zone 0 location is a location at which ignitible concentration of flammable gases or vapours are present continuously or for long periods of time.

Zone 1 location is a location at which ignitible concentration of flammable gases or vapours are likely to exist under normal operating conditions,

Zone 2 location is a location at which ignitible concentrations of flammable gases or vapours are not likely to occur in normal operation and if they do occur will exist only for a short period

Presenter

Presentation Notes

Besides flammable gas, liquids above their flash points must be identified, as they create hazardous areas Also, liquids above their auto-ignition temperature must be identified. Indeed, surface temperature of equipment/pipes located underneath lines with a liquid above its auto-ignition temperature shall be limited to 80% of the latter.


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The Explosion protection of Electrical and Instrumentation equipment located in Hazardous area is defined by means of: Zone 0/1/2 - Gas Group - Temperature Class

Presenter

Presentation Notes

Gas Group: example of gas group IIC or IIB+H2 is battery room and analyser shelters Temperature class = maximum surface temperature, selected as function of ignition temperature of the concerned flammable mixture


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The Explosion protection of Electrical and Instrumentation equipment located in Hazardous area is defined by means of: Zone 1/2/3 - Gas Group - Temperature Class

Presenter

Presentation Notes

Gas Group: example of gas group IIC or IIB+H2 is battery room and analyser shelters Temperature class = maximum surface temperature, selected as function of ignition temperature of the concerned flammable mixture


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Hazardous area classification extent of hazardous area (API RP 505)

Presenter

Presentation Notes

The type of zone depends on likeliness of discharge


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Presenter

Presentation Notes

The extent depends if the gas is heavier (left) or lighter (right) than air


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Presenter

Presentation Notes

Extent of hazardous area depends on quality of ventilation


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Presenter

Presentation Notes

Combustible liquid storage tank


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Presenter

Presentation Notes

Flammable liquid storage tank


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Why is the inside of the storage tank zone 1 for the tank on the left and zone 0 for the tank on the right?

Presenter

Presentation Notes

Combustible vs Flammable liquid storage tank As per NFPA: Flammable liquids: liquid with a flash point below 37.8°C Combustible liquids: liquid with flash point above 37.8°C. Example: kerosene, diesel


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Hazardous area classification drawings What is the use of the Hazardous area classification drawing?


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Hazardous area classification drawings

Presenter

Presentation Notes

It allows to specify type of explosion protection for Electrical equipment (motors etc.) and instrumentation It also defines the required equipment maximum surface temperature hence insulation requirements, e.g. reactors of SRU plants are refractory lined, to reduce steel temperature to 340°C and heat insulated to reduce surface temperature to below 200°C or so. Same thing for furnace: refractory lines and cold rain shield which channels air circulation. Surface temperature of equipment/pipes located underneath lines carrying a liquid above its auto-ignition temperature shall be limited to 80% of the latter.


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Quantitiative Risk Assessment (QRA)

PLANT Layout





Escape, Evacuation


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Quantitative Risk Analysis (QRA)

Objective: Define the scenarios of likely loss of containment Content: Identify flammable, toxic fluids, isolatable sections Identify possible consequence: fire, explosion, toxic etc. Identify ignition source Input: PFD, HMB, Plot Plan HAZID Report

Step 0:

Failure cases definition

Presenter

Presentation Notes

Done in the form of a workshop, with attendance of Process and HSE Design Small leaks: flange, valve/pump stuffing box, instrument tapping Medium leak: open purge valve, mechanical failure: impact, vibration etc. Large leak: pipe rupture


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Step 0:

Failure Case Definition

Case : Gas leak from random piping component rupture

Cause: installation error, corrosion,

material defect…

Possible consequence: Dispersion without ignition / jet fire / flash fire / explosion

Section considered: Compressor building


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Step 1:

Identification and characterisation of initiating events

Gas leak inside compressor buidling due to component rupture Hole size (% of component section)

5% 20% Full

Frequency (event/year) 1,11E-01 5,06E-04 6,83E-05

Outflow rate (kg/s) 5,7 90,8 2270,0

Σ risk components *failure rate (from statistics)


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Release Frequency Immediate ignition

ESD & Fire Fighting

Delayed Ignition

Explosion/ Flash-fire

Consequence Event Frequency (ev/y)

0,998 Jet fire ESD & FF 7,779E-030,070

0,002 Jet fire no ESD & FF 1,520E-05

1,11E-01Release/yr

0,949 Dispersion 9,827E-020,930

0,120 Explosion 1,774E-050,028

0,051 0,880 Flash fire 1,301E-04

0,972 Dispersion 5,133E-03

Yes Frequency (event/year)Jet fire ESD & FF 7,779E-03Jet fire no ESD & FF 1,520E-05Explosion 1,774E-05

No Flash Fire 1,301E-04Dispersion 1,034E-01

B04a/b/c/d 5%

Step 2: Event tree analysis


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ESD & Fire Fighting

Delayed Ignition



0,998 Jet fire ESD & FF 7,779E-030,070


1,11E-01Release/yr

0,949 Dispersion 9,827E-020,930

0,120 Explosion 1,774E-050,028

0,051 0,880 Flash fire 1,301E-04




B04a/b/c/d 5%

Probability of immediate ignition for 1-50 kg/s release rate is 7% (from statistical data)

Gas detectors are provided inside the building, that activate isolation and depressurization. It is assumed that they operate 95% of the time.

Probability of explosion vs flash fire (12%) depends on mass of gas and degree of confinement

?

What is the frequency of an explosion?

Probability of delayed ignition (2.8%) takes into account equipment explosion protection (Ex)



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Possible consequences of loss of containment

Presenter

Presentation Notes

Dispersions / Jet fire


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Presenter

Presentation Notes

Explosion


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ESD & Fire Fighting

Delayed Ignition



0,998 Jet fire ESD & FF 7,779E-030,070


1,11E-01Release/yr

0,949 Dispersion 9,827E-020,930

0,120 Explosion 1,774E-050,028

0,051 0,880 Flash fire 1,301E-04




B04a/b/c/d 5%



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Overpresssure (bar) 0.2 0.1 0.01

Distance (m) 96 167 1270

Step 3:

Consequence evalutation

CONSEQUENCE CLASS QUANTITATIVE CRITERIA EFFECTS

MINOR ≤0.1 bar locally (within 10m) No effect, no damage

SIGNIFICANT ≤0.1 bar locally (within 50m) Limited damage to plant and operators

SEVERE > 0.1 bar within plant Damage to plant and operators

MAJOR > 0.1 bar on populated areas Damage to plant, operators & public


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Unacceptable risk area– Design change necessary

As Low As Reasonably Practicable – Plant Management measures

Acceptable risk area ?

Final step:

classification of risk


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Unacceptable risk area– Design change necessary

As Low As Reasonably Practicable – Plant Management measures

Acceptable risk area

1.0E-02

1.0E-03

1.0E-04 Unlikely

1.0E-05 Rare

1.0E-06 Minor Significant Severe Major

Final step:


Severity

Prob

abili

ty

Presenter

Presentation Notes

The risk matrix is specified by CPY or by Authorities, for instance in S’poren in France (PPRT).


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Final step:


CONSEQUENCE CLASS QUANTITATIVE CRITERIA EFFECTS MINOR ≤0.1 bar locally (within

10m) No effect, no damage

SIGNIFICANT ≤0.1 bar locally (within 50m)

Limited damage to plant and operators

SEVERE > 0.1 bar within plant Damage to plant and operators MAJOR > 0.1 bar on populated

areas Damage to plant, operators & public

?


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Final step:









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Outcome?


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QRA results: Thermal radiation map (>37.5 kW/m2)

Presenter

Presentation Notes

This is used to specify the fire rating of buildings/structures and PFP


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QRA outcome: Risk Reduction Measures At FEED stage Explosion and fire radiation curves:

Distance between units, e.g., distance between process units and administration buildings, relocation of CCR etc.

Explosion resistance and fire rating of equipment, manned buildings, structures (design for 10-4 per year likelihood: API RP 752 ; ISO19901-3 ; NORSOK Z-013, …)

At Detail Design Stage

Addition of gas detectors Addition of blast/fire protection wall, e.g., between process and utility modules, for

protection of risers ESDV valves Relocation of muster point Relocation of adjacent human occupancy areas (maintenance yard, highway rest area etc.) Recommendation for operations, e.g., increased inspection


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Quantitiative Risk Assessment (QRA) • Failure cases identification and definition • Consequence Analysis • Frequency Analysis • QRA Outcome


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Another example: toxic gas release


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Quantitative Risk Analysis (QRA) Consequence analysis

Presenter

Presentation Notes

Rk: dispersion calculation depend on weather conditions. Worst is minimum wind. Continuous realease case means no ESD (isolation) is initiated. POD = Probability Of Death


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Quantitative Risk Analysis (QRA) Consequence analysis

What conclusion would you draw?

Presenter

Presentation Notes

The impact is determined at manned locations Recommendation: Install H2S detectors at HVAC inlet of Warehouse D and buildings in administration and maintenance areas to initiate automatic shutdown of HVAC upon H2S detection Remark: same dispersion calculations could be done considering ESD activitation, i.e., isolation and reduced inventory, which will show that the risk to workers (located inside buildings) is reduced. Note: the recommendations could be further submitted to confirmation during the QRA when the probability of occurrence will be evaluated.


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Another example: effect of congestion


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Quantitiative Risk Assessment (QRA) • Failure cases identification and definition • Consequence Analysis

VCE: a flammable gas or a flashing liquid released to atmosphere, if not immediately ignited, disperses to atmosphere creating a cloud which can develop in a Vapour Cloud Explosion (VCE), if the burning velocity of the cloud is increased due to turbulence generated by obstacles present in the cloud. Effects (damages) are associated to levels of overpressure generated by pressure wave.

Explosion strength depends on level of congestion. Congested areas are identified based on arrangement of equipment/group of equipment,

platforms, and structures within each Process Unit. Air coolers / pipe-racks / compressor shelters are considered as roofs underneath which gas

cloud can accumulate. Free areas between group of equipment within Process Unit reduce the size of the congested

areas. Flammable volume/mass is estimated for each unitary congested area.


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Identification of congested areas


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COMPANY Societal Risk Criteria

1.0E-8

1.0E-7

1.0E-6

1.0E-5

1.0E-4

1.0E-3

1.0E-2

1 10 100 1000 Number of Fatalities (N or more)

Freq

uenc

y (/y

r)

Intolerable above line Acceptable below line

ALARP Region


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Risk assessment

PLANT Layout





Escape, Evacuation


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Escape, evacuation


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Engineering disciplines: activities and deliverables

PROCESS

PLANT LAYOUT

EQUIPMENT

SAFETY & ENVIRONMENT

CIVIL

PIPING

PIPELINE

INSTRUMENTATION

ELECTRICAL


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Health and Environment Requirements Job Specification for Design

Environmental and health aspects

Regulatory requirements

Air emissions

Liquid effluents

Soil & groundwater contamination

Wastes

Pollution prevention

Noise

Presenter

Presentation Notes

Regulatory limits as well as monitoring requirements shall be identified


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Health and Environment Requirements Job Specification for Design

Environmental and health aspects

Regulatory requirements

Air emissions

Liquid effluents

Soil & groundawter contamination

Wastes

Pollution prevention

Noise

Presenter

Presentation Notes



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ENVID Environment Aspects Register

Presenter

Presentation Notes



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Environment Emissions regulatory limits


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Environmental Impact Assessment


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Noise study

dB(A)


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The Oil & Gas Engineering Guide

Get all this plus the same on other disciplines and the overall picture... in the newly published:


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The Oil & Gas Engineering Guide - 2nd edition

Table of Contents


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Table of Contents

This suite of training modules covered the discipline chapters of the book...


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Table of Contents

The Guide contains much more:

The overall picture, interfaces, methods & tools, etc.


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Table of Contents


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The Oil & Gas Engineering Guide 2nd edition

Order direct from the publisher:

http://www.editionstechnip.com/en/catalogue-detail/1111/oil-gas-engineering-guide-the.html




hse design engineering tutorial

Education

design safety discipline

ways design safety

loss of containment

plant hazards

safety automated functions

effect plant layout

likelihood qa

mechanical failure