lessons learned-final-old.pdf

8/14/2019 Lessons Learned-FINAL-OLD.pdf

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LESSONS LEARNED

Sr# SA10302 1/6

01 Remote monitoring of open/close position of tie-invalves.

02 Fail safe position of GOVs (Gas Operated Valves)which are being used as main isolation valves,should be "Fail Steady".

03 Provision to open the GOVs from remote location

should be provided in case it is inadvertently closed.04 Surge Analysis for the scenario of inadvertent

valve closure for the pipeline having liquid service,should be performed during FEED as well as duringDetailed Engineering Design.

05 Scope limits should be clearly defined for theupstream as well as down stream facilities and ifthere is any major impact due to the changes inoperating as well as maximum conditions of thesystem under the scope of project then it should beproperly communicated with the concerned stakeholders.

06 Normally this note is included during detailedengineering but it can be included in the FEEDdrawings so that it can be overlooked during DED.

07 When any branch line is entered into main pipelinethen check valve should be provided to preventback flow incase of low pressure in the branch line.

08 Existing Flare System should be evaluated beforeconnecting to existing flare system.



09 Manual isolation valves should be Car Sealed Open(CSO) for which open position is required for thesmooth operation of the facility.

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10 Surge Analysis will be done to decide that pipelineof higher class is required on the upstream of anyblock valve due to pressure surge created by theinadvertent closure of this valve.

11 It should be confirmed by the hydraulic analysis thatthe pressure in the branch line entering into the

main pipeline is higher than the pressure in the mainpipeline.

12 It should be confirmed by the hydraulic analysis thatthe pressure in the branch line entering into themain pipeline is higher than the pressure in the mainpipeline.

13 In the O&IM of the pipeline, maximum velocity of

scraping should be mentioned.14 All the buried lines need cathodic protection.15 Design of sump pit for oily water drain system will

be based on SAES-S-020 and for draining offlammable and combustible liquids to closed drainsystem will be based on SAES-A-400/401.

16 LEL detectors will be provided for the scraper traps

located in the manned facilities and portable LELdetectors will be used for scraper traps at remoteareas during scraping operations.

17 CSO (Car Sealed Open) isolation valves andthermal relief valves are provided on the jump over

18 Two local pressure gauges can be provided at the jump over line if its length is considerable so thatpressure at both ends can be measured.



19 When any branch line is entered into main pipelinethen check valve should be provided to preventback flow incase of low pressure in the branch line.

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20 Preference in ascending order for selection of typeof actuators for the valves having size more than 12inch is as under: 1. MotorOperated Valve2. Gas Operated Valve3.Hydraulic Operated Valve

21 LEL detectors are required to those locations wheremanned maintenance activities are being performed.

22 The velocity of the pipeline for continuousoperation should be within the range defined inSAES-L-132.

23 Flash back in the flare tip can be prevented by

purging out the oxygen in the blow down line withnitrogen gas before opening the blow down valve.

24 All the buried lines need cathodic protection.25 Two options can be evaluated for blow down lines:

1. Sizing of blow down will be done in such a waythat the back pressure will not exceed the maximum

pressure for 150 class flange rating. 2.The flangerating of blow down line on the upstream of blowdown line will be same as down stream of thisvalve.



26 Two options can be evaluated for blow down lines:1. Sizing of blow down will be done in such a waythat the back pressure will not exceed the maximumpressure for 150 class flange rating. 2.The flangerating of blow down line on the upstream of blowdown line will be same as down stream of thisvalve.Flash back in the flare tip can be prevented bypurging out the oxygen in the blow down line withnitrogen gas before opening the blow down valve.

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27 Option to use sales gas for igniting the pilot insteadof propane will be evaluated.

28 It should be evaluated whether solar system is morereliable or AC power for high energy ignitionsystem.

29 Flash back in the flare tip can be prevented by

purging out the oxygen in the blow down line withnitrogen gas before opening the blow down valve.

30 Option for redundant supply to the facility under theproject scope will be evaluated.

31 In order to eliminate the chance of closure of tie-invalve accidentally, it should be made "Car Sealed

Open" (CSO).32 Preferred option for tie-in valve is manual valvewith remotely monitored open/close position.

33 Before demolishing or retaining any existingfacility, it will be ensured that the operability ofwhole system will not be effected.



34 All manual valves on the line which is supplyingpower gas to the actuators of GOVs will be CSO inorder to provide uninterrupted supply of power gas.

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35 LEL detectors are required to those locations whereroutine manned maintenance activities are beingperformed.

36 Automatic Change over of the black powder filtersfor power gas to GOVs is not required because thechances of blockage is less as there is no continuous

flow. Provide differential pressure indicator andalarm to OSPAS in case there is filter blockage.

37 Fail Safe position of PCVs for the power gas shouldbe "Fail Steady".

38

39 Follow SAES-A-202 & SAES-334 for drafting the

demolition drawings.40 Design the closed drain system per SAES-A-

400/401 for draining of combustible & flammableliquids.

41 Size of vent for sump pit and closed drain systemshould not be less than 4 inch and there should beno isolation valve on the vent line.

42

Hot Tap Tie-in is preferred upon Cold tap tie-in as itwill not disrupt the operations. But if the shut downschedule is planned then cold tap is preferred. Itshould be confirmed with OSPAS.

43 Preferred Tie-in valve is Ball Valve.44 Vacuum Truck connection will be quick fitting type

and isolation valve is provided on this line.



45 No check valve should be provided on the relief lineof Pressure Relief Valve.

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46 Option of recycling the liquid in the closed drain

drum by the pump to the lateral line or to transferredto slop tank by vacuum truck will be confirmedfrom client.

47 No utility connection like nitrogen, utility water willbe connected directly with the connections providedfor scraper traps instead utility connection withquick fitting, isolation valve and pressure gauge is

provided.48 Temperature & pressure indicators are to be

provided at each valve station.49 Insulating flange is not required at the break point

of Above ground & Under ground for the mainisolation valve station.

50 For liquid service, one isolation valve on the by

pass line of main isolation valve is sufficient.51 For gas service, two isolation valves on the by pass

line of main isolation valve can be used.52 When defining the abandoning scope of the existing

facilities, it should thoroughly evaluated that theoperation of the already connected facilities will notbe affected.

53

Vendor name will not be required to mention on anydetails of valves during FEED stage.

54



LESSONS LEARNEDSA2057

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1 All the valves on the purge fuel gas line should be Car Sealed Open (CSO).2 Back pressure will be calculated at the surge relief valves for the scenario in

which more than one burn pits are in operation.3 Design the system down stream of Surge Relief Valve for the scenario in

which all Surge Relief valves are opened simultaneously.4 1 inch purge connection for nitrogen gas on the fuel gas line is provided to

remove any liquid left over in the line.5 Low Flow and high flow alarm should be provided to flow controller of fuelgas supply for purging.

6 It will be ensured that supply of fuel gas to pilots will free from any solidparticles like black powder. It is recommended that tie-in of the fuel gas supplyline should be at the down stream of black powder filtration system otherwisenew black powder filtration system will be suggested on the purge gas supplyline.

7 Sizing of the PZVs installed at the downstream of PCVs (Pressure ControlValves) will be based on the scenario of maximum flow through PCVs.

8 For NGL service, down stream system of Surge Relief Valves will be checked

for the low temperature produced due to expansion of NGL.9 Requirement of Rate of Rise Surge Relief valve should be carefully analyzed as

it has complex design and should be justified with surge analysis.

10 Anti-Cavitation Trim should be specified for the surge relief valves.



11 Each pilot of the flare tip should be connected to Flame Front Generator (FFG)with independent lines. 2/2

12 The system at the down stream of PCVs which may be under the scope ofvendor, should have design pressure equal to design pressure of system at the

upstream of PCVs. The basis of this assumption is failure of PCV.13 Two Thermocouples are to be provided for each pilot.14 Redundant Pressure control valves on the supply line of fuel gas for purging

should be provided.15 Material of construction for flare tips and ancillaries will be per 32-SAMSS-

022.16 Calculation of Radiation Contours for two phase flare system can be based on

the vendor's proprietary equations but it should be verified from the CSD.

17 Ambient Air Quality constraints defined in SAES-A-102 should be taken fromFlare Vendor.

18 Per SAES-J-600,minimum inlet flange rating of PZV is class 300#.



LESSONS LEARNED

SAG-10301 1/6

01Metal seated valves are to be used the service of sales gas due to presenceof black powder.

02 Provide bypass lines for black powder filtration system, flow control andmetering system. The requirement of bypass line across metering systemwill be confirmed by client.

03 Provide LEL detectors for manned facility for scraper launcher / receiver.For unmanned facility, portable LEL detectors will be used for cleaning,

maintenance/ scraping activities.

04 PLCs are better for automatic control of black powder filtration system.

05 For Nitrogen supply to actuate GOVs, only nitrogen connection should beprovided for actuation of GOVs and in case of non-supply of power gas,storage drums sized for three strokes of valves are to be provided during

non-supply of power gas.06 It is not recommended practice to use portable flaring system07 The existing burn pits shall be reviewed for its suitability and capacity and

utilize the existing burn pits as much as possible by providing additionalflare tips.Operation maintenance & radiation impacts due to the use of existing burnpits should be studied.

08

Provide future valve connections/provisions for metering systems/skiditems at one side of the meter run only.09 Isolation valves across EIVs should not be installed as stopple fittings are

to used for isolation of EIVs for maintenance purposes.10 Redundant power supply is not required as these valves are "fail steady"11 Provide remote pressure indicators downstream of FCVs.12 Any piping specialty line which has the chance of blockage, differential

pressure indicators should be provided.13 Provide high as well as low flow alarm on the gas metering station.



14 Provide the same pressure class of piping in the down stream as that ofupstream of FCVs. 2/6

15 Provide low/high pressure alarm to downstream of FCVs16 Provide LEL detectors at the manned facility of scraper launcher/receiver

and use portable for unmanned facility.17 Provide remote indication of pressure at the lateral line.18 Provide screen mesh at the flare tips19 Always verify the capacity and SA standard requirements for existing sump

pits/drainage system for additional quantities of flow.20 Provide nitrogen purge connection to the downstream of globe valve in

order to verify that flare lines are not blocked prior to start-up.21 Make sure that design of sump pits will follow SAES-S-020.22 Sump pit vent size should be min 4" and should have no isolation valve per

SAES-S-020.23 Depressurization valves for blow down should be designed to give back

pressure less than design pressure of selected class rating for downstreampipeline.

24 Vent locations should be 3m from the highest plat form or ground and 15horizontally from any ignition source.

25 Provide check valves on the blow down lines to prevent backflow due tolow pressure.

26 Requirement to use propane bottle or sales gas for igniting the pilot of burnpits should be evaluated.

27 Solar power can be considered as an alternative power source for burn-pitsat remote areas.

28 KM markings of valve stations shall be regularly updated from piping.29 Templates for Utility connection is like fire water, portable water shall be

followed.30 Isolation valves on the supply line of power gas to GOVs should be

L.O.(Locked Open)31 Inside the fence of one facility, one local horn can serve for more than one

LEL & H2S detectors.



32 Radiation Calculations for defining the distance of fence from the centre offlare tip should be the part of depressurization calculations during FEED &detailed engineering stage and this distance shall be informed to concerneddisciplines. 3/6

33 Note should be mentioned in the P&ID that sizing of globe valve should beconfirmed by LSTK contractor.

34 Hold list should be clearly shown on the P&ID and separate "HOLDSLIST" shall be prepared which shall be included in the overall scope ofwork.

35 Low temperature requirements should be checked during de-pressurization during FEED & Detailed Engineering.

36 Material of construction(MOC) of Flare tip shall always be stainless steel.Specify the MOC flare tip as SS and Insulating Flange (IF) shall be shownat the material break of SS to Low Temp Stainless steel (CA) or CarbonSteel (CS).

37 Blow Down line should be sloped toward burn pit and slope shall bementioned on P&IDs.

38 Insulating flanges at the break of Above ground & below ground nearMainline valve stations are generally not required. It should be confirmedfrom Electrical/CP.

39 Due to difficulty in finding suitable depressurization valve for thisapplication, consider the same pressure rating of piping for the downstreamof this valve.

40 Requirement of full flow by pass line across any isolation valve shall beconfirmed the requirements of SAES-J-601.

41 For stroke testing of OSPAS Class-1 lateral valve, it should be confirmedfrom client whether to use full flow size of kicker line or providing a fullflow bypass line across OSPAS Class-1 valve & kicker line of smaller sizeper Dwg: (AC-036541-001).

42 It is preferred practice to consider HOT TAPPING with the existing systemas it will not hamper the operation. But it should be confirmed with piping

and PMT .



43 Mechanical Handling equipments like Jib Cranes for scraper traps will notbe considered for line size less than 6 inch. 4/6

44Use ASME B31.4/B31.8 for scraper traps.

45 Always consider burn pits for flaring the blow down gas whether theservice is sweet or sour gas.

46 Provide Temperature and pressure transmitters at the bypass line ofmainline isolation valve.

47 Generally double isolation valves on bypass line of main isolation valve forgas service and single isolation valve for liquid service are considered.

48 Preference of the selection of actuators for valves having size more than 12inch is as follows: 1.Motor Operated Valve 2.GasOperated Valve 3.Hydraluicoperated valve

49 Never connect directly to utility water/nitrogen line to the connection

provided for cleaning/purging of the scraper traps. Instead provide quickfitting connection with isolation gate valve & spectacle plate and pressuregauge. Follow the templates for scraper launcher & Receivers.

50 For drainage of oily water containing flammable or combustible liquid, thedesign of drainage of system should be per SA standard for closed drainsystem (SAES-A-400/401).Consider recycle pumps for stabilized crude oil.

51

The use of vertical cyclone separator vessel will depend upon the blackpowder loading in the sales gas.52 Potable Water will be used for cleaning of black powder cyclone vessel and

filter.53 If instrument air is available then plot limit EIV should be SMART ZV

type.54 RO should be provided on the blow down line of filtration system as

pressure reducing device.



55 One high level switch and one high high level switch will be provided forVertical cyclone separator vessel for removing black powder from sales gas.

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56 Vertical cyclone separator vessel and horizontal filtration vessel should bedesigned for full vacuum if there is compression system at the downstream.

57 Check valves are provided on two connected lines when there is chance ofbackflow due to low pressure in one line.

58 Bypass line across metering skid shall be per SAES-Y-101.59 There is no need to connect vent line of metering skid to blow down system.

60 RO will be provided on the temporary by pass line of metering skid forcontrol of flow.

61 Close command to EIV from OSPAS should be given through flowcomputer and PLC.

62 Standard drawings of metering skid will be used depending of the type ofmeter run based on Sales gas flow rate per SAES-Y-101.

63

Pneumatic flow control valves are preferred on motor operated flow controlvalves.64 Requirement of analyzer shelters for meter run shall be based on SAES-Y-

101.65 Fail safe position of Flow control valves for meter run shall be "Fail

Steady" in order to avoid disruption in flow of sales gas to downstreamfacilities.

66

Potable water line for eye wash will have PVC material of construction forunderground portion and galvanized carbon for above ground portion.

67 Design of Power gas storage reservoir should always be under vendor scope(Follow Template for P&ID of GOV actuator system).

68 Open command for EIVs should be confirmed by client.69 Isolation valves and pressure gauges are to provided on all the utility

lines/stations.70 Fire hydrants in combination with fire monitors are to be considered.



71 RTR is the recommended material of construction for fire water pipelines.6/6

72 Provide H2S & LEL detectors for manned facility even for sweet sales gasas possibility of off-spec sales gas cannot be ruled out.

73 Option for providing sales gas instead of propane gas to ignite the pilot ofburn pit for automatic ignition system shall be reviewed.

74

Option for fully automatic ignition of burn pits shall be reviewed.75 No check valves shall be considered on the lateral lines of intermediatetraps.

76 Follow line specification nomenclature per SAES-L-105 and pipe materialspecification for the required service per SAES-L-132.

77 All tie-ins with existing systems and for modifications will be identified.

lessons learned-final-old.pdf

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