20243E00

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ONSHORE INSTALLATIONS ONSHORE INSTALLATIONS

DESIGN LAYOUT AND SAFETY SPACING DESIGN LAYOUT AND SAFETY SPACING

20243.VON.SAF.SDS. 20243.VON.SAF.SDS. Rev. 0 Rev. 0 May 1996 May 1996 0

0 EEMMIISSSSIIOONN SSTTIINN SSIICCII SSTTIINN 1155..55..9966 R

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FOREWORD FOREWORD

Rev. 0

Rev. 0 Total sheets 71Total sheets 71 May 1996 May 1996 Emission Emission

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FOREWORD FOREWORD

Rev. 0

Rev. 0 Total sheets 71Total sheets 71 May 1996 May 1996 Emission Emission

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CONTENTS CONTENTS 1 1.. GGEENNEERRAALL 1 1..11 SSccooppee 1

1..22 NNoorrmmaattiivve e rreeffeerreenncceess 1

1..22..11 EEuurrooppeeaan nn noorrmmaattiivve re reeffeerreenncceess 1.

1.2.2.22 NoNormrmatativive re refefererenenceces os of If ISOSO, , IEIEC aC and nd nanatitiononal al ororgaganinizazatitiononss 1

1..22..33 NoNorrmamattiivve re reefferereennccees os of of otthher er oorrggaanniizzatatiioonnss 1

1..22..44 LLeeggiissllaattiioonn 1

1..22..55 IInntteerrnnaal nl noorrmmaattiivve re reeffeerreenncceess

2

2.. FFUUNNCCTTIIOONNAAL L NNOORRMMAATTIIVVE E RREEQQUUIIRREEMMEENNTT 2

2..11 DDeeffiinniittiioonnss 2

2..22 OOppeerraattiivve e eennvviirroonnmmeenntt 2

2..33 SSaaffeetty y rreeqquuiirreemmeenntts s ffoor r tthhe e llaayyoouutt 2

2..33..11 PPrroocceesss s aannd d uuttiilliitty y uunniittss 2

2..33..22 SSaaffeetty y mmaaiin n uunniittss 2

2..33..33 ““CCrriittiiccaall” ” ppllaannt t uunniittss 2

2..33..44 PPrroocceesss s ppiippiinng g aannd d vveennttss 2

2..33..55 CClleeaarraanncceess 2

2..33..66 DDiivviissiioonnss 2

2..33..77 OOuutteer r iinnssttaallllaattiioonns s aannd d rraaddiiaattiioonn 2

2..33..88 CCoonnttrrool l ssyysstteemmss 2

2..33..99 EEssccaappe e wwaayyss 2.

2.3.3.1010 ClClasassisifificacatition on of of arareaeas ws witith h exexplplososioion n hahazazardrd 2

2..44 SSaaffeetty y rreeqquuiirreemmeenntts s ffoor r ssppaacciinngg 2

2..44..11 SSaaffeetty y ssppaacciinngg 2

2..44..22 GGeenneerraal l rreeqquuiirreemmeennttss 2

2..44..33 FFeenncceess 2

2..44..44 HHyyddrrooccaarrbboonns ss sttoorraagge te taannkkss 2

2..44..55 HHyyddrrooccaarrbboonns s llooaaddiinng g bbaayyss 2

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2.4.7 Oil treatment plants 2.4.8 Gas treatment plants 2.4.9 Compression stations

2.4.10 Glycol heating and reconditioning plants 2.4.11 Glycol storage tanks

2.4.12 Basins for oily waters treatment 2.4.13 Oil/gas pipelines

2.4.14 Process safety valves 2.4.15 Gas flares and vents 2.4.16 H2S process plants

2.5 Requirement of work health and environmental protection

2.6 Ergonomics

2.7 Requirements for Quality Management and Quality Assurance 2.8 Documentation

3 SUPPLEMENTARY ELEMENTS

3.1 Enclosures and informative annexes 3.1.1 Annexes

Annex 1 Plant general layout

Annex 2 Better location - Process and utilities units Annex 3 Better location - Safety main units

Annex 4 Better location - “Critical” plant units Annex 5 Safety spacing to be adopted

Annex 6 Pool fire - Computational method Annex 7 Jet fire - Computational method

Annex 8 Unconfined gas cloud explosion (pressurised) - Computational method

Annex 9 Unconfined gas cloud explosion (not pressurised) -Computational method

Annex 10 Heavy vapours dispersion - Computational method Annex 11 Hydrogen sulphide dispersion - Computational method

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1. GENERAL

1.1 Scope

This document has the aim to state the safety requirements for the layout and safety spacing to be adopted in the Oil and Gas treatment Units.

These requirements represent the minimum to be applied developing the basic and detail layout for the process areas of all the onshore installations.

Particular design requests, which impose alternatives not provided by this specification or by the mentioned legislation, shall be justified and evaluated by the internal expert Units.

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1.2 Normative references

1.2.1 European normative references

At this moment applicable European Normative References related to the specification does not exist.

1.2.2 Normative references of ISO, IEC and national organizations

Norme CEI 64.2 "Impianti elettrici in luoghi a rischio di incendio o esplosione"

1.2.3 Normative references of other organizations

API RP 500 B "Recommended practice for classification of areas for electrical installation at drilling rigs and production facilities on land and on marine fixed and mobile platforms"

API RP 520 "Design and installation of pressure relieving systems in refineries" (Part 1 “Design”, Part 2 “Installation”)

API RP 521 "Guide for pressure relieving and depressuring systems"

Industrial Risk Insurers (IRI) "General Recommendations for Spacing"

1.2.4 Legislation

In areas different from Italy the legislation of the involved country shall to be considered.

D.M. 31.7.1934 "Approvazione delle norme di sicurezza per la lavorazione, l'immagazzinamento, l'impiego e la vendita di olii minerali e per il trasporto degli olii stessi"

Ministero Interno "Caricamento e svuotamento nelle raffinerie Circolare dell'11.5.1954, n. 70 e nei depositi di olii minerali, dei veicoli a

cisterna ed a botte senza l'attuazione del ciclo chiuso"

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Ministero Interno Criteri di sicurezza per l'installazione e . Circolare del 9.7.1954 l'esercizio di centrali di compressione di gas n.21137/4105 metano"

Ministero Interno Serbatoi di grande capacità (integrazione del Circolare del 22.12.1962, DM 31.7.1934)

n. 132

D.P.R. 19.3.1956, n. 303 "Norme generali per l'igiene del lavoro"

"Protezione dei lavoratori contro i rischi derivanti da esposizione ad agenti chimici, fisici, biologici durante il lavoro"

D.P.R. 9.4.1959, n. 128 "Norme di polizia delle miniere e delle cave" Ministero Interno "Progetto di regolamento generale di

Circolare del 1965 prevenzione incendi"

Ministero Interno "Stabilimenti di lavorazione, depositi di olii Circolare del 15.1.1976, minerali. Misure di sicurezza"

n.10.03049/XV.H.24

D.M. 24.11.1984 "Norme di sicurezza antincendio per il trasporto, la distribuzione, l'accumulo e l'utilizzazione del gas naturale con densità non superiore a 0,8"

D.M. 31.3.1984 e "Norme di sicurezza depositi GPL di capacità D.M. 20.7.1993 non superiore a 5 m 3"

D.P.R. 24.5.1988, n° 203 "Attuazione delle direttive CEE n° 80/779, 82/884, 84/360 e 85/203 concernenti norme in materia di qualità dell'aria, relativamente a specifici agenti inquinanti e di inquinamento prodotto dagli impianti industriali, ai sensi

dell'art. 15 della legge 16 aprile 1987 n° 183" D.M. 12.7.1990 "Linee guida per il contenimento delle emissioni

inquinanti degli impianti industriali e la fissazione dei valori minimi di emissione"

D.L. 15.8.1991, n. 277 "Protezione dei lavoratori contro i rischi derivanti da esposizione ad agenti chimici, fisici, biologici durante il lavoro"

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D.Lgs 19.9.1994, n. 626 "Attuazione delle direttive CEE 89/391, 89/654, 89/655, 89/656, 90/269, 90/270, 90/394 e 90/679 riguardante il miglioramento della sicurezza e della salute dei lavoratori sul luogo di lavoro”

D.M. 13.10.1994 "Approvazione della regola tecnica di prevenzione incendi per la progettazione, la costruzione, l'installazione e l'esercizio dei depositi di GPL in serbatoi fissi di capacità complessiva superiore a 5 m 3 e/o in recipienti mobili di capacità complessiva superiore a 5000 kg"

DPGR n.7 Regione Sicilia "Regolamento di polizia mineraria"

1.2.5 Internal normative references

06744.VAR.ELE.SPC Classificazione luoghi onshore con pericolo di esplosione e scelta impianti elettrici di sicurezza e materiali

07486.PLI.MEC.PRG Specifica generale per condotte interrate

1.2.6 References

/Ref. 1/: L.Lusardi, A.Robertson, “Wellheads and Separators Areas Risk Analysis”, Mila Field Development, Snamprogetti Spc. 01-ZC-E-70458, 1984

/Ref. 2/: F.P.Lees, “Loss Prevention in the Process Industries” ediz. 1983 /Ref. 3/: G.L.Wells, “Safety in process plant design” ediz. 1980

/Ref. 4/: B.J. Wiekema - TNO / Institute of Environmental and Energy Technology, 1980

/Ref. 5/: E.P.A. - Environmental Protection Agency, “Technical Guidance for Hazards Analysis”

/Ref. 6/: NIOSH - National Institute for Occupational Safety and Health, “Chemical Hazards”

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2. FUNCTIONAL NORMATIVE REQUIREMENT 2.1 Definitions

The following definitions are valid in this document: Classified area:

Space of determined dimensions classified taking into consideration both the chemical properties, physical conditions and quantity of the contained dangerous substances processed or stored and the environmental characte ristics, which can influence the dispersion or accumulation of the dangerous substances.

The term “classified area”, generally used by AGIP, corresponds to “dangerous zone or AD area” by CEI.

Plant area:

Zone delimited by internal roads or enclosures, devoted to lodge only one or more plant units similar for pressure level, type of fluid, etc.

Dangerous area:

Space of undetermined extent where there is a dangerous atmosphere, so as defined by CEI 64-2 rules.

The term dangerous area, generally used by AGIP, correspond to “dangerous place” by CEI.

Water barrier:

Screen of water spray obtained with suitable nozzles in order to reduce quickly the concentration of the flammable gas under the E.L.L. (Explosivity Lower Limit)

Burning ray:

Burning gas jet coming from pressurised containers. Active defence:

Device operating directly on the event in order to reduce the consequences (i.e. fire fighting system).

Passive defence:

Device or design contrivance devoted to cancel or reduce the effects of an event on the areas or on installation areas close to the event place (i.e. fire breaker wall or safety distance).

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Safety distance:

This specification generally considers as safety spacing the distances between: - enclosure and hazardous equipment installed into the Unit;

- various hazardous equipment installed into the Unit;

- hazardous equipment and infrastructures installed into the Unit;

- hazardous equipment installed into the Unit and outer infrastruct ures . The main Italian legislation about distances is:

- D.M. 31-7-1934 (paragraphs 38÷56), for mineral oils installations; - D.M. 13-10-1994 (paragraphs 4.1÷4.5), for LPG tanks.

The definitions recalled by the above mentioned laws don’t agree each other; as an explanation each definition is listed with suitable annotations.

- protection spacing:

The D.M. 31-7-1934 doesn’t mention that but defines the distances between tanks/ warehouses/ decantation rooms and inner buildings to be respected.

The D.M. 13-10-1994 defines them as distances which determine, inside the tank, a respect zone (see it).

- respect spacing:

The D.M. 31-7-1934 mention them as distances between tanks/ warehouses/ decantation rooms and outer buildings, railways, tramways, bridges, monuments.

The D.M. 13-10-1994 doesn’t adopt this term but defines them as outer safety distances (see it).

- outer safety distance:

The D.M. 31-7-1934 doesn’t adopt this term but defines it as respect distance. The D.M. 13-10-1994 define it as distance between dangerous elements of the tank and outer buildings (divided as buildings in general and buildings with a big people concentration), railways and tramways.

- inner safety distance:

The D.M. 31-7-1934 doesn’t mention that but defines the mutual distances between tanks and tanks, tanks and decantation zones, decantation zones and

decantation zones.

The D.M. 13-10-1994 define it as mutual distance between dangerous elements of the tank (tanks, decantation zone, movable storage tanks, pumps, compressors, etc.).

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- protection zone:

The D.M. 31-7-1934 mention that as a minimum distances between tanks/ hazardous enclosed spaces and enclosure.

The D.M. 13-10-1994 doesn’t report distances from dangerous elements of the tank to the enclosure.

- respect zone:

The D.M. 31-7-1934 doesn’t mention that (see protection spacing) but defines the distances between tanks/ warehouses/ decantation rooms and inner buildings to be respected.

The D.M. 13-10-1994 defines that as a zone in which ignition sources, utilities building of the tank, (offices, laboratories, workshops, warehouses, services),

roads open to traffic and projection of air-ways, must not exist. Confined explosion:

Ignition in bulk of a cloud of flammable gas with explosion into an area confined by walls and ceiling with a whole open area less than 40% of the total walls area.

Unconfined explosion:

Ignition in bulk of a cloud of flammable gas with explosion outdoors. IDLH - Immediately Dangerous to Life or Health

Limit of concentration to which a man can be exposed for half an hour without any irreversible consequences for health or any impairment of escape possibility. (Ref. NIOSH - National Institute for Occupational Safety).

LOC - Level of concern

Concentration in air of a hazardous substance to which, for a relatively short exposure time, injuries for health can be expected (Ref. EPA - Environmental Protection Agency and ISPESL 1° Supplement of n°1/1993).

Preventive measure:

Measure or device able to prevent ignition into an area involved by the presence of explosive mixture as a consequence of releases from anomalous

events “reasonably expected”. Reasonably expected:

It is an event that, according to known incidental events (well-known data), can be considered frequent enough to found on it the dimensioning of active and passive defences. For this reason it is not generally the “most serious” event, since the serious event is also rare or not very frequent, so it is not a valid

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2.2 Operative environment

The design of oil and gas treatment units must take account of environmental conditions of the installation place, defined by the design specification.

All the environmental factors, that can influence the system reliability, shall be to consider:

- minimum and maximum temperature; - wind velocity and direction;

- snowfalls;

- presence of polluting and corrosive substances; - earthquakes;

- mechanical stress and vibrations due to normal operation; - direct or indirect fulmination;

- electromagnetic influences.

2.2 Functional requirements

The General Plot Plan shall be to realise in accordance with the criteria hereinafter stated.

Once the General Plot Plan is defined, for process and utilities areas shall be to respect the safety distances stated in subchapter 2.4 of this specification.

The General Plot Plan shall be to define in order to maintain the separation among the process equipment and from process equipment and manned areas (or areas that can be manned for emergency).

Defining the General Plot Plan the possibility of a next enlargement shall be to consider, in order that the future process areas do not determine an unacceptable reduction of the safety distances.

The layout of the areas into the Unit shall be defined so as to exploit main direction of the winds in order to reduce the possibility that gas or smoke release for fire occurrence can involve manned areas and main escape ways.

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The volume at /Ref.2/ (F.P. Lees: “Loss Prevention in the Process Industries”) suggests not to exceed the dimensions 100 x 200 m, in order to make emergency entrance and escape easy.

The criteria that have determined such layout are stated in the following paragraphs.

Units have been divided into the following groups: - Process and utilities Units

- Safety main Units - “Critical” plant Units

2.3.1 Process and utilities Units

Process and utilities Units considered by this specification are as follows; indications for their suitable location are stated in Annex 2:

Unit 120: Chemical injection for well head and plant Unit 190: Launching and/or receiving traps

Unit 200: Oil separation (Heaters)

Unit 200: Oil separation (Separators/ Oil column stabilisation) Unit 210: Oil treatment

Unit 220: Oil transport and storage (Oil removal pumps) Unit 300: Gas separation

Unit 310: Gas dehydration (Gas dehydration columns)

Unit 320: Liquid hydrocarbons recovery (Gasoline stabilisation column) Unit 350: Gas conditioning

Unit 380: Glycol for gas dehydration (Reconditioning glycol column) Unit 390: Glycol for gas dehydration (Glycol storage tanks)

Unit 430: Combustible gas oil.

Grouping the process or utilities units must be realised according to the following requirements:

- reduce areas containing toxic or corrosive products;

- bring the export pumps as close as possible to the relevant storage tanks; - maintain the (fractioning, absorption, etc.) column as close as possible to the

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- put the compressors of acid or sweet gas into the same area for easiness of maintenance, taking into consideration the length of inlet and sending pipes of acid gas (for instance installing the compression unit close to the sweetening unit);

- place the air heat exchangers as close as possible to the process areas connected to them and as far as possible from equipment with free burning flame (i.e. ovens, etc.).

The evacuation and access paths to the process and utilities areas must have the following characteristics:

- two accesses to the installation areas must always exist, one at least placed upwind.

- stairs to the installation areas must be provided with handrail; sailor stairs are allowed as escape and access ways only to out-of-the-way zones seldom visited by personnel (i.e. for maintenance);

- the access stairs must be placed on the side of plant or equipment more proofed against hazardous events, in order that the equipment itself can be a

shield for the personnel going upstairs a nd downstairs.

2.3.2 Safety main Units

Safety main Units considered by this specification are as follows; indications for their suitable location are stated in Annex 3:

Unit 230: Flares and vents

Unit 480: Electric power generation Unit 560: Oily waters treatment

Unit 580: Gaseous effluents treatment Unit 690: Civil buildings

Unit 730: Foam/water fire system

Main requirement for safety main Units is to be allowed to work during the foreseeable hazardous events, thus they must be protected against any consequence of those events.

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The evacuation and access paths from the areas with safety fundamental Units must comply with the following requirements:

- access to the Plant, adopted as the main escape way, must allow a fast access to the car parking;

- the plant for the treatment of liquid effluents must be in the centre of the area which it is devoted to and not near to one of the external roads, in order to be far from the vehicles entries.

2.3.3 “Critical” plant Units

“Critical” plant Units considered in this specification are the following; indications for their suitable location are stated in Annex 4;

Unit 220: Oil transport and storage (Oil storage tank)

Unit 310: Gas dehydration (Instrumentation rooms with fiscal metering equipment)

Unit 320: Liquid hydrocarbons recovery (Ethane removing / LPG

-LNG storage)

Unit 330: Gas deacidification (Gas deacidification column)

Unit 330: Gas deacidification (H2S absorber reconditioning column) Unit 330: Gas deacidification (Sulphur recovery)

Unit 360: Gas compression

Unit 370: Natural gas liquefaction (NGL) Unit 400: Cooling and refrigeration

Unit 410: Heating

Unit 420: Combustible gas Unit 460: Compressed air

Unit 910: Electric energy main supply >1000 V Unit 920: Electric energy main supply <1000 V Unit 970: Control system

A plant unit is considered as “critical” when results:

- high hazardous for design or process reasons (plant into a confined environment, with a high H2S concentration, etc.);

- an important unit for profitability reasons (high content of hydrocarbons, high investment cost, long supplying times);

- sensible or exposed to the consequences of incide nts; - a fundamental service;

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Areas with “critical” plant units must be protected against hazardous events that can be foreseen and thus can not be placed downwind of plants which in anomalous situations can release flammable gas or vapours.

2.3.4 Process piping and vents

Accordingly to the requirements of the layout defined in this specification, a particular attention shall be to pay when positioning the various plant

equipment, in order to avoid the connecting piping is too much long.

In particular, the length of highly pressurised piping, lines containing toxic products or liquefied gas and pipes of complex realisation (with inner passivation, outer insulation or tracing), shall be as short as possible.

The vent manifolds must be protected against the foreseeable incidents, thus they shall not be installed neither on pumps or process compressors, nor into storage vessels.

2.3.5 Clearances

The equipment and piping layout must be realised in order to minimise any hazard arising from collisions with heavy transports.

One horizontal and vertical free a rea must be left around the equipment in order to allow the removal for maintenance, building and assembling. For these reasons, the pipes connecting plant areas must be parallel to access roads or zones.

Along the shoulder of every road a free clearances of 1.5 m must be left, used as pedestrian crossing.

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The following minimal clearances must be maintained: Equipment Horizontal clearance Vertical clearance Pumps 1,5 m 4 m Compressors 3 m 4 m Columns 1,5 m ---Horizontal vessels 2 m 1,5 m Exchangers 1,5 m 1 m

Heaters and Heat exchangers

3 m

-Main pipes stands (1) 4,5 m 5 m (*)

Secondary pipes stands (1) 3 m 4 m

Underground pipes 1 m

---(1) From /Ref.3/ “Safety in process plant design” (*)7 m on areas with crane admittance

2.3.6 Divisions

Products performing in different ways to fire or requiring, in case of fire, specific extinguishing agents (i.e. flammable solids and liquids) are required to be separated.

In particular, the gas treatment areas must be kept separate from oil treatment areas (i.e. by dividing the control vessels).

The areas requiring the same type of fire protection must be as far as possible placed side by side.

2.3.7 Outer installations and radiation 2.3.7.1 General

The layout of the Plant areas must be such that the outwards consequences of a possible fire are minimised, by regarding the existing works.

Into the following table are reported the maximum allowable exposure levels due to radiation from flares and vents for an accidental ignition in the different situations.

The radiation values are referred to the maximum flowrate provided and in the worst conditions, including the value of the s un radiation.

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People are considered equipped when wearing safety protection clothes.

The escape ways are considered shielded if people can protect themselves behind walls or equipment when going away their work place.

2.3.7.2 Radiation values in an emergency and in lack of risk analysis

The radiation levels to be adopted are defined in the following table and represent the maximum allowable values in emergency when a dedicated risk analysis isn’t provided.

The values reported are valid both into and out of the installation.

Radiation values in an emergency and in lack of risk analysis

1 2 3

Condition of people into the

installation area - Not equipped - Outdoor continuous emergency intervention - Not equipped - Temporary presence in open area - Lack of shielded escape ways - Equipped - Occasional presence in open area - Escape ways shielded Condition of people out of the

installation fence - General outdoor area with presence of people (i.e. squares, playing fields, open space public places) - Outdoor area with temporary presence of people (i.e. cultivated lands) - Outdoor area where is not provided (i.e. motorways and railways) Maximum radiation values, including the value of the sun radiation

(kW/m2)

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2.3.7.3 Radiation values in an emergency and in presence of risk analys is

If a risk analysis has been realised and the probability occurrence has been verified within the acceptability limits, the radiation values stated in this table shall be used (radiation with considerable consequences)

Radiation values in an emergency and in presence of risk analysis

1 2 3

Condition of people into the

installation area - Not equipped - Outdoor continuous emergency intervention - Not equipped - Temporary presence in open area - Lack of shielded escape ways - Equipped - Occasional presence in open area - Escape ways shielded Condition of people out of the

installation fence - General outdoor area with presence of people (i.e. squares, playing fields, open space public places) - Outdoor area with temporary presence of people (i.e. cultivated lands) - Outdoor area where is not provided (i.e. motorways and railways) Maximum radiation values, including the value of the sun radiation

(kW/m2)

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2.3.7.4 Radiation values in standard operating conditions

For flares permanently burning and flares of thermodestroyer are not allowed radiation values higher than the following:

Radiation values in standard operating conditions

1 2

Condition of people into the installation area

- Not equipped - Outdoor continuous emergency intervention - Not equipped - Temporary presence in open area - Lack of shielded escape ways Condition of people out

of the installation fence

- General outdoor area with presence of people (i.e. squares, playing fields, open

space public places)

- Outdoor area with temporary presence of people (i.e.

cultivated lands)

Maximum radiation values, including the value of the sun radiation (kW/m2)

1.5 4.8

2.3.8 Control systems

Plants for liquid hydrocarbons treatment and storage tanks must be supplied with control vessels and piping and draining systems of the possible leaks.

The dimensioning of the control vessels must consider the following requirements.

- If the vessel is not drained, the volume must allow the control of the useful capacity of the tank or apparatus.

Products as propane, contained into no cryogenic tanks, make exceptions: in these cases it is sufficient to consider a vessel capacity of 32% of the total volume of the tank.

- The minimum distance between the upper part of the external sides of the control vessel of the storage tanks and the tank shell placed into the vessel must be equal to the tank height minus the sides height.

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The height on the country side of the vessel walls must not exceed 4 m, in accordance with the requirements of Ministry of the Interior 22-12-1962 n°132 (supplement of D.M. 31-7-1934).

Derogations are provided for high capacity tanks, in particular cases, (the document reports as an example a 50000 m3 tank).

Meeting the requirement of this document, when the control vessel height reaches 4 m, the tank shell must be accessible from the upper part of the sides by a gangway of sheet-steel, without going down into the vessel; the upper part of the vessel must be connected with the gangway with at least two external stairs.

- The slope of the drained control vessels must not allow a standing of possible flames under the tank (slope to be preferred: 20/00); the stairs to the

vessels and possible fire fighting installations must not be in that part of the vessel where slopes join.

The flammable liquids drainage must be completely separated from not hazardous drainage and the two systems must not have connections without shut off fittings.

The dimensions of the system collecting the plant drainage (oily waters) must comply with the volume of the liquid drained in emergency, contained into the higher process equipment.

The evaporation basin for LPG storage must be always present and placed at a distance so that a fire into the basin do not involve the tanks.

The basin must be dimensioned in order to contain the possible LPG leakages. The basin shall be placed at a level allowing a leaks accumulation, into the control vessel, higher than the basin capacity.

The width of the evaporation basin shall not exceed 2 m.

The drainage systems of the basin shall be dimensioned in order to evacuate the highest quantity of water coming from the control vessel (cooling water of the tank or meteoric waters).

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2.3.9 Escape ways

For the escape ways the following requirements are valid:

- no point of the closed enclosure must be more than 12 m away from an exit and no blind passage must be higher than 8 m /Ref.2/;

- escape ways outdoors must be at least 0.7 m width /Ref.2/;

- the doors along escape ways from rooms hazardous works an d materials must be at least 1.2 m width;

- the doors along escape ways with hazardous works and materials different from the previous must be at least 0.9 m width.

2.3.10 Classification of areas with explosion hazard

Areas classification shall be realised according to the specification 06744.VAR.ELE.SPC derived from CEI codes 64-2 and containing layouts and specific choices for the concerned plants of the Plant.

Area classification depends on the quantity of dangerous products into the area and particularly on the exceeding of the values stated by the above mentioned specification.

By adopting that code, the quantity of dangerous products into the area is always the total value of area whole plant and not of a single element of the plant.

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2.4 Safety requirements for spacing

This chapter is organised as follows: after the first two paragraphs reporting general requirements, a list of paragraphs is included according to the columns sequence of the tables of Annex 5.

Each paragraphs adopts the same title of the column reporting the reference spacing and provides the following information:

- available normative references and/or computational models; - national or regional normative references;

- consideration and reasons about choices operated;

- possible modifications or derogations offered to the designer.

2.4.1 Safety spacing

The safety spacing, reported in Annex 5, are the minimum to be adopted on onshore installations.

The tables, on the side of each spacing, state the relevant reference sources: Italian Legislation, Regional Legislation, Normative References of National Organizations or other Organizations, computational model, estrapolation from typical plant, etc.

Spacing reported in these tables comes mostly from “Normative references”; when these can not be applied spacing come from calculation mentioned in the following paragraphs and in Annexes 6 ÷ 11.

In order to evaluate the quantity of the product discharged, according to CEI 64 - 2 codes, the intervention time of the shut-off valves is considered equal to 15 minutes (manual valve from a station constantly manned).

2.4.2 General requirements

2.4.2.1 Spacing between hazardous equipment installed into the Plant 2.4.2.1.1 Protection of equipment adjoining to that involved in leakage

Legislation and decrees consider this element only regarding to LPG storage systems, to some equipment of mineral oils and gas-pipelines.

When this element can not be defined by legislation or codes, it is mandatory to be estimate by computational models of Annexes 6÷ 11.

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According to the indications from CEI 64-2 codes, the possible leakage points to be considered are valve gaskets and stuffing, flanges, pumps operating flammable fluids (the equipment breakdown is not considered, not even partial, and pipes are nor considered as hazard centres:

The diameter of the equivalent hole, to be used for computation of a “reasonably believable” leakage or to be used directly in the modelling shown in Annexes 6÷ 11, is considered equal to:

- 3.2 mm for RJ flanges (it corresponds to about 0.05 kg/s flowrates and valid for a pressure range 40÷200 bar for gas only) /Ref.1/;

- 15 mm for RF flanges and pump stuffing (it corresponds to about 0.5 kg/s flowrates for gas and 5 kg/s for oil; it is valid for pressures <40 bar) /Ref.2/;

2.4.2.1.2 Protection of plant area adjoining to that involved in leakage

Legislation and decrees consider this element only regarding to pipes, gas compressors and well heads.

For other flammable fluids, not covered by legislation or codes, the distance is determined by computational models of Annexes 6÷ 11.

The “maximum permissible leakage” and other reference data for calculation have been derived according to the following indications:

- as a characteristic diameter has been adopted 10% of the highest connecting piping diameter /Ref.2/;

- partial breakdown of storage tanks has been considered (roof sinking);

For computing the vapours into the explosive field, in case of oil evaporative pool, one of the following assumptions (the most conservative one):

• a fixed vapours volume of 300 m3 (whose explosive part is 2%) /Ref.2/;

• 10% of the discharged volume.

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2.4.2.2 Spacing between hazardous equipment installed into the Plant and the outer fittings

The minimum requirement is to protect buildings and works out of the fence. Legislation and decrees consider in details this matter.

When this element can not be defined by legislation or codes, it shall be evaluated each time by Risk Analysis computational models.

These spaces are measured horizontally from the external perimeter of the equipment to the point closest to the outer fittings or fence, respectively; the railway and tramway tracks (excluded the connections inside the Plant) are considered outer fittings.

2.4.3 Fences

The fence represents the boundary line between inner and outer elements of the Plant.

The safety spacing from the fences a re reported in Annex 5. The codes considered are:

- D.M. 31-7-1934;

- DPGR n°7 Regione Sicilia;

- Ministry of the Interior - Circular 9-7-1954;

- Industrial Risk Insurer (IRI) - “General Recommendations for Spacing”.

2.4.4 Hydrocarbons storage tanks

2.4.4.1 Liquid hydrocarbons storage tanks

The safety spacing from the storage tanks are reported in Annex 5. The codes considered are:

- D.M. 31-7-1934;

- DPGR n°7, Regione Sicilia;

- Ministry of the Interior - Circular 11-5-1954, n°70;

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The spacing determined according to national normative references can be modified, by using computational models, only if the spacing determined in this last way are more conservative.

The mutual spacing between tanks can be evaluated by using the pool fire model (see Annex 6) by supposing the burning tank have the roof sunk and the all liquid surface is involved in fire; the minimum spacing from the adjoining tank is determined by a limit radiation of 19 kW/m2.

2.4.4.2 LPG storage tanks > 5 m3

The safety spacing from the loading bays are reported in Annex 5. The normative reference adopted is D.M . 13-10-1994.

2.4.5 Hydrocarbons loading bays from tankers 2.4.4.1 Liquid hydrocarbons loading bays

The distances from loading bays are regulated by the Circular of Ministry of Interior, 11-5-1954, n°70: “Caricamento e svuotamento, nelle raffinerie e nei depositi di olii minerali, dei veicoli a cisterna ed a botte senza l’attuazione del ciclo chiuso”.

The spacing from loading bays to possible sources of ignition can be determined from the extension of the area classified according to CEI 64-2 codes.

Some spacing for loading bays can be derived from normative references of national organizations such as “General Recommendations for Spacing” of Industrial Risk Insurer (IRI).

(28)

2.4.5.2 LPG loading bays

The safety spacing from the loading bays are reported in Annex 5. The normative reference adopted is D.M . 13-10-1994.

2.4.6 Well heads

The safety spacing from the loading bays are reported in Annex 5.

The normative reference adopted is D.P.G.R. n°7 - Regione Sicilia, “Regolamento di polizia mineraria”.

The only normative references of national organizations concerning this argument are API RP 500 B.

2.4.7 Oil treatment plants

The safety spacing from the Oil treatment plants are reported in Annex 5.

Oil treatment plants include: oil treatment plants containing separators or stabilising columns and gas treatment plants (separation, dehydration and conditioning) containing oil quantity higher than 1 m 3.

No normative references does exist.

As a normative reference of national organizations “General Recommendations for Spacing” of Industrial Risk Insurer (IRI) has been adopted.

In order to determine the safety spacing between process equipment of oil treatment plants, the pool fire model is adopted (see Annex 6) by introducing as an input an oil flowrate of 5 kg/s.

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2.4.8 Gas treatment plants

The safety spacing of gas treatment plants are re ported in Annex 5.

Gas treatment plants include: gas treatment plants containing separators, dehydration or deacidification columns containing gas quantity below 1 m 3. No normative references or decrees do exist, from which safety spacing for

areas with gas treatment plants can be obtained.

As a normative reference of national organizations “General Recommendations for Spacing” of Industrial Risk Insurer (IRI) has been adopted, in order to define some safety spacing.

In order to determine the other safety spacing for gas treatment plants, computational models of gaseous jet fires in Annex 7 (for hazardous equipment spacing), or relating to unconfined gas cloud explosion in Annex 8 (for outer fittings spacing have been adopted too.

2.4.9 Compression stations

The safety spacing from gas compression stations are reported in Annex 5 and are valid for gas turbine too, since they have the same risk level.

An installation including a single gas compressor (and thus a single gas turbine) is considered a gas compression station too.

The normative reference is Circular of Ministry of the Interior n.21137/4105 -9-7-1954: “Criteri di sicurezza per l’installazione e l’esercizio di centrali di compressione di gas metano”.

Some spacing are determined by the requirements stated in D.M. 24-11-1984: “Norme di icurezza antincendio per il trasporto, distribuzione, accumulo e utilizzazione di gas naturale con densità non superiore a 0.8”.

The safety spacing from the fittings out of the fence is affected by the permissible noise level according to DL 15-8-1991 n°277.

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The safety spacing with equipment not covered by national and regional codes has been drawn from “General Recommendations for Spacing” of Industrial Risk Insurers.

Since national and regional codes don’t cover the spacing between compressors and gas and oil treatment plants or between compressors and oil and gas pipelines, a technical proposal is considered (“Progetto di Regolamento Generale di Prevenzione Incendi”, 1965) which estimates spacing in accordance with the parametric model.

The empirical relation is:

R = 0.0865 ⋅ 3 G D S ⋅ / where: R is the safety spacing in m

G is the flowrate in kg/h of compressor or compressors, if more than one D is the danger index (for methane D = 15500)

S is the equipment safety level

S is equal to 500 when are present simultaneously:

- effective equipment shut off capacity In case of leakage; - an adequate ventilation;

- presence of flame sensors for an autom atic equipment shutdown. For other situations S = 100 shall be adopted.

The safety spacing from treatment plants, oil and gas pipelines is thus: R = 0.27 ⋅ G0.33

The safety spacing between compressors into a same area is drawn by applying the gaseous jet fire model.

2.4.10 Glycol heating and reconditioning units

The safety spacing from glycol heaters and reconditioners are reported in Annex 5.

Italian legislation does not provide explicitly safety spacing from this type of equipment; they can be deduced from those ones provided for the above mentioned equipment; in particular, DPGR n°7 - Regione Sicilia “Regolamento di polizia mineraria”.

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As a normative reference of national organizations “General Recommendations for Spacing” of Industrial Risk Insurer (IRI) and CEI 64-2 codes have been adopted,

For gas heaters, the same models of gas treatment plants areas are used.

For glycol reconditioning units, computational models of unconfined gas cloud explosion such as in Annex 9 (since they are not pressurised equipment) are considered.

For oil heaters and diatermic oil systems, model relating to pool fires is considered, with a flowrate of 1 kg/s (see Annex 6).

2.4.11 Glycol storage tanks

The safety spacing from glycol tanks are reported in Annex 5.

The glycol tanks can be considered as tanks containing not less than 500 m 3 of atmospheric pressure gas (blanketing gas). The normative reference is then D.M. 24-11-1984: “Norme di sicurezza antincendio per il trasporto, distribuzione, accumulo e utilizzazione di gas naturale con densità non superiore a 0.8”.

They are classified as tanks of 3^ category, according to this rules.

No exceptions to the above mentioned spacing are allowed since neither other normative references of national organizations are available nor computational models can be applied to this case.

2.4.12 Basins for oily waters treatment

The safety spacing from oily waters treatment basins are reported in Annex 5. Italian legislation does not provide safety spacing from these equipment.

As a national normative references are adopted CEI 64-2 codes, which provide extension of classified area to drain wells and oily sewers.

For oily waters basins, spacing are derived from the heavy vapours dispersion model (see Annex 10).

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2.4.13 Oil/gas pipelines

The safety spacing from oil/gas pipelines are reported in Annex 5.

As regards the pipes, Italian legislation consider only spacing from outer structures.

If pipes are close to the fences and so near roads and outer structures, the spacing is calculated in accordance with normative reference (D.M. 24-11-1984: “Norme di sicurezza antincendio per il trasporto, distribuzione, accumulo e utilizzazione di gas naturale con densità non superiore a 0.8”).

As a normative reference of national organizations have been adopted “General Recommendations for Spacing” of Industrial Risk Insurer (IRI), which define the safety spacing for oil pipeline pumping stations.

The spacing between gas pipelines and outer fittings is covered by a technical proposal (“Progetto di Regolamento Generale di Prevenzione Incendi”, 1965)

which estimates spacing in accordance with the parametric m odel. The empirical relation is:

R = 0.0865 ⋅ 3 G D S ⋅ / where: R is the safety spacing in m

G is the flowrate in kg/h of gas pipelines

D is the danger index (for methane D = 15500)

S is the safety level varying in relation to the ground permeability and the piping ventilation level. If the piping is not underground the highest value equal to 500 can be adopted.

The safety spacing R from outer fittings is thus: R = 0.27 ⋅ G0.33

2.4.14 Process safety valves

The safety spacing from safety valves are reported in Annex 5.

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2.4.15 Gas flares and vents 2.4.15.1 Dry gas flares

The safety spacing from dry gas flares are reported in Annex 5.

Flares receiving gas without gasoline droplets dragging are defined as dry gas flares.

As a normative reference of national organizations have been adopted “General Recommendations for Spacing” of Industrial Risk Insurer (IRI), which define only the flares permanently burning.

The relation (2) of Annex 8 is adopted in order to determine the spacing between high pressure flares (if existing).

Into the enclosure limited by the minimum safety spacing (30 m) shall not be present any equipment; this spacing shall be to verify and if necessary

increased according to the ground level radiation calculations.

2.4.15.2 Wet gas flares

The safety spacing from wet gas flares a re reported in Annex 5.

Flares receiving gas with gasoline droplets entrainment are defined as wet gas flares.

As a normative reference of national organizations have been adopted “General Recommendations for Spacing” of Industrial Risk Insurer (IRI), which define only the flares permanently burning.

The relation (2) of Annex 8 is adopted in order to determine the spacing between high pressure flares (if existing).

Into the enclosure limited by the minimum safety spacing (60 m) shall not be present any equipment; this spacing shall be to verify and if necessary

increased according to the ground level radiation calculations. The safety spacing considers the gasoline droplets fallout too.

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2.4.16 H2S process plants

The safety spacing from H2S process plants are reported in Annex 5.

H2S process plants are those processing fluids with very high hydrogen sulphide concentration; into this fields are included the s ulphur recover unit and the H2S adsorber reconditioning unit.

No normative references of national organizations do exist about this matter. The safety spacing are thus determined by computational modelling such as the dispersion and following dilution of the hydrogen sulphide (see Annex 11) through which are determined the spacing from the emergency management areas, as control room, shut off valves and indoor areas where evacuation is not necessary (maximum concentration 100 ppm) and areas out of the plant (where concentration must not exceed 10 ppm).

2.5 Requirement of work health and environmental protection

The safety spacing defined in Annex 5 must be verified together with the legislation requirements about work health (in particular DPR 19-3-1956 n°303 and DL 15-8-1991 n°277 about noise and vibration exposure) and environmental protection (in particular DPR 24-5-1988 n°203 relating to DM 12-7-1990 about the air quality).

2.6 Ergonomics

The safety spacing reported in Annex 5 must be verified with the ergonomics legislation requirements.

2.7 Requirements for Quality Management and Quality Assurance

Eventual requirements for Quality Management and/or Quality Assurance are included in the applicable managerial specification enclosed to the offer request.

2.8 Documentation

Plants layouts shall be realised in accordance with the specifications enclosed to the design documentation.

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3 SUPPLEMENTARY ELEMENTS 3.1 Enclosures and informative annexes 3.1.1 Annexes

Annex 1 Plant general layout

Annex 2 Better location - Process and utilities units Annex 3 Better location - Safety main units

Annex 4 Better location - “Critical” plant units Annex 5 Safety spacing to be adopted

Annex 6 Pool fire - Computational method Annex 7 Jet fire - Computational method

Annex 8 Unconfined gas cloud explosion (pressurised) - Computational method

Annex 9 Unconfined gas cloud explosion (not pressurised) -Computational method

Annex 10 Heavy vapours dispersion - Computational method Annex 11 Hydrogen sulphide dispersion - Computationa l method

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Annex 1 Plant general layout STORAGE TANKS FLARE COMPRESSORS GENERATORS MULTIFUNCTIONAL BUILDING OFFICES PARKING ACCESS WAY INGRESSO CONTROL ROOM PROCESS LOADING PREVAILING WINDS WATER TREATMENT FIREFIGHTING

(37)

Annex 2 Better location - Process and utilities units

This annex reports in numerical order a series of card-files relating to the process and utilities Functional Units of a typical plant.

The file-cards include:

- Title: Functional Plant Unit and relevant name

- Plant: Indications on equipment involved in the relevant positioning - Location: Better and/or alternative location according to other plants and prevailing wind direction

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(Annex 2)

UNIT 120 : CH EMICAL INJECTIO N FO R WELL HEAD AND

PLANT

Plant : Methane Oil Storage Tanks

Better location: • DOWNWIND OF THE GAS

TREATMENT UNIT, INTO DEDICATED AREA

Alternative location:

---Position as to other Units:

( = prevailing wind)

UNIT 190 : LAUNCHING AND RECEIVING TRAPS

Plant : Launching and receiving traps

Better location: • UPWIND OF PLANTS

• DOWNWIND OF BUILDINGS AREA

(39)

(Annex 2)

UNIT 200 : OIL SEPARATION

Plant : Heaters

Alternative location: • CROSSWIND CLOSE TO THE

ARRIVALS UNIT

Position as to other Units:

Area involved by waste gas: the smokes temperature must be < 540°C into gas areas or < 250°C into oil areas

UNIT 200 :OIL SEPARATION

Plant : Separators/ Oil Stabilising Column

Better location: • DOWNWIND OF GAS TREATMENT

PLANTS(*)

(*) the control basin of this Unit is to separate from the Heating Unit one (if adjacent)

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(Annex 2)

UNIT 210 : OIL TREATMENT

Plant : Separators/ Oil Stabilising Column

PLANTS(*)

(*) the control basin of this Unit is to separate from the Heating Unit one (if adjacent)

UNIT 220 : OIL TRANSPORT AND STORAGE

Plant : Oil Export Pumps

Better location: • UPWIND OF THE STORAGE TANKS

• DOWNWIND OF THE COMPRESSORS

Alternative location: • CROSSWIND CLOSE TO THE TANKS

AREA

Area where hot liquids processing pumps must not be installed

(41)

(Annex 2)

UNIT 300 : GAS SEPARATION

Plant : Oil and Gas Heaters

Alternative location: • CROSSWIND CLOSE TO THE

ARRIVALS UNIT

Area involved by waste gas: the smokes temperature must be < 540°C into gas areas or < 250°C into oil areas

UNIT 310 : GAS DEHYDRATION

Plant : Gas Dehydration Columns

Better location: • UPWIND OF OIL TREATMENT UNITS

• UPWIND OF FLAMMABLE LIQUIDS

STORAGE

(42)

(Annex 2)

UNIT 320 : LIQU ID HYDROCARBONS RECOVERY

Plant : Gasoline Stabilising Column

PLANTS

UNIT 350 : GAS CONDITIONING

Plant : Gas Conditioning Plant

STORAGE

(43)

(Annex 2)

UNIT 380 : GLYCOL FOR GAS DEHYDRATION

Plant : Glycol Reconditioning Columns

UNIT 390 : GLYCOL FOR GAS DEHYDRATION

Plants : Glycol Storage Tanks

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(Annex 2)

UNIT 430 : COMBUSTIBLE GAS OIL

Plant : Gas Oil Tank and Pumps

UNITS

• DOWNWIND OF EQUIPMENT

(45)

Annex 3 - Better location - Safety main units

UNIT 230 : FLARES AND VENTS

Plant : Gaseous Effluents Treatment System

Better location: • DOWNWIND OF PLANTS

• DOWNWIND OF FLARES

Alternative location: • BARYCENTRIC AS TO THE PLANTS

Respect area (free from plants) around the 30 m radius flare for dry gas Plants and 60 m radius flare for gasoline gas Plants

UNIT 480 : ELECTRIC POWER GENERATION

Plant : Electric Power Generator

Better location: • UPWIND OF PLANTS IN SAFE AREA(*)

Alternative location: • CROSSWIND, BY ADOPTING SAFETY

SPACING FROM OTHER AREAS

(*)Avoid barycentric position as to the plants. Do not place above electric rooms or transformers

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(Annex 3)

UNIT 560 : OILY WATERS TREATMENT

Plant : Liquid Effluents Treatment System

Better location: • IN DEDICATED AREA DOWNWIND OF

PLANTS, MACHINERY AND

BUILDINGS

• OUT OF THE AREA DOWNWIND OF

STORAGE TANKS AND LPG/NLG UNITS

UNIT 580 : GASEOUS EFFLUENTS TREATMENT

Plant : Thermodestroyer

Better location: • DOWNWIND OF PLANTS

• DOWNWIND OF FLARES

Alternative location: • BARYCENTRIC AS TO THE PLANTS

Respect area (free from plants) around the 30 m radius flare for dry gas Plants

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(Annex 3)

UNIT 690 : CIVIL BUILDINGS

Plant : Multipurpose Building with or without Control Room

Better location: • UPWIND OF PLANTS IN SAFE AREA(*)

Alternative location: • CROSSWIND, BY ADOPTING SAFETY

SPACING FROM OTHER AREAS

(*)Avoid barycentric position as to the plants. Do not place above electric rooms or transformers

UNIT 730 : FOAM/WATER FIRE FIGHTING SYSTEM

Plant : Water Pumping Fire Fighting System

Better location: • UPWIND OF PLANTS IN SAFE AREA

Alternative location: • THE DISTRIBUTION SYSTEM MUST

BE PLACED 30 m FROM THE

PROVIDED FLAME UPWIND OF IT

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Annex 4 Better location - “Critical” plant units

UNIT 220 : OIL TRANSPORT AND STORAGE

Plant : Oil Storage Tanks

Better location: • DOWNWIND OF PLANTS, BUILDINGS

AND MACHINERY, 60 m FROM

GASEOUS EFFLUENTS UNIT

UNIT 310 : GAS DEHYDRATION

Plant : Instrumentation room with fiscal metering equipment

STORAGE UNITS

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(Annex 4)

UNIT 320 : LIQUID HYDROCARBONS RECOVERY

Plant : LPG-LNG Hethane removing unit/Storage

UNITS, BUILDINGS AND MACHINERY

• OUT OF AREA DOWNWIND OF

STORAGE TANKS AND DRAINAGE TREATMENT UNITS(*)

(*)For LPG/LNG storage, these criteria are valid only for evaporation basins

UNIT 330 : GAS DEACIDIFICATION

Plant : Gas deacidification column

Better location: • BARYCENTRIC POSITION AS TO THE

PLANTS

• OUT OF AREA DOWNWIND OF

STORAGE TANKS AND DRAINAGE TREATMENT UNITS

Alternative location: • 60 m FROM THE FENCE

to the barycentric position Position as to other Units:

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(Annex 4)

U

UNNIIT T 333300 :: GGAAS S DDEEAACCIIDDIIFFIICCAATTIIOONN P

Pllaanntt :: HH₂₂S Absorber Reconditioning ColumnS Absorber Reconditioning Column Better location:

Better location: •• BARYCENTRIC POSITION AS TO THEBARYCENTRIC POSITION AS TO THE PLANTS

PLANTS

•

• OUT OF AREA DOWNWIND OFOUT OF AREA DOWNWIND OF STORAGE TANKS AND DRAINAGE STORAGE TANKS AND DRAINAGE TREATMENT UNITS

TREATMENT UNITS Alternative location:

Alternative location: •• 60 m FROM THE FENCE60 m FROM THE FENCE to the barycentric position

to the barycentric position

Position as to other Units: Position as to other Units:

(( = prevailing wind) = prevailing wind)

U

UNNIIT T 333300 :: GGAAS S DDEEAACCIIDDIIFFIICCAATTIIOONN P

Pllaanntt :: SSuullpphhuur r RReeccoovveerryy Better location:

Better location: •• BARYCENTRIC POSITION AS TO THEBARYCENTRIC POSITION AS TO THE PLANTS

PLANTS

•

• OUT OUT OF OF AREA AREA DOWNWIND DOWNWIND OFOF STORAGE TANKS AND DRAINAGE STORAGE TANKS AND DRAINAGE TREATMENT UNITS

TREATMENT UNITS Alternative location:

Alternative location: •• 60 m FROM THE FENCE60 m FROM THE FENCE to the barycentric position

to the barycentric position

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(Annex 4)

U

UNNIIT T 336600 :: GGAAS S CCOOMMPPRREESSSSIIOONN P

Pllaanntt :: GGaas s ccoommpprreessssoorrss Better location:

Better location: •• UPWIND OF OIL TREATMENT PLANTSUPWIND OF OIL TREATMENT PLANTS AND LPG/LNG UNITS

AND LPG/LNG UNITS

•

• AS AS BARYCENTRIC BARYCENTRIC AS AS POSSIBLEPOSSIBLE RELATING TO THE NOISE

RELATING TO THE NOISE A

Alltteerrnnaattiivve e llooccaattiioonn::

---Position as to other Units: Position as to other Units:

U

UNNIIT T 337700 :: NNAATTUURRAAL L GGAAS S LLIIQQUUEEFFAACCTTIIOONN P

Pllaanntt :: LLPPGG--LLNNG G HHeetthhaanne e rreemmoovviinng g uunniitt//SSttoorraaggee Better location:

Better location: •• DOWNWIND OF GAS TREATMENTDOWNWIND OF GAS TREATMENT

UNITS, BUILDINGS AND MACHINERY UNITS, BUILDINGS AND MACHINERY

•

• OUT OUT OF OF AREA AREA DOWNWIND DOWNWIND OFOF STORAGE TANKS AND DRAINAGE STORAGE TANKS AND DRAINAGE TREATMENT UNITS(*)

TREATMENT UNITS(*) A

(*)For LPG/LNG storage, these (*)For LPG/LNG storage, these criteria are valid only for criteria are valid only for evaporation basins

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(Annex 4)

U

UNNIIT T 440000 :: CCOOOOLLIINNG G AANND D RREEFFRRIIGGEERRAATTIIOONN P

Pllaanntt :: PPrrooppaanne e CCoooolliinng g CCyyccllee Better location:

Better location: •• DOWNWIND OF GAS TREATMENTDOWNWIND OF GAS TREATMENT

UNITS, BUILDINGS AND MACHINERY UNITS, BUILDINGS AND MACHINERY

•

• OUT OUT OF OF AREA AREA DOWNWIND DOWNWIND OFOF STORAGE TANKS AND DRAINAGE STORAGE TANKS AND DRAINAGE TREATMENT UNITS(*)

TREATMENT UNITS(*) A

(*)These criteria are valid only for (*)These criteria are valid only for

evaporation basin evaporation basin

U

UNNIIT T 441100 :: HHOOT T OOIILL P

Pllaanntt :: FFrreee e bbuurrnniinng g HHeeaatteerrss

Better location:

Better location: •• UPWIND OF PLANTSUPWIND OF PLANTS

•

• DOWNWIND OF BUILDINGS AREADOWNWIND OF BUILDINGS AREA Alternative location:

Alternative location: •• CROSSWIND CLOSE TO ARRIVALSCROSSWIND CLOSE TO ARRIVALS UNIT

UNIT

Area involved by waste gas: the Area involved by waste gas: the smokes temperature must be < 540°C smokes temperature must be < 540°C into gas areas or < 250°C into oil into gas areas or < 250°C into oil areas

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(Annex 4)

UNIT 420 : COMBUSTIBLE GAS

Plant : Combustible Gas System

Better location: • UPWIND OF OIL TREATMENT PLANTS

STORAGE UNITS

UNIT 460 : COMPRESSED AIR

Plant : Instrumentation Air System

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(Annex 4)

UNIT 910 : MAIN POWER SUPPLY >1000V

Plant : Electric cabin or substation

Better location: • UPWIND OF PLANTS, AT THE PLANT

BOUNDARY, ACCORDING TO THE INNER AND OUTER CONNECTIONS

Alternative location: • CROSSWIND SAFE SPACED FROM

PLANTS

UNIT 920 : MAIN POWER SUPPLY <1000V

Plant : Electric cabin or substation

PLANTS

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(Annex4)

UNIT 970 : CONTROL SYSTEM

Plant :

PLANTS

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Annex 5 Safety spacing to be adopted

Inside the chapter “Safety requirements for spacing” has been realised, for each of the following tables, a paragraph with the same title providing the following information:

- available normative references and/or computational models; - national or regional normative references;

- considerations and reasons about choices operated;

- possible modifications or derogations offered to the designer.

The spacing reported in these tables represent obligations, requirements, guidance, interpretations and extrapolations coming from legislation, normative references, regulations and computational models considered absolutely, according their type, that is as independent documents.

Some discontinuity of the relative spacing assessment shall be possible; these spacing shall be to verify and rearranged according to the layouts operated for each design.

All the spacing into the tables are expressed in m.

LEGEND

D = main tank diameter (distance from the tank side) G = total flowrate in kg/h of the compressors station h = drilling/workover tower height

H = tank height

Q = gas flowrate in m3/g

a.c. = classified area according to CEI 64-2 code

d.s. = this safety distance is depending from the electric line voltage, and it must be calculated according to the reference normative (DM 13.10.1994)

e.i. = extrapolation from typical plant l.i. = Italian legislation

l.r. = regional legislation (DPRG n°7 Regione Sicilia) m.c. = computational models

n.i. = interior normative reference

n.n = normative references of national organizations or other foreign organizations

n.v. = no obligations

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(Annex 5)

FENCES HAZARDOUS EQUIPMENT

LIQU. HYDROC. STORAGE TANKS

z.p.non<<H (l.i.) LPG STORAGE TANKS > 5 m3 _{40 (l.i.)}

LIQU. HYDROC. LOADING BAYS 15 (n.n.)

LPG LOADING BAYS 40 (l.i.)

WELLS h(l.i.) 50 (l.r.)

OIL TREATMENT PLANTS 15 (e.i.)

GAS TREATMENT PLANTS 15 (e.i.)

COMPRESSION STATIONS 10 (l.i.)

GLYCOL HEATING AND RECOND.

30 (1)

GLYCOL TANKS 10 (e.i.)

OILY WATERS TREAT. BASINS 10 (e.i.) OIL PIPELINES/GAS PIPELINES 30 (n.i.)

PROCESS SAFETY VALVES 15 (e.i.)

DRY GAS FLARES 30 (n.i.)

WET GAS FLARES 60 (n.i.)

PRESSURE REDUCER 10 (l.i.) (2)

MEASUREMENT CABIN 10 (l.i.) (2)

FREE FLAME EQUIPMENT n.v.

GLYCOL PUMPS n.v.

MANUAL SOV n.v.

FITTINGS INSIDE THE PLANT

OFFICES, CONTROL ROOM n.v.

FIRE FIGHTING PUMPS n.v.

FIRE FIGHTING VALVES n.v.

AERIAL POWER LINES 3(e.i.)

FITTINGS OUTSIDE THE PLANT

CARRIAGE ROADS 3(l.i.)

NON-CARRIAGE ROADS 3(e.i.)

RAILWAYS AND TRAMWAYS 3 (e.i.)

PUBLIC PREMISES 3(e.i.)

STATIONS 3(e.i.)

(1) - reducible to 5 m if the fence is realised with a brick wall of thickness > 30 cm

(2) - it reduces to 5 m if the building is made of reinforced concrete of minimum thickness 15 cm, with beams covering or concrete slab and with upper vents area at least equal to 1/10 of the room plot area

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(Annex 5)

LIQUID HYDROCARBONS . STORAGE TANKS LPG STORAGE TANKS > 5 m3 HAZARDOUS EQUIPMENT LIQU. HYDROC. STORAGE

TANKS

D(m.c.) 40 (l.i.) LPG STORAGE TANKS > 5 m3 _40 (l.i.) _Σ_Σ

iDi/2 (3) LIQU. HYDROC. LOADING BAYS 30 (n.n.) 40 (l.i.)

LPG LOADING BAYS 40 (l.i.) 15 (l.i.) (4)

WELLS 30 (l.r.) 40 (l.i.)

OIL TREATMENT PLANTS 30 (n.n.) 40 (5)

GAS TREATMENT PLANTS 20 (e.i.) 40 (5)

COMPRESSION STATIONS 30 (l.r.) 40 (l.i.)

GLYCOL HEATING AND RECOND.

30 (n.n.) 40 (l.i.)

GLYCOL TANKS D(m.c.) 40 (l.i.)

OILY WATERS TREAT. BASINS 20 (e.i.) 40 (l.i.) OIL PIPELINES/GAS PIPELINES 30 (e.i.) 40 (l.i.)

PROCESS SAFETY VALVES 30 (e.i.) 40 (l.i.)

DRY GAS FLARES 60 (n.i.) 60 (n.i.)

WET GAS FLARES 60 (n.i.) 60 (n.i.)

PRESSURE REDUCER 15 (n.n.) 40 (l.i.)

MEASUREMENT CABIN 15 (n.n.) 40 (l.i.)

FREE FLAME EQUIPMENT 30 (n.n.) 40 (l.i.)

GLYCOL PUMPS 30 (e.i.) 40 (l.i.)

MANUAL SOV 30 (e.i.) 40 (l.i.)

FITTINGS INSIDE THE PLANT

OFFICES, CONTROL ROOM (*) (l.i.) 40 (l.i.)

FIRE FIGHTING PUMPS 30 (e.i.) 40 (l.i.)

FIRE FIGHTING VALVES 30 (e.i.) 40 (l.i.)

AERIAL POWER LINES 30 (e.i.) d.s.(l.i.)

FITTINGS OUTSIDE THE PLANT

CARRIAGE ROADS (*) (l.i.) 40 (l.i.)

NON-CARRIAGE ROADS (*) (l.i.) 40 (l.i.)

RAILWAYS AND TRAMWAYS (*) (l.i.) 40 (l.i.)

PUBLIC PREMISES (*) (l.i.) 60 (l.i.)

STATIONS (*) (l.i.) 60 (l.i.)

(3) - it reduces to 0.8 m if the tanks are underground (4) - it reduces to 7.5 m if the tanks are underground (5) - it reduces to a half if a water barrier is interposed (*) - to be defined each time according to the tank capaci ty