Hazad Area Classification fundamentals and codes

Hazard Area Classification

1. Hazardous Area Classification
Fundamentals & Cases
ATEX congres
Mei 2014, Dordrecht, Nederland
Erik van de KuilenShell Global Solutions Inc.
EX

2. Agenda
HFundamentals
HIgnition Source Control
HStandards & Practices
HArea Classification: the Concept
HArea Classification: a Multistep Process
H
Cases
2
HHot Surfaces
HManagement of Change –Gasgroup& Temperature class
HNegligible Extent
HAbnormal Operating Conditions -Temporary Zone 1
HManagement of Change –Release dispersion
HHeat Exchanger Leakage
HVentilation
H
Q&A

3. Ignition Source Control…. or Not (?)

3
Hot
Surface

4. Ignition Source Control
Ignition Source Control
H
Ignition Source Control is partof Process Safety Management
4
Loss of
Containment
Proper Ignition Source Control reduces explosion risk 10-100x

5. Ignition Source Control
H
Ignition Source Control:
HPermit to Work system (hot work)
H‘No smoking’ areas
HTraffic and vehicle control HHazardous Area Classification
# Ignition Sources
(EN 1127)
1 Hot surfaces
2 Flames & hot gases
3 Mechanical sparks
4 Electrical apparatus
5 Stray currents
5
HStatic Electricity control
HEtc.
6 Static electricity
7 Lightning
8 Radio waves
9 High Frequency EM
waves
10 Ionizing radiation
11 Ultrasonics
12 Adiabatic compression
13 Exothermic reactions
H
Essentially covering all 13 ignition
sources (ref. EN 1127)
H
Hazardous Area Classification
is only
a part of Ignition Source Control

6. Hazardous Area Classification: Stds& Practices
H
Area Classification is typically following industry stds& p ractices: H
USA / North America:
HAPI RP 500 –Recommended Practice for Classification of Locations for Elec trical
Installation at Petroleum Facilities Classified as Class I , Division 1 and Division 2. –
North Americas and locations that have ANSI/NEMA designs
HAPI RP 505 –Recommended Practice for Classification of Locations for Elec trical
6
Installations at Petroleum Facilities Classified as Class 1, Zone 0, Zone 1, and
Zone 2 – North America and locations that have ANSI/NEMA designs
H
Europe (ATEX 137 since 2003) + rest of the world:
HEU: IEC 60079-10 Classification of Hazardous Areas
HUK: IP-15 – Energy Institute (previously Institute o f Petroleum) Model Code
of Safe Practice, Part 15, 3rd edition, July 2005. – United Kingdom
HCountry local regulations, standards & practices

7. Hazardous Area Classification: the Concept
H
HazardousArea Classification principle:
1.Determine likelihood and dimension of a flammable atmosphere
(zone) around certain leak and/or exposure points (
LFLboundary
)
2.Manage(design,maintain, operate) or eliminate ignition sources
within the zone
7
UFL
LFL
LFL

8. Hazardous Area Classification: the Concept
H
Hazardous Area Classification scope:
HFlammable fluids (Hydrocarbons, H2, CO, NH3, …)
H‘Small’ release sources:
HFlanges, pump seals, vents, drains
HNo catastrophic equipment failure
H
(Semi)permanent ignition sources*:
8
H
(Semi)permanent ignition sources*:
HEquipment hot surfaces
HRoads / plant vehicles
HMachinery motors
HInstrumentation
*Open flame equipment is typically excluded from Area Classification
and located outside the classified area

9. Hazardous Area Classification: A Multistep Process
H
1: Determine
flammability properties for each fluid and/or
equipment item (in particular LFL, UFL, flashpoint, AIT)
9
Hydrocarbon
Auto Ignition
Temperature
(AIT)

10. Hazardous Area Classification: A Multistep Process
H
2: Determine Zone for all equipment items
a: Zone type (likelihood of flammable atmosphere):
Release Grade Equipment
(example)
Zone
(ventilated)
Zone
(confined/
non
-
10
b: Zone extension (dimensions of flammable atmosphere):
non
-
ventilated)
Continuous (>1000
hr/yr)
Inside tank
0
0
Primary (10 - 1000
hr/yr)
Sample
connection, pits
1
1/0
Secondary (< 10
hr/yr)
Flange, pump
seal
2
1

11. Hazardous Area Classification: A Multistep Process
H
2: Determine Zone for all equipment items
b: Zone extension (dimensions of flammable atmosphere):
11
IP 15: Direct Example Approach
IP 15: Point Source Approach

12. Hazardous Area Classification: A Multistep Process
a
3: Determine fluid ignition parameters (ref. Literature)
a: the Gasgroup for the released fluid*
b: the Temperature Class for the released fluid
Released
fluid
Ignition
Energy
(mIE)
Gasgroup Auto Ignition
Temperature
(AIT) (deg C)
T
class
Methane
0.28
I /II A
525
T1
Fluid (typical) Gas
group
Alkanes II A Ethylene, EO,
CO
II B
12
* Also ‘apparatus’ group or ‘explosion’ group; a pa rameter related to the sensitivity for ignition
Methane
0.28
I /II A
525
T1
Ethane 0.24II A510T1
Propane 0.25II A460T1
Hexane 0.24II A230T3
Ethylene 0.07II B425T2
Hydrogen 0.01II C560T1
Benzene 0.2II A498T1
Ethylene
Oxide
0.06II B429T2
T
class
Temperature
(deg C)
1 450
2 300
3 200
4 135
5 100
6 85
Ethylene, EO,
CO
II B
Hydrogen II C

13. Hazardous Area Classification: A Multistep Process
a
4: Complete the Hazardous Area Classification Design Basis
and develop the drawings….
13

14. Hazardous Area Classification: A Multistep Process
14
///// Zone 2

15. Hazardous Area Classification: A Multistep Process

16. a
5: Implement and/or verify in the field:
(incl. selected explosion protection: ia, ib, d, e, n,... )
aequipment nameplates
ahot surfaces
aroads & vehicles
a
6: Risk assess and/or modify any Hazardous Area Classification: A Multistep Process
NAME PLATE:
Universal Supplies Ltd,
CE 0999
Trans type 100
II G
EEX
ib
IIC T
4
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a
6: Risk assess and/or modify any deviations from the required area
classification
(Ignition Hazard Analysis)
a
7: Document !
(Area Classification Design Basis,
Explosion Protection Document)
EEX
ib
IIC T
4
40 C < Ta < 70 C
ACB 00 ATEX 9999
Apparatus parameters
Serial No. 991234

17. Hazardous Area Classification –Some Cases
1.
Hot Surfaces
2.
Management of Change –Gasgroup& Temperature class
3.
Negligible Extent
4.
Abnormal Operating Conditions -Temporary Zone 1 operation
5.
Management of Change
–
Release dispersion
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5.
Management of Change
–
Release dispersion
6.
Heat Exchanger Leakage
7.
Ventilation

18. Hot Surfaces
H
Hot equipment surfaces can be an ignition source, if the surfac e
temperature exceeds the Auto Ignition Temperature (AIT) of the
released fluid:
Operating temperature > Gasoline AIT
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19. Hot Surfaces
H
Ri
sk Considerations (Ignition Hazard Analysis):
aWhat is the actual Heating Medium line surface temp erature? Is the line
insulated or could it be ? Is the insulation gas ti ght? Are there any flanges?
aWill the Gasoline indeed reach the Heating Medium l ine and heat up to AIT?
aCould any Gasoline leak points perhaps be eliminate d or relocated?
aCould the Heating Medium line be rerouted/shielded off?
H
API RP
2216
-
03
:
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H
API RP
2216
-
03
:
Ignition Risk of Hydrocarbon Liquids and Vapors by Hot Surfaces in Open Air:
“ignition of hydrocarbons by a hot surface should n ot be assumed unless the
surface temperature is approximately 360 °F (182°C)above the accepted
minimum ignition temperature of the hydrocarbon inv olved.”
H
Consider ignition due to hot surface*:
HZone 0 & Zone 1: fluid AIT
HZone 2: fluid AIT + 180 °C.
* EN1127 indicates 80% of AIT for Zone 0 and 1 and AIT for Zone 2

20. Hot Surfaces

A new insulated Steam line (Operating Temperature > 300 C) into
an existing pipe track (conservatively) classified as Zone 1 with
fluids AITs < 250 C:

New steam line
Existing pipe trac
k

Zone 1

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Alternative: installing a new 2 km pipe rack
Risk Considerations(Ignition Hazard Analysis):
NAPI 2216 not applicable for Zone 1 (only for well v entilated systems)
NWhat is the Steam line surface temperature? What ab out flanges?
NWhere are the Hydrocarbon leak sources? Close to S team line hot points?
NCould the Steam line be shielded/segregated from th e Hydrocarbon lines?

21. Management of Change –Gasgroupand T Class
Existing / Replaced IIA-T3
Equipment / zone
(max surface temp. 200̊C)
New IIA-T2
equipment / zone
(max surface temp. 300̊C)
Existing IIA-T3 and IIC
-
T
3
Equipment /
T2 equipment
H
Installing new equipment in
existing facility
New IIC-T2 equipment / zone
(max surface temp. 300̊C)
New IIA-T2 equipment / zone
(max surface temp. 300̊C)
IIC
-
T
3
Equipment /
zone (max surface
temp. 200̊C)
in T3 zone
IIA equipment in
IIC zone

22. Zone with Negligible Extent (NE)
H
During facility decommissioning
residual Hydrocarbons at low/no
pressure may retain inside and
dictate need for Area
Classification .
H
EN 60079-10-1 has introduced
the concept of Zone with
Negligible Extend (NE). Negligible Extend (NE). Zone 2 NE is accepted by the UK
Health and Safety Executive
(HSE) and does not require
control of ignition sources within
it.
H
Approach is being considered for
de-commissioning of platforms in
North Sea:
Normal outside
conditions
Good High
Ventilation
required

23. Abnormal Operating Conditions (Drilling WHCP)
H
Platform Well Head Control Panel (WHCP)
cabinet (ca. 3 m3) is located in Zone 2 and
internally classified Zone 1. Zone 2 is
based on normal production.
H
During HAZOP it was found that for 3-6
months every 3-4 yrs, the platform is also
used to drill new wells. used to drill new wells. This would require
3 m radius Zone 1
conditions extending over the WHCP.
H
Relocate/renew the cabinet for Zone 0 ?
H
Alternative? During Zone 1 operation:
HProvide gas detection in/near the cabinet to indica te
increased gas concentration inside/outside the cabi net.
HInstall ventilation on the cabinet to maintain Zone 1 inside

24. Management of Change –Standards & Dispersion
H
New filter unit for FCC product
aDistance from proposed location to
nearby road: 7.5 m
aZone radius/distance to road
according local standard: 15 m
H
This would require closure or major rerouting of main access major rerouting of main access road to Control Room and Unit….
H
Physical Effect Modeling:
HDispersion analysis shows max release
size 4.5 m from filter unit leak points
HSupported by IP 15 Area Classification
point source method
IP 15 Point Source

25. Heat Exchanger Leakage (Cooling Water Return)
H
Leaking Heat Exchanger(s)
resulting in Hydrocarbon in open
Cooling Water Returns and may
be ignited
(CW Return not classified).
H
To reduce the risk:
H
To reduce the risk: H
Zone 1/2 for the CW Return?
H
Install gas / Hydrocarbon
detection in CW Return +
H
Close off the road in case of gas
detection to prevent ignition by
passing vehicle
H
A similar case:

26. Heat Exchanger Leakage (Cooling Water Return)
CW tower fire H
New designs would have closed CW return lines, classified
CW towers and Hydrocarbon vent in the return line:
Hydrocarbon Vent Line
CW Return Line
Ref. API 505

27. Ventilation(Winterizing)
H
During winter, some plants are ‘sheltered’ to prevent freezing
problems. This could impact the natural ventilation and the Z oning.

28. Ventilation(Winterizing)
NDesign and locate the screens such that (natural) ventilation is still
adequate:
N
50% LEL for secondary grade release
N
25% LEL for continuous & primary grade release
(ref. IEC 60079-10 ventilation calcs)
Winterizing screens
N
If not adequate, then need to consider artificial ventilation an d/or
gas detection
Zone 2 facility
Winterizing screens
Open area
for
ventilation

29. Q & A