HAZARDOUS AREA HAZARDOUS AREA CLASSIFICATIONDS/EN 60079-10-1 & UKENERGY INSTITUTE, IP15ENERGY INSTITUTE, IP15

BACKGROUND – DS/EN 60079-10-1CLASSIFICATION EXPLOSIVE GAS ATMOSPHERESCLASSIFICATION – EXPLOSIVE GAS ATMOSPHERES

ATEX 1999/92 EC Di ti / B h l di ti 92/91/EC ( ff h )• ATEX 1999/92 EC Directive / Borehole directive 92/91/EC (offshore)

• Danish Regulations (BEK 1480 + Guideline to that)

• Norway: PSA Facilities Regulation (Guideline) points towards IEC 61872-7 – which points towards IEC/EN 60079-10-1-

• Allow for correct selection of equipment (ATEX 94/9/EC)• Allow for correct selection of equipment (ATEX 94/9/EC)

• Classify for flammable gasses, vapours and mists

• Flammability: Dependent on flash point and design/service temperature

Probability for fire/explosion:

P(Release) x P(Ignition)

AREA CLASSIFICATION – ZONINGEN 60079-10-1 / IP 15

Zone 0: The part of a hazardous area in which a flammable atmosphere is continuously present or present for long periods

Zone 1: That part of a hazardous area in which a flammable atmosphere is likely to occur in normal operationoperation

Zone 2: That part of a hazardous area in which a flammable atmosphere is not likely to occur in normal p yoperation, and if it occurs, it will only exist for a short period

Non-hazardous: areas that do not fall into any of the above (IS NOT ‘SAFE AREA’)

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Definitions – EN 60079-10-1

• Source of Release: A point of location from which a gas, vapour, mist or liquid may be released into the atmosphere so that an explosive gas atmosphere could be formed.

• Grades of release: There are three basic grades of release, as listed in order of decreasing frequency and likelihood of the listed in order of decreasing frequency and likelihood of the explosive gas atmosphere being present:

• Continous grade

• Primary Grade

• Secondary Gradey

• Degree of ventilation (natural / artificial):

• High ventilation (VH)High ventilation (VH)

• Medium ventilation (VM)

• Low ventilation (VL)Low ventilation (VL)

HAZARDOUS AREA CLASSIFICATION –GRADE OF RELEASE – IP 15 DEFINITIONS

C d l l h lContinuous grade release: A release that is continuous or nearly so, or that occurs frequently and for short periodsIf it is likely to be present for more than 1000 hours per year.

Primary grade release: a release that is likely to occur periodically or occasionally in normal operations, i.e. a release which, in operating

y p p y

procedures is anticipated to occurIf it is likely to be present for between 10 to 1000 hours per year.

Secondary grade release: A release that is unlikely to occur in normal operation and, in any event, will do so only infrequently and for short periods i e a release which in operating procedures is not for short periods i.e. a release which in operating procedures is not anticipated to occur. Such release may be of unknown size e.g. fracture of a drain or unknown size e.g. corrosion hole.If it is likely to be present for 1 to 10 hours per year

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If it is likely to be present for 1 to 10 hours per year.

ZONE – VENTILATION – GRADE OF RELEASE

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Hazardous Area Classification Data SheetsPart I: Flammable Material List and data

Hazardous Area Classification Data SheetsPart II: List of sources of release

Hazardous Area Classification DrawingsEN 60079-10-1, SEC 7.2

WHY COMBINE EN 60079-10-1 WITH IP15

• For continous & primary grades of release, the leak size is typically known.

• We need some advise regarding size and types of leak sources for secondary grade of release – EN 60079-10-1 is very open on the subjectsubject.

R f t EN 60079 10 1 1 S• Ref. to EN 60079-10-1, 1. Scope:

For detailed recommendations regarding the extent of the hazardous areas in specific industries or applications, reference may be made to national or industry codes relating to those applications.

HAZARDOUS AREA CLASSIFICATION – IP 15

Risk Target is 10-5 year

For most offshore plants, where there is control of ignition sources outside the hazardous areas, IP 15’s LEVEL I is applied

Does not concern major releases (spread of flamables more than 30 m). These shall be minimised by design and operation to an acceptable residual riskto an acceptable residual risk.

IP 15, sec. 5.4.5.1: “As a guide, when there are more than 10 leak sources within close proximity (i e Where their notional zone 2 would sources within close proximity (i.e. Where their notional zone 2 would overlap), the area should be classified as zone 2”

Classification only required for fluids with flashpoints nearer than 10 Classification only required for fluids with flashpoints nearer than 10 deg. C to the handling/ambient temperature in the area.

Following: Open field, naturally ventilated, wind speed 0.5 – 2.0 m/s

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g p , y , p /

POINT SOURCE

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FLUID CATEGORY / CLASS

Fluid Category

Description

A A flammable liquid that, on release, would vaporise rapidly and substantially.

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

C A flammable liquid, not in Categories A or B, but which can, on release, be at a temperature above its flash point, or form a release, be at a temperature above its flash point, or form a flammable mist or spray.

G(i) A typical methane-rich natural gas.G(ii) Refinery hydrogen.

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FLUID CATEGORY - EXAMPLES

Fluid Categoryg yCondensate / LPG: ACrude / unstabilized: BCrude / stabilized: CWet/dry gas: G(i)Produced Water: CProduced Water: CDiesel: CHelifuel: CHydraulic oil: C

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RELATIONSHIP – CLASS & CATEGORY

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IP 15 PROCEDURE – SECONDARY GRADE RELEASE

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IP 15 – LEVEL I, II & III – FLANGES & VALVES

For offshore oil/gas installations, where there is a strong control of ignition sources outside the classified area LEVEL I is typically ignition sources outside the classified area, LEVEL I is typically selected.

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CLASSIFICATION AT SPECIFIC EQUIPMENT

Fig 1A. Pump mounted on plated deck – high integrity pump (typically double mechanical seals)

HOLE DIA

FLUID CAT.

PRESSURE BARG

RADIUS R1 R2 DIA CAT. BARG R1 R2

2 B 10<P<50 4000 5000 2 B P<10 4000 4000 2 C 10<P<50 4500 5500 2 C P<10 4500 4500

Refer to appendix 5 John Crane recommendations for mechanical Refer to appendix 5, John Crane recommendations for mechanical seals.

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CLASSIFICATION AT SPECIFIC EQUIPMENTFig. 1B, Pump mounted on grated deck – high integrity pump (typically double mechanical seals)

HOLE FLUID PRESSURE RADIUS DIA CAT. BARG R1 R2 2 B P<50 4000 N/A 2 C P<50 4500 N/A

Refer to appendix 5 John Crane recommendations for mechanical Refer to appendix 5, John Crane recommendations for mechanical seals.

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CLASSIFICATION AT SPECIFIC EQUIPMENT

Fig. 2A, Flange/valve installed over grated deckg , g / g

HOLE DIA

FLUID CAT.

PRESSURE BARG

RADIUS R1 R2

1 A / C P<50 2500 N/A 1 B P<50 2000 N/A 1 G(i) P<100 1100 N/A 1 G(i) P<100 1100 N/A 1 G(i) 100<P<150 1400 N/A 1 G(i) 150<P<200 1600 N/A

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CLASSIFICATION AT SPECIFIC EQUIPMENT

Control valves, often used block valves and valves not well maintained: A zone 1 with R = 0.3 m.with R 0.3 m.

A specific evaluation shall be made to decide if there is a further zone 2 around the zone 1.

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CLASSIFICATION AT SPECIFIC EQUIPMENT

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CLASSIFICATION AT SPECIFIC EQUIPMENT

SPO Compact FlangeFully welded ASME B31 3 piping Fully welded ASME B31.3 piping and SPO compact flanges

No classification!

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CLASSIFICATION AT SPECIFIC EQUIPMENTEN 1127-1, ANNEX BDefines equipment which are ”durably technically tight”,

• Canned motor pumps

examples:

• Magnetic coupled sealless pumps

• Tongue/groove flanges (EN 1092-1, Type C & D)o gu /g oo a g ( 09 , yp & )

• If rarely detached: NPT connections (up to DN 50)

Should normally not cause classified areas.

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CLASSIFICATION AT SPECIFIC EQUIPMENT

Seal Sealing Arrangement Description Max. Release Flow Rate (kg/s)

Hazard Radius R1/R2 (m)

John Crane recommendations for mechanical seal Maximum release flow rates for pumps in all fluid categories and process pressuresITA / Appendix 5:

John Crane Single

Single seal ( without fixed throttle bushing, in a pump with no wear rings). This may be a component or cartridge, general-purpose seal

Use IP-15 calculation ( Hole size. 0,23xshaft dia.)*

See IP-15

Single

Single seal with a fixed throttle bushing or a single seal in an API 610 pump. This may be a component or cartridge, general-

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0,0003 <2

John Crane recommendaations for Pumps / Mechanical Seals.

purpose seal

Single

Single seal,, supplied to ISO 21049, with a fixed throttle bushing ( code 1CW-FX) or a single seal, supplied to ISO 21049 with a solid floating bushing ( code 1CW-FL) in an API 610 or ISO 13709 pump.

0,00015 <2

Dual, unpressurised seal ( without fixed throttle bushing in a pump with (

For dry gas seals on J h C Dual unpress.

fixed throttle bushing, in a pump with no wear rings). This may be a cartridge or non-cartridge, general-purpose seal

Use IP-15 calculation ( Hole size 2 mm )** See IP-15 ( 4 to 6 )

Dual unpress.

Dual, unpressurised seal ( ISO 21049, code 2CW-CW, 2CW-CS, with auxiliary plan 52, 75 or 76 ) with a fixed throttle bushing or the same seal arrangement but in an API 610

0,00001 <2

compresors, John Crane states the two last rows for pumps will apply for th d l pump or ISO 13709 pump.

Dual unpress.Dual, unpressurised seal as above but containement system connected to an open vent pipe

0,00001 at seal. 0,0025 at vent <2

Dual pressDual pressurised seal (without fixed throttle bushing, innon-cartridge, general purpose seal

Use IP-15 calculation ( Hole size 2 mm )** See IP-15 ( 4 to 6)

Dual, pressurised Seal (ISO 21049, code 3CW-CW with auxiliary plan

the dry gas seals, depending on execution of the dry gas seal

Dual press

code 3CW-CW, with auxiliary plan 53 or 54 ) with a fixed throttle bushing or the same seal arrangement but in a API 610 or ISO 13709 pump

NIL _

Dual press

Dual, pressurised Seal (ISO 21049, code 3NC, with auxiliary plan 74 ) with a fixed throttle bushing or the same seal arrangement but in a API

0,01 2***

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610 or ISO 13709 pump

* Use seal chamber presssure as release pressure ( If not known use discharge pressure )** Use 5 bara as release pressure*** For R2, Cat C use 2,5 m

HAZARDOUS AREA DOSSIER

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ENCLOSED AREAS

• Minimum 12 ACH (IP 15), no stagnant zones to ensure area classification will correspond to grade of release.

• Pressurisation to safe a room adjacent to classified area: Min. 5 mm WG overpressure (IP 15)

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