HAZARDOUS AREA
CLASSIFICATION
DS/EN 60079-10-1 & UK
ENERGY INSTITUTE, IP15
BACKGROUND – DS/EN 60079-10-1
CLASSIFICATION – EXPLOSIVE GAS ATMOSPHERES
• ATEX 1999/92 EC Di
Directive
ti
/B
Borehole
h l di
directive
ti
92/91/EC (offshore)
( ff h
)
• 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)
• 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 – ZONING
EN 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
operation
Zone 2: That part of a hazardous area in which a
flammable atmosphere
p
is not likely
y to occur in normal
operation, 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’)
3
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
explosive gas atmosphere being present:
• Continous grade
• Primary Grade
y Grade
• Secondary
• Degree of ventilation (natural / artificial):
• High ventilation (VH)
• Medium ventilation (VM)
• Low ventilation (VL)
HAZARDOUS AREA CLASSIFICATION –
GRADE OF RELEASE – IP 15 DEFINITIONS
Continuous grade
C
d release:
l
A release
l
that
h is continuous or nearly
l so, or
that occurs frequently and for short periods
If it is likely
y to be present
p
for more than 1000 hours per
p year.
y
Primary grade release: a release that is likely to occur periodically or
occasionally in normal operations, i.e. a release which, in operating
procedures is anticipated to occur
If 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.
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.
year
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ZONE – VENTILATION – GRADE OF RELEASE
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Hazardous Area Classification Data Sheets
Part I: Flammable Material List and data
Hazardous Area Classification Data Sheets
Part II: List of sources of release
Hazardous Area Classification Drawings
EN 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
subject.
subject
• Ref.
R f to
t EN 60079
60079-10-1,
10 1 1.
1 Scope:
S
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 risk.
risk
IP 15, sec. 5.4.5.1: “As a guide, when there are more than 10 leak
sources within close proximity (i.e.
(i e Where their notional zone 2 would
overlap), the area should be classified as zone 2”
Classification
Classification only required for fluids with flashpoints nearer than 10
deg. C to the handling/ambient temperature in the area.
Following:
g Open
p
field,, naturally
y ventilated,, wind speed
p
0.5 – 2.0 m/s
/
13
POINT SOURCE
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FLUID CATEGORY / CLASS
Fluid
Category
A
B
C
G(i)
G(ii)
Description
A flammable liquid that, on release, would vaporise rapidly and
substantially.
A flammable liquid, not in Category A, but at a temperature
sufficient for boiling to occur on release.
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
flammable mist or spray.
A typical methane-rich natural gas.
Refinery hydrogen.
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FLUID CATEGORY - EXAMPLES
Fluid
Category
g y
Condensate / LPG:
A
Crude / unstabilized:
B
Crude / stabilized:
C
Wet/dry gas:
G(i)
Produced Water:
C
Diesel:
C
Helifuel:
C
Hydraulic oil:
C
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RELATIONSHIP – CLASS & CATEGORY
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IP 15 PROCEDURE – SECONDARY GRADE
RELEASE
18
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,
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
2
2
2
2
FLUID
CAT.
B
B
C
C
PRESSURE
BARG
10<P<50
P<10
10<P<50
P<10
RADIUS
R1
R2
4000
5000
4000
4000
4500
5500
4500
4500
Refer to appendix 5
5, John Crane recommendations for mechanical
seals.
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CLASSIFICATION AT SPECIFIC EQUIPMENT
Fig. 1B, Pump mounted on grated deck – high integrity pump (typically double mechanical seals)
HOLE
DIA
2
2
FLUID
CAT.
B
C
PRESSURE
BARG
P<50
P<50
RADIUS
R1
R2
4000
N/A
4500
N/A
Refer to appendix 5
5, John Crane recommendations for mechanical
seals.
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CLASSIFICATION AT SPECIFIC EQUIPMENT
Fig.
g 2A,, Flange/valve
g /
installed over grated
g
deck
HOLE
DIA
1
1
1
1
1
FLUID
CAT.
A/C
B
G(i)
G(i)
G(i)
PRESSURE
BARG
P<50
P<50
P<100
100<P<150
150<P<200
RADIUS
R1
R2
2500
N/A
2000
N/A
1100
N/A
1400
N/A
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.
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 Flange
Fully welded ASME B31.3
B31 3 piping
and SPO compact flanges
No classification!
25
CLASSIFICATION AT SPECIFIC EQUIPMENT
EN 1127-1, ANNEX B
Defines equipment which are ”durably technically tight”,
examples:
• Canned motor pumps
• Magnetic coupled sealless pumps
• Tongue/groove
o gu /g oo
flanges
a g (EN
(
1092-1,
09
, Type
yp C & D))
• If rarely detached: NPT connections (up to DN 50)
Should normally not cause classified areas.
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CLASSIFICATION AT SPECIFIC EQUIPMENT
ITA / Appendix 5:
John Crane
recommendaations for
Pumps / Mechanical Seals.
For dry gas seals on
compresors, John
J h Crane
C
states the two last rows
for pumps will apply for
th dry
the
d gas seals,
l
depending on execution of
the dry gas seal
John Crane recommendations for mechanical seal Maximum release flow
rates for pumps in all fluid categories and process pressures
Seal
Sealing Arrangement Description
Max. Release Flow Rate
(kg/s)
Single seal ( without fixed throttle
bushing, in a pump with no wear
Use IP-15 calculation ( Hole
rings). This may be a component or
size. 0,23xshaft dia.)*
cartridge, general-purpose seal
Single seal with a fixed throttle
bushing or a single seal in an API
0,0003
Single
610 pump. This may be a
component or cartridge, generalpurpose seall
Single seal,, supplied to ISO 21049,
with a fixed throttle bushing ( code
1CW-FX) or a single seal, supplied
Single
0,00015
to ISO 21049 with a solid floating
bushing ( code 1CW-FL) in an API
610 or ISO 13709 pump.
Dual, unpressurised seal ( without
fixed throttle bushing
bushing, in a pump with
Use IP-15 calculation ( Hole
Dual unpress. no wear rings). This may be a
size 2 mm )**
cartridge or non-cartridge, generalpurpose seal
Dual, unpressurised seal ( ISO
21049, code 2CW-CW, 2CW-CS,
with auxiliary plan 52, 75 or 76 ) with
Dual unpress.
0,00001
a fixed throttle bushing or the same
seal arrangement but in an API 610
pump or ISO 13709 pump.
Dual, unpressurised seal as above
Dual unpress. but containement system connected 0,00001 at seal. 0,0025 at vent
to an open vent pipe
Dual pressurised seal (without fixed
Use IP-15 calculation ( Hole
Dual press
throttle bushing, innon-cartridge,
size 2 mm )**
general purpose seal
Dual, pressurised Seal (ISO 21049,
code 3CW-CW
3CW-CW, with auxiliary plan
53 or 54 ) with a fixed throttle
Dual press
NIL
bushing or the same seal
arrangement but in a API 610 or ISO
13709 pump
Dual, pressurised Seal (ISO 21049,
code 3NC, with auxiliary plan 74 )
Dual press
with a fixed throttle bushing or the
0,01
same seal arrangement but in a API
610 or ISO 13709 pump
Hazard Radius R1/R2
(m)
Single
See IP-15
<2
<2
See IP-15 ( 4 to 6 )
<2
<2
See IP-15 ( 4 to 6)
* 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
_
2***
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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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