ACG Step PHASE 1 Recommendation Action Sheets v4 08-06-2012.docx

8/14/2019 ACG Step PHASE 1 Recommendation Action Sheets v4 08-06-2012.docx

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Facility / System: ACG STEP Phase 1

Date of Review: 27/02/2012

Chairman: Ian Herbert

Recommendation No: 1

Hazardous Event: Overpressure - Letdown gas KOD, Fuel Gas KOD and Off spec crude oilpumps

TRAC Safety FunctionReference

1S-72.5.1 OI

SIF or non-SIF LOPA Non-SIF

Event Severity: Safety Environmental Commercial

F

Event TMEL: 1.0E-3

Total Event Frequency Fe/yr ( fromTRAC)

7.0E-3

Purple (P), blue(B), turquoise (T) or

white (W)

T

Recommendation:

The potential for high pressures in the inlet sealine can generate high back pressures on Letdown gasKOD, Fuel gas KOD and off spec crude oil pumps. This introduces HP/LP interfaces back from the inletsealine section which could be above the design rating of the upstream equipment. The level of currentsafeguards is seen as potentially insufficient. A review of reverse flow HP/LP interface protection -including a review of PSV sizing cases should be undertaken to ensure that sufficient protection is inplace. Improvements could included, but review should not be limited to, the following potential areas:Confirm sizing of PSVs on route from off spec crude oil pumps (note: isolation valve on pump stopwould be better to reduce demand on NRVs which will be SRDs and hence safety critical), Closure ofvalves from letdown gas KOD and Fuel gas KODs.

Responsibility & Target date: Process TA

Response:

Does Response close Recommendation? (Yes / No)

Action Plan to implement change:

Review & Approval: Name Signature Date

Action Owner

Discipline DRE

AESTL (or Eng Manager)

(mandatory)

Process Safety Engineer DRE

(mandatory for P, B, T risks only)

Area Operations Manager

(mandatory for P, B, risks only)

Other (state)







Hazardous Event: Overpressure – Oil Heater Pipework


1S-11.17.1 Oil Htr



D F

Event TMEL: 1.0E-5 1.0E-3


2.3E-3 4.9E-3

Purple (P), blue(B), turquoise (T) orwhite (W)

B T

Recommendation:

A review of blockage on the oil heaters, particularly from potential wax following pigging, has identifiedthat there is a lack of overpressure protection on the heaters. The blockage over pressure (and also byits nature over temperature) protection on the heaters needs to be further reviewed and additionalprotection determined. The importance of any protection (including cage design of FV) should behighlighted in any SRD data sheets.

NOTE: Blockage of Oil heaters and tube failures is also a concern in Recommendation 28. Both thisrecommendation (2) and 28 should be closed out together.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overpressure – Closed Drain Drum

TRAC Safety Function

Reference

1S-96.2.5 CDD



E C




Recommendation:

It was reported to the LOPA team that the Closed drain drum pumps (phase 1 at least) have alreadybeen changed to address the low NPSH issue which required vent line isolation to be closed. This willresolve some significant risks identified in the HAZOP, for which a purple recommendation was raised.The LOPA team is concerned that this change has not been made fully aware to all plant operators. Asa result some operations may still try to close the vent isolation when pumping out. The Terminalshould ensure that full details of this pump change have been communicated and that a note isincluded with the LO/LC register for HV440409.


Response:




Action Owner

Discipline DRE

AESTL (or Eng Manager)(mandatory)





Other (state)







Hazardous Event: Overpressure – Gas Line


Reference

1S-PAHH-302303 GL

SIF or non-SIF LOPA SIF


F D



3.4E-4 1.1E-3


W B

Recommendation:

There are a number of high pressure trips on systems associated with the Gas line. These are at setpoints below that for the High High trip on the gas line. Line packing operations will increase thefrequency for high pressure from the slug catchers to gas line, with potential overpressurisation in theevent of PIC 300301 failure during the period when slug catchers are >80barg. In the case of theDPCU trip (internal trip at 47.5Barg) isolation of the DPCU unit will increase the potential for theoverpressurisation of the gas line and equipment upstream of the DPCU. The flash gas compressorswill also trip out and isolate at 51.5 barg, plus intertrips from PAHH 340004 at 49. The LOPA teamcould not identify reasons for the lower set points on these associated high pressure trips, and wasalso concerned with knock on (pressurisation) effects from the DPCU trip. The set point of FG andDPCU trips, and any others, should be reviewed against the equipment design rating of 80barg. Plusthe closure of gas line isolation valves should also be implemented if DPCU inlet isolation trips closed.

It should also be noted that DPCU trip will cause fuel gas supply to be lost, if the fuel gas is being takenoff downstream of DPCU. Avoidance of spurious DPCU trips is to be avoided.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overfill – Crude Oil Storage Tanks


1S-LAHH-230102A/202A/302A



E F C

Event TMEL: 1.0E-4 1.0E-3 1.0E-5


3.5E-5 1.4E-4 1.2E-3


white (W)

W W P

Recommendation:

The potential major commercial loss in the event of overfilling all three crude oil tanks while running incommon connection mode, results in a higher integrity requirement on the final tank High High leveltrips. Overfilling of Crude Oil storage in this mode is dominated by Human Error potential. A review of asimilar overfill scenario where tanks are filled individually results in a lower Integrity level on the HighHigh trip protection. Commercial IL is the dominating reason. Safety and Environment cases areacceptable in both operating modes. The business case for running with all three tanks commonedshould be reviewed and if continue in this modes to revise overfill protection.

Responsibility & Target date: Operation Manager

Response:




Action Owner

Discipline DREAESTL (or Eng Manager)

(mandatory)





Other (state)







Hazardous Event: Overpressure - Crude Oil Storage Tanks


Reference

1S-6.4.1 CO



E F D

Event TMEL: 1.0E-4 1.0E-3 1.0E-4


2.1E-5 5.0E-5 5.0E-4


W W B

Recommendation:

It was noted that during discussions on low temperature scenarios, from the crude oil heatersgenerating off spec crude, that current operations are out with the original BOD. Three currentlypresent conditions are increasing vapour generation. These are Lower outlet temperatures from crudeheaters, High LP sep pressure and under summer weather conditions higher rundown temperatures.There is a concern that higher vapour generation rates at the crude oil storage tanks could beincreasing the potential for rim seal damage and possible rim seal fires. The current operatingconditions out with original BOD values should be reviewed and any increased risk signed off asaccepted, if measures required to return to BOD condition are not feasible.

Note: It was subsequently determined that there were additional failures on Oil Heater (low temp), LPseparator (High Pressure) and rundown coolers (High Temperature) which initially identified as having

individual SIFs, are all linked to the same hazardous event, High RVP oil at COSTs. A Non-SIF LOPAhas been undertaken to review this Hazard, which has also raised a Recommendation (Rec 23). BothRecommendation 6 and 23 should be closed out together.

Responsibility & Target date: Operations Manager

Response:




Action Owner

Discipline DRE


(mandatory)







Other (state)





Chairman: Phil Eames


Hazardous Event: Methanol Tanker Drive Away


Reference

1S-58.19.1 Meth

1S-106.20.1 Meth



E

Event TMEL: 1.0E-4


1.0E-3


B

Recommendation:

The existing working practice should be verified to ensure sufficiently robust to eliminate the risk ofdrive away of methanol tankers. If this is not the case, then apply PTW control to unloading of methanoltankers or conduct a tanker unloading design review, in order to minimise the probability of a tankerdriver driving away from the Methanol unloading point whilst there is still inventory within the tanker andthe hose is still connected to the unloading pipework. The risk of drive away is the dominant factor inthe frequency of the scenario of a pool fire as a result of methanol unloading, for which the LOPA hasidentified a need for further risk reduction on the assumption that existing practices may not be fullyrobust.

Responsibility & Target date: Operations Manager

Response:




Action Owner

Discipline DRE

AESTL (or Eng Manager)(mandatory)





Other (state)







Hazardous Event: Overfill – Methanol Road Tanker


Reference

1S-106.2.1 Methano



E

Event TMEL: 1.0E-4


1.5E-4


B

Recommendation:

Methanol storage tank 1S-T42720 unloading dip pipe is shown on the P&ID (4209) to have an anti-syphon hole, however this hole is not shown on the vendor drawing (P9ME21A-B0001) and data sheet(P9ME21A-C0001). The action is to identify what exist on the other methanol tanks and adopt a unifiedphilosophy for protection against reverse flow of methanol and the potential for nitrogen blow back tothe methanol tanker. The LOPA for 1S-T42720 shows that there is a gap in protection against reverseflow of methanol without taking credit for the anti-syphon hole.

However, the risk of nitrogen blow back also needs to be considered in relation to whether reverse flowthrough the diaphragm pump is credible and whether the presence of an anti-syphon hole has animpact on this.

Responsibility & Target date: AESTL

Response:




Action Owner


(mandatory)





Other (state)







Hazardous Event: Less Flow – Hydrate Formation


Reference

1S-106.15.1 Methanol



E

Event TMEL: 1.0E-3


1.6E-1


B

Recommendation:

LOPA has concluded that there is insufficient protection against the loss of methanol to users leadingto hydrate formation, equipment blockage and reduced production (CIL 2 is required to meet the TMELfor a commercial severity E event). There is a need to consider additional means to improve methanolinjection system availability for the new methanol skid (1S-Z42770).

Responsibility & Target date: Discipline Engineering Manager

Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overpressure – Gas Blowby


Reference

1S-10.2.1 MPSep



E F C

Event TMEL: 1.0E-4 1.0E-3 1.0E-5


1.0E-2 1.0E-2 1.0E-2


B T P

Recommendation:

Determine whether gas blow by from the Letdown Gas KO Drum 1S-V3415 as a result of level controlvalve LV340152A/B failing open will result in an overpressure scenario, for example, in the oil inletfacility, off-spec crude oil tank and LP flare. Confirm the severity of this scenario and conduct LOPA todetermine whether there is adequate protection.

In studying the gas blow by case leading to crude oil heater tube failure (72.4.1), the LOPA team wereunable to determine if there is also an overpressure scenario.

Note: The potential for gas blow by has from Letdown Gas KO Drum has also been identified as one ofa number of potential overpressure cases on the MP Separator. There is an additionalrecommendation 22 which has been raised to further review the overpressure cases, including thisblow-by case. Recommendation 22 and this recommendation (10) should be closed out together.

Responsibility & Target date: Discipline Engineering Manager

Response:




Action Owner

Discipline DRE


(mandatory





Other (state)







Hazardous Event: Overfill – PW Tank


Reference

1S-LAHH-510202 PWT



F D



5.0E-3 5.0E-3


T B

Recommendation:

Configure a deviation alarm between LI510203 and LI 510201 on the produced water tank (1S-TS1020). This will provide an early warning of a discrepancy between the two level measurementsused to manage inventory. When LIT510202 is operating within range, this should be included in thedeviation alarm.

Responsibility & Target date: Area Ops Support Team Leader

Response:




Action Owner

Discipline DRE


(mandatory)

Process Safety Engineer DRE(mandatory for P, B, T risks only)



Other (state)





Chairman: Graeme Laughland


Hazardous Event: Overpressure – Diesel System


Reference

1S-79.5.2.1



F

Event TMEL: 1.0E-3


1.0E-1


T

Recommendation:

Provide a means of reducing the risk of overpressurising the diesel system (2"-OF-623015-B01E) dueto reverse flow from the oil pig receiver (V-20010). Failure to depressurise the pig receiver prior toadding diesel will leave the system at pressure. Risk reduction required is 0.01.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Flow Induced Vibration


Reference

1S-68.6.1.3 H2S



E

Event TMEL: 1.0E-4


1.7E-3


B

Recommendation:

a) Confirm that excess flow (versus design case of 250 MMSCFD) through the low flow mixer (M-34081) will result in flow induced vibration and loss of containment. Initiating causes are either failure toput the high flow mixer online or failure when an increased flow is being supplied from offshore, orfailure of pressure control loop (PIC-300301) when the low flow mixer is online. See HAZOPRecommendation 150.

Note that there is maximum velocity of 52.9m/s specified on the manufacturers data sheet (TD-1S-OPZZ-ME-DAT-0010-02). This far exceeds the maximum operating velocities in the 18" and 24" lines,as calculated by R Kozak. This therefore means that the mixer will not fail, however piping may fail.

b) If a loss of containment can occur then provide a means of avoiding this scenario or providing an IPLwith a PFDavg of 0.059.

Responsibility & Target date: Engineering Discipline Manager

Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overpressure – Hydrate Formation


1S-68.8.2.1 H2S



E

Event TMEL: 1.0E-4


2.5E-3


white (W)

B

Recommendation:

Provide a means of reducing risk of loss of containment due to hydrate formation following inadvertentaddition of water from the H2S scavenger water injection system. Consider removing the waterinjection point to the location upstream of PV300301 and PV-302301/ PV-302302 as the LOPA teamdo not see a need for this as it promotes hydrate formation and the Letdown KO Drum is now online.Either, the risk must be removed or an IPL with a PFDavg of 0.04 is required.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overpressure – Hydrate Formation


Reference

1S-48.12.1 SC



E

Event TMEL: 1.0E-4


9.3E-2


B

Recommendation:

Provide a means of reducing risk of loss of containment due to hydrate formation following failure toadd methanol upstream of the pressure protection control valves ( PV300301, PV-302301 and PV-302302). Provide a means of reducing the risk with an IPL with a PFDavg of 0.011.

Determine if a suitable alarm could be provided as an IPL as part of the risk reduction required.

Note: See HAZOP Recommendation 299: It is not considered to be good hydrate risk management tobe waiting until evidence of hydrate formation is occurring e.g. DP downstream of PCVs300301/302301/302302. Methanol addition should be triggered by low gas temperature irrespective ofwhen in the year this can occur. Current winterisation plan only has preparation of methanol system tobe available, but methanol addition is only made when DP is seen to be increasing.

Responsibility & Target date:

Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: LOC – Excessive Cooling


Reference

1S-73.12.3.1 H2S



E

Event TMEL: 1.0E-4


1.0E-1


B

Recommendation:

Provide a means of reducing the risk of low temperature embrittlement of the H2S scavenger separatorcoalescer (V-34083) by providing an IPL with PFDavg of 0.00099. This event could be initiated bymanual depressurisation or by a BDV.

See Recommendation 170: H2S scavenger separator coalescer (V-34083) design temperature is -29deg.C however H2S scavenger coalescer (V-34288) has a design temperature of -46deg.C. HAZOPteam unsure why there is a discrepancy between the minimum design temperatures between the twovessels.

A design check is required to ensure that H2S scavenger coalescer (V-34083) minimum designtemperature of -29deg.C is acceptable.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overpressure – Potential Fire


Reference

1S-PAHH-482008 FG



E D


Total Event Frequency Fe/yr (fromTRAC)

2.0E-2 2.0E-2


B B

Recommendation:

Confirm that the 2oo3 voting system (PIT-482008A/B/C on the gas line from the slug catcher to theFuel Gas KO Drum meets a PFDavg of 0.005 to ensure there is adequate protection for a reverse flowcase and overpressure of the DPCU outlet line or the H2S scavenger outlet line to the KO Drum. Notethat this is for both Safety and Commercial reasons.


Response:




Action Owner

Discipline DRE


(mandatory)




Other (state)







Hazardous Event: Overpressure – Produced Water Tank


Reference

1S-51.3.2 PWT



D

Event TMEL: 1.0E-4


1.2E-4


B

Recommendation:

There is a potential safeguard gap on protection of the PWT in the event of FG purge gas inlet PCVfailure, causing overpressure failure of the PWT. This is due to potential significant commercialconsequences. A review of safeguards to improve pressure protection should be undertaken. Inaddition it was identified that there could be potential Ice formation in the impulse line to PSVs due towater vapour in the PWT vapour space and cold ambient conditions. This should also be reviewed toensure PSV operation.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Internal Explosion – Produced Water Tank


Reference

1S-51.2.1 PWT



D

Event TMEL: 1.0E-4


2.5E-2


P

Recommendation:

There is a significant deficiency in protection against internal PWT explosion, following air being pulledinto the tank as a result of FG purge pressure control failure, causing underpressure in the PWT. Theinternal explosion case should be further reviewed to determine additional protection measures.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Nitrogen Asphyxiation – Gas Turbine


Reference

1S-122.4.1 GT



E

Event TMEL: 1.0E-4


2.0E-3


B

Recommendation:

There is an identified gap on protection on the GT enclosure. HAZOP recommendation 296 should beclosed out and the risk (LOPA) of nitrogen asphyxiation re-evaluated.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overpressure – MP Separator


Reference

1S-10.2.1 MPSep



E

Event TMEL: 1.0E-4


1.5E-4


W

Recommendation:

There are a number of high pressure cases that can impinge upon the MP Separator. These includeupstream blow by events as well as Pressure control failure on the separator. There is also a complexkey interlock system on the PSVs for when running with Heater 7. The LOPA has been undertakenonly as a means for providing an initial review of the scenarios and means to identify the potentialscenarios of greatest concern (Slug catcher blow by, PIC failure on MP separator and 3rd stagedischarge scrubber blow by). There needs to be a full review and assessment of the potentialoverpressure scenarios. This should include where necessary dynamic modelling and validation ofcapacities and response of pressure relief, trips and control systems, including trip correct actions(including response times and potential trip failures e.g. incorrect trip settings on heater 7 use).

Note: There is also an additional recommendation on potential overpressure caused by blow-by from

letdown gas KO drum, recommendation 10. This recommendation (23) and Recommendation 10should be closed out together.


Response:




Action Owner

Discipline DRE


(mandatory)







Other (state)





Hazardous Event: Overpressure – Crude Oil Storage Tank


1S-6.4.1 CO



E D



5.5E-4 1.3E-2


B P

Recommendation:

The potential for high RVP in the Crude Oil Storage Tanks, damaging tank seals and leading toincreased rim seal and tank fires, is a combination of multiple upstream causes. This is from failures atthe oil heaters temperature control (which is under high demands due to current operating conditions),higher pressure in the LP separator, Rundown cooler failures and failures to control other feeds to theCrude Oil Storage Tanks. The control and risk assessment of this hazard should be subject to a fullerreview and appropriate re-assessment. The LOPA has been undertaken to provide a coarse reviewand highlights significant commercial and safety protection gaps.

Note: A previous recommendation 6 was also raised to review the hazard for operating out-with originaldesign basis and high RVP generation under current operation. This recommendation 23 should beclosed out with previous recommendation 6.


Response:




Action Owner

Discipline DRE


(mandatory)







Other (state)







Hazardous Event: Overpressure – Off-Spec Crude Oil Tanks


Reference

1S-1.41.4 Offspec



E F D

Event TMEL: 1.0E-4 1.0E-3 1.0E-4


4.5E-5 1.1E-2 1.1E-3


W T B

Recommendation:

The LOPA identifies that there is a gap on safeguards for overpressure protection of the Off SpecCrude Oil Storage Tanks. This is principally driven by pessimistic assumption on relief case sizing fromthe Off Spec Storage Tanks. A review of relief cases for Off Spec Storage should be undertaken. Thescenario for Slug catcher blow by should be assessed as part of overpressure combined case on bothOff Spec Crude Tank and MP Separator. See Recommendation 22.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overpressure – Off-Spec Crude Oil Tanks Inlet Pipework


Reference

1S-97.9.1 OffSpecCO



E F D

Event TMEL: 1.0E-4 1.0E-3 1.0E-4


4.6E-6 1.1E-3 1.1E-4


W T B

Recommendation:

There is a minor safety gap on the protection of the low (150 rated) in let lines into the off-spec crudeoil storage tanks. This is dominated by mal-operation of the cross over connection isolation valve(HV200454) which would negate the function of the inlet lank isolation valve key interlock system. Thisvalve should be reviewed and either included in interlock or permanently disabled.


Response:




Action Owner

Discipline DRE


(mandatory)




Other (state)







Hazardous Event: Internal Explosion – Crude Oil Storage Tanks


Reference

1S-132.3.1 CO



F D



1.0E-2 1.0E-2


T B

Recommendation:

There is a gap for internal deflagration on refilling of the floating roof storage tanks. The currentprocedure only has low fill rate to avoid mist formation as a means of protection. This is correct wherethe material is below effective Flash point conditions. This would be expected for stabilise heavyhydrocarbons, but not for liquids that could under normal ambient conditions generate flammablevapours. The flammability characteristics of Azeri crude oil as stated in SDS SAZ2201 'Azeri crude oil'has the flash point at <19C. If this is correct then the procedure for filling should be reviewed in order tomanage the potential for deflagration.


Response:




Action Owner


(mandatory)





Other (state)







Hazardous Event: Overfill – Electrostatic Coalescer


Reference

1S-LAHH- 211401 EC



E D



2.1E-4 5.0E-3


B B

Recommendation:

The exact failure and consequences following high water levels in the Electrostatic Coalescer are notknown. The LOPA has been undertaken on the basis of one potential hazard scenario, however, thismay not be the true or the sole hazard on the EC operation. The vendor should be involved in a furtherreview of EC operations to identify and assess the hazards on this unit.


Response:




Action Owner

Discipline DRE


(mandatory)




Other (state)







Hazardous Event: Overtemperature – Oil Heater


Reference

1S-96.6.2 OH



D

Event TMEL: 1.0E-4


1.2E-2


P

Recommendation:

The assessment of tube failure in the oil heaters as a result of tube overheating has raised a potentialsafeguard gap. For example possible wax issues as introduced wax blockage as a means for individualtube failure (blockage in oil inlet manifold which is external to heater and could be cold enough to allowfor wax to settle). There are also other potential low flow high internal burner flame conditions whichcould allow for tube overheating and there is no validation that other safeguards e.g. downstreamtemperature and low flow trips can protect against these scenarios. The LOPA has undertaken areview of potential causes but not completed the full review of potential safeguards as it wasdetermined that there was a safeguard gap and lack of validating information. A full review of tubethermal failure potential cases should be undertaken and, if required, safeguards improved. This canuse the identified causes in the LOPA as a basis but should also look for any additional causes.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Internal Explosion – Oil Heaters


1S-96.6.2 OH



N/A N/A N/A

Event TMEL:



white (W)

Recommendation:

The LOPA team was unable to undertake an assessment of internal explosion in the oil heaters due toa lack of understanding of the functioning and internal safeguarding of the BMS against failures thatcould generate a flammable atmosphere in the oil heater. The LOPA reviewed and revised the HAZOPconsequences and has determined that there are potential Safety E (fatality) and Commercial D(investigation down time and heater replacement costs) consequences. There should be a risk reviewwith the BMS vendor to assess the failure mechanisms that could lead to internal explosions and todetermine the adequacy of the BMS safeguards (integrity).


Response:




Action Owner


(mandatory)





Other (state)







Hazardous Event: Overfill – LP Flare Header


Reference

1S-25.20.1 LPFC



F

Event TMEL: 1.0E-3


5.1E-3


T

Recommendation:

The LOPA team reviewed the hazards associated with failure to drain the LP Flare header. This hasregular generation of condensates. The current drainage is a manual operation which is only initiatedby the high level alarm on the drainage pot (LAH 440103). This level instrument is now a criticalinstrument to avoid liquid build-up in the LP flare header. There should be a review of the liquiddrainage from the LP flare header to determine improvements to the integrity for flare drainage. Thismay include improvements to the procedures to reduce reliance on the instrument.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Internal Explosion – HP Flare


Reference

1S- 22.2.3 HPF



E D



8.4E-4 2.6E-3


B B

Recommendation:

The LOPA assessment has identified a potential gap on Phase 1 HP flare in the event of a failure of thenitrogen inert gas purge to the flare stack downstream of the flare isolation valves (as part of flare gasrecovery system operation). This system relies on manual checks and adjustment, there are nosafeguards to protect or warn of N2 failure. The risk of stack internal explosion should be reviewed(GP44-80 section 11.5, indicates possible high pressure generation following purge failures, whichcould cause rupture) and further risk reduction measures determined.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Generic – Control of Work Review


Reference

Generic

SIF or non-SIF LOPA N/A


N/A N/A N/A

Event TMEL:



Recommendation:

There are a number of LOPA scenarios that meet the LOPA consequence criterion, but which aresolely failures of Control of Work type operations, e.g. Pig receiver, Flare / vent line isolations, Flaresystem re-instatement. These have been excluded under ToR section 5.2a, for which LOPA is not themost appropriate assessment methodology. All scenarios where exclusion 5.2.a has been used shouldbe subject to some form of review of the associated procedures and Human factor assessment toensure that these are adequate control measures.

Responsibility & Target date: Process Safety TA

Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overfill – LP Flare KO Drum


Reference

1S-28.2.1 LPFD



E D



5.9E-4 2.8E-2


B P

Recommendation:

High level in LP flare KOD has been assessed as a non SIF LOPA as the High High level trip action offLAHH 440100 may not be adequate in the case of high liquid loading on LP flare following overfill of theClosed drain and BTC closed drain vessels. Overfill of the BTC closed drain vessel in particular hasbeen increased following increase in de-watering exercises from Crude Oil storage tanks. The ClosedDrain vessels also rely on a single level instrument with no additional safeguards against overfill. Thevents from Closed drain tanks are connected to LP flare and will result in increased liquid loading on LPflare. The Overfill cases require further review to confirm potential liquid overflow routes anddetermination of additional safeguards. This should also review action of LAHH440100 to determine ifcredit can be taken for production shutdown in such cases.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overpressure – HP Flare KO Drum


Reference

1S-22.2.1 HPF



E C



9.1E-5 9.1E-5


W B

Recommendation:

HP flare system is a commercially critical operation. There is a potential small safeguard gap whenrunning to alternative phase 2 HP flare stack. This is as a result of Human Error in not ensuring that thecross over valve HV430481 is open (at start of switch over) or is incorrectly closed during period ofrunning to phase 2 HP stack. This is an operator critical activity and either a human factor review andacceptance of this Human Error dominated risk is undertaken or additional safeguards are determinedfor this overpressure hazard (possible interlock with isolations on route to Phase 1 that does not allowfor isolation of route to Phase 1 unless cross over valve HV430481 is open).

The LOPA assumption that HP flare system, if isolated, will not overpressurise from normal HP flareloads, should also be confirmed. If Overpressurisation could occur for normal HP flare loads (normallyrecovered through the Flash Gas compressor), then the acceptability for relying on a single

PAHH430101 operation should also be reviewed.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)







Hazardous Event: Overtemperature – Crude Oil Pipeline


Reference

1S-18.11.1 OE



F F D

Event TMEL: 2.5E-4 2.5E-4 2.5E-3


1.0E-3 1.0E-3 1.0E-4


W W B

Recommendation:

The oil lines from Crude Oil Storage Tanks to oil export booster pumps (1S-P-24010/20/30/40 and 2S-P-24050/60/70) will be boxed in (by closure of tank MOVs and Pump discharge MOVs) when exportpumps are shut down. This would occur when export is shutdown, which from plant experienceindicates that this could be for up to 12hrs twice per year. Although export temperature is greater thanambient and this is a low operating pressure line, it will be liquid locked and exposure to high solarradiation could generate sufficient pressure to cause joints to fail. This relies on a single PSV 230102(note an additional PSV has been removed from tank B export line). The LOPA identified a commercialsafeguard gap by relying on this single PSV in what could be a high demand scenario. The Thermalprotection on Oil export should be assessed particularly for lines to /from tanks to pumps (Suction andmin flow return). This should include calculations of potential effects from solar radiation on the lengthsof exposed line.


Response:




Action Owner

Discipline DRE


(mandatory)







Other (state)







Hazardous Event: Generic – IPL Review


Reference

Generic

SIF or non-SIF LOPA N/A


N/A N/A N/A

Event TMEL:



Recommendation:

All identified Relief devices (PSVs/PSEs), Alarms, and BPCSs which have been identified as IPLS inthe LOPA assessments need to be reviewed and their functions validated. This is to ensure that thesedevices will provide the protection for which they have been taken credit for in LOPA. There are also anumber of SIFs which have been included as IPLs in some Non-SIF LOPAs. These also should bereviewed to ensure that they can meet the required PFD quoted in the LOPA assessments.


Response:




Action Owner

Discipline DRE


(mandatory)





Other (state)

ACG Step PHASE 1 Recommendation Action Sheets v4 08-06-2012.docx

Documents

Transcript of ACG Step PHASE 1 Recommendation Action Sheets v4 08-06-2012.docx